Note: Descriptions are shown in the official language in which they were submitted.
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BACXGROUND OF THE ~NVEUTION
(1) ~ield of the Invention
This invention relates to a temperature pattern measur-
ing me!thod for obtaining the distribution of surface temperatures
over the surface of an object, and to devicesfor carrying out
the method.
(2) Description of the Prior ~rt
Generally, temperature pattern measuring methods have
widely employed an infrared ray system which picks up by an in-
frared ray detection element in;a two-dimensional pattern the op-
tical energy of infrared rays emitted from an object the surface
temperature distribution of which is to be measured, and scans
the two-dime~sional pattern and produces and displays a tempera-
ture pattern of the surface area of the object, for example,
graphically on a cathode-ray tube (CRT). ~ measuring method
using an infrared ray system, however, is inadequate for an object
which changes temperature rapidly`because two or more seconds are
required for scanning to produce one picture. ~oreover, the in-
frared rays picked up as representing temperature information are
apt to be affected by the atmosphere surrounding the light propa-
gation path due to the existence of vapor or dust, thereby lowering
the sensitivity and accuracy. It is impossible in practice to
avoid the influence of the surrounding atmosphere by the use o`f
an image guide, because the attenuation of the quantity of light
within the image guide is large in the infrared ray wavelength
range. Furthermore, the minimum visual field within which measure-
ment can be carried out i8 a 10 to 20 centimeter-angle, so that a
temperature pattern in a smaller area cannot be measured. Hence,
~ 1 6544 ~
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the infrared ray system cannot be used for measurement of the
temperature pattern of an object, such as a slab in a continuous
casting process in a steel mill or an electrically seamed steel
pipe which is being welded, which is in a bad atmosphere having a
lot of vapour or dust and which is undergoing a large temperature
change. Moreover, it is impossible for this system to measure tha
temperature pattern in a small area, such as a heated portion of
the edge of an electrically seamed steel pipe.
On the other hand, a two-color thermometer, which is
used to carry out the present invention, picks up two particular
wavelength components in visible light emitted from an object,
thereby carrying out non-contact measurement of the surface tem-
perature of the object. The two color thermometer can measure
a typical temperature within the temperature range in which
visible light is emitted, but cannot measure a temperature pat-
tern. Because iron manufacturing and steel manufacturing processes
often require the measurement of a temperature pattern, the above
described temperature measuring methods cannot easily fulfill such
a requirement.
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1 1 6~14
OBJECTS AND SUMMARY OF THE INVENTION
This invention has been made to solve the above des-
cribecl problems.
An object of the invention is to provide a temperature
pattern measuring method which utilizes a two-color thermometer
and a video information pr~cess so that the measurement is sub- i
stantially unaffected by the surrounding atmosphere, and which
method is capable of making a temperature pattern measurement
with high accuracy and high resolving power. t
Another object of the invention is to provide a te~-
perature pattern measuring device capable of carrying out the
above temperature pattern measuring method.
Stillanother object of the invention is to provide
a temperature pattern measuring device in which an image guide
can be used and which is capable of measuring the temperature
pattern in a small area or an area which is deep within an object
and is invisible from the exterior of the object. ~'
A further object of the invention is to provide a
supervisory device for a weld zone of an electrically seamed
pipe, which uses the temperature pattern measuring device of
the present invention.
To achieve these objects, this invention provides a
temperat~re pattern measuring method which views an object the
temperature pattern of which is to be measured by an image pickup
device to obtain the temperature distribution on the portions of
the object in the picked-up picture of the objects. The light
from the object is passed through first and second optical filters
which pass different selected wavelength components of the light
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~ 1 65444
emitted from the objec~, and a two color temperature determining
operation is carried out for every area of one or more video
picture frames produced by the light passing through ~he respec-
tive first and second optical filters, whereby a temperature is
determined for each portion of the object corresponding to the
respective areas of the picture frames.
The device used in the above described measuring method
in order to pick up the light emitted from the object can utilize:
a first system in which the light emitted form each portion of the
object within the visual field simultaneously passes first and ~ ;
second filters arranged at slightly different positions in a plane
pattern in a single filter for a single pickup device; a second
system in which the light from the object passes to a single
pickup device through a first optical filter for a certain period
of time and then light from the object passes to the pickup device
through a second filter for a period of time; or a third system
in which the light emitted from the object simultaneously passes
through the first and second filters to separate image pickup
devices. The picture portions of t~e video signal from the pickup
devices corresponding to an area for which the temperature is to
be determined is used as data for a two-color temperature deter-
minin~ operation. Tn the first system the areas for which data
is obtained are in slightly different positions, and the data is
obtained at the same time, while in the second system the areas
are in the same position but the data is obtained at different
times. In the third system the obtaining of-data is for the areas
in the same position and the data is obtained at the same time.
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In accordance with a particular embodiment
of the invention, there is provided a temperature
pattern measuring method, The method includes the
steps of passing portions of light from parts of an
area of an object the distribution pattern of the
temperature of which is to be measured. The parts
are in a predetermined pattern. The portions of
light are passed through first and second optical
filters which pass different wavelengths of light
respectively. The level of energy passed by the
respective filters for ~he respective portions of
light is determined, and the thus determined energy
levels are used to carry out a two-color temperature
determining operation for the respective parts of`the
area for determining the temperature on each part of
the area of the object. Thus, the temperature pattern
of the area of the object can be determined from the
temperatures of the parts of the area.
In accordance with a further embodiment of
the invention there is provided a method of measuring
the temperature pattern of an object. The method
includes the steps of directing light from the area
of the object the temperature pattern of which is to
be determined along a light path and inserting into
the light path an optical filter having a plurality
of areas in a predetermined pattern with adjacent areas
being of optical filter material which pass different
wavelengths of light. The light coming through the
adjacent areas of the filter is scanned by a picXup
device for determining the level of energy passed by
the adjacent areas, and the output of the pickup
device is used to carry out a two-color temperature
determining operation for the respective pairs of
adjacent areas.
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From a different aspect, and in accordance
with the invention, there is provided a temperature
pattern measuring device for obtaining the surface
temperature distribution of an object to be measured.
The device includes a two-dimensional image pickup
means and first and second optical filters provided
along a light path extending from the object to the
image pickup means. me filters are arranged to select
two different optical wavelength components of light
from the object to be measured. An arithmetic means
is operatively connected to the image pickup means for
determining the temperature on the surface of the
object to be measured based on the ratio of the magnitude
of the two different wavelength components of light.
