WO2008059129A2

WO2008059129A2 - Tranparency analysis device

Info

Publication number: WO2008059129A2
Application number: PCT/FR2007/001783
Authority: WO
Inventors: Patrice Pennel
Original assignee: Patrice Pennel
Priority date: 2006-10-27
Filing date: 2007-10-29
Publication date: 2008-05-22
Also published as: FR2907900A1; FR2907900B1; WO2008059129A3

Abstract

The device for analysing the transparency of a product includes an analysis area (170) for containing a sample of said product, a matrix electronic image sensor (110) for providing a signal representative of an amount of light reaching the same and located on a first side of the analysis area, a light source (100) comprising at least one LED (105) provided on the other side of the analysis area and capable of illuminating the analysis area so that at least a portion of the light rays from the light source reaching the sample further reaches the image sensor, and a processing circuit (165) for receiving the signal provided y the image sensor and for processing at least the glare surface of said image sensor for determining the transparency of the sample in each transmission spectral range of each LED.

Description

TRANSPARENCY ANALYSIS DEVICE

The present invention relates to a transparency analysis device for solid products, fluid or complex, structured or not. It applies, in particular, to the transparency analysis of industrial liquids, especially for dyeing textiles.

In the field of the analysis of industrial liquids, spectrometers are known which provide a very precise analysis of the transparency of the liquid. However, these products are of a very high cost, of a certain fragility and a limited lifetime. They remain, therefore, confined to industrial laboratories and do not allow the enslavement of processes in real time.

Document PCT FR2004 002706, filed on October 21, 2004, discloses the use, for the purpose of monitoring the exhaustion of a dyeing or rinsing bath, of an analysis chamber, an image sensor, a source of light in such a way that the light source is, according to the pixel of the image sensor surface, at different distances and / or at different solid angles in proportions of at least one to ten . An image processing is then performed to select the signals from the image sensor points which exploit the dynamics of the image sensor and which are not influenced by image points undergoing too much illumination. Preferably, excess electrical charges are eliminated and these are not likely to disturb the transparency measurement. Avoiding any glare effect reduces the dynamics of the device. In addition, the respective positioning of a sensor and a light source around a very hot fluid which comprises fibers may, on the one hand, obstruct the space between the sensor and the source and, d on the other hand, to damage the sensor for temperature reasons.

The present invention aims to remedy these disadvantages. For this purpose, according to a first aspect, the present invention aims a device for analyzing the transparency of a product, characterized in that it comprises: an analysis zone adapted to retain a sample of said product,

a matrix electronic image sensor adapted to supply a signal representative of a quantity of light reaching it, placed on a first side of the analysis zone, a light source composed of at least one light-emitting diode placed on the other side of the analysis zone and capable of illuminating the analysis zone so that at least a portion of the light rays originating from the light source reaching the product sample then reaches the image sensor and - a processing circuit adapted to receive the signal provided by the image sensor and to process at least the glare surface of said image sensor to determine the transparency of the sample, in each emission spectral range of each light-emitting diode.

Thanks to these provisions, the dynamic glare of the sensor is exploited and allows an accurate estimation of the transparency of the sample. In addition, the components used are commonly sold in the consumer market, they do not represent a high cost and allow implementation of the device on industrial machines for real-time monitoring of their operation and, possibly, for enslavement of this operation. According to particular features, the device which is the subject of the present invention, as briefly described above, comprises a means of focusing the light coming from the light source on the image sensor. Thus, the image of the light source is sharp on the image sensor and the glare halo appears around this sharp image faster than when the light rays from the light source are scattered on the surface of the sensor image. The device object of the present invention thus has a better dynamic.

According to particular features, the light source comprises at least one light-emitting diode adapted to emit successively in several spectral ranges, the device as briefly described above comprising means for controlling the spectral range of emission of the light source. , the processing means being adapted to successively process the signals provided by the image sensor for the different spectral ranges.

