JPH029710B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polarization-type egg checking device that optically detects eggs in which the yolk is partially mixed in the egg white after breaking (so-called disordered eggs).

Food manufacturing industries that manufacture confectionery, mayonnaise, dressings, etc. often use eggs as a raw material. Eggs used as raw materials for these foods are roughly divided into three types depending on the state of use: those that use only the egg yolk, those that use only the egg white, and those that use the egg yolk and white as whole eggs.
In order to use eggs in the former two ways, it is necessary to separate the cracked eggs into yolks and whites. Currently, this separation process is automated using a separate type egg breaking machine, but the yolk and egg white are not completely separated during this separation process, and the yolk is partially mixed into the egg white. There is. Eggs in this state are conventionally called "disturbed eggs," but the disturbed egg whites are
Since it is a defective product for raw materials consisting only of egg whites, it is necessary to remove it before it is mixed into raw materials consisting only of egg whites. Removal of disturbed egg whites has traditionally been carried out by workers visually monitoring the process, but since this method relies on human judgment, it speeds up the egg-breaking process. This has led to a decrease in work efficiency.

Against this background, in order to automate the detection of disturbed eggs, egg checking devices using polarized light are being considered. The configuration and measurement principle of such an apparatus will be explained with reference to FIG. 1. 1 is a light source 11 and a polarizer 1
2 is a sample egg white, 3 is an analyzer, 4 is a detection means that converts the detected light into an electrical signal, and 5 is a determination section that receives the electrical signal and measures "disturbance". It is. Here, for convenience of explanation, the polarizer 12 is set to transmit only linearly polarized light having an oscillating component of an electric field perpendicular to the light incident plane (plane of paper), and the analyzer 3 It is assumed that the setting is made so that only linearly polarized light beams whose vibration direction is shifted by 90 degrees from the vibration direction of , that is, linearly polarized light beams having a vibration component parallel to the incident plane, are transmitted. In this setting, first, the light beam from the light source 11 passes through the polarizer 12 and becomes linearly polarized light with the vibration direction perpendicular to the plane of incidence, and the sample egg white 2
It is incident on and is scattered and reflected. When measurements are performed under conditions where there is no influence of disturbance light, the incident linearly polarized light is scattered and reflected, and the polarization is partially canceled, resulting in a polarized light whose vibration direction is parallel to the plane of incidence in the scattered reflected light. The reflected light is detected by the detection means 4 only when it is included. Egg yolk has a strong property of scattering and reflecting light, and also has a property of almost eliminating polarization when polarized light is reflected. On the other hand, since egg white is transparent, it has a weak property of scattering and reflecting light, and does not have the property of depolarizing polarized light when it is reflected. Therefore, when the sample egg is only the albumen, the linearly polarized light rays irradiated to the albumen are not scattered and reflected very much, and the polarization is not canceled much, so the number of rays passing through the analyzer 3 is small, while the sample egg When the egg is a disordered egg with yolk mixed in, many of the rays pass through the analyzer 3 because the yolk scatters and reflects the irradiated linearly polarized light well and also cancels the polarization well. In this way, since the amount of reflected light differs between those with and without egg yolk mixed in, it is possible to determine the presence or absence of "disturbance". Specifically, the determination section 5 makes the determination based on the output signal from the detection means 4.

However, the above-mentioned egg checking device had the following drawbacks. That is, when eggs are broken using an egg breaking machine, a portion of the eggshell often gets mixed into the egg white.
However, since eggshells are white, they scatter and reflect light more than egg yolks, and they also have the property of depolarizing light.
For this reason, egg yolk and egg shell give similar detection outputs and cannot be distinguished, so even if a very small amount of egg shell is mixed into the egg white, it will be erroneously detected as a "disturbance". However, unlike egg yolks, eggshells can be removed in later processes through methods such as filtration, so egg whites contaminated with eggshells do not originally need to be removed as defective products. If it is determined to be "disturbed" and removed, the yield will be considerably low.

The present invention has been made under these circumstances, and is an egg checking device that can automatically detect disturbed eggs with high reliability, and can provide a practically efficient yield. The purpose is to provide the following.

