JPH0324271B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Application The present invention relates to a color sorting machine for sorting the colors of objects to be sorted, such as rice grains, and is particularly designed to automatically adjust the color sorting. This invention relates to an automatic adjustment device in a color sorting machine.

(b) Prior Art Conventionally, a color sorting machine has been known to have a configuration roughly shown in FIG. 6. In FIG. 6, the part surrounded by broken lines is the observation part 1 for observing the objects to be sorted, and this part is equipped with four light sources 2, a backlight plate 3, a lens 4, and an optical sensor 5. It is configured. Objects to be sorted 7 sequentially delivered from a chute 6 pass through the observation section 1 . The object to be sorted 7 is continuously irradiated with light of a constant intensity by the light source 2 while passing through the observation section 1, and is reflected by the backlight plate 3 to reduce the brightness of the background of the object to be sorted. The background light that gives the image is also illuminated. The light transmitted and reflected by the object to be sorted 7 is collected by the lens 4, received by the optical sensor 5, converted into an electrical signal, and sent to the amplifier 8 as a color display signal. This amplifier 8 is provided with a variable resistor 9 for gain adjustment, and the color display signal amplified here is sent to a comparator 10.
is applied to one of the input terminals. The comparator 10 compares the level of the color display signal with the sorting reference signal applied to the other input terminal, and if the level is higher than the reference level, outputs a defective product detection signal and sends it to the ejector 11.
is operated to send air and change the trajectory of the defective objects to be sorted that have passed through the observation section 1, thereby eliminating defective products.

Note that, as omitted in FIG. 6, the above-mentioned configuration is provided for each channel in a multi-channel machine.

FIG. 7 shows another configuration example of the observation section, in which a backlight light source 12 and a translucent plate 1 are used instead of the backlight plate 3 as backlight means for providing background light to the objects 7 to be sorted.
3 are provided.

(c) Problems to be solved by this invention In the color sorting machine described above, the sorting state of the color sorting machine may change due to changes in the type or color state of the objects to be sorted, or due to dirt on the light source 2, etc. . As a countermeasure for this, in particular, it is necessary to adjust the brightness of the light irradiated to the objects to be sorted, that is, the background light, to increase the difference between the peak values of good and defective products in the color display signal, and to increase the difference in the peak value of the non-defective products and defective products in the color display signal. It is necessary to adjust the screening reference signal applied to the comparator.

FIG. 8 shows changes in the waveform appearing in the color display signal due to the difference in brightness of the background light. Figure 8A shows a case where the background light irradiated to the object to be sorted is too bright, and therefore the color display signal is darker than level a indicating the background light (in the X direction in Figure 8). A waveform corresponding to the object to be sorted 7 appears, and among these waveforms, a waveform exceeding a certain level in the darkness direction is determined to be defective. FIG. 8B shows a case where the background light is almost adjusted to the brightness of the non-defective object 7 to be sorted, and in this case, the waveform corresponding to the non-defective object 7 is near level a, and the waveform corresponding to the non-defective object 7 is near level a. In the waveform corresponding to a non-defective product, the peak in the dark direction is emphasized, and the difference between the waveforms of the non-defective product and the defective product is shown to be large. FIG. 8C shows a case where the background light is too dark compared to the brightness of the object to be sorted 7. In this case, the waveform corresponding to the object to be sorted 7 is exposed in the brightness direction (Y direction in FIG. 8). Sorting item 7
It appears in a size proportional to the reflected light. In this way, in order to accurately sort the objects 7 into good and bad, it is necessary to
As shown in FIG. 8B, it is necessary to match the background light to the brightness of the object to be sorted.

The previously mentioned adjustment of the brightness of the background light and the level of defective product determination has traditionally been done manually, which not only is complicated and requires a lot of time and effort, but also reduces the sorting accuracy. There was a risk that it would happen.

The purpose of this invention is to be able to automatically provide background light with optimal brightness in a color sorter,
An object of the present invention is to provide an automatic adjustment device that can always maintain an optimal sorting state.

Another object of the present invention is to provide an automatic adjustment device in a color sorting machine that automatically creates an optimum sorting reference signal to be given to a comparator, thereby always maintaining an optimum sorting state. It is to be.

(d) Means for Solving the Problems In order to provide background light with optimal brightness, the automatic adjustment device of the present invention uses a signal sample that extracts a plurality of positive and negative peak values of a signal waveform in a color display signal. a circuit, an arithmetic circuit that calculates each arithmetic mean value of positive and negative sample values obtained from the signal sampling circuit, and further calculates a ratio of the positive and negative arithmetic mean values; A backlighting means is provided for controlling the backlighting means so that the ratio becomes a predetermined value, and adjusting the intensity of the background light to the objects to be sorted.