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1 1 654'~ ~
BRIEF DESCRIP~IO~ OF THE DRA;~JING~
Other and further objects and novel features of the
invention wil~ be Dore fully apparent from the ~ollowing detailed
description together with the accompanying drawings, in which:
Fig. 1 is a schematic block diagram of a first embodiment
of a device according to the invention for carrying out the method
of the invention by usin~ the first system;
Fig. 2 is a schematic reprsentation of the pattern of an
optical filter;
Fig. 3 is a block diagram of a video signal processor used
in the embodiment of Fig. 1;
Fig. 4 isa representation of the wave form of a video signal;
Fig. 5 is a schematic representation of the contents of a
memor~ device;
~ Fig. 6 is a flow chart of arithmetic unit and Fig. 7 is a
detailed flow chart of a part of Fig. 6;
Fig. 8 is a schematic block diagram of a second embodiment
of a device according to the invention for carrying out the method
of the invention by using the second system;
Fig. 9 i8 a ~hematiC representation of the patt.ern of a rotar~
~ilter;
Fig. 10 is a schematic representation of contents of a memory
device;
~ ig' 11 is a schematic diagram of a third embodiment of a
- device according to the invention for carrying out the method Or
the invention by using the third s~stem;
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1 1 6544~ `
Fig.12 is a graph showing the relationship between the
magnitudes of the waveforms penetrating an optical filter.
Fig.l3 is a view exemplary of the output waveforms and
used to illustrate the operation of a video signal partial-
removing circuit.
Fig.14 is a view exemplary of a raster showing a
scanning area of an image pickup device.
Fig.15 is a plan view exemplary of the arrangement of
objectives on the electrically seamed pipe manufacturing line.
Fig.l6 is a schematic view of a display pattern on
a monitor.
Fig.17 is an enlarged view exemplary of the relationship
between received pictures and scanning lines.
Fig.~8 is a view exemplary of the level of the video
signal corresponding to the scanning line and relating to the
position of the electrically seamed pipe.
Fig.19 shows the waveforms of signals output from the
comparator 7l.
Fig. ~0 is a graph showing the relationship of the
positions in the abscissa X with dimensions between the opposite
edges .
! Fig. 2l 18 a ~iew explanatory o the principle o
computing a V angle.
Fig. 22 shows a schematic diagram of another embodLment
of the device in accordance with the present invention.
Fig. 23 & Fig. 24 show the patterns of rotary filter~.
Fir~s. 2$ (A~ ) & (C) show a flow c~art of micro-computer.
1 1 B5~44
~ETAILED DESCRIPTION OF THE INVENTION
A temperature pattern measuring method according to
the invention and using the first system will be described in
detaiLl. In this method an optical filter is disposed in a light
path within or outside an image pickup device, and the filter
has first and second filter segments combined in a given pattern,
through which segments pass first and second wavelensth components
which are different from each other. A two-color temperature
operation is carried out for every area corresponding to two fil-
ter segments in each frame picked up by the image pickup device,
using the light passing through the first and second filter seg-
ments and the temperature at each portion of the object corres- -
ponding to each such area is determined, thereby obtaining a
temperature pattern.
An embodiment of a device accoraing to the invention,
which carries out the above described method, will be described in
connection with Figs. 1-7.
Fig. 1 is a schematic block diagram of à device according
to the invention, in which W designates the object the temperature
pattern of which is to be measured, reference numeral 1 designates
an image pickup unit facing the object, 2 designates an optical
filter disposed in proximity to the image pickup means of the image
pickup unit 1, 3 designates a monitoring cathode ray tube tCRT)
to display an image of the object picked up by image pickup unit
1, 4 designates a video signal processing unit for data-processing
the video signal output from image pickup unit 1, 5 designates a
memory for storing data from the video signal processing unit 4,
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I Jfi5~4~
and 6 designate~ an arithmetic unit which carries out a two-color
temperature determining operation,ba~ed on the contents of memory
5 and the signal output from video signal processing unit 4.
The image pickup unit 1 i8 a conventional video camera,
which should have an image pickup tube with a dynamic range su~fi-
cient to receive light of wavelengths ~1and A2 passing the optical
filter 2 to be described in detail hereinafter. For example,a tu~e
using ~iliconvidicon or Chalnicon (Trade name of To~hiba Co.) ia
suitable for use in the vi~ible ~avelength range. Suc~ an image
pickup tube as we~l as a solid image pickup element, such aa a
charge-coupled device (CCD), if it has a goo~ spectral sensitivity,
can be used. The pickup unit ehould alao have an interior control
unit similar to a conventional one for outputting a composite ~idao
signal including a picture signal, horizontal ~ynchronizing signal,
and vertical synchronizing signal.
~ The optical filter 2, as shown in Fig.2, has the shape
of a rectangle to conform with the vi~ual fie~ld of image pickup
l~n; t 1, but need not ha~e special dimensions,but can be about 18
x 24 mm ~here the effe3ctive visual field is;3:4. The opt.-ical
filter 2 comprises a number of first filter ~egments (unshaded~
and ~econd filter ~egments (hat~hed) in the form o~ ~mall reotangl~.
or ~quare~ of equal ai~e, which are d~i~poaed alternately in a
matrix extending hori~ontally and vertically corre~pondi~g bo ~h~
means in the pickup device for detecting the pattern o~ light
entering the pickup device. Between the-f~rst and~ the ~cond
filter segments;are interposed strip~-like shade zones 23 to bloc~
passage oi light. The first and aecond filter ~egment~ are optical
band-pass;~iltera re~pactively having wavelength~ ~1 and ~2 a~
1 1 6 5 ~
~ center of the wavelengths`passed thereby, and which have a
high transmitt`ivity and a narrow band width in order to raise the
measurement accuracy. It is preferable to use an interference
filter rather than an absorption-type filter. Such optical filter
2, if it is assumed that Al<~2, has, in the areas formed by filter
segments 21, low-pass filters allowing passage of light with a
wavelength from a waveleng~h slightly below up to a wavelength
slightly larger than Al, and in the areas formed by filter segments
22, high-pass filters allowing passage of light with a wavelength
above a wavelength slightly smaller than up to a wavelength slightly
larger than ~2 The filter 2 is thus oonstructed of a complex
pattern of band-pass filters throughout the area thereof which
pass light with wavelengths in a band with wavelength Al at the
center and in a band with wavelength A2 at the center.
The pattern of the arrangement of filter segments 21 and
22 is not limited to that shown but may of course be other forms
of longitudinal or transverse arrangements. The size of the respec-
tive filter segments 21 and 22 controls the resolving-power, so
that is is desirable to reduce the size as much as possible. As
a practical matter, the size is limited by the manufacturing tech-
niques for optical filters and also by the memory capacity of memory
5 and the computing speed of arithmetic unit 6. In this embodiment,
filter segments 21 and 22 are rectangular, and the number in the
matrix is vertical 128 x horizontal 128, and the shading zones are
about 40 ~m in width. The aforesaid wavelengths Al and A2 are
selected corresponding to the spectral sensitivity of the image
pickup unit, a temperature of the object ~ to be measured, and tha
atmosphere.