The gist and measurement principle of the present invention will now be explained. The present invention has been made by focusing on the fact that the eggshell is white and the egg yolk is yellow. In other words, since the eggshell is white, it can absorb the entire wavelength range of visible light (400~
700nm), but because egg yolk is yellow, it absorbs specific wavelengths. Figure 2 is a graph showing an example of the absorption spectrum of egg yolk. In this example, the absorption spectrum is about 400 to 500 nm.
It has an absorption peak at Therefore, in the present invention, the first detection section has a light reception sensitivity within the wavelength range of light absorbed by egg yolk, and the first detection section has light reception sensitivity within a visible light wavelength range excluding the wavelength range of light absorbed by egg yolk. The second detection section is included in the detection means. For example, as shown in FIG.
The light-receiving sensitivity characteristic of the detection unit is assumed to be a latency shown by B. By the way, in the conventionally proposed device, the detection part has light reception sensitivity over the entire wavelength range of visible light, so the reflected light is proportional to the degree of scattering and the degree of depolarization in the sample albumen, regardless of whether it is egg yolk or eggshell. However, in the present invention, the above-mentioned two detection sections are used and the detection results of each detection section are combined, so that the egg yolk and the egg shell can be distinguished. In other words, the first detection section, which has the light receiving sensitivity characteristic indicated by A in Figure 3, only detects light in the wavelength range of 400 to 500 nm, so a white object like an eggshell will detect visible light in the 400 to 700 nm wavelength range. Since light is scattered and reflected over the entire wavelength range, the reflected light is detected, but since the egg yolk absorbs light in the wavelength range of 400 to 500 nm, the reflected light is not detected. On the other hand, in the second detection section having the light receiving sensitivity characteristic indicated by B,
Since there is no absorption peak in the wavelength range of 500 to 700 nm, both reflected lights are detected. Therefore, 2
If both of the two detection units detect reflected light with a larger amount of light than the reflected light of the egg white, it is determined that it is an egg shell, and the reflected light detected by the first detection unit is equal to the amount of reflected light of the egg white. If they are substantially the same and the amount of reflected light detected by the second detection unit is greater than the amount of reflected light from the egg white, it is determined that it is the egg yolk, and in this way, the egg yolk and eggshell can be distinguished. .

Next, examples of the present invention will be described.

4 and 5 are a configuration diagram and a block diagram, respectively, schematically showing an egg checking device according to an embodiment of the present invention, and the same reference numerals as in FIG. 1 indicate the same or corresponding parts. The polarized light beam unit 1 consists of a light source 11, a lens 13, and a polarizer 12. The light source 1 may be a tungsten lamp, a halogen lamp, or a Canon lamp, which has a continuous spectrum in the wavelength range of visible light of about 400 to 700 nm, for example. , or a high-pressure mercury lamp or the like is used.

The detection means 4 includes a condenser lens 41 that condenses the light beam from the analyzer 3, and a beam splitter 4 that splits the light beam condensed by the condenser lens 41 into two.
2, and a first detection section 6 and a second detection section 7 that respectively detect the two light beams separated by the beam splitter 42 and convert them into electrical signals. Here, the analyzer 3 is set to transmit only the light beam in the vibration direction shifted by 90 degrees from the vibration direction of the light beam from the polarizer 12. The first detection unit 6
consists of an optical filter 61, a light-receiving element 62 that converts the light from the optical filter 61 into an electrical signal, and an amplifier 63. Due to the combination of the optical filter 61 and the light-receiving element 62, the light-receiving sensitivity characteristics of the first detection section 6 are as follows. The characteristics as a whole are shown by A in FIG. Therefore, the first detection unit 6
In this case, light in the wavelength range of 400 to 500 nm will be detected. The second detection section 7 similarly includes an optical filter 71, a light receiving element 72, and an amplifier 73, and the overall light receiving sensitivity characteristic is as shown by B in FIG. 3. Therefore, the second detection section 7 detects light in the wavelength range of 530 to 700 nm.

