JP2730479B2 - Pixel shift detector for optical camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pixel shift detecting device for an optical camera, and more particularly to a pixel shift detecting device for an optical camera which detects a pixel shift of an optical camera mounted on a spacecraft such as an artificial satellite. Things.

[0002]

2. Description of the Related Art In a multi-band optical camera mounted on a space vehicle such as an artificial satellite, each band element deviates from an optimum value due to vibration at the time of launch of the space vehicle, or pixel deviation between bands occurs. May occur.
Conventionally, in such a multi-band optical camera, when the above-described displacement of each band element or pixel displacement between bands has occurred, there has been no camera that directly detects these displacements inside the camera. Therefore, the deviation of each band element from the optimal position and the pixel deviation between bands, which have occurred after the launch of the spacecraft, could not be recognized until the data photographed by the multi-band optical camera was processed on the ground.

In the technique disclosed in Japanese Patent Application Laid-Open No. 3-239942, a method has been proposed in which a reference cross slit plate is added to an internal light source calibrating device to detect a pixel shift for each band of an optical camera. I have. This corrects the detected pixel shift by moving the photodetector of the optical camera on the artificial satellite based on the detection result,
This eliminates the need for complicated image correction relating to pixel shift on the ground.

[0004]

Therefore, in such a conventional multi-band optical camera, according to the former method, the deviation of each band element from the optimum position and the pixel deviation between the bands are detected on the spacecraft. Since it is not directly detected, after acquiring data from the multi-band optical camera in which the pixel shift has occurred, the data is evaluated and analyzed on the ground to detect the pixel shift, and in this case, complicated pixel shift is performed. There is a problem that it is necessary to perform a detection operation, and there is a limit in improving the accuracy of detecting a pixel shift. According to the latter method, a pixel shift is detected using a reference cross slit. Therefore, a pixel shift cannot be detected during observation with a multi-band optical camera, and a driving mechanism for inserting and removing the reference cross slit is also required. There is a problem that the number of components mounted on the navigation body increases and the reliability decreases. An object of the present invention is to solve such a problem, and an object of the present invention is to provide a pixel shift detecting device of an optical camera capable of accurately detecting a pixel shift even during observation without increasing the number of components. And

[0005]

In order to achieve the above object, an apparatus for detecting a pixel shift of an optical camera according to the present invention comprises an observation optical system for observing an object to be photographed, and an observation field of view of the observation optical system. An observation image sensor that captures an image in the corner,
Irradiating means for irradiating the observation optical system with laser light at a predetermined angle, and a laser disposed near the observation image pickup device and having a two-dimensionally expanded light receiving surface, and irradiated from the irradiating means A light-receiving sensor that spot-receives light on a light-receiving surface; and a light-receiving data processing unit that measures a light-receiving position of the laser light on the light-receiving surface of the light-receiving sensor and calculates a pixel shift amount of the observation image sensor based on the measured light-receiving position. It is provided. The irradiating means irradiates the observation optical system with laser light at a predetermined angle from outside the observation viewing angle of the observation optical system. In addition, the light reception data processing means, according to the positional relationship between the observation imaging element and the light reception sensor,
The pixel shift amount of the observation image sensor is calculated based on the light receiving position of the laser beam on the light receiving surface of the light receiving sensor and the reference position on the light receiving surface of the light receiving sensor of the observation image sensor measured in advance during adjustment. It is. Further, the light receiving sensor comprises a large number of light receiving elements which form a two-dimensionally expanded light receiving surface and output a light receiving signal indicating a light receiving level in accordance with driving, and the light receiving data processing means outputs a predetermined reference clock. A light-receiving element driving unit that drives each light-receiving element of the light-receiving sensor by surface scanning based on the reference clock, and sequentially calculates a scanning position on the light-receiving sensor based on the reference clock, and outputs laser light from the irradiation unit. A scanning position calculating means for outputting scanning coordinate data indicating a scanning position of the light receiving element based on a light receiving signal output when the light receiving element receiving the spot light is driven; A memory for storing reference coordinate data indicating a reference position at which a spot of the laser light from the irradiation unit measured in advance is received, and a scanning position calculation Those comprising calculating means for calculating a pixel shift amount based on the reference coordinate data of the scanning coordinate data and memory from stage.