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The video signal processing unit 4 discriminates pic-
ture signals from among the video signalsoutputted by the image
pickup unit l,the picture signal portions each corresponding to
the light passing the first and second filter segments, and out-
puts a two-dimensional position signal for correlating each pic-
ture signal component of the video signal with a filter segment.
Fig. 3 is a schematic block diagram of an example of
the construction of a video signal processing unit 4, and Fig. 4
shows a wave form of a video signal VDS with negative modulation.
The video signal VDS includes vertical synchronizing signals VS
which appear once (for sequential scanning) or twice tfor jumping
scanning) per one frame, horizontal synchronizing signals HS appear-
ing once per one scanning line, and picture signals PS changing
in level corresponding to the brightness or darkness of the picture.
The pictuxe signals PS include signal components PSl and PS2 which
represent the lightness and darkness of the surface portions of the
object W at positions corresponding to the positions of the respec-
tive filter segments, that is, data corresponding to the radiant
energy at the respective portions of the surface of the object,
the information being obtained for each scanning period of the
scanning of the portions of light from the object passing the res-
pective first and second ilter segments. The signal component
PS3 between the components PSl and PS2 is that obtained by the
scanning of the portions of the filter corresponding to shade
zones 23, and indicates that the shade zones 23 are dark. The
filter segments 21 and 22 are disposed alternately horizontally
and shade zones 23 are positioned between filter segments 21 and 22,
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9 1 654~
so t~at the portions of the picture signal appear in the order
PS1, P~3, PS2, PS3, PS1 ....... The signal components between the
segments PS~ have smaller and black levels, and even when only a
little light passes filter segments 21 and 22, the transmittivity
of each shade zone 23 i~ selected so that signal component PS3
between the se~ments PS1 and P~2 has level higher than that of sig-
nal co~ponent8 PS1 and PS2.
In t'le video signal processing unit 4, which receives
video sig~al VDS, a control signal ~eneratin~ unit 41 extracts
the vortical synchronizing signals VS and outputs a picture
change signal TP each time a new frame is to be started, the
picture change si~nal TP being fed into arithmetic-unit 6. Video
signal VDS is also fed into control signal generating unit 42
which outputs a position signal ~S which indicates a position
in a two-dimensional system, and the signal ~S is fed to arithmetic .
unit 6. The control signal generating unit 42 also outputs gate
control signals TG, which are supplied to ~espective gates 43 and
44. ~he gate control signals TG are fed to gates 43 and 44 at a
high level to open the respective gates while portions of li~ht
from the object whic~ pass through the respective filter segment
21 or 22 ar3 being scanned. Gates 43 and 44, thus allow video signal
YDS to pass, so that there is fed into date generating units 45
and 4~r~ connected behind the gates 43 and 44 only respective
picture signal portions P~1 and PS2 corresponding to the portions
of light passing the~respective filter segments 21 and 22.~ The
data generating units 45 and 46 consist of peak-hold units and
analog/digital converter3 and hold a minimum value (the peak value
is the white level) of the respective signal components PS1 and
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~ 1 65~4~ `
PS2 ~ed while respective ~ates ~3 and 44 are open, and output
co~pt)nents P~1 and PS~ to memory ~ as data to be written through
an analos/digital converter each time the gates 43 and 44 close.
Hence, the data to be written WDl and WD2 represent values of
radi~mt energy corresponding to wavelengths A1 and ~2 from the
s~lrface portions of the object ~ correspondin~ to the above pic-
ture si~nal portions from the respective fllter segments 21 and
22.
The position signal ~S is substantiall~ pulse signal
corresponding to the component PS3 and is fed ~nto arithmetiC
unit 5 as writing address information. The gate control signalq
~G is obtained as outputs of flip-flop which composes control sig-
nal generating unit 42 and is connected to be triggered by PS3.
When arithmetic unit 6 permits memory 5 to write-in
data, the data of one picture are written in the memory 5, the
data-writing being per~itted to begin at the moment picture change
signal ~P is supplied. Memory 5 stores date WD1 and WD2 into -
predetermined addresses according to the position signals ~S.
~or example, the writing in is carried out in such a manner that
when the arrange~ent of filter segments 21 and 22 in optical filter
2 is as shown in Fig. 2 so as to show the ob~ect W as viewed from
the image pickup unit 1, and the portion of the li~ht from the
ob~ect which passes through the filter segment 21 at the upper left-
hand corner, i.e. in the first line and first row, is scanned, the
data WD1 corresponding to this portion is fed to the memory 5,
and being related by position signal ~S to the filter segment 21
in such position, is stored in the address corresponding thereto.
Next, when the portion of light which passes through tho
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~ 1 6~44~
ne~ filter segment 22 to the right, i.e. in the fir~t line, secon~
row, data WD~ co~responding to thi~ portion i8 f~d to the memory
5, and being related by ths positio~ signal TS to the filter seg-
ment 22 in such po~ition, i8 stored in the addre~ c~rresponding
thereto. Thus, upo~ a f~ni-~h of writing in data for ~canning alon~
one line of the filter, horizontal synchronizing ~ignal HS appaars
to cause tho electron beam of the pickup unit l to return to the
left end of the filter. The next scan ~tarts with either the filter
segment 21 at the left upper corner or the segment 22 directly
thereunder in the second line, first row, depending upon the size
of the filter segment, the number of acann~ng lines; and whether
~equential scanning or jumping ~canning is carried out, however,
at this embodiment, scanning density and segment size are choosQd
80 that one line ofse~ments is scanned once a picture. Such step~
are repeated to store data for a complete picture in memory 5, 80
that memory 5 sort~ and atores values of radiant energy at the
re~pective wavelengths ~1 and ~ from the surface portionsiof the
obaect W divided according~ to the arrangement of filter segmenta
21 and 22.The atored data which corresponds to the maximum bright-
ne~a on the raster, correspond~ to value o~ the radiant energy~
Thua the contents of memory 5, in the pattisrn of filter ~egment~
21 and 22, can be!expressed a~ ahown in ~ig.5. In Fig.5, i ; (i,~
1~2 ... n~ where n 128) represent~ value~io~ radiant snergy
corre~ponding to wavelength ~lor ~2 pasaing the filter segment in
the line i, ro~ ~, in optical filter 2.
