JPS6222104B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an imaging device that automatically directs an imaging field of view toward a target and automatically tracks the target.

Conventionally, as a method of directing the imaging field of view of an imaging device toward a target, the imaging device is mounted on a mount that can control the orientation.
There is a method in which a captured image signal is displayed on a monitor scope and a person instructs the user to place the target image in the center of the visual field using a joy stick or a light pen. In the case of this method, a link is required to transmit the captured image signal and the orientation control signal between the imaging device and the place where the person is present. Conventionally, the tracking device extracts image signals obtained in two axial directions across the target, compares them into binary values at an appropriate level, and calculates the difference between the previously compared signal and the currently compared signal. There is a method in which when the target does not move, the differential output is zero, and when the target moves, a differential output proportional to the amount of movement is obtained, and this output is used to move the azimuth control frame. In this method, the difference output may differ from the actual amount of movement depending on the shape of the target and the direction of movement. Further, when target movement is detected and the direction of the imaging field of view is changed, a differential output equivalent to that when the target moves in the opposite direction as the field of view moves is generated, making it difficult to control in the target direction.

The present invention has a plurality of photodetectors in the imaging optical system, and indirectly directs the imaging field of view toward the target by detecting the light emitted by the target object or the reflected light of the irradiated light. , target characteristics (one or more of brightness, hue, size, and shape) of the image signal obtained by the imaging photodetector
The above-mentioned drawbacks are solved by extracting objects with the same characteristics from within the imaging field of view using the system, and the system automatically faces the target and provides tracking imaging.

The tracking imaging device of the present invention includes an imaging optical system that detects light from a target and has a plurality of first detectors arranged on a plane in an imaging optical path, and an imaging optical system that detects light from a target. a second imaging photodetector installed at an imaging position; a drive circuit for rotating the first photodetector around an optical axis of an imaging optical path; and detecting a rotation angle of the first photodetector. a coordinate converter for determining the direction of the incoming light with respect to the optical axis from each photodetector output signal obtained by the first photodetector; a storage device for extracting and storing a signal indicating at least one characteristic of the brightness, hue, size, and shape of the target from the image signal obtained from the image signal obtained from the second imaging photodetector; a comparator that searches for a feature that matches the feature of the target stored in a memory; an angle detector that determines the angular error from the center of the visual field of the object for which a match is found by the comparator; and an output of the coordinate converter. Alternatively, it is configured to include an azimuth controller that controls the visual field azimuth of the optical system based on the output of the angle detector.

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

FIG. 1 shows an embodiment of the optical system and photodetector of the tracking imaging device of the present invention, and FIG. 2 shows an example of the optical system and photodetector of the tracking imaging device of the present invention. This is a view seen from the side, and the symbols in the figure correspond to the components with the same symbols shown in FIG. FIG. 3 shows a system diagram of a tracking imaging device constructed using the optical system shown in FIG. 1.

In FIG. 1, A is a primary reflecting mirror constituting a Cassegrain optical system, and incident light is reflected toward a secondary reflecting mirror C supported by three pillars B.
As shown in Fig. 2, three optical filters D are attached to the secondary reflecting mirror C, which transmits the light having the wavelength for target detection contained in the incident light.
to the first photodetector. In FIG. 1, the light reflected from the portions without the three optical filters D forms an image on the second imaging detector F. G is A, B,
It is a rotating sphere for rotating the Cassegrain optical system consisting of C, D and E and the first photodetector around the optical axis, and by rotating around the optical axis, the secondary reflecting mirror of C This eliminates the space that is not imaged by the optical filter that creates the non-reflective area above. A magnet H is used to electrically create a rotor magnetic field to provide rotation around the optical axis, and to indirectly measure the rotation angle by the detection coil I.

FIG. 3 is a system diagram of the tracking imaging device. In FIG. 3, 1 is a system diagram of the tracking imaging device. It is an azimuth controller that controls the azimuth. 2 is a drive circuit for rotating the optical system 3 and the photodetector 4 around the optical axis. The reflected light of the pulsed laser beam irradiated from the pulsed laser transmitter 26 toward the target object 27 and the light emitted by the target object 27 are collected by the optical system 3, and the pulsed laser reflected light is transmitted to the photodetector 4. Therefore, it is converted into a pulse signal, which passes through the slip ring 6 and is taken out from the imaging section.

The light emitted by the target object 27 that has entered the optical system 3 is converted into an image signal by the imaging photodetector and extracted from the imaging section. Each pulse signal taken out through the slip ring 6 is provided to match the transmission time of the pulse signal with the detection delay time of the light amount detector 7 and the light amount detector 7 for determining the total amount of light incident on the photodetector 4. The signal is guided to a delay circuit 8. The pulse signal time-adjusted by the delay circuit 8 is guided to the gain adjustment amplifier 9, and is amplified and outputted by the output of the light amount detector 7 so that the sum of the amplifier output signals always maintains a constant value. . The output amplified by the gain adjustment amplifier 9 is guided to a difference detector 10, where an error signal in a two-dimensional polar coordinate format centered on the optical axis and with one of the three photodetectors 4 as a reference is determined. It will be done. 11 is a coil that detects the rotation angle rotating around the optical axis of the optical system;
is a sample hold that extracts the rotation angle at the moment when the photodetector 4 detects light. The rotation angle obtained from the sample hold 12 and the error signal output of the difference detector 10 are led to a coordinate converter 13 and output as error outputs for two orthogonal control axes (EL and AZ axes in FIG. 2) of the azimuth controller 1. The coordinates are transformed and guided to the switch 23. If the switch 23 is configured to select the output of the coordinate converter 13, the coordinate converter 13
The error output of is guided to the direction controller 1 and the photodetector 4
A tracking imaging loop is realized.

