JPH04194692A - Fish-finder - Google Patents

Abstract

PURPOSE:To enable removal of interference by transmission-reception signals of another fish-finder by a method wherein pixel values based on the current, the last and the before-last image data are arranged in sequence, beginning with the largest one, and the value positioned in the center of the sequence is used as pixel data for the center of a region. CONSTITUTION:Static RAM (SRAM) 9 equipped with line buffers B1 to B4 of a memory length being equivalent to the number of display dots in the verti cal direction of CRT 17 and the data subjected to a median processing, the current data, the last data and the before-last data are stored in the buffers B1 to B4 respectively. CPU 10 arranges the data of 3 X 3 pieces of the buffers B2 to B4 stored in the SRAM 9 in the sequence of pixel values, beginning with the largest one, and makes pixel data M positioned in the center be stored as the pixel data of the buffer B1. In succession, it processes the storage data of the buffers B2 to B4 and makes the data stored in the buffer B1. By executing the median processing in this way, interference by transmission-reception signals of another fish-finder can be removed effectively and thereby an improvement in the visibility of an image can be attained.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a fish finder, and more particularly to a fish finder that can prevent interference caused by transmitted and received signals from other devices.

[Conventional technology]

If the transmitted/received signals from the fish finder installed on another fishing boat mix into the main fish finder, interference will occur, causing problems such as a distorted display screen. Performing such interference removal using hardware requires a large number of circuit elements and is complicated, so a method of performing image processing using software is adopted.

[Problem to be solved by the invention]

As a method using software, a correlation method is generally used in which pixel data at a certain coordinate is compared with past pixel data and the smaller value is used as pixel data for the coordinate. When the number of correlations is increased (increasing the number of correlations), the image becomes mosaic-like and difficult to see, and the fish school response becomes small.The present invention was made to solve the above-mentioned problems. The purpose of the present invention is to provide a fish finder with high interference removal ability.

[Means to solve the problem]

The present invention is a fish finder that can eliminate interference caused by transmission and reception signals from other fish finders, and in which old image data is sequentially displayed for one line of the display screen, such as current image data and previous image data. When n line buffers B to B n + for storing each and n line buffers are captured two-dimensionally and an area of n×n pixels is considered, n in the area is pixel data processing means for arranging ×n pixel values in ascending order and selecting the value located in the center or the pixel value in a desired order as pixel data for the center of the area; Another line buffer B stores the pixel data for one line as data for one line.

[Effect]

The data for one line detected this time is in line buffer B.
, is stored in . At this time, the data stored in line buffers B to Bn are transferred to line buffers B3 to Bn as previous data, respectively. After this, the line buffer B or B1 captures the n×n square memo 1 area W8, and arranges the n [data in the area W in descending order of pixel value, and selects the pixel located in the center. Data M or pixel data M-1 smaller by one is stored in the corresponding memory of line buffer B. Next, similar processing is performed on other n×n memory areas Wt that have been shifted by one stage, and are stored in the corresponding memories of the line buffer B1. By performing such processing, the median-processed 1 is stored in line buffer B1.
Line and minute data are stored.

