JPH01229989A - Image displaying method of fish detector - Google Patents

Abstract

PURPOSE:To make it possible to display one image for multiple frequencies which can be readily observed, by allocating and displaying a color having the different hue from the group of the predetermined different hues in correspondence with the magnitude of the difference among echo signals matching the received frequencies. CONSTITUTION:The title detector 10 is composed of a transceiver part 12, a main-body processing part 14, a display part 16 and the like. A transmitting part 26 generates high frequency transmitting pulses 22 and low frequency transmitting pulses 24 based on a signal from a trigger generating part 20 and guided to a high frequency receiving part 28, a high frequency transceiver 22, a low frequency receiving part 30 and a low frequency transceiver 34. The reflected waves from the school of fish and the like are guided to the receiving parts 28 and 30. Digitized 37 and 38 high-frequency and low-frequency echo signals are guided to an operating part 42. The intensities of the signals are compared and operated. When the difference is less than a predetermined threshold value, the images are displayed for standard hues. When the difference is higher than the threshold value, one color of the hue other than said hues is set and displayed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a screen display method for a fish finder that transmits and receives ultrasonic waves to determine and detect the presence of schools of fish in the water. When transmitting ultrasonic pulse signals of different frequencies from the transducers constituting the transmitter and receiving echo signals from underwater targets and displaying images on a display such as a CRT (cathode ray tube), the received echoes of different frequencies Areas where there is a large signal difference are displayed with various hues depending on the difference, while areas where the difference is small are displayed as is on the same screen by displaying the echo signal of one of the frequencies as is. Regarding the screen display method of a fish finder.

[Background of the Invention] Underwater acoustic equipment has been widely used to confirm underwater targets. A good example of this would be a fish finder. The fish finder uses a transducer consisting of a single vibrating element or a plurality of vibrating elements arranged in an appropriate shape to repeatedly emit sound waves, especially ultrasonic pulses, into the water in a predetermined range, and then reflect them from underwater targets. This is a device that receives echo signals returned from the echo signals and displays them on a display such as a CRT. That is, focusing on the fact that the intensity of an echo signal from an underwater target such as a school of fish is generally proportional to the size and density of the school of fish, etc., the intensity of an echo signal from an underwater target such as a school of fish is generally proportional to the size and density of the school of fish. This is a device that distinguishes or confirms the presence of schools of fish, etc. by displaying them in color or in shading on recording paper.

By the way, as is well known, there are fish of various sizes, such as small fish such as milt and small fish, and relatively large fish such as mackerel and mackerel. requires the transmission and reception of multiple types of ultrasound signals. Therefore, for example, by using ultrasonic signals of high and low image frequencies, a dual-frequency fish finder is capable of simultaneously capturing small fish such as milt using high frequencies, and simultaneously capturing large fish such as mackerel using low frequencies. is proposed.

This dual-frequency fish finder emits ultrasonic pulse signals of different frequencies into the water, and accumulates and records echo signals from the fish school in the image memory of the dual-frequency fish finder for each frequency.

Then, a CRT that corresponds to the echo signal of this high and low two-layer wave
As shown in FIGS. 1a and 1b, the display screen on the display unit is configured to display a low frequency echo display and a high frequency echo display in a vertically or horizontally divided display.

In the figure, reference numbers 2a and 2b indicate echo signals corresponding to the sea surface, 4a indicates an echo signal corresponding to a large fish that responds particularly sensitively to low frequencies, and 4b indicates an echo signal that responds particularly sensitively to high frequencies. Echo signals of small fish are shown, and 5a and 6b show echo signals corresponding to the seabed, respectively. Therefore, in the display example of FIG. 1a, the left side of the figure shows the display of low frequency echo signals, and the right side shows the display of high frequency echo signals. Also, the second
In the display shown in the figure, the lower part shows the display of the low frequency echo signal, and the upper part shows the display of the high frequency echo signal. Conventionally, the net casting range, net casting position, type of net, etc. are determined or selected from this vertically divided display or horizontally divided display.

However, such two-sided vertically or horizontally-split displays require fisheries chiefs and others who judge the timing to cast nets to judge the timing by comparing both screens alternately, which is cumbersome and difficult to use. There is a risk that the optimum timing for casting the net will be lost.

Therefore, in order to improve this, as disclosed in Japanese Patent Application Laid-open No. 53-117470 filed by the present applicant,
A multi-frequency color fish finder has been proposed that assigns a specific color to each frequency and displays the image on a color cathode ray tube as a single screen display.