In addition, in order to automatically create an optimal selection reference signal, the automatic adjustment device of the present invention includes a signal sampling circuit that extracts a plurality of peak values of a signal waveform in a color display signal, and a signal sampling circuit that extracts a plurality of peak values of a signal waveform in a color display signal; It is equipped with a sorting standard generation circuit that generates a sorting standard signal for determining whether the object to be sorted is good or bad based on the distribution of the values and the number of samples and outputs it to the comparator.

(e) Effect By adjusting the backlight means so that the ratio of the arithmetic mean values of the positive and negative peak values of the signal waveform in the color display signal becomes a predetermined value, the background light is adjusted to an optimal state. As a result, the waveform of the object to be sorted in the color display signal is adjusted to the optimum state as shown in FIG. 8B.

In addition, by determining the distribution of the peak values of the signal waveform indicating the objects to be sorted in the color display signal together with the number of samples, it is possible to calculate the peak value distribution between the peak value distribution indicating good items to be sorted and the peak value distribution indicating defective items. A peak value with a relatively small number of samples compared to the distribution is determined as a selection reference value.

(F) Embodiment FIG. 1 shows a preferred embodiment of the color sorting machine of the present invention.
is omitted because it is the same as the configuration shown in FIG. FIG. 1 shows a multi-channel machine, in which the sorting operation of the objects to be sorted is performed for each channel. Each channel is provided with an optical sensor 5, an amplifier 21, a variable gain amplifier 22, a comparator 23, a signal sampling circuit 24, an ejector 11, a motor 25, and a background plate 3, and a control unit 26 is common to each channel. It is configured as follows.

The color display signal output from the optical sensor 5 is amplified by an amplifier 21, and its output is given to a variable gain amplifier 22. A gain control signal is input to the variable gain amplifier 22 from the control section 26, and the gain is adjusted in accordance with this gain control signal. The color display signal output from the variable gain amplifier 22 is applied to one input terminal of a signal sample circuit 24 and a comparator 23. A selection reference signal is input from the control unit 26 to the other input terminal of the comparator 23,
The comparator 23 compares the levels of the selection reference signal and the color display signal, and outputs a selection signal to the ejector 11.

FIG. 2 shows a configuration diagram of the signal sampling circuit 24, which is roughly composed of a positive side sampling circuit and a negative side sampling circuit.Since both circuits have the same configuration, the same parts are given the same reference numerals. The positive side sample circuit will be explained. The color display signal input to the signal sample circuit 24 shown in FIG.
The peak detection circuit 2 is taken out as shown in Figure B.
8 and a differentiating circuit 29. Differential circuit 29
differentiates the rectified signal shown in FIG. 3B and outputs the differentiated signal shown in FIG. 3C to the comparator 30. Comparator 30
is when the input differential signal switches from positive to negative,
That is, a sample pulse is output as shown in FIG. The delay circuit 31 delays the signal by a certain period of time as shown in FIG. 3E and supplies it to the peak detection circuit 28 as a reset signal. The peak detection circuit 28 detects the peak value of the input rectified signal and outputs it to the sample hold circuit 32, and is reset by the reset signal and prepared for peak detection of the next signal. As a result, the peak detection circuit 28
A peak detection signal shown in FIG. 3F is output from the peak detection signal shown in FIG. The sample hold circuit 32 holds the level of the peak detection signal as shown in FIG. 3G at the rising edge of the input sample pulse, and outputs it to the control section 26 as a positive peak value. In exactly the same way, in the negative side sample circuit, the peak value of the waveform on the negative side, that is, in the brightness direction from the level a indicating the background light of the color display signal, is extracted and output to the control section 26.

In FIG. 1, the control unit 26 is connected to the input/output port 3.
3, A/D (analog/digital) converter 34,
D/A (digital/analog) converter 35,
It is configured with a CPU (central processing unit) 36, a ROM (read only memory) 37, and a RAM (random access memory) 38. The positive and negative analog peak values output from the signal sampling circuit 24 are provided to an A/D converter 34, where they are converted into digital peak values.
It is given to the CPU 36. The CPU 36 includes an arithmetic circuit 36a that performs addition and division of peak values, a control circuit 36b that compares this arithmetic result with a predetermined value, and outputs the difference as a control signal to the input/output port 33, and a control circuit 36b that determines the magnitude of the peak value and its number. is stored in the RAM 38 to obtain the distribution of peak values and the number of peak values, and a sorting standard creation circuit 36c is provided that creates a sorting standard value for the objects to be sorted from this distribution state.