Arithmetic unit 6 reads out the stored contents of the
memory and perform~ a two-color temperature determining operation
~ith the data from each two adjacent filter segment~. For example,
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if ei ~ ~ep*e~nts data for wavelength ~ obtained from filter
segment 21, ~ is data for wave~ength ~2 obtained from the next
adjacen,t filter element 22. ~he well-known two-color temperature
operation equation (1) gives a temperature T~X~ for the area of
the ob~ect from which the portions of light giving the above two
data come.
d i~; _ + ~ ....................... (1)
~ i, j+1
where ~ and ~ are constants determined by ~1 and ~2 respectively.
In addition, the equation (1) holds because the relationship
between the energy ratio i ~! i ~+1 and the temperature ~ i9 ap-
proximately linear in practice. ~hus, arithmetic unit 6 sesuentially
computes the temperature for each area to obtain a temperature pa-
ttern for the whole picture or frame, i.e., whithin the visual
field of the pickup device 1, the results of which are displayed
by an indicator, such as a CR~ display (not shown ), or recorded
by a plotter or printer as visual information. ~ig.6 shows a flow
chart of arithmetic unit 6 . When arithmetic unit 6 receives picture
change slgnal ~P, the initial addres~ of memory 5 is set at the
address counter in arithmetic unit 6, and each time it receives
the positio~ signal T~ the data WD1 or WD2 is written in and the
address is changed. When ~T~ becomes n2 , that i9~ all the segment8
have been ~canned, data writing process is terminated and temperature
determining operation begins`~ Fig.7 shows a flow chart of this
operation.
Alternatively the memory 5 can have a memor~ capacit~
sufficie~t to hold data for two frameY, and in use can carry out
data storage for the next frame while holding data for a prior
picture for the arithmetic operation, thereby making it possible
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to carry out measurement once per 1~30 sec. when using a television
sys~em having a capacity of 3~ frames per second.
It isalso possible to have the plotter or printer
print oult the average for a plurality of frames. Also, instead
of the arithmetic unit carrying out a two-color temperature de-
termining operation using data for each measurement of the energ~
level for wavelengths ~1 and ~2~ it can carry out two-color
temperature determining operation on the basis of the average
of a plurali-ty of measurements or the maximum value thereof
where it iQ desired to obtain a typical temperature distribution
over a wider area. If the number of filter segments is small,
the arithmetic unit can be an analog arithmetic unit.
A temperature pattern measuring method according to
the invention and using the second system will be described in
detail. In this method light from the ob~ect is caused to pass
alternately through first and second optical filters for respec-
tively passing first and second wavelength componets which are
different from each other, and the two-color temperature deter-
mining operation is carried out for each area ofthe ob~ect using
the data indicating the levels of energy for each area derived
from the light passing through the first optical filters and the~
the light for the same area passing through the second optical
filter, so that the temperature of each area of the ob~ect is
obtained and together the temperatures give the temperature pattern.
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An embodiment of a device for carrying out this above
described ~e~od will be described with reference to Figs. ~-10.
In Fig. ~, reference numeral 1 designates an image
piC7~Up unit similar to that in ~ig. 2, ~' designates a video
signal process unit which functions as hereinafter described, and
3, 5 and ~-~, designate a monitor, a memory, and an arithmetic unit
similar t~ those in Fig. 2 respectively, and ;" designates a
disc-shaped rotary filter as shown in Fig. 9~ The filter "
comprises a semicircular portion constituting a first optical
bandpass filter 21' or the liXe havin~ a wavelength of ~1 at
the center of the wavelengths passed thereby, and another semi-
circular portion constituting a second optical bandpass filter
22' having a wavelength of ~2 at the center of the wavelengths
passed thereby. The filter 2' is disposed in front of the image
pickup unit1and is parallel to the objecti~e thereof
(not sho~!m), so that an intermediate portion approximately
~id,ray between the center and the outer periphery of rotary filter
2' is coincident with the optic~ll axis of the objective.
Reference numeral 7 designates a motor connected to the
rotary filter 2' to drive it around the center thereof, and 8
designates a rotational position detector comprising a pulse
generator,which is connected with the motor and outputs
constant numbers of pulses per one rotation of rotary filter2',
the detector 8 feeding an output signal to video signal
process unit 4' .
~ he image pickup unit 1, when facing the ob~ect W the
temperature of which is to be measured, receives light which
~asses through the rotary filter 2' and reaches image pickup
unit 1.The present embodiment further has an auxiliary lens
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9 between the object W and the rotary filter 2` for con-
verging the light from the object w to effectively guide
it to image pickup unit 1.
In operation, the motor 7 rotates to drive
rotary filter 2', for example, at 15 rotations/second,
so that the time needed to form one fr~me, e.g. 1/30
sec., coincides with the frequency of passage of the
optical filters 21' and 22' positioned in front of
image pickup unit 1, so that the image pickup unit 1
alternately receives light which passes the optical
filter 21' and that which passes the optical filter 22'.
The video signal process ~nit uses vertical synchroni~-
ing signal for each frame in the video signal VDS
generated by the image pickup unit 1 as a pause signal
for one frame and writes the video signal generated
in the time between such pause signals alternately
into two areas of memory 5. The data signals from
the individual parts of the pickup unit 1 are written
into corresponding addresses in one of tWQ groups of
addresses in the memory, the addresses being arranged
according to the successive scanning lines separated
by the horizontal synchronizing signal within the
video signal VDS, so that at each address of the
one address group is data corresponding to the level
of energy received from an area of the object by
the respective part of the pickup unit after passing
through one of the filters. Video signal process
unit 4' produces~a timing signal to set the time
for sampling the picture signal portions of the video
signal on the basis of a horizontal synchronizing
signal thereof for sampling the level of picture
signal portions, the sampled levels being fed to
the respective addresses in the one group of
addresses in memory 5 as data radiant energy at
wavelength ~1 or ~2 from the object.
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The output signal genarated by rotary position detector 8 is
~uppli?d to arithmetic unit 6 to ~pecify to which group of addrQsses;
in memory 5 the video signal i9 to be directed, i.e. whether to ~tore
data as to wavelength ~1 or ~2. Then, when the data has been written
into both groups of addresses in memory 51 the content~ of the memory 5
will be a~ sho~ in Fig. 10. Fig. 10 ~hows the viewing area of the
pickup device divided into area in two matrixes of n lines, n corres-
ponding to the number of scanning lines in one frame and m rows, m co-
rresponding to the number of areaswithin one scanning line. ~he areas
of the pickup unit pickup light pa~ing the respective optical filters
21~ and 22', 90 that ~1 ; and ~i2 j (i= 1,2 ... n, j=1,2 ... m) rapre-
sents values of radiant energy of`wavelengths ~ and ~ received by areas
in the i line and the ; row of the pickup unit, after passing through
optical filters 21' and 22' respectively.