According to particular characteristics, the light source comprises at least two light-emitting diodes adapted to emit, each in a different spectral range, the device as briefly described above comprising a means for controlling the spectral range of emission of the light source, the processing means being adapted to successively process the signals provided by the image sensor for the different spectral ranges.

Thanks to each of these arrangements, the device as succinctly described above can adapt to different products, or different colors, to analyze more finely their density or their evolution. According to particular features, the device as briefly described above further comprises means for sampling the product and means for removing the sample after analysis.

According to particular features, the processing means is adapted to process the evolution of the transparency of the sample and to emit a signal according to this evolution.

According to particular features, the processing means is adapted to compare the value of the transparency with a predetermined transparency limit value and to emit a variable signal according to the respective position of these transparency values.

According to particular features, the processing means is adapted to compare the value of the speed of evolution of the transparency with a predetermined value of speed of evolution and to emit a variable signal according to the respective position of these values of speed. According to particular features, the processing means is adapted to determine said predetermined value during an initialization phase as a function of the transparency of a sample.

Thanks to each of these provisions, the operator of the device can be automatically notified of the occurrence of an event represented by the value of transparency or by the value of its speed of evolution and consequently act on an industrial process. , such as, for example, automatically stop, by the device, a dyeing or rinsing phase of dyeing machine.

According to particular features, the processing means is adapted, for processing the glare surface, to measure the surface of the image sensor for which this sensor provides a signal greater than a predetermined value.

Thanks to these provisions, the treatment is easy, fast, efficient, reliable, not very sensitive to noise and economical in terms of means implemented.

According to particular features, the processing means is adapted to measure the average illumination of a portion of the surface of the image sensor for which the signal from the image sensor represents an illumination greater than a predetermined value.

Thanks to these arrangements, even when the image sensor is not, or little, dazzled, the transparency of the sample can be estimated. The dynamics of the device is thus improved. According to particular characteristics, the treatment means is adapted to determine the end of a dye bath or rinse exhaustion process by putting a predetermined number of spectral ranges lower than the number of emission spectral ranges of the light-emitting diodes.

According to particular features, the device which is the subject of the present invention, as briefly described above, comprises means for determining said predetermined number as a function of at least the type of process and a dye color used and / or an initial concentration of dye in the bath.

Thanks to each of these provisions, the device adapts to different types of processes and color and / or concentration conditions to consider without always taking into account all the spectral ranges that can be implemented. Other advantages, aims and features of the present invention will emerge from the description which follows, made for an explanatory and non-limiting purpose with reference to the accompanying drawings, in which: FIG. 1 represents, schematically, an embodiment of the invention; device object of the present invention; FIG. 2 represents, in the form of a logic diagram, the steps implemented by the embodiment of the device illustrated in FIG.

FIGS. 3A to 3C show, schematically, the treatment of the illuminations received successively by an image sensor and their processing.

FIG. 1 shows a light source 100 illuminating, via an optical system, an image sensor 110 provided with a lens 115. The optical system comprises, in particular, a convergent lens 120 and a lens. diverging lens 125 surrounding a light pipe 145. The light pipe 145 is separated from a sample pipe

150 through two blades 140. The intersection of the two conduits forms an analysis zone 170. The sample conduit 150 is from a sample collection means 135 to a sample discharge means 155. The source 100 comprises a plurality (here ten) of light-emitting diodes 105 and an emitted spectral range control means

160. A signal processing means 165 receives and processes the signals from the image sensor 110 to determine the transparency of a sample placed in the analysis zone.