[Object of the Invention] The present invention has been made in connection with such a technical idea, and the present invention is based on the above technical idea.
When displaying on a display device such as the above, the echo signal corresponding to each frequency is calculated in a predetermined manner and displayed in a predetermined color according to the signal level of the calculation result, thereby making it easy to see and displaying multiple frequencies on one screen. The purpose is to provide a screen display method for a fish finder.

[Means for achieving the object] In order to achieve the above object, the present invention emits ultrasonic signals of different frequencies into the water, and then returns echoes corresponding to the respective frequencies reflected from the underwater target. receive the signal,
A screen display method for a fish finder that displays the echo signals on a display by assigning predetermined different hue groups according to the signal levels of the respective echo signals, the echo signals corresponding to the respective received frequencies. The display is characterized in that a color having a different hue from the predetermined different hue groups is assigned and displayed depending on the magnitude of the difference in signal level.

Further, the present invention emits ultrasonic signals of different frequencies into the water, receives echo signals corresponding to the respective frequencies reflected from the underwater target, and receives the echo signals corresponding to the respective frequencies according to the signal levels of the respective echo signals. A screen display method for a fish finder that displays the echo signals on a display by assigning predetermined different hue groups, the method comprising: It is characterized by displaying a specific hue among a predetermined group of different hues or other hues by modulating the brightness.

Further, the present invention provides a portion where the difference in signal level of the echo signals corresponding to each received frequency is equal to or greater than a predetermined value by assigning a hue different from the predetermined different hue group or by assigning a hue different from the predetermined different hue group. A specific hue among the hue group or other hues is displayed by modulating the luminance with luminance according to the magnitude of the difference, and an echo signal of one of the frequencies is predetermined for the part where the difference is less than a predetermined value. It is characterized by displaying in hue groups.

The present invention also provides a method in which a difference in signal level of echo signals corresponding to each received frequency is extracted, and a hue different from the predetermined different hue group is assigned based on the difference signal, or a hue different from the predetermined hue group is assigned. It is characterized by displaying a specific hue among different hue groups or other hues by modulating the brightness.

Further, in the present invention, the sum of the signal levels of the echo signals corresponding to each received frequency is extracted, and based on the sum signal, a hue different from the predetermined different hue group is assigned or It is characterized by displaying a specific hue among different hue groups or other hues by modulating the brightness.

[Embodiments] Next, preferred embodiments of the screen display method in the fish finder according to the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 2, reference numeral 1O indicates a fish finder according to this embodiment. The fish finder 10 basically includes a transmitting/receiving section 12, a main body processing section 14, a display section 16, and an operation panel 1.
It consists of 8.

The transmitting/receiving section 12 includes a trigger generating section 20 and a high frequency transmitting section 2.
2 and a low-frequency transmitter 24, a receiver 32 consisting of a high-frequency receiver 28 and a low-frequency receiver 30, and a transducer consisting of a high-frequency transducer 33 and a low-frequency transducer 34. The trigger generating section 20 introduces a constant or irregular periodic trigger signal into the transmitting section 26 based on a periodic control signal from the control section 38 forming the main body processing section 14 .

Based on the trigger signal, the transmitter 26 causes the high-frequency transmitter 22 and the low-frequency transmitter 24 to generate a high-frequency transmit pulse and a low-frequency transmit pulse, which are electrical signals with a constant pulse width, respectively,
It is introduced into the receiving section 32 and the transducer section 36. In that case, the high frequency transducer 33 and low frequency transducer 34 constituting the transducer section 36 are connected to the ship Sh on which the fish finder 10 is mounted.
It is installed on the bottom of the ship (see Figure 3) and has, for example, an electrostrictive element, which vibrates based on the high-frequency transmission pulse and low-frequency transmission pulse, and generates a high-frequency ultrasonic pulse signal and a low-frequency ultrasonic wave. Each pulse signal is emitted into the water. These ultrasonic pulse signals are transmitted to the plankton layer P1 of M in the ice.
It is reflected by hitting a target object such as a school of fish F1 or the seabed Sv,
Ultrasonic reflected signals returning from these underwater targets are received by the electrostrictive elements constituting the image frequency transducer 33 and 34, and converted into electric signals (hereinafter referred to as echo signals) by the electrostrictive elements. Ru. This echo signal is introduced into the high frequency receiving section 28 and the low frequency receiving section 30, which constitute the receiving section 32, respectively. In this case, there is a time delay between when the ultrasound pulse signal is emitted and when the echo signal is received while the ultrasound waves travel back and forth. A value obtained by converting approximately 1/2 of this time delay into a distance is obtained as the distance to the underwater target such as the school of fish F.