Arithmetic unlt 6 reads out the content of memory 5 and using
data from the corresponding addresses of the two group~ of addresses,
carrie~ out a two-color temperature determination operation. For example,
for the area at i line, j row,the tem~erature T fK~ at the surface
portion of object corresponding to the area is given by the following
equation: 1
T = ~ ~ .............................. (2 )
In other word~, while the first sy~tem obtains temperature~
from two pieces of data obtained at the same time but at slightly
different po~itions, the second system obtain~ temperatures
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~ 1 fi5444
om two pieces of data for the sàme place but taken at slightly
different times. It is of course possible to obtain the tempera-
ture from pieces of data taken at slightly different times at
slightly different places.
After the arithmetic unit 6 sequentially computes the
temperature for each area and supplies the temperature to means,
such as an indicated CRT dlsplay or the like,(not shown) as in
the first embodiment for displaying the desired temperature pat-
tern, and/or recording i~. After the finish of the processing of
data from the two groups of addresses, writing-in of the data from
the next two frames starts.
The above method is advantageous in that it provides
a high resolving power while using an optical filter which has
a much simpler construction than that used in the first system.
In addition, while the apparatus used in this method does not
permit connection of an image guide directly to the image pickup
unit 1, when the auxiliary lens 9 is used as in the embodiment
of Fig. 8, the end of the image guide can be connected optically
to the objective face side of lens 9, thereby making possible the
use of the image guide. In addition, the rotary filter of course
can have a different configuration, for example four portions al-
ternately passing light with wavelengths ~1 and ~2
A temperature pattern measuring method accordin~ to
the inYention and using the third system will be described in
detail. In this method light from the object is simultaneously
picked up by first and second image pickup units after passing
through first and second optical filters which respectively pass
light of different wavelengths, and the data from the first and
19;
~ ~65444
second ima~e pickup units is used to carry out a two-color tem-
perature determining operation for each area of the object, the
temperature of each portion of the object corresponding to the
areas giving the temperature pattern of the object.
~ n embodiment of a device for carrying out the above
described method will be described with reference to the figur~.
~ ig.ll is a block diagram of the optical and electrical
systems of the device, in which reference numeral 30 designates
an electrically`seamed pipe in a welding process which is the
object to be measured so as to obtain its temperature pattern.
The pipe 30 is facing an objective 32 which is attached to the
utmost end of an image guide 31. Image guide 31 comprises a
number of optical fibers, each of about 25 ~m in diameter, con- !
verged to about 5 x 6 mm in thickness, which gains at the base
end thereof a constant visual field under optical conditions of
objective 32 and object 30. The image guide 31 extends toward
the location where a case 33 is disposed so as to avoid a dusty
and hot atmosphere, and is fixed by a means ~not shown) so that
the optical axis o~ guide 31 corresponding to the horizontal
optical axis of an image pickup lens 34, the case 33 being en-
closed so as to be a dark box and the enclosure accommodating
camera heads 51a, 52a of first and second two-dimensional image
pickup devices 51, 52 and a third two-dimensional image pickup
\
-20-
ilfiS~114
~_vice 53, which are optically arranged in position. On the opti-
cal axis of image pickup lens 34 are disposed a 10% N.D. (neutral
density) filter 35, a dichromic mirror 36, and a camera head 52a
Oc the second two-dimensional image pickup device 52. The N.D.
filter 35 reflects 10% of the incident light, regardless of its
wavelength, and al~ows the remainder of the incident light to
penetrate. The filter 35 is slanted at an angle of 45 so that
the light is reflected vertically upward so as to be picked up
by the third two-dimensional image pickup device 53. The dichro-
mic mirror 36 permits penetration of light of a wavelength ~3,
e.g., 650 nm, or more and reflects light of a wavelength under
A3. Mirror 36 is slanted at an angle of 45 with respect to
image pickup lens 34 so that the light is reflected vertically
downward so as to be picked up by camera head 51a of the first
two-dimensional image pickup device 51. The third image pickup .
device 53 is a usual color or black-and-white television camera
without its image pickup lens, the image pickup lens 34
serving as the image pickup lens thereof. The image pickup
device 53 is provided to observe the shape of object 30 and
outputs video signals to a video signal partial-removing unit
54.
` The first and second two-dimensional image pic~up
devices 51, 52 each employ an image dissector as a photo-
electric conversion element which is capable of random-access-
scanning, and respectively comprise camera heads 51a, 52a and
control units 51b, 52b. The image pickup lenses of camera
heads 51a, 52a are removed therefrom, so that image pickup lens
34, as in the case of the image pickup device 53, functions as
9 1 65~4`4
the image pickup lens for camera hèads 51a, 42a respectively.
For example, random access cameras~ Model Number C1186 which
are made by Hamamatsu Television, are used for image pickup
devices Sl, 52.
As seen from the above, image pickup lens 34, which
is usecl as the image pickup lens for three image pickup devices
51, 52 and 53 in common, is positioned so as to be equal in
distance from the lens 34 to the photoelectric conversion element
of each image pickup device. Transparent glass is used at the
portion where the image pickup lena of image pickup device 53
has been removed, and first and second optical filters 37, 38
are mounted at the position where the image pickup lenses of cam-
era heads 51a, 52a have been removed, utilizing screws for moun-
ting the image pickup lenses respectively. The first optical
filter 37 is of a band-pass type having a main penetrating wave-
length component Al, (where Al < A3, and where the penetrating
wavelength component is selected in range of All to ~12~ e.g.,
550 to 600 nm). The second optical filter 38 is a high-pass
filter having a lower limit value of A21 (e.g. 700nm), where A
is larger than A3, thereby substantially forming a band-pass
filter between A21 and A22, wherein wavelength A22 (e.g., 850nm)
is ~he upper limit value of the sensitive wavelength being limited
by the spectral sensitivity of image pickup device 52. The main
component of the penetrating wavelength between A21 and A22 is
A2. Fig.12 is a graph of the relative relationship of wavelengths
Al, A2 and A3. In brief, image pickup devices 51 and 52 receive
light of respective passbands centered atlAl and A2 and imase
pickup device 53 receives light throughout the visible region.