The input/output port 33 receives the control signal and outputs a gain control signal to the variable gain amplifier 22 or a backlight adjustment signal to the motor 25, respectively. The motor 25 rotates the backlight plate 3 by a predetermined amount in the forward or reverse direction according to the backlight adjustment signal. Further, the selection reference value outputted from the selection reference generation circuit 36c is converted into an analog signal by the D/A converter 35, and is provided to the comparator 23 as a selection reference signal.

The brightness of the background light is adjusted in detail as follows. Now, one channel in the color sorter mentioned above will be explained. Positive side peak values P ₊₁ , P ₊₂ ...P _+n and negative side peak values P _-1 , P _-2 , ... P _- given from the sample circuit 24 to the arithmetic circuit 36a of the control unit 26 Ratio of each average value of _o (P ₊₁ +P ₊₂ +...P _+n )/m/(P _-1 +P _-2 +...+P _-o )
/n is required. Then, in the control circuit 36b, in order for the ratio to be a constant value K (usually = 1),
A control signal is output. As a result, a backlight adjustment signal via the input/output port 33 is given to the motor 25 to rotate the backlight plate 3 to adjust the intensity of the background light, so that the ratio is equal to K, that is, the background light is the one to be sorted. It is automatically adjusted to match the brightness of the object.

The color sorting machine is a multi-channel machine, and the backlight plate 3 may not be provided for each channel, but a single backlight plate common to each channel may be used.
In this case, the angle of the backlight plate is adjusted so that K is the average value of the ratio of the average positive peak value to the average negative peak value for each channel extracted during a certain period of time. . That is, let the number of channels be I, and the positive peak value of each channel is 1P ₊₁ ...1P _+n1 , 2P ₊₁ ...2P _+n2 , IP ₊₁ ...
The negative peak value of IP _+nI is 1P _-1 ...1P _-o1 , 2P _-1 ...2P _-o2 , IP ₊₁ ...
If IP _-oI , {1P ₊₁ +1P ₊₂ +...+1P _+n1 )/m1/1P _-1 +1P _-2 +...
+P _-o1 )/n1+...+IP ₊₁ +IP ₊₂ +...+IP _+nI )/mI
The backlight plate is adjusted so that /IP _-1 +IP _-2 +...+IP _-oI )/nI}/I becomes K.

FIG. 4 shows a schematic circuit diagram of the control section of the color sorting machine when the light source 12 is used as a backlighting means as shown in FIG. 7. In FIG. 4, the input/output port 41 outputs the gain control signal, and the background light control signal output from the CPU 36 is converted into a voltage or current backlight adjustment signal by the D/A converter 42, and the backlight light source Twelve light intensity or background light adjustments are made.

In order to create a standard for determining good/bad, that is, a selection reference signal to the comparator 23, the signal sample circuit 2 is used.
4 to a certain time or a certain number of A/D converters 34
The peak value obtained through the selection standard creation circuit 3
6c, a distribution of the peak values and numbers, that is, a histogram as shown in FIG. 5 is created. In FIG. 7, the value in the valley between the large peak showing the distribution of peak values of good products and the small peak showing the distribution of peak values of defective products is detected, and this level value is calculated as D/
It is outputted as a selection reference signal to the comparator 23 via the A converter 35.

When the color sorting machine is a multi-channel machine,
In order to correct the difference in the level of the color sorting signal between each channel, the positive peak value P ₊₁ ...P _+n or the negative peak value P _-1 extracted by each signal sampling circuit 24 is used. +P _-2 +...Adjust the average value of +P _-o to a constant value C for each channel,
In other words, the control signal is output from the CPU 36 to the input/output port 33 so that (P ₊₁ +P ₊₂ ... +P _+n ) / mC or P _-1 +P _-2 ... +P _-o ) /n = C. The signal is then applied to the variable gain amplifier 22 as a gain control signal to adjust the gain. Note that comparator 2 is installed separately for each channel.
It is considered that the above-mentioned gain adjustment is unnecessary if a selection standard for 3 is provided and the selection standard signal is adjusted by the selection standard generation circuit 36c described above. However, as shown in FIG. 5, there are cases where good products and defective products cannot be clearly distinguished, and in this case, it is necessary to manually adjust the selection criteria while checking the selection results. In this case, it is advantageous to use a common selection criterion for each channel to eliminate differences between the channels, which simplifies the adjustment operation.

(g) Effects The present invention can automatically adjust the background light to the objects to be sorted in a color sorter, and can also automatically adjust the sorting reference value. Therefore, the complicated adjustment work that was conventionally performed manually is freed, and the optimum sorting condition is always automatically maintained even when the sorting condition of the color sorting machine changes due to dirt, etc. . For this reason,
Decrease in sorting accuracy can be prevented, and sorting can be performed with constant accuracy.