In FIG. 3, reference numeral 24 denotes a sample signal generator, and a scanning signal generator 25 for scanning the instantaneous field of view of the imaging photodetector 5 with an error signal for the center of the field of view selected by the switch 23 and guided to the azimuth controller 1. A sample pulse is generated for extracting a signal indicating the target from the image signal output of the imaging photodetector 5 from the scanning signal of the image pickup photodetector 5. In accordance with the sample pulse, the sample hold 14 samples and holds an image signal value corresponding to the target brightness, and stores it in the memory 18. Reference numeral 15 denotes a brightness extractor which extracts a portion that matches the target brightness from the image signal of the imaging detector 5 based on the past target brightness stored in the memory 18, and extracts the signal during the period of time when the brightness matches. occurs.
The output signal of this brightness extractor is led to a width detector 16, where it is converted into a signal proportional to the width of the object whose brightness matches, and is also led to a size detector 17, where it is converted to a size by performing integration. converted into a proportional signal. The output of width detector 16 is directed to memory 18 and comparator 19. Comparator 19 is memory 18
The past target width signal obtained from the width detector 16 is compared with the output of the width detector 16, and if a similar value occurs, an output signal is output. The output of magnitude detector 17 is directed to memory 18 and comparator 20. Comparator 20 is memory 18
The past target and integral values obtained from the magnitude detector 17 are compared with the output of the magnitude detector 17, and if a similar value occurs, an output signal is output. The outputs of comparator 19 and comparator 20 are
It is led to an AND circuit 21 and outputs when both comparators determine that both are close to the target.

The output of this AND circuit 21 is led to a memory 18 and used as a command signal to store the output of the width detector 16 and the output of the size detector 17.
This signal is used to determine the angular error of the target relative to the center of the field of view. When the switch 23 is switched to select the output of the angle detector 22, the error angle from the center of the visual field of the target determined by the imaging photodetector 5 is guided to the azimuth controller 1, and tracking imaging is performed to place the target at the center of the visual field. The loop is visible.

The embodiment shown in Fig. 3 is a method that uses the brightness, shape, and size characteristics of the target, but which of the target characteristics to use is determined based on the characteristics of objects other than the target that exist within the field of view. Even if this selection is made and another combination is made, the tracking imaging device is established.

As explained above, the present invention configures a tracking loop using the first photodetector and the second imaging photodetector, so that, especially when the tracking imaging device of the present invention is mounted on a flying object or the like, It eliminates the need for a transmission link between the flying object and the ground in order to direct the field of view to the captured image signal and the target direction, and it also becomes possible to teach the flying object the target and follow it, improving target selectivity. It is also effective in reducing the size and weight of the flying body.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the optical system and photodetector of the tracking device of the present invention, and FIG. 2 is a diagram showing a secondary reflecting mirror that constitutes the optical system of FIG. 1, viewed from the imaging photodetector. FIG. 3 is a system diagram showing an embodiment of a tracking imaging device constructed using the optical system shown in FIG. 1. A...Primary reflecting mirror, B...post, C...secondary reflecting mirror, D...optical filter, E...first photodetector, F...second imaging photodetector, G... …Rotating ball,
H...Magnet, I...Detection coil, 1...Direction controller, 2...Drive circuit, 3...Optical system, 4...Photodetector, 5...Imaging photodetector, 6...Slip ring , 7... Light amount detector, 8... Delay circuit, 9...
Gain adjustment amplifier, 10... Difference detector, 11... Coil, 12... Sample hold, 13... Coordinate converter, 14... Sample hold, 15... Brightness extractor, 16... Width detector, 17 ...Size detector, 18...Memory device, 19,20...Comparator,
21...AND circuit, 22...Angle detector, 23
...Switcher, 24...Sample signal generator, 25
...Scanning signal generator, 26...Pulse laser transmitter, 27...Target.

Claims (1)

[Claims] 1 Abbreviation for detecting light from a target - an imaging optical system that has a plurality of first photodetectors arranged on a plane in the imaging optical path, and installation at the imaging position created by the optical system a second imaging photodetector;
a drive circuit for rotating the photodetector around the optical axis of the imaging optical path, a coil for detecting the rotation angle of the first photodetector, and a photodetector obtained by the first photodetector. A coordinate converter that determines the direction of the incoming light with respect to the optical axis from each first photodetector output signal, and a coordinate converter that determines the brightness, hue, size, and shape of the target from the image signal obtained from the second imaging photodetector. a storage device for extracting and storing a signal indicating at least one feature of the target; and searching for a signal that matches the target feature stored in the storage device from an image signal obtained from the second imaging photodetector. a comparator, an angle detector for determining the angular error from the center of the visual field of the object for which a match is obtained by the comparator, and a visual field direction of the optical system is controlled by the output of the coordinate converter or the output of the angle detector. A tracking imaging device comprising: an azimuth controller;