170, in a spectral range emitted by the light source 100. The image sensor 110 provided with the objective 115 comprises a matrix image sensor and is, for example, a monochrome sensor camera, for example similar to the cameras. video doorkeepers. Preferably, the image sensor 110 has no filter eliminating infrared rays so that the device can determine the transparency of the sample, in the analysis zone 170, not only in the visible range, but also in the the near infrared. The optical system, including the camera lens, the converging lens 120 and the diverging lens 125 forms an image of the light source at the photosensitive surface of the image sensor 110. The lens divergent 125 forms a virtual image 130 of the light source 105 so that light rays from the light source 105 can enter the light conduit 145. The convergent lens 120 has a focal length equal to the distance between this virtual image 130 and the lens 120. Preferably, the blades 140 are transparent throughout the emission domain of the light source 100 and received by the image sensor 110. The sample collection means 135 is adapted to taking a sample, in particular of liquid product, in a product stream. For example, the sample collection means 135 comprises a solenoid valve connected at its inlet to a bath circulation circuit in a dyeing machine. The sample evacuation means 155 is adapted to evacuate the sample after analysis. For example, it comprises a solenoid valve connecting the conduit 150 to a sink. In the case where two solenoid valves are thus implemented, one in each of the sampling means 135 and the evacuation means 155, these solenoid valves are simultaneously open when the set of spectral ranges to be treated have been processed by the processing means 165.

Light-emitting diodes 105 have different spectral ranges. For example, each of the electroluminescent diodes 105 emits in a spectral range extending over 40 nanometers. Together, they cover virtually the visible range and the near infrared. In particular embodiments, at least one light-emitting diode 105 emits light in different spectral ranges, depending on its power supply, for example as a function of the voltage applied to these terminals. Thus, a reduced number of diodes 105 can be used while allowing transparency analysis in a large number of spectral ranges.

The control means 160 is preferably adapted to successively light each of the diodes 105 so that only one of them emits light at a given instant. The spectral range control means 160 emitted by the light source 100 is preferentially connected to the processing means 165 so that the spectral range changes are made between the instants of images analyzed by the processing means 165. the control means 160 receives, from the processor means 165, a switching signal indicating which of the diodes 105 is to be turned on.

Signal processing means 165 receives the signals from image sensor 110 and applies to them the processing steps described with reference to FIG. 2. Processing circuit 165 receives the signal provided by image sensor 110 and processes at least the glare surface of the image sensor 110 to determine the transparency of the sample, in each emission spectral range of each light-emitting diode. Preferably, means (not shown) for monitoring the temperature of the image sensor 110 and / or the signal processing means 160 are provided and, if a limit value is exceeded, a cooling means is triggered ( not shown), a warning means (not shown) of an operator and / or a stop of the operation of the device.

As illustrated in FIG. 2, during a step 205, the emission spectral range of the light source 100 is switched. For this purpose, according to the embodiments, the light-emitting diode 105 is switched on or a modification is made. power setting of a light-emitting diode on. Then, during a step 210, an image capture is performed by digitizing a signal representative of an image, or a frame, and placing in memory the digitized signal.

During an image 215, a first threshold value is applied to binarize the digitized signal, that is to say, to represent it by binary values, "0" or "1", indicating, for each pixel element if the value of the illumination received has exceeded the first threshold value. During a step 220, the area of the image sensor for which the image representative signal is greater than the first threshold value is determined by counting the number of pixels for which the binary value is "1". Optionally, preliminary to step 220, an analog or digital filtering of the image representative signal is performed. For example, to determine this surface of the image sensor, the number of image points (or "pixels") for which the illumination value is greater than the first threshold value is counted.

It can be observed that the light source is relatively punctual, by counting the number of image elements for which the signal coming out of the image sensor represents an illuminance value beyond the first threshold value. image elements for which local glare propagates. The glare of the image sensor is thus treated and thus exploits not only the dynamics of each point of the sensor but also the dynamic offered by the propagation of the effects of glare (in particular the effect known as "blooming" which consists in the fact that the excess of electric charges created in a picture element is poured, at least in part, on the neighboring picture elements).

Thus, the processing means or circuit 165 receives the signal provided by the image sensor 110 and processes at least the glare surface of the image sensor 110 to determine the transparency of the sample, in each spectral range of emission of each light emitting diode.