--22-
~ 1 6~4
Video signal partial-removing unit 54 functions to
display, by means of a monitor 56, the left upper area of the
image pickup visual field scanned by image pickup 53 except
for b~md-shaped areas of a right-hand portion thereof and a lower
portion thereof. Video signals havingposit~e modulation, as
shown in Fig.13, are made black at the rear portion corresponding
to about l/4 of the video signal for lH corresponding to one
line, and black at a predetermined number of lines corresponding
to the lower portion of about l/4 of one frame. Such cir~uits
are well-known to those ski}led in the art and accordingly, the
description thereof has been omitted. The unit 54 comprises;
means for receiving vertical and horizontal synchronizing pulses
from video signals provided by image pickup device 53, pulse
generating means for setting the horizontal position; a preset
counter which is reset by vertical synchronizing pulses,and which
counts the number of horizontal synchronizing pulses, and which
generates a signal when the count corresponds to the preset value;
another preset counter which is reset by horizontal synchronizing
pulses and which counts the clock pulses so as to generate a
signal when the count corresponds to the preset value; and a gate
circuit to inhibit the output video signal to be transmitted to
monitor 56 until the two preset counters~are reset after respec-
I tively generating the above-noted signals. In addition, the
¦ output of the gate circuit is tran~mitte~to monitor 56 through
picture composing unit 55 so as to display a composite signal
having other signals (to be hereinafter described) which are fed
into picture composing unit 55.
.
,. . .
~ 1 654~
~ ef~rence numeral 60 designates a micro-computer,
for example, using a Z-80A microprocessor unit which is made by
Zilog Co., for the central processing unit (CPU); the micro-
computer 60 performs scanning control and two-color temperature
determining operation of the signal o~ image pickup device~ 51,52.
The scanning control of image pickup device
51, 52 will first be detaiied. Reference numeral 61 designates
a register comprising a number of digital switches, such as ~humb
wheel switches, the register 61 indicating an area to be scanned
so as to obtain the temperature pattern. Fig.14 shows the scan-
ning areas of image pickup devices 51, 52, in other words, the
areas scanned so as to obtain the temperature pattern. The areas
can adopt one or both of either a laterally elongate area having
a main scanning direction of Y (vertical) and a sub-scanning
direction of X (horizontal) or a longitudinally elongate area
having a main scanning direction of X and a sub-scanning direc-
tion of Y, so that when both the areas are scanned, the micro-
computer is programmed so as to alternately scan each area. In
this embodiment, register 61 can set the main scan starting
positions Pr, ~x of each area and the widths Wy, Wx thereof;
the number of scanning lines thereof is made constant, for
example - 128, in any direction. Micro-computer 60 controls
the system so as to carry out the scanning as shown, on a basis
of the stored values of Py, Px, Wy and Wx. Between the micro-
computer 60 and the X-direction deflection input terminals of
control units 51b, 52b are interposed a counter 62X and a D/A
converter 63X for the digital/analog conversion of the counted
values of counter 62X so that the analog output of converter 63X
-24--
,
i~6S~4:~
lS ~Itilized for the X-direction deflection signals for both
control units 51b and 52b. Between the micro-computer 60 and
Y-direction deflection input terminals of control units 51b,
52b are interposed a counter 62Y and a D/A converter 63Y for
converting the counted values of counter 62Y, so that the analog
output of converter 63Y is utilized for the Y-direction deflec-
tion signaIs for both control units 51b and 52b, where the X
(or Y) direction deflection signal of device 51 has a reversed
polarity from ~hat of image pickup device 52 because image
pickup device 51 receives a mirror image in comparison with
device 52.
Now, operation and control of micro-computer 60 as
to the laterally elongate scanning area will be detailed.
Micro-computer 60 sets data corresponding to a value of Py
in counter 62Y ~ sets data corresponding to the first position
in the sub-scanning direction in counter 62X. Micro-computer 60
provides high frequency clock pulses to counter 62Y so as to cause
counter 62Y to count up. Upon counting up to a value correspond-
ing to the value of Py + Wy, counter 62Y is reset to a value
corresponding to Py, at which time counter 62X receives a clock
pulse to advance its count by one step. Such a process is re-
peated 128 times to cause the scanning of the laterally elongate
band-like area of Py to Py + Wy of image pickup devices 51 and
52. Nicro-computer 60 provides a signal to television interface
64 so as to display vertical and horizontal line,s at the positions
of Py, Py + Wy and Px, Px + Wx respectively, such that the output
of television interface 64 is transmitted to picture composing
unit 55, thereby causing monitor 56 to display the portion of
-2~-
~ 1 ~S~
an ob~ect's image corresponding to the tempsrature measuring area.
In this embodiment, video signal partial removing unit 54, picture~
com~osing unit 55 and televi~ion interface 64 are made discretely,
however, ~pecial efect mixing smplifier M~A-5100 or ~EA-7500 produced
by Ikegami Communication Co., or color special effect device SEG-120
produced by Sony Corp. can be used for the three circuits.
Video signal output terminals of control units 51b and 5~b
output photo-electric conversion signals from the portion ~canned,
as described above, corresponding to the scanning operation.
The output~of units 51b and 52b are input to integrators 651,652--res-
pectively. The integrated values thereo~ are c~onverted into digital
data by A/D ~onverters 661,662 andithen read-in by micro-compu*er 60.
The read-in timing of micro-c~omputer 60 is made approximately synchro-
nous ~ith the time of completion of the main scanning. Hence, micro-
computer 60 aequentially reads-in signals corresponding to the ene~rgy
of ths light of main wavelength components of ~ 2 contained within
the light emitted from the same portion, and ~n an approximately
$ynchronous fashlon, and in the same area within the visual ~ield
obtained by both image pickup devices; 51 and 52. Thus, micro-computer
60 reads-in one datum per one scanning line, and thus, 128 piece~ o~
data are read-in per one laterally or longitudinally elongate ~can,
ning area.
On the other hand, prior to the use of thi~;device,image
pickup lens 34 i~ covered by a shutter (not shown), 90 as to obtai~
an offset value for each of the image pickup devices 51 and 52, the
v~lue being atored in a predetermined area o~ memory 67, ~uch data
corre~ponding to the respective laterally and longitudinally elongate
area~;of image pickup de~ice~ 51 and 52.
The program of micro-computer 60 ic con~tructed such that
every time it read~-in data from A/D converters 661, 662, it deducts
the offset value of the corresponding ~canning position from the
read-in data to determine the radiant energy corre~ponding to eac~
wavelength ~ 1 or~A2 at the scanning position being m~asured, and
-26-
il~S~4~
execute~ the t~o-color temperature determining operation according
to the fol:Lowing equation (3~:
~1()tJ Y)
T(~,Y) ~ ~2(x, y)
where ~(~,Y) [K]: a typical temperature at the position corre~ponding
to a scanning line; ~1(X,Y),2(X,Y): radiant energy corre~-
ponding~to sach of wavelength ~ 2 with the off~et valus9
noted above; and ~ conatants~chosen for ~ 2.