The determining unit 5 compares the output signal from the amplifier 63 of the first detecting unit 6 with a predetermined threshold, and when the output signal exceeds the threshold, the output terminal is turned ON and the detection signal is output. The first comparison circuit 51 outputs
The output signal from the amplifier 73 of the second detection unit 7 is compared with a predetermined threshold value, and when the output signal exceeds the threshold value, the output terminal is turned ON and a detection signal is output. It consists of a second comparison circuit 52 and a determination circuit 53 that determines whether egg yolk is mixed into the egg white based on the comparison results of the two comparison circuits 51 and 52. 54 and 55 are setting circuits for setting threshold values, and the threshold value set by one of the setting circuits 54 is, for example, when scattered reflected light from egg white enters the first detection unit 6. Time first detection unit 6
The threshold value set by the other setting circuit 55 is set to a value slightly larger than the output signal of the second detection section 7 in the same case. The setting circuit 53 outputs a disturbance detection signal only when the output terminal of the first comparison circuit 51 is OFF and the output terminal of the second comparison circuit 52 is ON.

In the above, the combination of the optical filter and the light-receiving element allows each detection section 6, 7 to
The optical filter used in this combination is a colored glass filter for three-color separation, a sharp-cut colored glass filter, or a colored glass filter with a multilayer deposited film formed thereon. A photodiode, a phototransistor, a CdS, a phototube, a photomultiplier tube, etc. can be used as the light receiving element. As the polarizer and analyzer, a plastic sheet-type polarizing plate, a polarizing prism, a pile-type polarizer, or other means for decomposing natural light into linearly polarized light can be used.

Next, the operation of the egg checking device having such a configuration will be described. A light beam from a light source 11 is converted into a linearly polarized light beam by a polarizer 12, and this light beam is irradiated onto the egg white. When the egg yolk is mixed in the egg white, the linearly polarized light is well scattered and reflected in the egg yolk, and the polarization is well resolved. The number of linearly polarized light rays in the direction of vibration that is shifted by a degree increases, and therefore the number of light rays passing through the analyzer 3 increases. The light beam passing through the analyzer 3 is then split into two parts by the beam splitter 42.
The light beam is split into two light rays, one of which enters the first detection section 6 and the other light ray enters the second detection section 7 . The light beam incident on the first detection section 6 passes through an optical filter 61 and is converted into an electrical signal by a light receiving element 62, and this electrical signal is amplified by an amplifier 63 and used as an output signal of the first detection section 6. Further, the light beam incident on the second detection section 7 is similarly converted into an electric signal, and is emitted from the amplifier 73 as an output signal of the second detection section 7. And as mentioned earlier, the egg yolk
Since it absorbs light in the wavelength range of 400 to 500 nm, the light beam incident on each detection section 6 and 7 is 400 to 500 nm.
Although the light in the wavelength range of m is missing, the light receiving sensitivity of the first detection section 6 is in the wavelength range of 400 to 500 nm, so the magnitude of the output signal from the first detection section 6 is extremely large. It is smaller than the threshold value.
Therefore, the first comparison circuit 51 does not generate a detection signal. On the other hand, the light receiving sensitivity of the second detection section 7 is
Since the wavelength range is from 530 to 700 nm, the output signal from the second detection section 7 has a magnitude exceeding the threshold value, and therefore, a detection signal is generated from the second comparison circuit 52. The result determination circuit 53 determines that the egg is a disturbed egg and issues a disturbance detection signal. On the other hand, when there is no egg yolk mixed in the egg white but there is egg shell mixed in, the linearly polarized light is well scattered and reflected by the egg shell, and the polarization is well resolved. As a result, the detector 3 More rays of light pass through. However, unlike the case of egg yolk, the light scattered by the eggshell includes the entire range of visible light wavelengths, so the output signal of the first detection section 6 and the output signal of the second detection section 7 both reach the threshold value. Therefore, both of the two comparison circuits 51 and 52 generate a detection signal. The result determination circuit 53 does not determine that the egg is a disturbed egg and does not issue a disturbance detection signal. In addition, if neither the egg yolk nor the shell is mixed in the egg white, the egg white has a weak light scattering property and does not have the property of canceling polarization, so the number of light rays passing through the analyzer 3 is small. Since both the output signal of the first detection section 6 and the output signal of the second detection section 7 are smaller than the threshold value,
Neither of the two comparison circuits 51 and 52 generates a detection signal, and the determination circuit 53 does not generate a disturbance detection signal.

