JP3429362B2 - Fish finder - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a fish finder.

[0002]

2. Description of the Related Art A fish finder detects seabed information by an ultrasonic wave transmitter / receiver and displays a seabed image on a display screen so that it can be used for searching for a school of fish and seabed topography. .

[0003]

By the way, the seabed image displayed on the display screen is displayed on the screen as it is based on the reflected waves captured every moment. That is, the depth is determined by measuring the time until a pulse is emitted from the transmitter / receiver to the seabed, reflected on the seabed, and received by the seabed. A seabed image is displayed based on this one sampling time. . Therefore, the scroll speed of the display screen was constant corresponding to the sampling time. For this reason, as can be understood by comparing a and b and c and d in FIG. 6, respectively, even if the seabed information is the same, when looking at one screen, when the speed of the ship is high, the scroll direction (left in the figure). Direction)) and the speed slows down, the image spreads along the scroll direction as well, and it looks as if they are different even though they have the same seabed information.

Further, when the depth range that defines the equivalent depth corresponding to the length dimension (scale) of the screen is changed, as will be understood by comparing a, c, and b of FIG. 6,
When the depth range is deep, the depth dimension on the screen becomes relatively small, and the depth is compressed in the vertical direction as compared with the case where the depth is shallow. That is, comparing a and b in FIG. 6 when the depth range is 40M with c and d when the depth range is 80M,
Although the same seabed information is used, the latter is vertically compressed to 1/2. This gives the impression that the images are different, as described above.

As described above, according to the conventional configuration, it is not always possible to accurately judge the state of the seabed because the same seabed can be expressed in different forms by selecting the speed and depth range of the ship.

The present invention aims to eliminate such problems.

[0007]

SUMMARY OF THE INVENTION The present invention comprises a range selection means for selecting a depth range, a ship speed detection means for detecting the speed of a ship, and a display device for displaying a seabed image on a screen in a vertical cross section. , The range selecting means, the ship speed detecting means and the display device are connected, and an arithmetic expression S = CD / V (where S is a time required to create an image for one screen, C is a constant, and D is a range A central control unit CPU having a control content for instructing a display device to display a seabed image on the screen moment by moment while establishing the relationship between the depth range determined by the selection means and V is the ship speed). It is a fish finder equipped.

Here, the depth range D means an equivalent depth corresponding to the length dimension (scale) of the screen, and the range selection means of this depth range D corresponds to the depth to the seabed. An automatic control means (configured by a calculation means in the central control unit CPU) for automatically setting the seabed to fit within the screen is used, or an input means such as a key switch for designating the depth range D is used. be able to.

As a ship speed detecting means, GPS (Glob
al Positioning System; a configuration that uses a satellite to measure the position) or Loran (a system that receives signals from multiple transmitters to measure the position) and determines the speed by changing its position is adopted. . A speed sensor may be used instead of this means.

The above equation S = CD / V is T = nt (where T is the shortest time required to densely fill the image by each sampling, n is the number of pixels in the horizontal direction of the screen, and t is from the transducer). Assuming that one cycle time until the ultrasonic wave is emitted, the reflected wave is received, and the next ultrasonic wave is emitted), it may be established only in the range of S ≧ T 2.

[0011]

The seabed image is displayed on the screen of the display device based on the arithmetic expression S = CD / V. Therefore, when the speed of the ship is high, the time S required to create an image for one screen becomes short. This means that the scrolling speed in the width direction of the image increases in proportion to the speed of the ship. Also, the slower the speed, the slower the scrolling speed of the image in the width direction becomes. Therefore, even if the speed of the ship is different, the image scrolls in proportion to the speed, so that if the depth ranges D are equal, the same seabed image can be obtained for the same seabed information.

On the other hand, when the depth range D is large, the depth fluctuation range of the seabed becomes relatively small on the screen and the seabed is compressed along the depth direction. By the way, arithmetic expression; S = CD
Due to the relationship of / V, the scroll speed in the width direction of the image becomes faster as the depth range D becomes deeper. For example, if the scroll speed is the same as in the conventional case, comparing a and c in FIG. 6 shows that c has a depth twice as large as that in a, and therefore the depth fluctuation range of the seabed on the screen is It will be halved. Therefore, in the case of FIG. 6C, if the scroll speed is doubled as compared with the case of FIG. 6A, it is compressed in the scroll direction, so that it is halved vertically and horizontally. It is possible to visually recognize that the seabed information is similar.

As described above, the speed V of the ship and the depth range D are related to the time S (inversely proportional to the scroll speed) required to create an image for one screen by the calculation formula; S = CD / V. To be Therefore, even if the speed V of the ship and the depth range D change, it is possible to obtain a seabed image of a similar shape.