The high frequency echo signal e and the low frequency echo signal e2 amplified by the high frequency receiving section 28 and low frequency receiving section 30 that constitute the receiving section 32 are sent to the first A/D converter 37 and the second A/D converter in the main body processing section 14. After being converted into a high frequency echo signal edl and a low frequency echo signal ed2 which are digital signals via the converter 39, they are introduced into the first terminal 40a and the second terminal 40b of the electronic switch 40, and are also input to the arithmetic processing unit 42. will be introduced in In this case, the content of the arithmetic processing executed by the arithmetic processing unit 42 is determined by the screen display mode selected by the operation panel 18.

Next, the output signal of the arithmetic processing section 42, for example, the differential echo signal ed3, is introduced into the third terminal 40C constituting the electronic switch 40. The first to third terminals 4
Digital echo signal edl introduced from 0a to 40C
to ed3 are connected to the buffer memory 4 via a common terminal 40d.
4 will be introduced as an alternative. In this case, buffer memory 4
4 has a capacity to store a signal obtained by one transmission/reception of an ultrasonic pulse signal, and a CRT 46 in the display section 16
The video data corresponding to one scanning line is stored.

Echo output signal edl (1=
1.2.3) is color-modulated by the color/brightness modulation lookup table 47 according to the signal strength, and then transferred to the main memory 48, and the video data stored in the main memory 48 is controlled by the control unit 38. The signals are sequentially read out and introduced into the D/A converter 50 in the display section 16. and,
Main Memo The video data introduced from January 8th is converted by the D/A converter 50 into an analog signal, that is, a signal similar to the received echo signal, and sent to the CRT 46. In this case, since the synchronizing signal from the synchronizing signal generator 52 is supplied to the other input terminal of the CRT 46, the received echo signal is displayed as a color image based on the synchronizing signal. Note that the operation panel 18 is a CRT46
It has data-powered functions such as setting the display mode of the screen displayed on the screen.

The fish finder that implements the screen display method according to the present embodiment is basically configured as described above, and its operation and effects will be explained next.

First, use the operation panel 18 to set the screen display mode according to the present invention to the CRT 46 based on the flowchart shown in FIG.
Select interactively using the text displayed on the screen. That is, first, a screen display mode start key (not shown) on the operation panel 18 is pressed (STPI). Then, CR
At T46, a menu for the sum mode or difference mode shown in the second step is displayed. Here, the sum mode represents the calculation process 1edl+ed21 of the sum of the high frequency and low frequency echo signals edl and ed2, and the difference mode represents the calculation process 1e6+e, +21 of the difference. In this embodiment, the difference mode is selected (SrF2). When this selection step is completed, the value of the threshold E is selected to be a specific value, for example 7 dB, within the level range of the transmission signal from O dB to 40 dB according to the next menu (SrF2). With these settings, the arithmetic processing unit 42 performs the arithmetic processing shown in the following equations (1) and (2), that is, compares the difference echo signal ed3 with the threshold value E5.

ed3=l edl ed2 l≧E s
-Q) ea3= l ear ea21 < Es
”・(2) Next, when the above-mentioned formula (2) holds true, that is, when the difference between the high-frequency echo signal edl and the low-frequency echo signal ed2 is less than the threshold value E3, which signal is activated by the electronic switch 40? It is set whether to allow the signal to pass through, or in other words, whether to display it on the CRT 46 (SrF4).

In this embodiment, the high frequency echo signal edl is selected. Therefore, when the formula (2) is satisfied, in this embodiment, the terminal 40a and the common terminal 40d in the electronic switch 40 are connected, and the high frequency echo signal edl is introduced into the buffer memory 44.

Next, when the above formula (1) holds true, that is, when the difference between the high frequency echo signal edl and the low frequency echo signal ed2 is a value equal to or greater than the threshold value E3, brightness modulation (in this embodiment, when brightening the brightness) is performed. Determine the hue to be applied (referred to as brightness modulation). This hue determines one of the standard colors described later or another specific color, such as pink or purple (SrF2). In this embodiment, pink color is selected.

