JP2846550B2 - Image position correction half-circle sonar device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display of a horizontal plane position and a direct distance mark of a reflection image in a reflection image display of a half-circle sonar device.

[0002]

2. Description of the Related Art An image display in a conventional half-circle sonar device displays an azimuth and a direct distance on a depression angle plane of a transducer. FIG. 4 is a diagram showing an example of the display screen. Assume now that the depression angle of the transducer is 60 °. Referring to FIG. 4, an image of the school of fish A is projected at a position 150 m away from the azimuth 30 ° left on the screen, and an image of the school of fish B is projected 100 m away from the azimuth 45 ° right. However, both the direction and the distance of these fish school images are on a plane with a depression angle of 60 °.

Accordingly, as can be seen from FIG. 5, the horizontal distance immediately above each school of fish is cos 60
It is a value obtained by multiplying ° = 0.5. That is, it is 75 m in the case of the fish school A and 50 m in the case of the fish school B. Further, the azimuth angle is large when viewed on a horizontal plane (on the sea surface).

[0004]

However, due to such a difference, when a fishing boat detects a school of fish and tries to approach directly above the school of fish, it is difficult to rely on the conventional image display. There has been a problem that the vehicle may go too far beyond the distance directly above or the traveling direction may be shifted.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, an object of the present invention is to provide a half-round image display for visually displaying the distance and direction to a position on the water surface directly above a school of fish or other target reflector in water. It is intended to provide a sonar device.

[0006]

The present invention has the following means in order to achieve the above object. That is, a first aspect of the present invention provides a transducer in which vibrators are arranged in a semicircular cylindrical shape, transmit and receive ultrasonic waves in a semicircular azimuth, and provide a depression angle θ by mechanically tilting; A transmitting unit for transmitting an ultrasonic frequency electric signal to the transmitter / receiver; a pencil-shaped directional receiver that receives a received signal received by the transmitter / receiver and scans the azimuth in a half-circumferential azimuth by a separately received received azimuth signal A receiving unit that forms a beam and outputs a received signal based on the received beam; an A / D converter that converts the received signal into a digital signal; and counts an elapsed time from a time point when the transmitting unit transmits a pulse. A azimuth / distance generator for outputting a azimuth signal indicating the azimuth α of the azimuth scan of the azimuth and distance information L; a depression angle θ of the transmitter / receiver, and an azimuth α and distance information from the azimuth distance generator Receiving L and reflecting target from transducer The distance L ′ to the horizontal plane projection position is calculated and output by Expression 5 or a modified expression thereof,

[0007]

(Equation 5)

Similarly, the azimuth α ′ of the horizontal projection position is calculated and output according to Equation 6, Equation 7, Equation 8, or a modified equation thereof.

[0009]

(Equation 6)

[0010]

(Equation 7)

[0011]

(Equation 8)

An arithmetic unit; a coordinate conversion unit for converting a polar coordinate position comprising the distance L 'and the azimuth α' obtained by the arithmetic unit into a rectangular coordinate address; digital reception converted by the A / D converter A video RAM for storing a signal in accordance with the rectangular coordinate address converted by the coordinate conversion unit; a distance mark generating unit; a display device for reading out the received video stored in the video RAM by raster scanning and displaying a video with a distance mark; An image position correction half-circle sonar device, comprising:

According to a second aspect of the present invention, a distance mark generation unit includes a semicircular distance mark indicating a predetermined distance centered on the position of the transducer, and a depression angle θ in the direction of the transducer azimuth center. 2. An image position correcting half-circle sonar device according to claim 1, wherein two types of distance marks, which are elliptical distance marks compressed by a factor of cos [theta], are generated by selecting one or both of them at the same time.