Here, the constant C includes, as a factor, the relative ratio between the depth (vertical scale) and the distance (horizontal scale) in forming the similar image. For example, if the horizontal scale is reduced to 1/2 with respect to the depth scale, the value of the constant C is doubled. The ratio may also be appropriately selected by the operator.

On the other hand, the depth is determined by measuring the time until a pulse is emitted from the transmitter / receiver toward the seabed and the reflected wave from the seabed or the school of fish is received, but from this sampling to the start of the next sampling. The time (one cycle time) is constant. Therefore, the ship becomes fast and the image scroll speed is too fast, and the time S required to create an image for one screen is shorter than the shortest time T (= nt) required to densely fill the image by each sampling. When the detection time is short, if the detected position is plotted on the screen as it is, the seabed image displayed on the screen becomes a discontinuous rough image. Therefore, in order to solve this problem, the above relationship may be established within the range of S ≧ T.

When S <T, the depth range D is automatically changed to a deeper one to satisfy S ≧ T, or
Alternatively, with one sampling, the number of pixels in the width direction is 2 pixels,
The image is made continuous by displaying it at or higher.

When S <T, S = nt (constant) may be set so that the scroll speed does not exceed a predetermined speed.

Further, the screen may be corrected by computer graphic technology to form a continuous screen.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to the accompanying drawings.

As shown in FIG. 1, the detector main body 1 equipped with a display device 3 for displaying a seabed image in a vertical section on a seabed information screen 4 is constituted by a control switching device 2 in which a group of key switches is arranged. , The output content of the display device 3 is selected.

A central control unit CPU shown in FIG. 3 is built in the detector main body 1. This central control unit CPU
A wave transmitter / receiver 12 is connected as an input device, and similarly, the control switching device 2, the speed sensor 13 and the like are connected. Further, the display device 3 is a display RAM 7
And the display control unit 8 are connected. Further, the control program ROM 10 and the arithmetic control RAM 11 are connected.

Next, the output mode of the display device 3 will be described.

As shown in FIG. 2, the display device 3 displays a seabed information screen 4 based on the input information from the transducer 12 by the switching control of the control switching device 2. This seabed information screen 4 scrolls to the left in the figure as the ship advances. Also, on the seabed information screen 4,
The depth scale is displayed in the right margin area, and the speed is displayed in the upper and lower margins.

Then, ultrasonic waves are radiated to the seabed from the wave transmitter / receiver 12, the reflected wave is received by the wave transmitter / receiver 12, the depth is detected by the time difference, and one or a plurality of times of sampling is performed. Plotting at any depth position of the vertical pixel lines on the seabed information screen 4, and by continuation thereof, the depth of the seabed topography x or fish shadow y and their temporal changes are displayed together with the leftward scroll of the screen. Draw on top. Therefore, on the seabed information screen 4, a seabed image that changes according to the traveling distance of the ship is displayed in a vertical cross section.

On the other hand, the speed of the ship is detected by the ship speed detecting means. GPS (Global Pos)
itioning System; a position measurement system using artificial satellites) or Loran (a system for measuring the position by receiving signals from a plurality of transmitting stations) is used to determine the speed by changing the position. Change to this method,
A speed sensor may be used.

Further, the depth range D of the seabed information screen 4 is determined by the range selecting means. The range selecting means is easily configured by an automatic adjusting means for automatically selecting the depth range D corresponding to the depth of the seabed or a manual setting means for arbitrarily selecting the depth range D according to the detection purpose by the input means. obtain. This automatic adjustment means and manual setting means
It can be arbitrarily selected by mode switching by the control switching device 2. Thus, the range selecting means is embodied by the central control unit CPU and the control switching unit 2 in this embodiment.

By switching the mode to the automatic adjusting means, the maximum display depth is automatically changed from 40 m to 80 m so that the maximum depth of the seabed falls within the range of 2/3 of the maximum depth on the screen. Is set within the screen, and the depth dimension on the screen is as large as possible so that it is easy to see.

Next, the essential part of the present invention will be described.

The display of the seabed image on the seabed information screen 4 is performed by the arithmetic processing by the central control unit CPU.
The arithmetic expression is controlled so that the relation of S = CD / V is established.

Here, S is the time (second) required to create an image for one screen, and the width dimension W of the seabed information screen 4 and the scroll speed u of the image are determined by determining S. The scroll speed u is determined from the relationship u = W / S.

The constant C includes, as a factor, the relative ratio between the depth (vertical scale) and the distance (horizontal scale) in forming a similar seabed image. For example, if the horizontal scale is reduced to 1/2 with respect to the depth scale, the constant C will be doubled. The ratio may also be appropriately selected by using the control switching device 2. Other factors of the constant C include the width dimension W of the seabed information screen 4.

The above calculation formula is the depth range D at that time.
Letting T be the shortest image feed time in S, S ≧ T.