Further, the present invention extracts a plurality of positive and negative peak values of a signal waveform in a color display signal, calculates an arithmetic average value of each of the positive and negative sample values obtained from this signal sampling circuit, and and the negative arithmetic average value, and the backlighting means is controlled so that the ratio becomes a predetermined value, so adjustment can be made by increasing or decreasing the amount of objects to be sorted passing through the observation section. Operation is not affected. That is, for example, in a conventional adjustment operation using an average value of a color display signal or a rectified signal, the average value or rectified signal fluctuates due to fluctuations in the amount of objects to be sorted that pass through during the adjustment period, and the adjustment operation takes a long time. However, in the present invention, the adjustment operation is performed without being affected by fluctuations in the amount of passage.

[Brief explanation of the drawing]

FIG. 1 is a schematic system configuration diagram showing an embodiment of the present invention, FIG. 2 is a circuit configuration diagram of a signal sampling circuit, FIGS. 3A to 3G are waveform diagrams for explaining the operation of the signal sampling circuit, and FIG. Figure 4 is a diagram showing another embodiment of the control section of the color sorter, Figure 5 is a diagram showing the relationship between the peak value obtained from the sample circuit and the number of samples, and Figure 6 is an outline of a conventional color sorter. Diagram,
FIG. 7 is a diagram showing another configuration example of the observation section of the color sorter, and FIGS. 8A, B, and C are color display signal waveform diagrams for explaining the influence that the brightness of background light has on the color display signal. It is. 1...Observation section, 2...Light source, 3...Backlight plate, 5
... Optical sensor, 7 ... Object to be sorted, 12 ... Light source for backlighting, 13 ... Transparent plate, 22 ... Gain amplifier,
23...Comparator, 24...Signal sample circuit, 2
5...Motor, 26...Control unit, 33...I/O port, 36...CPU, 36a...Arithmetic circuit,
36b...Control circuit, 36c...Selection standard creation circuit, 38...RAM, 42...D/A converter.

Claims (1)

[Scope of Claims] 1. The objects to be sorted are sequentially passed through an observation section including a light source that irradiates the objects to be sorted with light of a certain intensity and backlighting means that provides background light to the background of the objects to be sorted; The object to be sorted is then judged as good or bad by condensing the light that passes through and reflecting through the object and converting it photoelectrically with an optical sensor, and comparing the level of the color display signal obtained with a sorting reference value. The color sorter includes a signal sampling circuit that extracts a plurality of positive and negative peak values of a signal waveform in the color display signal, and an arithmetic average value of each positive and negative sample value obtained from the signal sampling circuit. an arithmetic circuit that calculates the ratio of the positive and negative arithmetic mean values; and an arithmetic circuit that calculates the ratio of the positive and negative arithmetic mean values; An automatic adjustment device for a color sorting machine, comprising: a backlight adjustment means for adjusting the brightness; 2. The automatic adjustment device according to claim 1, wherein the signal sample circuit includes a rectifier circuit, a peak detection circuit, a differentiation circuit, a comparison circuit, a delay circuit, and a sample hold circuit. 3. The backlight means is a backlight plate that reflects light in the direction to be sorted, and the backlight adjustment means includes a motor for changing the angle of the backlight plate in order to adjust the amount of reflected light. The automatic adjustment device according to item 1. 4. The automatic adjustment device according to claim 1, wherein the backlight means is a backlight light source, and the backlight adjustment means includes voltage or current control means for adjusting light emission of the backlight light source. 5. The color sorter is a multi-channel color sorter that detects whether the object to be inspected is good or bad in a plurality of channels, and the backlight means is common to each channel, and the signal sample circuit is used for each channel. The arithmetic circuit calculates the arithmetic mean value of all channels of the ratio of the arithmetic mean value of the positive and negative peak values for each channel, and the backlight adjustment means calculates the arithmetic mean value of the arithmetic mean value of all the channels. controlling the backlighting means so that the value becomes a predetermined value;
An automatic adjustment device according to claim 1. 6. The object to be sorted is sequentially passed through an observation section that includes a light source that irradiates the object to be sorted with constant light and a backlight means that provides background light to the background of the object to be sorted, and at this time, the object to be sorted is passed through and reflected. A color sorting machine that sorts out whether the object to be sorted is good or bad by comparing the level of the color display signal obtained by condensing the light and photoelectrically converting it with an optical sensor with a sorting reference value, the color display signal a signal sampling circuit for extracting a plurality of peak values of a signal waveform in the signal, and a sorting reference signal for determining whether the object to be sorted is good or bad is created based on the peak value obtained from the signal sampling circuit and the distribution of the number of samples. , and a selection standard creation circuit that outputs to the comparator, an automatic adjustment device for a color sorter.