JPS6242080A - Fish egg detecting device - Google Patents

Abstract

PURPOSE:To identify whether there are fish eggs or not stably with simple constitution by determining and deciding variation in attenuation characteristics due to a difference in organization structure among fish bodies on the basis of the waveform of a received ultrasonic pulse train. CONSTITUTION:The pulse train waveform of the 1st pulse reflected by fish and received by a receiving transducer 3 and many pulses which are reflected, delayed, and attenuated at the boundary between flesh and eggs, particle boundary parts of the eggs, etc., is written in a memory 11. The 1st pulse position detecting circuit 12 detects the propagation time of the 1st pulse from the storage contents of the memory 11 and an attenuation quantity calculating circuit 13 digitizes the quantity of attenuation of a received pulse train within a constant time after the 1st pulse. Then, the output numeral of the circuit 13 is normalized by a normalizing circuit 14 with the reciprocal of the propagation time sent out of the circuit 12 to determine the quantity of attenuation of the received ultrasonic wave train which varies according to the difference in organization structure among fish bodies which is not affected by the thickness of the eggs. This quantity of attenuation is compared with a threshold value and a decision circuit 15 identifies whether there are fish eggs or not with the simple constitution.

Description

[Detailed Description of the Invention] [Summary] A fish body is inserted between a transmitting transducer that sends out ultrasonic pulses and a receiving transducer facing the transmitting transducer, and the ultrasonic pulses propagating through the fish body are Multiple ultrasonic pulse sequences are input to the receiving transducer by being reflected and scattered within the fish body, but the attenuation characteristics of the received waveform formed by these multiple ultrasonic pulse sequences differ depending on the presence or absence of fish eggs. Therefore, by extracting the feature quantity of this attenuation characteristic and the propagation time of the ultrasonic pulse propagating through the fish body,
The presence or absence of fish eggs is detected by obtaining numerical values of feature quantities that do not depend on the thickness of the fish body.

[Industrial application field]

The present invention relates to a fish roe detection device that detects the presence or absence of fish eggs based on the propagation state of an ultrasonic pulse that passes through the abdomen of a fish. The present invention relates to a fish roe detection device that makes it possible to detect fish eggs by normalizing the attenuation characteristics of a pulse sequence generated by being reflected in a fish body.

In the fisheries industry, eggs are removed from captured fish and sold as cod roe, shiko, etc.

Therefore, it is necessary to determine the sex of captured fish, and it is desired to be able to detect the presence or absence of fish eggs using a simple method.

[Conventional technology]

Conventionally, in order to detect the presence or absence of fish eggs, the abdomen of the fish was incised and the fish eggs were visually confirmed. Methods to detect the presence or absence of eggs are being considered.

(Method for determining the sex of fish and shellfish, JP-A-54-29797 and JP-A-57-37387) [Problems to be solved by the invention] The method of incising the abdomen of a fish does not damage the fish; Also, since the presence or absence of fish eggs is detected manually, there is a problem in that processing time and labor are required.

In addition, identification using ultrasonic hologram images requires the fish body to be placed in the water, which requires a dedicated aquarium, and image processing, which requires two-dimensional image memory, etc., making the system difficult to identify. The problem is that the scale of the project is large and it is not practical.

In view of these problems, the present invention takes advantage of the fact that when an ultrasonic pulse propagates through the Mi weave of a fish body, there are differences in the attenuation characteristics of the pulse series that are reflected and generated due to differences in the M weave structure. It is an object of the present invention to provide a fish roe detection device with a relatively simple configuration that extracts stable feature quantities for identifying the presence or absence of fish eggs from the received waveform of a sound wave pulse.

[Means for solving problems]

FIG. 1 is a block diagram of the principle of the present invention.

The transmitting transducer 2 and the receiving transducer 3 have their central axes aligned, and the abdomen 7 of the fish body is inserted between them.

The pulse generating circuit 1 repeatedly sends out electric pulses at regular intervals, and these electric pulses are sent to the transmitting transducer 2 and the determining section 5. This electric pulse is converted into an ultrasonic pulse by the transmitting transducer 2 and sent to the abdomen 7 of the fish body. This ultrasonic pulse passes through meat 8 and fish eggs 9,
The received waveform is received by the receiving transducer 3, converted into an electrical signal, and input to the receiving amplifier 4, where the received waveform is amplified and sent to the determining section 5.

The ultrasonic pulse sent to the abdomen 7 by the transmitting transducer 2 is reflected at the first pulse attenuated by the meat 8 and the fish roe 9 and at the change point of the biological tissue of the meat 8 and the fish roe 9, and is delayed and The signal is divided into a plurality of attenuated pulses and received by the receiving transducer 3.

The determination unit 5 uses the electric pulse sent out by the pulse generation circuit 1,
The propagation time of the fish body is detected from the first pulse received at the beginning of the ultrasonic pulse sequence input from the reception amplifier 4, and based on this propagation time, the pulse sequentially attenuates and the delay time is also determined following the first pulse. The attenuation characteristics of a plurality of sequentially longer pulse sequences are normalized, the presence or absence of fish eggs is determined, and the display unit 6
The configuration is such that it is displayed in

FIG. 2 is a diagram explaining the present invention in detail.

FIG. 2 (al shows the case where fish with eggs are inspected.

The ultrasonic pulses sent out from the transmitting transducer 2 travel straight in areas where the biological tissue is uniform as shown by the arrow, and partially travel at the boundary between the meat 8 and the fish roe 9 or at the boundary between each particle of the fish roe 9. is reflected or scattered, and the transmitted energy is attenuated.

