Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~'110733
RWE Entsorgung Aktiengesellschaft Essen, 7 December 1392
T-2 Dr.Hov/Ka EAG 36
A Method to identify Object~
and a Device to implement ~uch a Method
Description of the Invention
The present invention relates to a method to identify
objects by radiating them with electromagnetic waves in W
to IR ranges, processing the waves incidenting from the
object by means of an electronic signal processing unit and
output of signals from the electronic signal processing
unit, whereby the waves incidenting from the object stri~e
at least one chip equipped with photodiodes which feeds the
taken photoexcitation to a spectral analysis and/or a cut-
off filter and/or a texture filter, whereby the spectral
light, the object contour provided by the cut-off filter
and the surface structure of the object provided by the
texture filter are compared with data memorized in a data
memory, and certain sequence steps defined by at least one
signal are initiated after identification of the object.
The invention rel~tes also to a device for implementing the
method.
The identification of objects is of great importance in
many fields. This applies primarily to a series of techni-
2S cal fields. Thus, for instance, in automatic processing ofobjects it may be required to identify an object at first
and then transfer it to a further processing stage. The
exact identification of materials in sorting processes is
of particular importance. Hereby, state of the art devices
are used which registrate electromagnetic waves incidenting
from an object, compare them with memorized data, and
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subsequently transmit signals which initiate e.g. a sorting
means.
In applying these known methods images of concrete objects
are generated by means of electromagnetic waves incidenting
from the objects and compared with memorized images.
DE-OS 41 25 045 for instance discloses a method for sorting
waste mixtures by radiating the waste objects with electro-
magnetic and/or acoustic waves, receiving the waves inci-
denting from the radiated waste objects in a signal proc-
essing unit for identification of the waste objects, and
transmitting signals from the signal processing unit to a
sorting means which sorts the identified waste object out.
The signal processing unit detects features such as exter-
nal object shapes, e.g. bottle, cup, collapsible tube,
cubic and other shapes as well as logos, product names,
corporate and manufacturer names respectively, trade marks
and colours.
Correspondingly, the known methods require a possibly
complete data base for object identification and taking
certain measures, converting incidenting electromagnetic
waves into defined images and comparing such images with
comparison data possibly completely memorized in the data
base. After the objects have been identified, a signal is
triggered which for instance puts a sorting means into
operatlon that sorts the identified object out.
The applicant has now succeeded in developing a substan-
tially improved method for object identification without
requiring a comparison with voluminous data memories by
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radiating the objects with electromagnetic waves in W to
IR ranges, processing the waves incidenting from the
objects by means of an electronic signal processing unit
and output of signals from the electronic signal processing
unit, characterized in that the waves incidenting from the
objects strike at least one chip equipped with photodiodes
which feeds the taken photoexcitation to a spectral analy-
sis, in that the gray light from the spectral analysis is
eventually fed to a cut-off filter and/or a texture filter,
in that the spectral light and/or the object contour pro-
vided by the cut-off filter and/or the surface structure of
the object provided by the texture filter are compared with
data memorized in a data memory, and certain sequence steps
defined by at least one signal are initiated after object
identification.
The method according to the invention is excellently suited
to identify objects from an object mixture, the identifica-
tion being supported by the fact that the objects are at
first separated from the object mixture. A very important
sequence step is the initiation of ~ sorting means which
sorts the identified object out.
The object identification takes place in such a way that
the objects are at first radiated with électromagnetic
waves in ultraviolet range, within the range of visible
light or in infrared range. The waves incidenting from the
object, e.g. by object reflection or after penetrating or
partially penetrating the object and reradiation of elec-
tromagnetic waves respectively, strike at least one chipequipped with photodiodes. However, a plurality of chips
may be provided according to the invention. The photoexci-
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tation transmitted from the chip is fed to a spectral
analysis unit, whereby the gray light is supplied to a cut-
off filter or a texture filter. The spectral analysis is
hereby preferably carried out electronically. The features
thus obtained, preferably any, but also individually, or
the combination of two features, namely spectral light,
object contour provided by the cut-off filter and surface
structure of the object provided by the texture filter, can
now be compared with corresponding data memorized in a data
memory. After identification of the object, the electronic
signal processing can transmit at least one specific signal
in order to initiate certain sequence steps, the sorting
out of an identified object being a particularly important
sequence step.
As a matter of principle, further method and device fea-
tures such as phase shifting and other features suitable
for object identification may be used in addition to the
mentioned features.
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The method according to the invention and the device
according to the invention are of special importance in
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identifying objects from waste mixtures and sorting out
such objects. It is well k wn that sorting out pure grades
of plastics from plastic waste mixtures is of speciàl
importance in view of recycling synthetic materials.
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The sorting out operation according to the state of the art
may be differently performed, e.g. pneumatically, hydrauli-
cally, mechanically or otherwise. Object identification and
sorting out are particularly improved by separating the
~ objects from an object mixture and waste mixture respec-
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tively, for instance on a conveyor belt, before applying
the method according to the invention.
The work according to the invention is preferably executed
with visible light, however, W and IR light according to
- the invention may be also used with excellent results.
The method according to the invention permits to reliably
identify plastics on the basis of the features according to
the invention, and this without generation of object images
and memorization of which in a data base. Thus, grade-pure
plastics can be recovered and supplied to a correspondingly
high-quality reutilization.
The present invention relates to a device to identify
objects which comprises a radiation source for electromag-
netic waves from W to IR ranges and an electronic signal
processing unit, characterized by at least one chip
equipped with photodiodes for receiving electromagnetic
waves incidenting from a radiated object, a means for
spectral light analysis and/or a cut-off filter and/or a
- texture filter for receiving and processing the photoexci-
tation supplied by the chip as well as a signal processing
system with data memory, in which the spectral light and/or
the object contour provided by the cut-off filter and/or
the surface structure provided by the texture filter are
compared with memorized data, whereby the signal processing
system is capable to initiate certain sequence steps
defined by at~least one signal after object identification.
Sorting out the identified objects is the preferred
sequence step.
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As already mentioned above, it is preferred to connect a
separating means for separating objects from an object
mixture in series with the device.
The invention relates further to the application and use of
the method and device for identification, and identifica-
tion and sorting out of objects, respectively.
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