Since the selection of the screen display mode is completed as described above, after pressing the screen display mode end key (not shown), the fish finding operation is started at a predetermined measurement depth.

In this case, the control unit 38 decodes the command and sends it to the transmitting/receiving unit 1.
A periodic signal corresponding to the measured depth is sent to a trigger generating section 20 constituting 2. Therefore, the trigger generating section 20 generates a trigger signal based on the periodic signal and sends it to the transmitting section 26. In this case, the high-frequency transmitter 22 and the low-frequency transmitter 24 transmit high-frequency ultrasonic pulses and low-frequency ultrasonic pulses gated by the trigger signal to the high-frequency transducer 33 and the low-frequency transducer 34, respectively. It is introduced into the receiving section 32. Next, the high-frequency transducer 33 and the low-frequency transducer 34 convert the high-frequency and low-frequency transmission pulses into high-frequency and low-frequency ultrasonic pulse signals, and emit them into the underwater M.

In this way, the high frequency transducer 33 and the low frequency transducer 3
The ultrasonic pulse signal of the two-layer liquid emitted from 4 into the ice M is the sea surface S lj% plankton layer P, fish school F and seabed S
It is reflected from a target object such as V and returns to the high frequency and low frequency transducers 33 and 34 again. In this case, a school of fish F with a small body such as milt and small fish reflects the high-frequency ultrasonic pulse signal well, and a school of relatively large fish F such as mackerel and mackerel reflects the ultrasonic pulse signal of high and low image frequencies. do. In this way, the reflected ultrasonic signal is received again by the high frequency and low frequency transducer 33, 34 and converted into an echo signal which is an electric signal.

Next, after being amplified by the high frequency and low frequency receiving section 28.30, the first and second A/D converters 37.39
will be introduced in

The high-frequency and low-frequency echo signals edl and ed2 as digital data, which are the output signals of the first and second A/D converters 37 and 39, are introduced into the arithmetic processing section 42, and the above-mentioned equations (1) and (2) are The comparison process shown in the equation is performed, and it is determined whether the signal to be introduced into the buffer memory 44, that is, the difference echo signal ed3 or the high-frequency echo signal edl, is on the terminal 40c side or the terminal 40a side of the electronic switch 40. It is selected by being switched.

Therefore, for example, the target fish schools F+, F2 and F
3 (not shown) and the signal level corresponding to the low frequency echo signal ed2 are as shown in Table 1, the echo signal introduced into the buffer memory 44 By considering that the threshold value E,=7, it will be understood that the signals shown in the rightmost column of Table 1 are introduced.

Table 1 Echo output signals e, introduced into the buffer memory 44
(i=1) is modulated into a predetermined color by the color/luminance modulation lookup table 47 for each signal level as shown below.

In this case, the look-up table 47 for color modulation is configured as shown in the schematic diagram of FIG. That is, when the level of the transmitted signal T is 40 dB, the echo signal e
1 level up to 21 dB is divided into 3 dB increments and assigned to colors ranging from light blue, blue, white to red. This lookup table 47 allows the buffer memory 44
Among the echo signals stored in the high-frequency echo signal edl
The display color of is determined to be green, corresponding to the target F1, and is introduced into the main memory 48. Further, the echo signals ed3 of the difference corresponding to the targets F2 and F3 are determined to be pink, which is a color whose luminance is modulated with a luminance corresponding to the magnitude of the difference, and is introduced into the main memory 48, as described above. The echo signal after color/luminance modulation recorded in the main memory 48 in this way is sent to the D/A converter 50 based on the address signal of the control section 38, and is sent to the D/A converter 50 in a color matrix (not shown) in the D/A converter 50. The circuit converts the signals into analog signals of the three primary colors of red, green, and blue, and supplies them to the CRT 46. In this case, the synchronization signal generator 52 uses the clock signal from the controller 38.
Color display is performed based on the synchronization signal generated from.

An example of an image displayed based on such a control sequence is shown in FIG. As shown in the figure, the target F1, which is equally reflected as the high-frequency echo signal e1 and the low-frequency echo signal e2, is displayed in green, and the target object F1, which is reflected equally as the high-frequency echo signal e1 and the low-frequency echo signal e2, is displayed in green. Target F2 is displayed in a slightly dark pink color, and also has a signal strength threshold of E.