The transmitted ultrasonic pulse is converted into an electrical signal by the receiving transducer 3, and FIG. 2 fb) is a diagram explaining the state of this received signal. If the horizontal axis is the propagation time t and the vertical axis is the voltage of the received signal, then first the receiving transducer 3
The first pulse ■ arriving at 1. has a propagation time 1. which is proportional to the thickness of the abdomen 7. After that, the signal is received by the receiving transducer 3 as shown in (■) in FIG. 2 (bl).

The ultrasonic pulse reflected twice by the boundary between the meat 8 and the fish roe 9 and the particles of the fish roe 9 is delayed, and multiple pulses are received in sequence following the first pulse (■), but since the scattering by the fish roe particles is large,
The attenuation of the received pulse is large, and the longer the delay time, the greater the attenuation is.

FIG. 2(C) shows a case where a milt (male) is examined.

The ultrasonic pulses sent out from the transmitting transducer 2 travel straight through areas where the living tissue is uniform, as shown by the arrow. Milt 1
Since pulse 0 has a thick core-like structure, there is relatively little scattering, and the first pulse ■ which arrives first is received after a propagation time t2, as shown by ■ in FIG. 2 [d].

The plurality of twice-repeated ultrasound pulse sequences received following the first pulse (2) are less attenuated within the milt 10 and have different attenuation characteristics from those in FIG. 2 ib).

By quantifying the attenuation characteristics of the received waveform formed by this ultrasonic pulse sequence, the presence or absence of fish eggs can be determined. By the way, since the amount of attenuation of the received ultrasonic pulse depends on the thickness of the abdomen 7 of the fish, this numerical attenuation characteristic L7 needs to be normalized by the thickness of the fish.

Due to the property that the propagation velocity of an ultrasound pulse in a living body is approximately constant, the above-mentioned time 1. and 2 are proportional to the thickness of the abdomen 7. Therefore, this time 1. Alternatively, by extracting t2 and normalizing the numerically expressed attenuation characteristic with this value, it is possible to obtain a numerical value that does not depend on the thickness of the fish.

The presence or absence of fish eggs can be determined by comparing this value with a certain threshold. That is, when it is smaller than the darkness value, there are fish eggs, and when it is larger than the darkness value, it is albino.

[Effect]

With the above configuration, the determination unit 5 digitizes the attenuation characteristic of the received waveform formed by the received ultrasonic pulse sequence,
By normalizing this value with the propagation time of the ultrasonic pulse, it becomes a value that is independent of the thickness of the fish body, and if it is smaller than a certain darkness value, it can be determined that fish eggs are present.

〔Example〕

FIG. 3 is a block diagram of a circuit showing an embodiment of the present invention.

The operations of the pulse generating circuit 1, the transmitting transducer 2, the receiving transducer 3, and the receiving amplifier 4 are the same as in FIG. The memory 1) of the determining section 5 starts capturing the received waveform sent out by the receiving amplifier 4 using the pulse sent out by the pulse generating circuit 1.

The first pulse position detection circuit 12 determines the propagation time of the first pulse from the received waveform stored in the memory 1), that is, as shown in FIG.
The propagation time t1 in FIG. 2(d) or the propagation time t2 in FIG. 2(d) is detected. The attenuation amount calculation circuit 13 digitizes the amount of attenuation in the received pulse train within a certain period of time after the first pulse.

That is, the amount of attenuation is calculated and quantified based on the envelope indicated by the dotted line fb) or fdl in FIG. The normalization circuit 14 normalizes the numerical value sent out by the attenuation calculation circuit 13 with the reciprocal of the propagation time sent out by the first pulse position detection circuit 12, and calculates a normalized attenuation amount that does not depend on the thickness of the fish body.

The determination circuit 15 compares the normalized attenuation amount sent by the normalization circuit 14 with a certain darkness value, and when it is smaller than this threshold value, it determines that there is a fish roe and displays it on the display section 6.

If it is larger than the threshold value, it is determined that there are no fish eggs, and the result is displayed on the display section 6.

C. Effects of the invention] As explained above, the present invention inserts a fish body between the transmitting and receiving transducer, and from the attenuation characteristics of the observed ultrasonic pulse sequence, numerical values that enable relatively simple and stable identification of fish eggs are obtained. Therefore, it is possible to provide a simple and efficient fish roe detection device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the principle of the present invention, FIG. 2 is a diagram illustrating the present invention in detail, and FIG. 3 is a block diagram of a circuit showing an embodiment of the present invention. In the figure, 1 is a pulse generation circuit, 2 is a transmitting transducer, 3 is a receiving transducer, 4 is a receiving amplifier circuit, 5 is a determination section, 6 is a display section, 7 is an abdomen of a fish body, 8 is a meat,
9 is a fish roe, 10 is a milt, 1) is a memory, 12 is a first pulse position detection circuit, 13 is an attenuation calculation circuit, 14 is a normalization circuit, and 15 is a determination circuit. Figure 5 1 Figure Detailed explanation of the present invention 2nd Flash

Claims (1)

[Claims] A transmitting transducer (2) that converts an electric pulse into an ultrasonic pulse and sends it to the abdomen of a fish body; Receiving transducer (to convert into electrical signal)
3), a pulse generation circuit (1) that sends an electric pulse to the transmission transducer (2), and an ultrasonic pulse sequence that combines the electric pulse sent by the pulse generation circuit (1) and the ultrasonic pulse sequence received by the reception transducer (3). a determination unit (5) for detecting fish roe in the abdomen of the fish body; A fish roe detection device characterized in that the presence or absence of fish roe is determined by determining the characteristic amount of the attenuation characteristic to be a value unrelated to the thickness of the abdomen of the fish body, based on the time it takes for the ultrasonic pulse to propagate through the abdomen of the fish body.