JP2650128B2 - Color display detection video signal processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a color display detection video signal processing apparatus for displaying the strength of a detection signal in different colors, such as a color fish finder and a color scanning sonar.

[0002]

2. Description of the Related Art In an underwater acoustic detector such as a color fish finder or a color scanning sonar, the level of a received signal fluctuates depending on the rolling and pitching of an equipped ship and the sea conditions. Therefore, signal averaging is indispensable to obtain a stable image. Therefore, as shown in FIG. 4, the received signal is converted by the A / D converter 5 into a digital signal having the number of color identification bits (for example, 3 bits in the case of 7-color identification) and storing the same number of bits. The data is stored in the device 6 and sent to the averaging circuit 7 having the same number of bits (for example, SN7483 manufactured by Texas Instruments).

An averaging circuit 7 performs an averaging of the digital signal from the A / D converter 5 and the digital signal one cycle before stored in the storage device 6 to obtain a color display detection video signal having the same number of bits. Output. For example, when the color display is a seven-color identification, the A / D converter 5 and the storage device 6 each have 3 bits, and the addition by the averaging circuit 7 results in 4 bits. 1 is discarded, that is, the lower one digit ($ 1) is cut off, so that a 3-bit color identification signal of $ 2, $ 3, and $ 4 can be obtained.

[0004]

However, if the larger one of the received signal levels changes in magnitude exceeds the maximum level represented by the number of bits of the A / D converter, the maximum level is reached. It is in a clipped state.

For example, the number of bits of the A / D converter is 3 bits, the level 0 of the input signal is 000, and the level 1 of the input signal is 00.
In the case where 1, the level 2 is 010, and the maximum level 7 is 111, all input levels exceeding the level 7 become 111 and are treated as the level 7. This is illustrated in FIG.

[0006] (a) and (b) in the figure are received signals. (C) is a waveform obtained by converting the received signal (a) into a digital signal using a 3-bit A / D converter, and (d) is a waveform obtained by converting the received signal (b) into a digital signal. Since the received signal (a) exceeds the maximum level 7,
The crossed portion has a waveform (c) clipped at level 111.

On the other hand, since the received signal (b) is smaller than the maximum level 7, the digitally converted waveform (d) is not clipped by 111 but corresponds to the waveform (b) of the received signal. The averaging of the digital signal waveform (c) and the digital signal waveform (d) means averaging of the signal of level 111 and the signal of a lower level. The waveform is close to the waveform of (b), and there is a problem that the strongest color is not output even though a strong received signal (a) actually exists.

SUMMARY OF THE INVENTION An object of the present invention is to provide a color display detection video signal processing apparatus capable of better displaying the presence of a strong signal when an averaging of a strong signal and a weak signal is performed in view of the above-mentioned problems of the prior art. Is to do.

[0009]

The present invention has the following means in order to achieve the above object. That is, the color display detection video signal processing device of the present invention includes an A / D converter that converts the amplitude value of an ultrasonic detection video signal received periodically into a digital signal, and an A / D converted digital signal. A color image signal processing device comprising: a storage device for storing an A / D converter; and an averaging circuit for averaging and outputting the output of the A / D converter and the output of one cycle before extracted from the storage device. A color display detection device, wherein the number of output bits of the converter and the storage device is larger than the number of color identification bits of the color video signal, and a bit processor for processing the number of bits of the output of the adder circuit into the number of color identification bits is provided. It is a video signal processing device.

[0010]

The operation of the color display detection video signal processing apparatus of the present invention having the above-mentioned configuration will be described below. In the device of the present invention, the number of bits of the A / D converter and the storage device is made larger than the number of color identification bits.
When the level clipped by the converter is higher than the strongest level of the color identification bit, and the average of the strong reception signal and the weak reception signal before and after the reception cycle is taken, the average value is the strongest color level of the color identification bit. The average value can be clipped by the bit processor at the highest level of the color identification bits and output as a color display detection video signal. Can be displayed in color.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. The number of color identification bits is 3 bits.
The D converter 1 and the storage device 2 have 4 bits, which is one bit larger than the number of color identification bits. As the averaging circuit 3, a 4-bit full adder (for example, SN7483 manufactured by Texas Instruments) is used. The output is 5 bits because of the addition of 4 bits and 4 bits.