FIG. 5 shows the results of measurements carried out using the apparatus of the above embodiment, which uses a plastic sheet polarizing plate as a polarizer and a detector, a colored glass filter as an optical filter, and a photodiode as a light receiving element. It is a graph, and the vertical axis of this figure shows the ratio of the detection output with the detection output of albumen as 1, and the horizontal axis shows the diameter of the egg yolk or egg shell mixed in the sample albumen. In addition, in the figure, the white circles are the outputs when the yolk is detected by the first detection unit, the black circles are the outputs when the yolk is detected by the second detection unit, and the white triangles are the outputs when the yolk is detected by the second detection unit.
The black triangle indicates the output when the eggshell is detected by the second detection section, and the black triangle indicates the output when the second detection section detects the eggshell. The white squares indicate the first detection unit and the second detection unit.
This shows the output when egg white is detected by the detection unit. As can be seen from this result, the above output ratio of the first detection section is approximately 1 and does not change for egg yolk, regardless of the amount, whereas for egg shell, it sharply changes as the amount of contamination increases. Because it grows to
When egg yolk is mixed in, there is no risk of the first comparison circuit emitting a detection signal regardless of the amount, and when egg shell is mixed in, even if the amount is small, the first comparison circuit will not emit a detection signal. The detection signal is reliably emitted by the circuit, and as can be seen from the black circle and black triangle graphs, the output ratio of the second detection section increases in the same manner regardless of whether egg yolk or egg shell is mixed in. Therefore, by combining the detection results of the two detection units, it is possible to reliably distinguish between egg yolk and egg shell. In contrast, conventionally proposed devices detect light over the entire visible wavelength range, so the output ratio of the detection section is similar to that shown by the black circles and black triangles for egg yolk and egg shell, respectively. Since the output ratios are similar to each other, it is practically impossible to distinguish between egg yolk and egg shell.

As described above, in the present invention, since the presence or absence of egg yolk contamination is determined using an optical method, the detection of disturbed eggs can be automated and the detection speed is high. It is possible to increase the speed of the line and improve work efficiency compared to the case where this method is used. Furthermore, we focused on the fact that the eggshell reflects all visible light, while the yolk absorbs specific wavelengths, and we developed a first detection section that has light-receiving sensitivity within the wavelength range of the light that the egg yolk absorbs. A second detection section that has light reception sensitivity within the visible light wavelength range excluding the wavelength range is provided, and the detection results of the two detection sections are combined to determine the presence or absence of egg yolk contamination. and egg shells can be reliably distinguished. Therefore, there is no risk of erroneously determining that egg whites containing eggshells are disordered eggs, and disordered eggs can be detected with high reliability, and as a result, the yield of egg whites is improved. In addition, when eggshells are mixed in, the output signals of the two detection parts each exceed the threshold, so if a signal for determining whether eggshells are mixed in is output at that time, it can be used as an eggshell detection device. Can also be used.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing a conventionally proposed egg checking device, Fig. 2 is a graph showing an example of the absorption spectrum of an egg yolk, Fig. 3 is a graph showing an example of the light receiving sensitivity characteristics of the detection section, and Fig. 4 5 is a block diagram showing the egg checking device according to an embodiment of the present invention, FIG. 5 is a block diagram showing the same device, and FIG. 6 is a graph showing an example of measurement results by the same device. DESCRIPTION OF SYMBOLS 1... Polarized light source part, 2... Sample egg white, 3... Analyzer, 4... Detection means, 5... Judgment part, 6... First detection part, 7... Second detection part, 11... Light source, 12... Polarizer, 42... Beam splitter, 51... First comparison circuit, 52... Second comparison circuit, 53... Judgment circuit, 61, 71... Optical filter, 62, 72... Light receiving element.

Claims (1)

[Claims] 1. A polarized light source for irradiating linearly polarized light onto the egg white after breaking, an analyzer that transmits the reflected light reflected from the albumen by the irradiation of the light from the polarized light source, and this analyzer. a beam splitter that splits the transmitted light beam into two; and a beam splitter that has a light-receiving sensitivity within the wavelength range of light absorbed by the egg yolk and receives one of the light beams split by the beam splitter and converts it into an electrical signal. a first detection section, and a second detection section that has light receiving sensitivity within the visible light wavelength range excluding the wavelength range of light absorbed by egg yolk, and that receives the other light beam split by the beam splitter and converts it into an electrical signal. The second detection unit compares the output signal of the first detection unit with a predetermined threshold value, and also compares the output signal of the second detection unit with a predetermined threshold value, and compares these. An egg checking device comprising: a determining section that determines whether or not egg yolk is mixed into egg white based on the results.