[0014]

The operation of the image position correcting half-circle sonar device of the present invention having the above-described structure will be described below. FIG. 2 is a diagram showing a projection position Q ′ point on the horizontal plane of a reflection target at a point Q at an azimuth angle α and a distance L on a plane with a depression angle θ from the own ship position (position of the transducer) at a depression angle θ. The azimuth of the Q 'point on the horizontal plane is indicated by α', and the distance is indicated by L '. L ′ and α ′ are obtained from this figure. First, L 'is obtained. L ′ is obtained by Pythagorean theorem by Expression 9.

[0015]

(Equation 9)

D in Equation 9 is obtained by Equation 10;

[0017]

D = R sin θ

R in equation (10) is obtained by equation (11).

[0019]

R = L cosα

Therefore, when Equation 11 is substituted into Equation 10 and Equation 10 is substituted into Equation 9, L 'is obtained by Equation 12.

[0021]

(Equation 12)

Next, α 'is obtained. First, when R ₁ is obtained from L ′ and α ′, Equation 13 is obtained.

[0023]

R ₁ = L ′ cosα ′

By the way L 'is because given in Equation 12 R ₁ is as Equation 14.

[0025]

[Equation 14]

On the other hand, R ₁ can be obtained from R and θ according to equation (15).

[0027]

R ₁ = R cos θ

By the way, when R is given by Expression 11, when this is substituted into Expression 15, Expression 15 becomes Expression 16.

[0029]

R ₁ = L cosα · cos θ

Therefore, from equations (14) and (16), R ₁ and L
Is eliminated, cos α ′ is obtained as in equation (17).

[0031]

[Equation 17]

Therefore, α 'is obtained as shown in Expression 18.

[0033]

(Equation 18)

Further, using the formula of Expression 19,

[0035]

[Equation 19]

By substituting Equation 17 into this and performing a deformation operation, Equation 20 is obtained.

[0037]

(Equation 20)

Therefore, α 'can be obtained as shown in Expression 21.

[0039]

(Equation 21)

Further, if the left and right sides of Equation 20 are divided by the right and left sides of Equation 17, Equation 22 is obtained.

[0041]

(Equation 22)

Α ′ can also be obtained as shown in Expression 23.

[0043]

(Equation 23)

In this manner, the azimuth α ′ and the distance L ′ of the position Q on the horizontal plane at the horizontal projection position Q ′ are known from the depression angle θ and the azimuth α and the distance L of the target position Q on the plane of the depression angle θ. Therefore, the azimuth and the distance in the horizontal plane can be displayed on the screen.

In this case, the direct distance to the target position Q on the depression angle plane cannot be known only by the distance mark indicating the distance on the horizontal plane, but the distance mark obtained by projecting the semicircular distance mark on the plane at the depression angle θ onto the horizontal plane is obtained. If it is used, the direct distance to the target on the depression angle plane can be known. FIG. 3 illustrates this relationship.

In FIG. 3A, reference numeral 13 denotes a semicircle having a radius R on the depression angle plane of the depression angle θ. When this semicircle 13 is projected on a horizontal plane, the distance from the base line to each point on the projected curve is cosθ times the distance to each point on the semicircle 13 as is apparent from FIG. Therefore, when this is illustrated, the semi-ellipse 14 has a major axis of 2R and a minor axis of 2R cos θ.
If this semiellipse 14 is displayed as a distance mark of the distance R on the depression angle plane as needed, the direct distance to the target can be known.

In the present invention, the azimuth distance generating unit obtains the azimuth α on the depression angle plane and the distance information L and sends them to the calculation unit. In addition to the azimuth angle α and the distance information L, the depression angle θ of the transducer is input to the calculation unit, the distance L ′ in the horizontal plane is calculated by Expression 12, and the azimuth α ′ in the horizontal plane is calculated by Expression 1.
8 or Equation 21 or Equation 23 or a modified version thereof.

Since the position display based on the azimuth α ′ and the distance L ′ on the horizontal plane thus calculated is a position display based on polar coordinates, the image R having the address of the rectangular coordinate system is displayed.
Since the address for storing the received signal in the AM cannot be used as it is, the position represented by α ′ and L ′ is converted into a position display (address) in the rectangular coordinate system by the coordinate conversion unit.

