Note: Descriptions are shown in the official language in which they were submitted.
1152788
FIELD OF THE INVENTION
This invention relates to the field of
scanning graphical line data. More particularly,
this invention relates to an optical scanning head
composed of a plurality of optical fibres that can
be used in a semi-automatic mode to scan graphical
data and transmit the optical data for assimilation
by a digital computer.
BACKGROUND OF THE INVENTION
With the use of coordinate digitizers it
is known to track and convert graphical data such
as well logs, maps and charts into digital form.
Present coordinate digitizers function by encoding
the displacement over time of a cursor in the X and
Y coordinate directions, as the cursor is tediously
moved manually by an operator in a tracing or
tracking manner along a line on the graph. The
accuracy of the information processed by the
digitizer depends directly and entirely on the
degree of precision with which the operator keeps
the cursor positioned on the graph line on the
document as it is being traced by the operator~
The manual cursor tracing method is unsatisfactory
and expensive because it is extremely time
consuming, prone to inaccuracy, and is mind-numbing
for the operator expecially when the line has
numerous tightly spaced undulations, as occurs with
well-logs .
In an attempt to deal with and overcome
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the forego ng difficulties, automatic methods have
been developed together with equipment that auto-
matically scans the graphic data. These automatic
scanning machine~ function by scanning the entire
document bearing the graphical data that is to be
digitized. This technique necessarily results in
the generation of a large volume of data, most of
which is extraneous and irrelevant because it is
not part of the trace line to be captured. The
extraneous information, which includes such things
as grid lines, other traces, and annotations, must
be removed before the desired trace line can be
identified and recovered. Lack of known reference
points, and many heretofore unresolvable situ-
ations, make this task basically impractical for
complicated graphical data. As a consequence,
conventional automatic line 3canners are used only
for very simple tracing which thus limits their
applicability because the majority of graphical
data to be processed is complex.
One method of dealing with the problem of
using automatic line scanners for complex graphical
data has been to have an operator transcribe a
simple version of the graphical data onto another
document, and then scan this simpler version with
the automatic scanner. This solution is somewhat
self-defeating because it results in the inclusion
of a manual step, and the accuracy of the method
thus depends on how accurately the original trace
1~52788
is manually transcribed. A~ can be seen from the
foregoing discussion, there i8 a real need for an
apparatus and method of scanning graphical data
that eliminates the need for an operator to trace
the graph line and yet does not automatically
generate unmanageable volumes of irrelevant data.
SUMMARY OF THE INVENTION
The present invention co~bines features
of both the manual and the automatic methods to
provide a unique apparatus and method which can
quickly provide large volumes of accurate digitized
data.
The invention comprises an optical
scanning head formed by a specially configured
plurality of optical fibres, the ends of which in
one direction face the graphical line document to
be scanned. To maximize scanning capacity, the
array of optical fibres i8 arranged in a spread-out
configuration of some suitable form such as the
shape of "C", or a vertical trunk with two hori-
zontal branches extending horizontally from the
respective end~ of the vertical trunk. One
particularly u~eful configuration for ~canning
graphical data displayed on linear X and Y
coordinates is to have the optical fibres arranged
.in a rectilinear "C" configuration, the open side
facing the direction of tracking of the graphical
data.
Parentheticall~, it should be noted in
reading this disclosure that by referring to X and
llSZ7~
Y coordinates, the applicant does not necessarily
mean that such X and Y coordinates are rectilinear.
One or both of the x and Y coordinates may be
curvilinear. The invention can accomodate such
curvilinear coordinates. However, it is generally
contemplated that the X and Y coordinates will be
rectilinear in most applications.
The scanning head is mounted on the
cursor of a digitizer and is used in association
with a light source in such a way that light
travelling from the source enters the facing end of
the fibre array after having passed through or
having been reflected from the document being
scanned. Light passing through or reflected from
the document at any particular point as viewed by
an optical ibre varies directly according to
whether there i~ a line on the document or the
document i~ blank at that point.
m e various fibres in the array transmit
the respective light signals received by each fibre
to a remote photo-detection device which converts
the light signals into corresponding electrical
signals. The electrical signals 80 produced are in
turn converted into corresponding digital elect-
; rical signals representative of an "on" or "off"
state (e.g. if the light inten~ity transmitted by a
given fibre is below a threshold value, the light
input condition to the given fibre may be consid-
ered "off": otherwise, it may be considered "on").
