JPH0484792A - Sonar display - Google Patents

Abstract

PURPOSE:To make possible the exact grasp of a receiving state of a target signal by variably expressing luminance information for expressing the intensity of the receiving state by the use of an S/N ratio and further performing color display corresponding to luminance gradation equal to the S/N ratio. CONSTITUTION:A receiving signal in a sonar device is processed in a signal processor 1 for input processing and S/N ratio improvement. In the output the ratio of signal to noise is calculated by the use of an S/N ratio calculation circuit 2 and its result is supplied to a luminance gradation conversion circuit 3. The circuit 3 is converted into the gradation corresponding to one of the preset luminance gradation in accordance with the S/N ratio to output to a color information conversion circuit 4. In the circuit 4 the signals R, G, B corresponding to colors assigned to each gradation are generated to supply to a display 5 utilizing a color CRT so as to display thereon.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sonar display device, and more particularly to a sonar display device that displays a received signal of a sonar device.

[Conventional technology]

The display method of the received signal in the sonar device is P.
A display method called PI display or B-1 display is generally used. FIG. 3(a) is a diagram showing an example of a PPI display, and FIG. 3(b) is a diagram showing an example of a B-suf-1 display. In displaying these received signals, the direction of arrival of the signal is expressed as a circumference in PPI display.

In the B-1 display, the distance to the signal corresponds to the horizontal axis, while in the PPI display, the distance to the signal corresponds to the length from the center, and in the B-1 display, the distance to the signal corresponds to the vertical axis, and the strength (level) of the received signal. is expressed as brightness. Therefore, the strength of the received signal can be determined by the brightness.

[Problem to be solved by the invention J] In the conventional sonar display device described above, the intensity (level) of the received signal is displayed in brightness, so the range of signal levels to be displayed, that is, the dynamic range, depends on the brightness characteristics of the display device. It will depend on. CRTs, which are currently the mainstream in terms of performance and cost, have a dynamic range of about 20 dB for luminance information, but sonar devices generally display only the dynamic range of the received signal. It is related to the dynamic range of the instrument. Furthermore, the brightness characteristics of a CRT are not linear with respect to the input signal level.

Some processing on the received signal 1 For example, lo on the received signal
Measures are taken to match the dynamic range and input/output characteristics of the display device by applying g-conversion, gamma correction, etc. When performing display processing on the received signal in this way when displaying brightness, it becomes easy to grasp the correct received signal2.
For example, log conversion can cover a wide dynamic range, but on the other hand, the amplitude difference between strong and weak signals is compressed so much that it becomes difficult to intuitively determine the strength of the signal, making it difficult to accurately determine the reception status. The drawback is that it cannot be grasped.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sonar display device that eliminates the above-mentioned drawbacks, allows the dynamic range of a received signal to match well with the dynamic range of a display, and allows easy understanding of the reception status of the received signal.

[Means to solve the problem]

The sonar display device of the present invention is a sonar receiving device that displays a sonar reception signal on a display, and includes an S/N ratio calculation circuit that calculates the signal-to-noise ratio of the sonar signal, and
The signal-to-noise ratio output from the /N ratio calculation circuit is divided into N luminance gradations obtained by dividing the display luminance range of the sonar display into N gradations, and the luminance gradation is assigned to the luminance gradation corresponding to the magnitude of the signal-to-noise ratio. A brightness gradation conversion circuit that converts and outputs the brightness gradation conversion circuit, and a color information conversion circuit that converts the brightness PI tone outputted from this brightness gradation conversion circuit into color information assigned to the brightness gradation and outputs it to the sonar display. Prepared and configured.

Further, in the sonar display device of the present invention, the brightness gradation conversion in the brightness gradation conversion circuit is such that the minimum value of the signal-to-noise ratio corresponds to the minimum brightness gradation, and the maximum value of the signal-to-noise ratio corresponds to the maximum brightness gradation. It has a configuration in which brightness gradations are assigned based on the brightness characteristics of the sonar display device in correspondence with the brightness characteristics of the sonar display device.

〔Example〕

Next, nine aspects of the present invention will be described with reference to the drawings.