In addition, equation ~3) holds be~cau~e the relation~hip between t~e
energy ratio 1(X,Y)/~2(X,Y) and the temperature T(X,~) is approxi-
mately linear.
The thus obtained temperature data i~ storea withi~ a pre-
determined area in memory 67 corre~onding a plurality of frames
includ~ng those frames being scanned, and the~data i8 fed into micro-
computer 60 ~o as to be available for a predetermined purpose, and
thereby capable being transmitted to various external in~trument~.
A typical u~e for the data i8; to provide a print-out of the temperature
values by mean~ of a printer or the graph~ic~digplay of a temperature
psttern (i.e. - the temperature distribution at 128 horizontal or
~rtical pointa of the visual field of the image pickup dev~ice). Al~o,
when u~ed for the ~upervision of weld zonea, the temperature i~ ava~lab~e
for use as heating control information.
The embodiment of Fig.ll i~ adapted to di~play, on monitor
56, the horizontal or vertical temperature pattern by the uae of the
generated temperature pattern gained, as described above.
-27-
~ 1 65~44
Fig.15 is plan view exemplar~ of the arrangement of
image guide 31 and objective 32 when an electrically seamed pipe
being manufactured is selected as the object 30. An open pipe
90 of a copper sheet being bent into a tubular shape is biased
at both edges by contact tips 92 disposed at the upstream side
of squeeze rolls 93, and welded into pressed contact by squeeze rolls
93 so as to be formed into the electrically seamed pipe, and then
conveyed to a seam-annealer. The objective 32 is so disposed
that an area including the weld abutment, the so-called V point,
positioned slightly at the upstream side rather than the phantom
line connecting the axes of squeeze rolls 93 is used as the
image pickup visual field. Fig.~6 shows the display form on
monitor 56 when the above-noted image pickup visual field is selec-
ted ; the left upper area displays the image pickup picture re-
ceived by image pickup device 53, and in which the open pipe 90,
the electrically seamed pipe 9l, the weld saam zones and the V
point, appear. Also, two horizontal and vertical lines indica-
ting the aforesaid scanning area appear respectively. Such
portions, except for picture display area 56a, are uniformly black-
levelled by a video signal partial-removing circuit 54, and are
used for displaying the temperature pattern. Firstly, the area
56b located below the picture display area 56a is a laterally
elongate scanning area of Py to Py + My, and in this instance,
is the horizontal distribution display area used to display the
lengthwise temperature distribution of the pipe along the welding
seam. The area 56c at the right side of areas 56a and 56b, is a
vertical distribution display area used to display the circumfer-
antial temperature distribution of the pipe along the longitudi-
nally elongate scanning area of Px to Px ~ Wx. A video random
~ 8-
, ,, ~ .
~ ~ 65~4
lccess memory tVIDEO RAM) 6~, having storage locations coxres-
ponding to scanning areas 56b and 56c is provided, and into
which are written-in temperature scales corresponding to hori-
zontal and vertical ruled lines to ~e displayed within horizontal
distribution display area 56b and vertical distribution display
area 56c, and having data stored therein to be used to display
temperature values corresponding to the temperature scales.
Data to be stored in video RAM 68, as is well-known, may be
displayed by means of a white dot raster pattern. The address
location of video ~AM 68 corresponding to the position within
areas 56b and 56c to be~displayed by the white dots, is computed
from temperature data obtained from the predetermined temperature
scales with respect to the signal data and each scanning line, so
that white dot data is written into the location of RAM 68 corres-
ponding to said address. To write such display data in video RAM
68, a time period, such as that corresponding to the signal gene-
rating the timing of the vertical synchronizing pulse of the
video signal input to monitor 56 from picture composing unit 55,
and not relevant to said display, is selected. The display signals
transmitted to monitor 56 relate to vertical and horizontal syn-
chronizing pulses of the video signal so that the read-out address
of video RAM 68 is read out in correspondance with the read-out
~ddress, the read-out data being input to picture composin`g unit
55 via television interface 64, whereby a composite pattern, such
as that shown in Fig.16, is displayed on monitor 56. Such a
display makes it possible to observe the welding operation and its
corresponding temperature distribution in every direction. In
addition, the arrows in Figs.15 and16 show the direction of forward
--2 q- ~
1 ~65~4
~novemen~ of the pipe. In the case where the temperature distri-
bution is carried out as noted above, data stored within video
RAM 68 is written not every time the temperature data is renewed,
but once per several data renewals, so as to avoid flickering
and thereby improve viewing. When in use with the aforesaid
device, the two color temperature operati~ measures the tempera-
ture, whereby the measurement is less affected by the surrounding
atmosphere in comparison with the prior art infrared ray system
and is high in accuracy. When used with the image guide as in the
embodiment of Fig.ll, it is possible to measure the temperature
pattern without being affected by the atmosphere, or to measure
the pattern at a minute area or deep bottom which is not visible
directly from the extexior thereof. Furthermore, the resolving
power can be raised until restricted by the resolution of image
pickup devices 51 and 52. Also, the device in this embodiment
uses the image pickup device providing an image dissector to
snable random access scanning, thereby readily obtaining the
temperature pattern with respect to an optimum area. In other
words, when a ~ldicon camera is used, seguential scanning is per-
formed, so that complex software is required for obtaining tem-
perature patterns other than those vertical or horizontal to the
image pickup picture, thereby causing difficulty in practical use.
The device in accordance with the invention, however, facilitates
the obtaining of a temperature pattern in a desired direction and
no scanning is performed on a portion not pertinent to its opera-
tion. Furthermore, an image pickup tube having no accumulation
effect is used so as to be free from the influence of residual
images, and is suitable for the measurement of an object which
~ 1 6544~ `
~ i~ly changes its temperature. Furthermore, the image pickup
tube is wider in its dynamic range than that of a vidicon
camera to thereby have an advantage of measuring a wider range of
temperature measurement.
Fig. 22 shows another embodiment of a measuring device
in accordance with this invention, which makes it possible to eli-
minate one of the image pickup devices 51 or 52. Lens 1, N.D.
filter 35 and mirror 5 are arranged such that the device 51 picXs
up the light passed through the lens 1 and N.D. filter 35, and
the device 53 picks up the light passed the lens 1 and reflected
by the mirror 5. A rotary filter 2 is located between N. D. fil-
ter 35 and the pickup device 51. As shown in Fig. ?3 or Fig.24 ,
the rotary filter 2 is discal and separated into two or four areas,
respectively. Each area consists of optical filter 21 or 22,
whose representative penetrating wavelength is Al or 12, and
filters 21 and 22 are alternately arranged. The rotary filter
2 is driven so as to rotate at a high speed by motor 23. Pickup
device 51 receives the light passed through filter 21 or 22, and
its output is input to an arithmetic unit 3. A pulse generator
(not illustrated) is mechanically attached to either the motor 23
or rotary filter 2, anq the arithmetic unit 3 discriminates between
the two kinds of data (one is via filter 21 and the other is via
filter 22) according to said output of the pulse generator,and execut~
two-color temperature operation in a fashion corresponding to
that of the elements of Fig.ll. Reference numeral 4 designates
a picture composing unit and 56 designates a monitor.