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Each of the fibres in the spread-out
array functions individually and separately, and
can~ in effect, "sense" a line when the array is
passed over the graphic data on the document. This
ability of the spread-out optical fibres to
cooperate together to track the line permits a
strip or band of the document on both sides of the
line to be scanned at once, so ~ong a~ at least
some portion of the fibre array is kept over the
line. Thus, the operator, by simply moving the
cursor carrying the spread-out fibre array broadly
in a band pattern over the line to be traced,
captures a particular ribbon-like ~ection of the
document including the desired line. This
procedure is much faster and more efficient than
the presently employed system using a target point
on the cursor because with that system the operator
must painstakingly and tediously track a complex
wavy line with ~he target point on the cursor.
Operator lapses necessarily occur and hence with
the manually operated system, the data collected
manually has a certain amount of inaccuracy
therein. With the present invention, the operator
needs only to keep some point of the relatively
broad fibre array, instead of a precise point, over
the line being traced in order to track the line
quickly and accurately. To assist in illustrating
the method, an analogy can be dr~wn between tracing
over a line with a brush rather than a pencil
point.
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~152788
Digital signal information captured from
the optical fibre array in the manner described
above may be recorded or stored in digital form for
discrete positions of the cursor as the cursor is
moved in relation to the document being scanned.
The stored information may then be electronically
processed to remove or substantially remove
extraneous information such as coordinate or grid
lines, thereby leaving the re~uired graph line
naXed.
me combination of a scan device, rather
than a pin-point target device, with a coordinate
-~ digitizer is believed to be entirely unique. The
optical fibre array scanner provides a relatively
simple salution to the problem of scanning a
complex wavy line in compari60n to already known,
; and previously discussed fully automatic methods,
for several reasons. The volume of data generated
by the invention is considerably reduced, since
only a relatively narrow relevant strip of the
document, including the desired line, is captured
for assimilation. For any given position of the
cursor relative to the document being scanned, the
logical state of light signal inputs to the optical
fibres gives information locating a point or points
on lines of the document relative to the cursor as
a frame of reference. Such information, combined
with X and Y coordinate positional information of
the cursor relative to a selected reference point
on the document being scanned gives all the
11S2~88
information necessary to locate the position or
positions of the point or points on lines of the
document relative to the selected reference point.
(X and Y coordinate positional information from the
cursor may be obtained by various known techniques.
Usually such information will be in analog form or
have an analog component. For purposes of sub-
sequent analysis, it is contemplated that analog
signals corresponding to X and Y coordinate
positions will be converted to digital signals.) In
use, information concerning fibre optic states and
corresponding X and Y coordinate positional inform-
ation is taken at a plurality of cursor positions
relative to the document being scanned. Such
information can readily be stored in digital form
for sub3equent analysis enabling digital recon-
struction of graph lines on the document.
In some cases, it may occur that a graph
line travels directly over a coordinate or grid
line for a certain distance. If information being
taken from the document at such locations is
processed or analyzed to remove information such as
coordinate or grid lines, then the graph line
itself may al~o be removed. To accomodate this
situation, the cur~or may include a visible target
point which is used to manually trace the area of
o~erlap between the graph line and the coordinate
or grid line. Information from the optical fibre
array is used only as an aid in identifying grid
information during the period of manual operation.
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~152788
'l'~e position of the graph line during manual
operation corresponds to that of the target point.
As will be apparent to those skilled in
the art, raw information from the optical fibre
array and cursor may be processed by a digital
computer when programmed with suitable software to
extract therefrom a desired graph line.
The in~ention is directed to an optical
scanning head for scanning graphical line data
comprising elongate scanning means capable of
detecting at discrete points along its length
variations in light intensity caused by the
presence or absence of graphical line data on the
graph when proximate to the scanning means.
In the scanning head described, the
scanning means may be comprised of a plurality of
optical fibres. me scanning means may be in the
~hape of an elongated bar.
In the scanning head described, the
scanning means may be constructed in the shape of
two elongated bars, each extending in a different
direction.
The invention is also directed to an
optical scanning head for scanning graphical line
data presented on an X-Y coordinate graph
comprising: `
a) a first scanning bar extending in the
Y-ordinate direction;
b) a second scanning bar extending in
the X-ordinate direction and
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c) a third scanning bar extending in the
X-ordinate direction;
each scanning bar being capable of detecting at
discrete points along its length variations in
light intensity caused by the presence or absence
of graphical line data on the graph when proximate
to the respective bar.
In the invention, the first, second and
thixd scanning bars may be arranged in the con-
figuration of a "C".