Since the target F3 with a difference of more than =7 is displayed brighter in pink, it is estimated from the display screen that the green display is a relatively large school of fish such as mackerel and mackerel, and the darker pink color It is presumed that the display is a school of relatively small fish such as milt and small fish, and the bright pink display is estimated to be approximately the plankton layer.

[Effects of the Invention] As described above, according to the present invention, when displaying echo signals corresponding to ultrasound signals of different frequencies on a display such as a CRT, signal intensities of received echo signals are compared and calculated. ,
If the difference is less than a predetermined threshold, the echo signal from one of the frequencies is selected and displayed in the standard hue, while if the difference is greater than the threshold, the echo signal is displayed in the standard hue or A predetermined one among the other hues
In addition to setting the color, the brightness is modulated and displayed integrally on the same screen. Therefore, it is possible to accurately grasp the difference between images of two high and low frequencies from the same viewpoint. Moreover, when the difference is small, the image corresponding to the original echo signal from each frequency can be clearly distinguished from the part with a large difference without being processed more than necessary. Therefore, the person who determines the timing for casting a net, such as the fishery chief, can determine the optimal timing for casting a net from the image.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments.
For example, it is possible to make various improvements and design changes without departing from the gist of the present invention, such as increasing the ultrasonic frequency to a frequency higher than that of the two-layer liquid and displaying fish species in even more finely divided categories. Of course.

[Brief explanation of the drawing]

Figures 1a and b are explanatory diagrams showing the display state of echo signals in a fish finder to which a screen display method according to the prior art is applied, and Figure 2 is a fish finder to which a screen display method according to the present invention is applied. 3 is a schematic illustration of a look-up table set in the color modulation look-up table in the fish finder shown in FIG. 2, and FIG. 4 is a diagram of the screen display method according to the present invention. A flowchart explaining mode setting, FIG. 5 is an explanatory diagram of an image displayed on a CRT display constituting the fish finder. 10...Fish finder 12...Transmitting/receiving section 1
4... Main body processing section 16... Display section 18.
...Operation panel 26...Transmission section 32...
Receiving section 36...Transducer/receiver section P...Plankton layer M...Underwater F...Fish school
Sh...Ship Sv...Seafloor Sat...High frequency echo signal Sd2...Low frequency echo signal Sd3...Difference echo signal FIG, 1 (Q) (b)

Claims (5)

[Claims] (1) The present invention emits ultrasonic signals of different frequencies into the water, receives echo signals corresponding to the respective frequencies that are reflected from underwater targets, and transmits ultrasonic signals according to the signal levels of the respective echo signals. A fish finder screen display method for displaying the echo signals on a display by assigning different hue groups predetermined in advance, the method comprising: A screen display method for a fish finder, characterized in that a color of a different hue from the predetermined different hue groups is assigned and displayed. (2) After emitting ultrasonic signals of different frequencies into the water,
Receiving echo signals corresponding to respective frequencies reflected from underwater targets and displaying the echo signals on a display by assigning predetermined different hue groups according to the signal levels of the respective echo signals. A screen display method of a fish finder, which displays a specific hue among the predetermined different hue groups or other hues depending on the magnitude of the difference in signal level of echo signals corresponding to received respective frequencies. A screen display method for a fish finder characterized by displaying by modulating brightness. (3) In the method according to claim 1 or 2, a portion where a difference in signal level of the received echo signals corresponding to respective frequencies is equal to or greater than a predetermined value has a hue different from the predetermined different hue group. A specific hue among the predetermined different hue groups or other hues is displayed by modulating the brightness with a brightness according to the magnitude of the difference, and the portion where the difference is less than a predetermined value is displayed by one of the different hue groups or other hues. A screen display method for a fish finder, characterized in that frequency echo signals are displayed in a predetermined hue group. (4) In the method according to any one of claims 1 to 3, a difference in signal level of the received echo signals corresponding to each frequency is extracted, and the difference between the predetermined different hue groups and the different hue groups is determined based on the difference signal. A screen display method for a fish finder, characterized in that a specific hue is displayed by assigning different hues or by modulating the brightness of a specific hue among the predetermined different hue groups or other hues. (5) In the method according to any one of claims 1 to 3, the sum of the signal levels of the echo signals corresponding to each received frequency is extracted, and the predetermined different hue groups are determined based on the sum signal. A screen display method for a fish finder, characterized in that a specific hue is displayed by assigning different hues or by modulating the brightness of a specific hue among the predetermined different hue groups or other hues.