The bit processor 4 comprises three OR gates, and one input terminal of each OR gate has an averaging circuit 3
, The signal of the second highest bit (# 4) of the output of the averaging circuit 3 is input to the other input terminal of the OR gate in the upper stage, Similarly, the signal of the third highest bit (# 3) is input to the other input terminal of the OR gate of the OR gate, and the signal of the fourth bit (# 2) of the fourth highest is also input to the other input terminal of the lower OR gate. A signal is input. The least significant bit ($ 1) is truncated because it takes the average, or half. By doing so, the received signal can be A / D converted to twice the level of the conventional signal, and the averaging up to twice the level can be obtained.

That is, the A / D is limited to the conventional level of 0-7.
0 that could not be converted and was clipped at level 8 or higher
Since the A / D conversion can be performed up to the level of １５15, the storage device 2 can also store the output of the A / D converter because it is 4 bits, and the averaging circuit 3 is also a 4-bit full adder. The output of the D converter 1 and the output from the storage device 2 can be added, and the output is 5 bits. However, since the output is averaged (1/2), the least significant bit is not used and the upper 4 bits are used. Average output.

Here, the number of color identification bits of the video signal is three.
Since the bits are 0 to 7, the signal of the most significant bit (C4) is input to each OR gate of the bit processor 4 so that the level exceeding 7 is clipped at 7. By doing so, the 3-bit output is 111 at level 7 and the most significant bit is always 1 at level 8 and above.
If this is input to each OR gate, all outputs of the OR gate become 1 and eventually become 111.

With the above configuration, the output of the bit processor 4 when a received signal similar to that of FIG. 3 is input is shown in FIG.
become that way. In the figure, the A / D conversion output corresponding to the received signal (a) is as shown in a waveform (c), and a signal that exceeds the level 15 without being clipped to a level 15 (1111) which is twice as high as the waveform (c) in FIG. Is clipped. The waveform (d) of the A / D conversion output for the received signal (b) does not reach the clip level, and is therefore exactly the same as the waveform (d) in FIG. The waveform (e) is obtained by taking the average of the waveform (c) and the waveform (d) and clipping the average at level 7 (111). Comparing this with the waveform (e) in FIG. 3, the waveform (e) in FIG. 3 does not reach the level 7 (111), but the waveform (e) in FIG. 2 sufficiently reaches the level 7 (111). I understand.

As described above, the number of bits until the averaging is taken is made larger than the number of color identification bits to increase the clip level, and after the averaging, the level exceeds the strongest level when converting into the number of color identification bits. By clipping the portion, a high level of the received signal can be displayed in the strongest color better than before.

[0017]

As described above, the color display detection video signal processing apparatus according to the present invention receives an A / D converter, a storage device, an averaging circuit and the like with the number of bits being larger than the number of color identification bits. After increasing the clip level with respect to the signal input, taking the average of the output of the A / D converter and the output of the storage device, the bit processor clips the level higher than the strongest color level when converting it to the number of color identification bits. Therefore, the strongest color display for a high-level input signal is performed more sufficiently than in a conventional video signal processing device in which the number of bits of an A / D converter and a storage device is the same as the number of bits for color identification. There are advantages.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of operation waveforms in the embodiment of FIG.

FIG. 3 is a block diagram showing a configuration of a conventional color display detection video signal processing device.

FIG. 4 is an explanatory diagram of operation waveforms in the conventional device of FIG. 3;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 A / D converter 2 Storage device 3 Addition and averaging circuit 4 Bit processor 5 A / D converter 6 Storage device 7 Addition and averaging circuit

Claims (1)

(57) [Claims] An A / D converter for converting an amplitude value of an ultrasonic detection image signal received periodically into a digital signal, a storage device for storing the digital signal obtained by the A / D conversion, and an A / D converter In a color video signal processing device having an averaging circuit for averaging and outputting the output of the D converter and the output of one cycle before taken out from the storage device, the number of output bits of the A / D converter and the storage device A color display detection video signal processing device, comprising: a bit processor that processes the number of bits of the output of the adder circuit to the number of color identification bits, which is larger than the number of color identification bits of the color video signal.