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

A signal processor 1 that performs input processing on a received signal, improves the signal-to-noise ratio (hereinafter referred to as S/N ratio), and outputs the result, and an S/N ratio that calculates the S/N ratio of the output of the signal processor 1. Calculation circuit 2
, a luminance gradation conversion circuit 3 that converts the S/N ratio calculated by the S/N calculation circuit 2 into a corresponding luminance gradation and outputs it, and a color information conversion circuit 4 that converts the luminance gradation into color information. 1 display unit 5, among which are an S/N ratio calculation circuit 2. The brightness gradation conversion circuit 3 and the color information conversion circuit 5 are the parts directly related to the present invention.

Next, the operation of the fifth embodiment will be explained.

The received signal in the sonar device is input processed.

The signal is processed by a signal processor 1 to improve the S/N ratio. The signal-to-noise ratio of this output is calculated by the S/N ratio calculation circuit 2, and the result is supplied to the brightness gradation conversion circuit 3. brightness l
The ll' tone conversion circuit 3 selects one of the brightness gradations set in advance in accordance with the S/N ratio.

It is converted into a corresponding gradation and output to the color information conversion circuit 4. The color information conversion circuit 4 generates R, G, and B signals corresponding to the colors assigned to each gradation, and outputs color C.
Supply 1 is displayed on the display 5 that uses RT.

FIG. 2 is an explanatory diagram of brightness gradation conversion of the S/N ratio in the embodiment of FIG. 1.

In the present invention, the input/output characteristics are expressed by the S/N ratio of the received signal for the input, and for the brightness, the range between the minimum brightness and the maximum brightness is divided into N gradations. There are 16 gradations, and N gradations correspond to N colors. Namely.

Set the minimum brightness when the S/N ratio is -oo (received signal is only noise)1. , S·′N ratio or the maximum value (determined by the dynamic range of the receiver) is set as the maximum brightness. If the S/'N ratio is between the minimum value and the maximum value, one of the intermediate gradations is set depending on the value of the S/N ratio. In this way, the brightness gradation of the received signal is determined by its S/N ratio, and the color assigned to the brightness gradation is displayed.

For example, if the number of gradations per gradation is N=16 and the gradation increases by 1 every time the S/N ratio improves by 3 dB, then 3 dBx
It becomes possible to display an input dynamic range of 16=48 dB. In addition.

The relationship between the S/N ratio, brightness gradation, and color can be arbitrarily changed according to the purpose of signal detection.

Second, it is possible to display the received signal in color while ensuring a wide dynamic range.

〔Effect of the invention〕

As explained above, the present invention uses luminance information representing the strength (level) of a received signal as a signal, and instead of the absolute value of Hell, S/
By variable expression using the 'N ratio and color display corresponding to the brightness gradation corresponding to this S/N ratio, a wide dynamic range can be ensured and the S/N ratio of the displayed received signal can also be determined. This has the effect of making it possible to accurately grasp the reception status of the target signal.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram of brightness gradation conversion of the S/N ratio in the embodiment of FIG. 1, and FIG.
FIG. 3(a) is a diagram showing an example of PPI display, and FIG. 3(b) is a diagram showing an example of B-1 display. 1... Signal processor, 2... S/N ratio calculation circuit, 3.
...Brightness gradation conversion circuit, 4...Color information conversion circuit,
5...Display device.

Claims (1)

[Claims] 1. In a sonar display device that displays a sonar reception signal on a display, an S/N ratio calculation circuit that calculates the signal-to-noise ratio of the sonar reception signal, and an output of this S/N ratio calculation circuit. The signal-to-noise ratio of the sonar display brightness range is N
a luminance gradation conversion circuit that converts and outputs the divided N gradation luminance gradations into luminance gradations assigned in accordance with the magnitude of the signal-to-noise ratio; and a luminance gradation output from the luminance gradation conversion circuit. 1. A sonar display device comprising: a color information conversion circuit that converts gradations into color information assigned to each luminance gradation and outputs the converted color information to a sonar display device. 2. The brightness gradation conversion in the brightness gradation conversion circuit is performed by making the minimum value of the signal-to-noise ratio correspond to the minimum brightness gradation, and making the maximum value of the signal-to-noise ratio correspond to the maximum brightness gradation. 2. The sonar display device according to claim 1, wherein the brightness gradation is assigned based on the brightness characteristics of the sonar display device.