Then, during a step 225, it is determined whether the number of points for which the illumination value is greater than the first threshold value is less than a second value. threshold value. If no, go to step 240. If yes, during a step 230, select the image points for which the illumination value is greater than a third threshold value.

During a step 235, the average value of the illumination values of the image points selected during step 230 is determined.

During a step 240, the values obtained during steps 220 and, possibly, 235, values which are each representative of the illumination received by the image sensor 110 are stored.

Then, during a step 245, each of these values is compared with a fourth threshold value.

During a step 250, the evolution of the transparency is measured, for example by determining, for the. spectral range being analyzed, the difference between the values obtained in steps 220 and, optionally, 235, and the corresponding values obtained previously for the same spectral range. Then, during a step 255, this evolution, or difference, is compared with a fifth threshold value.

During a decision step 260, it is determined whether, for all the spectral ranges, the transparency value is greater than the fourth threshold value or the evolution is less than the fifth threshold value. If yes, during a step 265, a signal is transmitted, for example to stop a dyeing or rinsing procedure in a dyeing machine or to alert a user or operator of the device and a industrial machine from which the analyzed samples are taken.

Otherwise, or at the end of step 265, step 205 is returned to cyclically process another spectral range.

In FIG. 3A-3C, different absorbance curves are observed as a function of the spectral range, during an industrial process.

It can be seen in FIG. 3A that a single light-emitting diode 105 is first lit and produces a glare halo on the image sensor, a halo represented by a dark circle. The measurement of this halo is inserted, in ordinate, in a graph whose abscissa represents the spectral range (ten spectral ranges are used here).

It can be observed in FIG. 3B that only one other light-emitting diode 105 is then turned on and produces a glare halo on the image sensor, a halo represented by a dark circle. The measurement of this halo is inserted, in ordinate, in the graph whose abscissa represents the spectral range (ten spectral ranges are used here).

This is followed immediately for the other spectral ranges emitted by the light-emitting diodes 105 and the cycle is repeated continuously. A plurality of graphs are thus obtained (only two graphs are represented in FIG. 3C).

In the case of the detection of the exhaustion of a dyeing bath, when, for each spectral range, the evolution of the transparency has been negative or zero, between two successive graphs corresponding to a predetermined time interval, for example for one minute, it is considered that the bath is exhausted and a signal is sent indicating this event, for example to stop, purge and / or rinse a dyeing machine.

In a variant, the parameters of the choice of analyzed curves are automatically set to determine the change of slope, according to the color of the bath, by a command on the inputs of the card.

For depletion, the system determines a slope on programmable measurements (usually spaced ten seconds apart) and for a set threshold. When this threshold is reached for a spectral range, the system positions a flag. When six flags (resulting from six of the ten light-emitting diodes) are positioned, the system gives an output information that allows the associated automation to proceed to the next step, i.e., in particular, to consider that the dyeing phase is complete.

The tests carried out by the inventor show that, depending on the dyes to be made, it is necessary to be able to choose the threshold and the number of flags which, when it is reached, triggers the passage to the next step. If, for example, yellow is a dye that runs out less quickly than the others and if the desired final color is a dark color, a yellow dye residue in the bath will have no effect on the final shade of the fiber. On the other hand, if the desired color is a light green, the same residue will not be acceptable.

The levels of requirements therefore depend on the colors to be obtained and require appropriate programming.

In a variant, a learning programming system is provided, in particular when the device that is the subject of the present invention is used to determine an end of the rinsing period. In the calibration phase of the device, ^" this programming system can manually initiate the push button monitoring type for example" dark dye. "When the operator estimates the level of rinsing sufficient for this dye, it indicates, with a Another push button is the level of requirement that it considers sufficient for a dye of this intensity, and the system stores this threshold, and it does the same for a clear dye and an intermediate dye.