The significance of the shortest image feed time T will be described.

An ultrasonic wave is radiated from the transmitter / receiver 12, the reflected wave is received, the depth is measured from the time until the reflected wave,
Further, one cycle time t (second) until the next ultrasonic wave is emitted (until the next sampling) is calculated by the following equation. t = (2 × depth range / 1500) + α

[1500] is the speed of sound in water (m /
s) and "2" represent round trip times. Also, α
Is an empirical value required for experiments. That is, by starting the next sampling with an interval of α seconds after the end of one sampling, the irregular reflection of the ultrasonic wave in the previous sampling is received as noise at the time of the sampling, and no measurement error occurs. I am trying.

On the other hand, the above-mentioned minimum image feed time T is expressed as T = nt. Here, n is the number of pixels in the horizontal direction for displaying the seabed information screen 4. That is, when plotting at any position in the vertical pixel line and scrolling horizontally to fill one screen, the minimum required number of samplings is n, which is equal to the number of horizontal pixels.
Therefore, the product of the number of times n and one cycle time t is the minimum time (shortest image feed time) T required to fill the entire seabed information screen 4. Therefore, if the scroll speed is too fast and S is shorter than the shortest image feed time T, the seabed images cannot be densely plotted on the seabed information screen 4. Therefore, the condition of S ≧ T is given.

In the case of S <T, the depth range D is automatically changed to a deeper one, or the number of pixels in the width direction is displayed as 2 pixels or more by one sampling. Make images continuous.

FIG. 4 is a flow chart showing a configuration in which, in the case of S <T, the number of pixels in the width direction is displayed by two pixels or more in one sampling.

That is, when the seabed information is obtained by the transceiver 12, the depth range D is determined from the maximum depth. Then, the ship speed information is obtained by GPS or the like, and S = CD
/ V. Then, with T = nt, it is determined whether or not S ≧ T is satisfied. If yes, then S is determined by the above equation. In the case of no, it is assumed that two pixels in the horizontal direction are plotted by one sampling, and T = n / 2 ·
When t is set, it is determined whether or not S ≧ T is satisfied. Similarly, only in the case of No, the number of pixels per sampling m is further increased, and S is calculated based on T = n / m · t.
The determination of ≧ T is performed and S is determined.

In addition, as a means for obtaining a uniform image on the seabed information screen 4 when the ship becomes high speed,
If S <T, S = nt may be set so that the scroll speed does not exceed a predetermined speed. Further, a continuous screen may be formed by a computer graphic technique using a screen correction means such as predicting the plot position of the cutout portion from the immediately preceding seabed slope.

Here, FIG. 5 shows the seabed information screen 4 created by the above-mentioned flowchart shown in comparison with FIG. As in this screen, the same (when the depth range D is constant) or similar seabed image can be obtained. Since the image is thus constant, the depth scale 5 and the distance scale 6 on the upper edge of the depth scale 5 can be clearly displayed, so that the positions of the seabed topography x and the fish shadow y can be accurately confirmed. .

[0042]

According to the present invention, the seabed images are sequentially displayed on the screen 4 of the display device 3 on the basis of the arithmetic expression; S = CD / V.
Even if the number changes, it is possible to obtain a similar seabed image, so you can check the seabed information more accurately, and the usefulness of the fish finder can be further improved. effective.

[Brief description of drawings]

FIG. 1 is a front view showing an example of a fish finder.

2 is a front view showing an example of a seabed information screen 4 of the display device 3. FIG.

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

FIG. 4 is a flow chart diagram of an embodiment of the present invention.

FIG. 5 is a front view showing another example of the seabed information screen 4.

FIG. 6 is a front view showing a seabed image of a conventional configuration.

[Explanation of symbols]

1 Detector body 2 Control switching device 3 display devices 4 Subsea information screen 12 Transceiver

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Claims (2)

(57) [Claims] 1. A range selecting means for selecting a depth range, a ship speed detecting means for detecting a speed of a ship, a display device for displaying a seabed image in a vertical cross-section on a screen, the range selecting means, the ship speed. Connected to the detection means and the display device, the arithmetic expression S = CD / V (where S is the time required to create an image for one screen, C is a constant, and D is the depth range determined by the range selection means. , V is the speed of the ship), and a fish finder comprising a central control unit CPU having control contents for instructing the display device to display a seabed image on the screen moment by moment. 2. The equation S = CD / V is T = nt (where T is the shortest time required to densely fill the image by each sampling, n is the number of pixels in the horizontal direction of the display screen, and t is the transmission / reception). The ultrasonic wave is radiated from the vessel, the reflected wave is received, and the next ultrasonic wave is emitted (one cycle time). Then, S is satisfied in the range of S ≧ T. The fish finder according to 1.