In the scanning head, the first, second
; and third scanning bars may each be composed of a
plurality of optical fibres.
In the scanning head, the optical fibresmay have a diameter ranging from 1 mil to 20 mils.
In future configurations, to accomodate the trend
to the metric system, it may be preferable to
specify the diameter of the optical fibres in
metric measurements. In a particular embodiment,
each of the optical ibres in the scanning head may
have a diameter of about 10 mils. Optical fibres
of about 10 mils diameter are available under the
trade mark CROFON from DuPont of Canada, Limited.
In the scanning head, the first scanning
bar may be made up of sixteen 1~ mils diameter
optical fibres arranged in a linear row, and the
second and third scanning bars may each be made up
of eight 10 mils diameter fibre~ arranged in a
linear row, positioned at each end of the first
scanning bar and extending in the same direction
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1~5278~
from the first scanning bar in a more or less
:' parallel manner.
The invention i~ also directed to an
optical scanning head comprising:
a) a vertical scanning bar;
b) an upper horizontal scanning bar
extending horizontally from some
point along said vertical scanning
. bar (a); and
c) a lower horizontal scanning bar
opposed in position to said upper
horizontal scanning bar (b) and
extending horizontally from some
point along said vertical scanning
bar (a);
said scanning bars each comprising a plurality of
optical fibres.
A method of optically scanning and
as~imilating graphical data capable of being
captured according to X-Y coordinate position
comprising:
a) passing the ends of an array of
optical fibres over the illuminated
data to be scanned to capture and
transmit light:
b) converting the light transmitted by
each of the fibres to corresponding
electrical signals:
c) converting each of the electrical
signals into re~pective logic states,
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d) tracking the X-Y position of the
array and converting the position
into an X/Y count and direction; and
e) transmitting the data from (c) and
(d) to a digital computer for
processing.
DRAWINGS
In the drawings:
FIGURE 1 illustrates a perspective
exploded view of the scanning head;
FIGURE 2 illustrates a perspective view
of a digitizer (incorporating a digital computer)
including the scanning head;
FIGURE 3 illustrates the optical fibres
in the scanning head as arranged in a rectilinear
"C" pattern;
FIGVRE 4 illu~trates a section of a
typical well-log;
FIGURE 4A illustrate~ the raw data
received from the well-log section illustrated in
FIGURE 4 when scanned with the scanning head and
processed by the digital computer
FIGURE 4B illuQtrate~ the raw data of
FIGURE 4A after the transverse grid (Y ordinates)
has been removed;
FIGURE 4C illustrates the data of FIGURE
4B after the longitudinal grid (X ordinates) has
been removed;
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llSZ78~3
FIGURE 4D illustrates the data of FIGURE
4C after noise has been eliminated;
FIGURE 4E illustrates the data of FIGVRE
4D after curve identification and incorporation of
the data obtained by manual tracing of sections of
the curve with the target point;
FIGURE 5 illustrates a typical plot of
the finished product from the data of FIGURE 4E:
FIGURE 6 illustrates in block diagram
. 10 form the major components in the graphical line
scanning and digitizing process;
FIGURE 7 illustrates in block diagram
form the major components of the cursor assembly;
FIGURE 8 illustrates in block diagram
form the major components of the cursor support
hardware~
FIGURE 9 illustrates in block diagram
form the major components of ~he interface hard-
ware;
kIGURE 10 illustrates in block diagram
form the major components of the interface
software-operations software;
FIGURE 11 .illustrates in block diagram
form the major components of the analysis software.
DETAILED DESCRIPTION OF ONE
.
EMBODIMENT OF THE INVENTION
Referring to the drawings, and FIGURE 1
first, FIGURE 1 illustrates the portion of the
scanning head 5 that contains the array of optical
30 fibres arranged in a rectilinear "C" pattern,
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115Z78~3
wherein upper linear hori7ontal bar 1 is made up of
a plurality of optical fibres arranged in a row,
vertical linear bar 2 is made up of a plurality of
optical fibres arranged in a row, and lower linear
horizontal bar 3 is made up of a plurality of
optical fibres arranged in a row. The respective
optical fibres forming the three bars are arranged
around three adjoining side~ of a clear plastic
panel 4 through which the document is viewed.
(FIGURE 1 illustrates the part carrying the three
bars positioned to the right of base of the
cursor 4a. This is for purposes of illustration
only. In practice, the part with the three bars
is clamped such that the vertical bar 2 is adjacent
the base of the cursor 4a). The target point is
located on panel 4 approximately at 4b. These four
components make up the rnain elements of the
scanning head 5.