On the other hand, the received signal from the receiving unit, which is received by the received beam that is azimuthally scanned by the azimuth signal from the azimuth distance generation unit in the half azimuth at the depression angle θ, is converted into a digital signal by the A / D conversion unit. After being converted, it is sent to the video RAM,
The data is stored in the memory position specified by the rectangular coordinate address from the coordinate conversion unit.

Thus, the image obtained by projecting the image on the depression angle plane onto the horizontal plane is stored in the image RAM. The image stored in the image RAM is read out together with the distance mark of the distance mark generation unit by a raster scanning signal from the display device and displayed on the cathode ray tube of the display device. When the distance mark is semicircular, it indicates the distance on the horizontal plane, and when it is semielliptical, it indicates the distance on the depression angle plane.

[0051]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of an image position correcting half-circle sonar apparatus according to the present invention. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. The azimuth distance generation unit 5 has a reference clock generation circuit. The azimuth distance generation unit 5 generates a transmission timing signal having a constant period from the reference clock and sends it to the transmission unit 4. In addition, an azimuth signal indicating an azimuth angle α for azimuthally scanning the receiving beam is transmitted to the receiving unit 2. Further, the distance information L is generated by measuring the elapsed time from the transmission time of the transmission unit 4. The transmission unit 4 is activated by the transmission timing signal to generate a pulse-like ultrasonic frequency electric signal, which is transmitted to the transducer 1 via the transmission / reception switch 12.

The transducer 1 has a vibrator arranged in a semicircular cylindrical shape, and transmits an ultrasonic wave in a semicircular azimuth by an input electric signal. The depression angle is given by mechanically tilting the transducer 1 so that the angle θ can be known. Ultrasonic waves that are reflected back from a reflection target such as a school of fish in each direction are also received by the transmitter / receiver 1, converted into electric signals, and transmitted to the receiver 2 via the transmission / reception switch 12.

The receiving unit 2 forms a pencil-shaped directional receiving beam by an internal phase shift circuit, and uses the azimuth signal indicating the azimuth α from the azimuth distance generating unit 5 to azimuth the receiving beam within a half-circumferential azimuth. Scan. The received signal received by the received beam that is azimuthally scanned is converted into a digital signal by the A / D converter 3.

The arithmetic section 6 receives the signal of the azimuth angle α and the distance information L from the azimuth distance generating section 5 and further receives the depression angle θ from the depression angle detecting circuit or the depression angle specifying circuit of the transducer 1, and
Is calculated to obtain the distance L ′ on the horizontal plane.
8, the azimuth α ′ in the horizontal plane is obtained by one of the equations (21) and (23). The obtained distance L 'and azimuth α' are applied to a coordinate conversion unit 7 and converted into rectangular coordinate addresses. Now, assuming that the horizontal coordinate of the orthogonal coordinate is X and the vertical coordinate is Y, the conversion is performed as in Expressions 24 and 25.

[0055]

X = L'cos α '

[0056]

## EQU25 ## Y = L'sin α '

The rectangular coordinate address (XY
Address) is sent to the address control unit 8. A raster scanning signal (sweep signal) for reading is sent from the display device 11 to the address control unit 8. The address at the time of writing and the address at the time of reading are switched in a time division manner and sent to the video RAM 9. I have. At the time of writing, an XY address from the coordinate conversion unit 7 and a write control signal for instructing writing are sent to the video RAM 9.

On the other hand, a digital reception signal is input from the A / D converter 3 to the image RAM 9, and this reception signal is written (stored) in the storage element of the designated XY address, and the horizontal plane projection image is obtained. Is formed. At the time of reading, the video RAM
A raster scanning address is sent to 9 and read out by raster scanning, sent to a display device, and displayed on a raster scanning display CRT.