When the device is used for the supervision of the weld
zone of an electrically seamed pipe, it is very convenient for
3i-
f ~, ~
1 ~65~44 ~
e.control of the production line to obtain the V point and also
~he V angle (an angle formed by both edges of open pipe 90 at
the vertex of V-point), which is possible by using a device in
accordance with the present inventlon. In other words, the video
signal olutput of the second image pickup devlce 52 (or the first
image pickup device 51) is utilized as follows:
The video signal is input to an analog switch 69 (See
Fig.11) which allows the video signal to pass therethrough only
while the deflection signals in the X and Y directions which are out-
putfrom D/A converters 63X and 63Y correspond to the scanning of th~e
laterally elongate areas of Py to Py + Wy, whose main scanning
direction is Y and whose; sub-scanning direc,tion is X. The output
of analog switch 69 is input to integrator 70 whose output feeds
comparator 71 for setting the threshold value at a given level.
The image pickup picture generated by image pickup device 52,
from a temperature distribution of the object within the visu,al
field thereof, is in a bright re,d hot condition at opposite edges
of the open pipe 90 and the seamed portion of the electrically
seamed pipe, and becomes dark due to low temperatures away from
the red hot portions, and becomes the darkest when the bottom of
a gap between the opposite edges of open pipe is received.
Fig.17 is an enlarged view exemplary of a pickup pic-
ture and scanning lines between Py and Py + Wy. Fig.18 shows
video signal levels corresponding to the scanning lines, and
which relate to the position of electrically seamed pipe 91.
Since brightness at this portion is in the aforesaid distribution,
the video signal has waveforms as shown in Fig.l9, which has peaks
at opposite edges of the open pipe 90 and the seamed portion of ,
1 3 65~4
tne electrically seamed p~pe 91, i~e~, the red hot portions.
Hence, integrator 70 which receives the video signal, generates
an output signal showing a steep change at the portion corres-
ponding to opposite edges in contrast to the part of video signal
which scans the open pipe 90. The output signal of integrator 70
is input to comparator 71, setting the threshold value at a given
level. The comparator 71 provides pulses when the scanning spot
passes through the opposite edges. If scanning lines, as shown
in Figs.17 andl8, are designated by numbers 1, 2 ... i from the
upstream side of open pipe 90, the output signal of comparator
71, as shown in Fig.l9, changes to sequentially reduced pulse
intervals tl, t2, ... ti. Also, the output signal of comparator
71 is input to a clock unit 72 comprising a clock oscillator and
counter, and in which pulse intervals tl, t2, ... ti corresponding
to the respective scanning lines are measured, the clock unit 72
being provided with deflection signals in the X and Y directions
for discriminating each scanning line.
The micro-computer 60 se~uent~ally reads-on the output
of the counter of clock unit 72, i.e., tl, t2 .~. ti~ which cor-
respond to dimensions gl~ g2' -~ gi of intervals between opposite
edges of the open pipe 90 as shown in Fig.18. Since the order
of each sead-out data, i.e., the scanning line numbers 1, 2, .., i,
each correspond essentially to the position in the axial (or tra-
velling) direction, micro-computer 60 can determine the length of
the interval between opposite edges at each position in the X
direction. Fig. 20 schematically shows the relationship between
both the measured data, in which the abscissa represents the posi-
tion in X direction and the ordinate represents the dimension g
between both edges. In addition, Xl, X2 ... Xi are values showing
-33-
.
~ ~ 6544~
c -esponding positions of scanning lines 1~ 2, ... i, in which,
for exapmle, the left end of the visual field is made e~ual to
0.
Now, in this embodiment, the position in the X direction,
when g = 0 as to the specified V point, is not read-in from
clock unit 72, but by the following method. Data after the
value g becomes smaller than the prescribed value, is neglected,
and (Xi, gi)i=l~2 .. n (where n>3) is made the target of the
operation process. From the above, a straight line is obtained by
the least squares approximation method, so that the position in
the X direction, where the straight line becomes g = O (intersect-
ing the abscissa X in ~ig.20 ) is made to be the V point.
Fig. 21 is a view explanatory of the computing principle
of the V angle. If an angle between the line obtained as noted
above and the abscissa X in Fig.20 , is represented by ~, between
the V angle ~V (an angle formed in the vici~ity of the V point by
opposite edges of open pipe 90 as shown in Fig.17) to be obtained,
the following relationship holds:
~V
tan 9 = 2 tan
Micro-computer 60 then computes a value of ~V from the
following equation using the above-noted relationship,
~V ~ 2 tan~l tan 9 ....................... ~2)
where 3 is obtained by a well-known method on a basis of the
previously obtained straight line.
The V point position and V angle ~V are output to a
printer 73 for display and recording, and, when used for a heating
control, to the control unit therefor. ~ig~,25(A),(~)&(C) show a
n ow chart for measurement. At first the temperature of laterally
,
3~ .
... .
,. ,.i, ...~ .
~ ~ 6~444
elongate area 1~ measured, secondary, the temperature of longitudi-
nally elongate are~ is measured and subsequentry V point and
are specified.
As can be seen from the foregoing description r the method
and device of this invention obtai~ the temperature pattern of an
object by using a two color temperature determining operation
using energy emitted from the object in respective bands with cen-
ter wavelenghts of ~1 and ~2~ which energy is not easily affected
by the atmosphere, as compared with a thermometer using infrared
rays. The present invention makes possible;the use of an image
guide which cannot be used with infrared rays due to tran~mission
loss. Furthermore, this invention can measure the temperature
pattern of a minute area or that at a deep bottom of a structure
when the bottom is not visible directly from the exterior. Also,
the resolving power can be increased to the limit of the light
sensing part of the image pickup device. Moreover, the method
and device of this invention have extremely high reliability in
comparison with a conventional device of the non-contact type, and
can accurately detect the temperature pattern of an object under-
going a great temperature change, e.g., electrically seamed pipes
being welded on a production line. Hence, the present invention
has great advantages and contributes greatly to advances in this
~ind of temperature measurement technique.
3 5-
,~.,