Scanning head 5 is mounted on the
cursor 6 of the digitizer, which i8 shown in per-
spective detail in FIGURE 2. The digitizer is
conventional and is constructed so that the
cursor 6 rests above a lighted panel, the cursor 6
being connected to the digitizer by wiring and
various connections 90 that the digitizer can keep
track of the position of the cursor 6 in relation
to X and Y coordinates. The document bearing the
graphical line data to be scanned rests on the
lighted panel 7 below the cursor 6.
Immediately abov~ ~he cursor 6 is located
a small Xeypad 8 and indicators 8a. The keypad 8
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115278~
enables the operator to enter into the digitizer
mode changes (automatic to manual, or vice versa)
and to enter other information that may be required
while the graphical line is being traced by the
operator using the cursor 6. The indicators 8a are
used to display to the operator information
relating to the current mode and other states of
the digitizing system. The data gathered by the
scanning head 5 is relayed optically through the
fibre optic cable 9a to electronics module 10. The
keypad 8 and indicators 8a are connected to
electronics module 10 through electrical cable 9.
The X-Y encoder data gathered by the encoders 11 is
connected by electrical cables 12 to the elect-
ronics module 10.
FIGURE 3 illustrates an optical fibre
array preferred for tracing well-log data compris-
ing a plurality of optical fibres lla, in this case
thirty-two optical fibres, arranged to form an
upper scanning bar 1 comprising eight equi-diameter
optical fibres arranged in a horizontal row, a
vertical bar 2 comprising sixteen equi-diameter
optical fibres arranged in a vertical row and a
lower bar 3 comprising eight equi-diameter optical
fibres arranged in a horizontal row. This con-
figuration of optical fibres is ideally suited for
the purpose of scanning an undulating graphic line
that appears on X and Y coordinate graph paper such
as in well-logs. The operator scans the graphic
line by ensuring that at least one o the optical
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3 15278~
fibres in the array of thirty-two fibres is over
the graphic line at some point in time as the scan
is made.
The applicant has determined that suit-
able optical fibres for the applicant's inventlon
are those which exhibit properties oE flexibility,
durability and have a thin cladding thickness to
reduce as much as possible the dead band effect
between adjacent fibres. Plastic fibres such as
those available under the trade mark CROFON, from
DuPont of Canada Limited, despite reasonably high
attenuation properties, have been found to be
suitable.
FIGURE 4 illustrates a typical section of
a well-log showing the trace of an undulating curve
with associated l~ngitudinal and transverse grid
lines.
FIGURE5 4A through to 4E illustrate in
sequence the manner in which the curve appearing in
the section of the well-log illustrated in FIG~RE 4
is captured by the scanning head and processed by
the digital computer. FIGURE 4A illustrates the
raw data, including the curve together with
grid lines, that are obtained by scanning a well
log using the optical fibre scanning head of the
invention. This data is then processed to identify
and remove the grid lines and extraneous unwanted
information. FIGURE 4B illustrates the data as it
appears after the transverse grid lines have been
removed. FIGURE 4C illustrates the appearance of
115Z7~i38
the data after the longitudinal grid lines have
been substantially removed. FIGURE 4D illustrates
how the data appears after "noise" has been
eliminated. FIGURE 4E illustrates the appearance
of the curve data after curve identification and
the incorporation of manually obtained data.
Finally, after pas~ing through these
data processing procedures, the curve is plotted
in the form that appears in FIGURE 5. In FIGURE 5,
the transverse scale appears by means of indicator
points at the bottom and top of the plot. Other
salient information required by users of digital
well-log information is also di~played according to
present procedures.
FIGURE 6 illustrates in block diagram
form the manner in which the data picked up by the
cursor assembly 12, which includes scan head 5,
cursor 6, indicators, keypad and encode~s, is
transmitted through variou~ proce~ing procedures
in order to yield the final printout product. The
cursor assembly 12 i6 connected to cursor support
hardware 13, which in turn is connected to inter-
face hardware 14. The in~erface hardware 14 in
sequence is connected to interface software 15,
operations software 16, and analysis software 17
before the final product is produced.
FIGURE 7 illustrates in block diagram
form the major components of the cursor assembly.
The light source 18 casts light on the document 19,
the light from the document then being transmitted
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- 115Z788
into the fibre optic array 20. Cursor movement,
illustrated by the dotted-line block 21, i9
converted to shaft rotation by the encoder drum 22.