Embodiment FIG. 1 is a control block diagram showing an embodiment of the apparatus of the present invention. 2 is a transducer, which converts the transmission signal from the transmitter 3 via the transceiver switch 2 into an ultrasonic wave and transmits the wave, and receives the echo thereof. Reference numeral 4 denotes a receiving section that detects a received signal from the transducer 1 via the transmitter/receiver switch 2. 5 is
An 8-bit A/D converter converts the output signal from the receiver 4 from analog to digital, and 6 is an 8-bit A/D converter that converts the output signal from the A/D converter 5 (256 types of signal levels). ) is a pit converter that converts the signal into 4 pits in order to divide it into 16 types of signal levels. 7 is a latch circuit that latches the signal converted by the bit converter 6;
is DMA (direct memory access),
The signal for one line is read directly from the latch circuit 7 (without going through the CPU) and loaded into the SRAM (static RAM).
Write in 9. This SRAM, as shown in Figure 2,
Equipped with four line buffers B to B4 having the same memory length as the number of display dots (n+1) in the vertical direction of the CRT 17,
Line buffers B and B4 respectively store current data, data from the previous time, and data from the second time before, and line buffer B1 stores median-processed data as will be described later. be done. 10 is a CPU, which performs median processing from the data stored in the SRAM 9; 11 is a ROM that stores a processing program executed by the CPU10. 12 is
The control panel is connected to the CPU10 via the input section I3, and is equipped with various switches and borders. 14 is the CPU
This is a controller that converts the signal processed by l0 into image data. 15 is a VRAM (video RAM) that stores image data processed by the controller 14; 16 is V
It is a D/A converter that reads data from the RAM 15 and converts it into an analog signal, and J7 is a CRT for displaying image data from the D/A converter 16. Next, the operation of the apparatus having the above configuration will be explained. The received signal from the transducer 1 is passed through the A/D converter 5 to the latch circuit 6, and when one line of data is latched, it is read out by the DMA 8 and stored in the line buffer of the SRAM 9. It is stored in B. At this time, the data stored in line buffer B2 is used as the previous data. The data transferred to line buffer B3 and stored in line buffer B is transferred to line buffer B as data from the previous time.
Transferred to 4. Therefore, for each line of the CRT 17, the second
As shown in the figure, the current data and the past two data are stored. Next, the median processing performed by CPU10 will be explained. As shown in FIG. 2, line buffer B or B4
3x3 memory areas W1 are captured, and as shown in FIG. The next smaller pixel data M-1 is stored as pixel data N(1) in the line buffer B1. Pixel data N(2) of line buffer B is similarly selected from region W shown in the figure. In this way, the median-processed pixel data N(1) to N(n-1) are stored in the line buffer B. Next, when the detected data for one line is latched into the pixel latch circuit 6, the data is transferred to the SR via the DMA 8.
It is stored in line buffer B of AM9. At this time,
The data stored in line buffers B and B3 are sequentially transferred to line buffers B3 and B4, and the data stored in line buffer B4 is discarded. After that, in the same way as above, line buffer B or B
Median processing is performed on the stored data of No. 4, and the processed data is stored in line buffer B. The data stored one after another in the line buffer B in this way is sent to the controller 14 via the CPU 10 and converted into image data, and is subsequently stored in the VRAM 15, D
An image with interference removed as a result of the median processing is displayed on the CRT 17 via the /A converter 16. In the above embodiment, the nine pieces of data in the memory area are arranged in descending order of pixel value, and the pixel data M located in the center or the pixel data M- that is one smaller than the pixel data M-
1 is stored as pixel data in line buffer B, or pixel data M-2 is smaller than pixel data M-1.
, even smaller pixel data M-3 may be stored. [Effects of the Invention] As explained above, the present invention uses data obtained by median processing the current detection data and past detection data, so interference caused by transmitted and received signals from other devices is are effectively removed, and an easy-to-read image is displayed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the fish finder of the present invention. FIG. 2 is a diagram showing the memory configuration of the SRAM in the device shown in FIG. 1. FIG. FIG. 3 is a diagram illustrating areas of median processing performed on the image; DESCRIPTION OF SYMBOLS 1... Transmitter/receiver, 2... Transmitter/receiver switch, 3... Transmitting section, 4... Receiving section, 5... A/D converter, 6... Bit converter, 7... Latch circuit,
8 DMA19...SRAM, 10...
cpu. 11・ROM, 12・・Operation panel, 13
Human Power Department, 14 Controller, 15 ・VR
AM, 16・D/A converter, 17・CRTo Patent applicant: Furuno Electric Co., Ltd., agent Patent attorney: 1 person (1 person) Figure 1 Figure 2 Figure 3/

Claims (1)

[Claims] (1) A fish finder that can eliminate interference caused by transmitting and receiving signals from other fish finders, which displays old image data for one line of the display screen in the order of current image data, previous image data, etc. If we capture n line buffers for storage and n line buffers two-dimensionally, and consider an area of n x n pixels, we can increase the values of n x n pixels within the area. pixel data processing means for arranging the pixel data in order and selecting the pixel value located in the center or the pixel value in a desired order as the pixel data for the center of the area; A fish finder characterized by comprising: another line buffer for storing data as data;