As a variant, when, after analysis of each spectral range, the average value of the evolution speed of the opacity of a bath (decreasing during a depletion, increasing during a rinsing) determined by considering, according to the opacity level of the color and / or depending on the color, a predetermined number of such changes in opacity is less than a given value, it is considered that the depletion or rinsing process is completed.

Thus, in variants, the treatment means 165 is adapted to determine the end of a dyeing bath or rinse-out process, by implementing a predetermined number of spectral ranges lower than the number of spectral ranges. emission of light-emitting diodes. Preferably, the device also comprises means for determining said predetermined number as a function of at least the type of process (bath exhaustion or rinsing) and a dye color used and / or an initial concentration of dye in the bath .

Claims

1 - device for analyzing transparency of a product, characterized in that it comprises: an analysis zone (170) adapted to retain a sample of said product, - a matrix electronic image sensor (110) adapted to supplying a signal representative of a quantity of light reaching it, placed on one side of the analysis zone, a light source (100) composed of at least one light-emitting diode (105) placed on the other side of the analysis zone and capable of illuminating the analysis zone so that at least a portion of the light rays from the light source reaching the product sample reaches, subsequently, the image sensor and a a processing circuit (165) adapted to receive the signal provided by the image sensor and to process at least the glare surface of said image sensor to determine the transparency of the sample, in each spectral emission range of each light emitting diode.

2 - Device according to claim 1, characterized in that it comprises a means for focusing the light from the light source on the image sensor.

3 - Device according to any one of claims 1 or 2, characterized in that the light source (100) comprises at least one electroluminescent diode (105) adapted to emit successively in several spectral ranges, the device as briefly described ci above comprising a control means (160) for the spectral emission range of the light source, the processing means (165) being adapted to successively process the signals supplied by the image sensor for the different spectral ranges. 4 - Device according to any one of claims 1 to 3, characterized in that the light source (100) comprises at least two light-emitting diodes (105) adapted to emit, each in a different spectral range, the device such as briefly described above comprising means (160) for controlling the spectral range of emission of the light source, the processing means (165) being adapted to successively process the signals supplied by the image sensor for the different spectral ranges.

5 - Device according to any one of claims 1 to 4, characterized in that it further comprises means (135) for sampling the product and means (155) for evacuation of the sample after analysis. 6 - Device according to any one of claims 1 to 5, characterized in that the processing means (165) is adapted to process the evolution of the transparency of the sample and to emit a signal according to this evolution. 7 - Device according to claim 6, characterized in that the processing means (165) is adapted to compare the value of the transparency to a predetermined limit value of transparency and to emit a variable signal according to the respective position of these values. transparency. 8 - Device according to claim 6, characterized in that the processing means (165) is adapted to compare the value of the speed of evolution of the transparency to a limit value of predetermined speed of evolution and to emit a variable signal depending on the respective position of these speed values.

9 - Device according to any one of claims 7 or 8, characterized in that the processing means (165) is adapted to determine said predetermined value during an initialization phase according to the transparency of a sample .

10 - Device according to any one of claims 1 to 9, characterized in that the processing means (165) is adapted, for treating the dazzle surface, to measure the surface of the image sensor (110) for which this sensor provides a signal greater than a predetermined value.

11 - Device according to any one of claims 1 to 10, characterized in that the processing means (165) is adapted to measure the average illumination of a portion of the surface of the image sensor for which the signal from the image sensor represents illumination greater than a predetermined value. 12 - Device according to any one of claims 1 to 11, characterized in that the processing means (165) is adapted to determine the end of a dye bath or rinse exhaustion process by implementing a predetermined number of spectral ranges lower than the number of emission spectral ranges of the light-emitting diodes. 13 - Device according to claim 12, characterized in that it comprises means for determining said predetermined number as a function of at least the type of process and a dye color implemented and / or an initial concentration of dye in the bath.