Shaft rotation iR coverted to quadrature ~ignals
by shaft encoder 23.
FIGURE 8 illustrates in block diagram
form the major components comprising the cursor
support hardware. Light received by the fibre
optic array 20 (see FIGURE 7) i~ tran~mitted by the
fibre optic cable to a detector pre-amplifier 24,
-^ which converts the light intensity into electrical
signals. These electrical signals are transmitted
into amplifier 25, from which the electrical
signals are then transmitted to a logic switch 26
which converts the electrical qignal~ into fibre
logic state~.
In turn, as seen in FIGU~E 8, the
quadrature signal~ received from the shaft encoder
23 (see FIGURE 7) are tran~mitted to a quadrature
detector 27, which then provides an X~Y count and
direction.
FIGURE 9, by means of block diagrams,
illu~trates the major components of the interface
hardware, which processes the information received
from the cursor support hardware, illustrated in
FIGURE 8. ~he fibre logic ~tates received from
logic switch 26 (see FIGURE 8) are transmitted to
data registers 29. The X/Y coun~ and direction
information received from the quadrature detector
27 (~ee FIGURE 8) are tran~mitted through an X
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1152788
counter, Y counter, fibre diameter counter 28
before being transmitted to the data registers 29.
The data from the data registers 29 is transmitted
to command registers 30. Command registers 30
receive information from keypad 8, and provide
information to the indicators which are followed by
the operator. Information from the command
registers 30 is then`transmitted to PDP~
computer registers 31. A specialized interface has
been designed by the applicant to connect a
digitizer to a PDP-ll~ computer. As mentioned
previously, the applicant's digitizer consists of a
standard X-Y encoder digitizer which has been
retrofitted with a scanning device including an
optical fibre array to provide additional
information for the computer. The interface
provides support for the X-Y encoders, scanning
device, keypad and various indicators used for
operator interaction. The applicant's interface is
designed using conventional methods employed by
many PDP-ll~ interfaces. The applicant's interface
registers consist of six registers which are
organized sequentially in address space. The first
two registers are control registers while the next
four are data registers. The six interface
registers 31 are as follows: command/status
register 32, operator action register 33, X
register 34, Y register 35, vertical scan register
36 and horizontal scan register 37.
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115Z78~
Command/status register 32 is the main
interface control register. It iB used to imple-
ment interface commands and to indicate movement of
the cursor 6.
Operator action register 33 i9 concerned
with providing additional operator interaction
facilities. This register controls the keypad 8
and indicators 8a.
The X register 34 contains the X value
of the cursor 6 position. The value is stored as a
sixteen bit binary number.
The Y register 35 contains the Y value of
the cursor 6 position. This value i~ also stored
as a sixteen bit binary number.
The vertical scan register 36 contains
the scan information from the vertical part of the
scan bar 2. The bits are arranged such that bit 0
corresponds to the topmost fibre of the vertical
bar 2 and bit 15 corresponds to the bottommost
fibre of vertical bar 2.
The horizontal scan register 37 contains
the scan information received from the horizontal
fibres making up the upper bar l and the lower bar
3. The bits are arranged such that bits 0 and 8
correspond respectively to the rightmost fibres in
the upper and lower bars and bits 7 and 15 cor-
respond respectively to the leftmost fibres in the
upper and lower bars.
FIGURE 10 illustrates how the PDP-ll
registers 31 are lin~ed with the interface software
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-
ll~Z7~8
38 and operation software 39 of the applicant' 8
computer.
FIGURE 11 illustrates by means of
sequential block diagrams the major components of
the analysis software, whereby the mapped data
received from the operations software 39 is
processed to remove the transverse grid (block 40),
the longitudinal grid (block 41), noise (block 42),
identify the curve, (curve identification block 43)
and finally convert the data into the final product
as represented by data conversion block 44.
FIGURES 4 through 4E, discu~sed previously,
illustrate the results obtained when this procedure
is followed.
The specific details as to the operation
of the interface depend upon associated programming
used in the PDP~ computer. The applicant's
interface is configured to resemble the type of
operation which i9 commonly used by many PDP-11
peripherals.
As will be apparent to those skilled in
the art, in the light of the foregoing disclosure,
many alterations and modifications are possible in
the practice of this invention without departing
from the spirit or scope thereof. Accordingly, the
scope of the invention is to be construed in
:,
accordance with the substance defined by the
following claims.
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