The raster scanning signal (sweep signal) from the display device 11 is also sent to the distance mark generator 10. At the time of reading, the distance mark signal is sent to the display device 11 while being superimposed on the video signal from the video RAM 9. ing. The signal of the depression angle θ is sent to the distance mark generation unit 10. If necessary, the distance mark on the depression angle plane can be formed by converting the semicircular distance mark into a semi-elliptical shape compressed by cos θ. Has become. Depending on the selection, the distance mark can be displayed with only a semicircular distance mark, only with a semi-elliptical distance mark, or with both.

[0060]

As described above, the video position correcting half-circle sonar device of the present invention converts a video signal obtained on the plane with the depression angle θ so as to be displayed as a video projected on a horizontal plane. The advantage is that the position on the water surface just above the target can be accurately recognized and grasped, and when a school of fish is detected, it is very easy for the fishing boat to reach directly above it, that is, there is not enough or too much The advantage is that it is easy to judge the length of the cast net because it can know the direct distance to the school of fish if necessary. Bring.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram for obtaining an azimuth and a distance of a projection position of a target on a horizontal plane on a depression angle plane.

FIG. 3 is an explanatory diagram in the case where a semicircle of a distance R on a depression angle plane of a depression angle θ is projected on a horizontal plane.

FIG. 4 is a diagram showing an example of a display screen of a conventional half-circle sonar device.

5 is a diagram showing that the horizontal distance to fish school A and fish school B in FIG. 4 is shorter than the distance read in FIG. 4;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 transducer 2 receiver 3 A / D converter 4 transmitter 5 azimuth distance generator 6 calculator 7 coordinate converter 8 address controller 9 video RAM 10 distance mark generator 11 display device 12 transmission / reception switch 13 depression plane Semicircle with radius R at 14

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-90874 (JP, A) JP-A-54-72080 (JP, A) JP-A-60-78372 (JP, A) 61479 (JP, A) JP-A-57-103077 (JP, A) JP-A-3-503801 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01S 7/62 G01S 15 / 96 G01S 7/04-7/298

Claims (2)

(57) [Claims] 1. A transducer in which vibrators are arranged in a semicircular cylindrical shape, transmit and receive ultrasonic waves in a semicircular azimuth, and give a depression angle θ by mechanically tilting; A transmission unit for transmitting an electric signal to the transducer;
Receiving a received signal received by the transmitter / receiver, forming a pencil-shaped directional receiving beam for azimuthally scanning in a half azimuth direction by a separately received receiving direction signal, and outputting a received signal by the received beam An A / D converter for converting the received signal into a digital signal; and a receiving direction indicating the azimuth α of the receiving direction scanning by measuring an elapsed time from a time point when the transmitting unit transmits a pulse. An azimuth / distance generator for outputting a signal and distance information L; receiving a depression angle θ of the transducer and an azimuth α from the azimuth distance generator and the distance information L, from the transducer to a horizontal projection position of a reflection target. Distance L '
Is calculated and output by Expression 1 or a modified expression thereof, and Similarly, the azimuth α ′ of the horizontal projection position is expressed by Equation 2 or Equation 3.
Alternatively, the output is calculated by Equation 4 or its modified expression. (Equation 3) (Equation 4) An operation unit; a coordinate conversion unit that converts a polar coordinate position consisting of the distance L ′ and the azimuth α ′ obtained by the operation unit into a rectangular coordinate address; and a digital reception signal converted by the A / D converter. A video RAM for storing in accordance with the orthogonal coordinate addresses converted by the coordinate conversion unit; a distance mark generation unit; and a display device for reading out the received video stored in the video RAM by raster scanning and displaying a video with the distance mark. An image position correcting half-circle sonar device. 2. A distance mark generating section, comprising: a semicircular distance mark indicating a predetermined distance centered on the position of the transducer; and a compression of the distance mark by cos θ times the depression angle θ in the direction of the transducer azimuth. 2. An image position correcting half-circle sonar device according to claim 1, wherein only one of the two types of distance marks of the elliptical distance mark or both of them are generated simultaneously by selection.