[0006]

Accordingly, the irradiating means irradiates the observation optical system with a laser beam at a predetermined angle, and the light receiving data processing means causes the light receiving surface of the light receiving sensor arranged near the observation image pickup device of the observation optical system. The light receiving position of the laser beam at is measured, and the pixel shift amount of the observation image sensor is calculated based on the measured light receiving position. The irradiation unit irradiates the observation optical system with laser light at a predetermined angle from outside the observation viewing angle of the observation optical system. Further, according to the positional relationship between the observation imaging element and the light receiving sensor,
The pixel shift amount of the observation image pickup device is calculated based on the light receiving position of the laser beam on the light reception surface of the light reception sensor and the reference position on the light reception surface of the light reception sensor of the observation image pickup device which is measured in advance during adjustment. Further, the light receiving sensor is composed of a large number of light receiving elements constituting a light receiving surface that is two-dimensionally developed, and each light receiving element of the light receiving sensor is surfaced based on a predetermined reference clock by light receiving element driving means of light receiving data processing means. Driven by scanning, the scanning position calculating means outputs scanning coordinate data indicating the scanning position of the light receiving element spot-receiving the laser beam based on the reference clock, and the calculating means outputs the scanning coordinate data from the scanning position calculating means. The pixel shift amount is calculated based on the reference coordinate data indicating the reference position measured in advance in the memory.

[0007]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing a pixel shift detecting device of an optical camera according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an observation target, 2 denotes an optical camera main body that photographs the observation target 1 and outputs various image data, and 8 denotes an optical data processing unit that calculates a pixel shift amount based on image data from the optical camera main body 2. is there. In the optical camera body 2, 3A and 3B are two optical system condenser lenses arranged on the central axis of the cylindrical optical camera body 2, and 4 is arranged behind the optical system condenser lenses 3A and 3B. An optical system spectral lens that splits the image condensed by these condenser lenses by transmission and reflection;
Reference numerals 7A and 7B denote observation imaging elements which are disposed so as to have an angle of 90 ° with respect to the optical axes of the transmitted light and the reflected light, and convert an image spectrally separated by the optical system spectral lens 4 into image data.

Reference numeral 5 denotes a laser light emitting device which is disposed on the inner peripheral portion of the distal end of the optical camera body 2 and irradiates the optical system condenser lens 3A with laser light, and 6A and 6B each comprise a two-dimensional CCD element or the like. This is a laser light receiving sensor that converts the laser light from the laser light emitting device 5 into measurement data including a light receiving position and a light receiving amount, and has the same positional relationship on the same holding mechanism as the observation imaging elements 7A and 7B. It is arranged in.

Next, the operation of the present invention will be described with reference to FIG. The image of the observation target 1 is condensed within the range of the observation viewing angle α of the optical system condenser lenses 3A and 3B incorporated in the optical camera main body 2, and is condensed on the optical system spectral lens 4. The optical system spectral lens 4 disperses the images condensed by the optical system condenser lenses 3A and 3B,
A, 7B, and an image of the observation target 1 is acquired by the observation imaging devices 7A, 7B, converted into electric signals, and transmitted to the ground as observation data.

A laser light emitting device 5 for irradiating the optical system condenser lens 3A with laser light from outside the range of the observation viewing angle α is incorporated at the tip of the optical camera body 2.
The laser light emitted from the laser light emitting device 5 passes through the optical condenser lenses 3A and 3B and the optical spectral lens 4, and the laser light receiving sensor 6A disposed near the observation imaging elements 7A and 7B. , 6B, is converted into an electric signal composed of a light receiving position and a light receiving amount of the laser light, and is output to the light receiving data processing unit 8 as measurement data.

The received light data processing unit 8 includes the observation image pickup device 7
Pixels of the observation imaging elements 7A, 7B are processed by processing measurement data from the laser light receiving sensors 6A, 6B, which are physically displaced in association with A, 7B, and calculating the deviations of the laser light receiving sensors 6A, 6B. The shift amount is calculated. That is, the received light data processing unit 8 includes the observation image pickup devices 7A and 7B.
Is stored at the optimum position, measurement data from the laser light receiving sensors 6A and 6B measured in advance during the assembling adjustment on the ground, for example, reference position data including coordinate data to be described later is stored. Based on the position data and the measurement data from the laser light receiving sensors 6A and 6B, the displacement of the laser light receiving sensors 6A and 6B is calculated, and the observation image pickup device provided in the same holding mechanism as the laser light receiving sensors 6A and 6B. The pixel shift amounts of the observation imaging devices 7A and 7B are calculated according to the positional relationship with the observation image sensors 7A and 7B.

FIG. 2 is an explanatory diagram showing an image forming state in the laser light receiving sensor 6A and the observation image pickup device 7A.
In the figure, reference numeral 1a denotes observation light from the observation target 1, 5a denotes laser light emitted from the laser light emitting device 5, only the laser light 5a is imaged on the laser light receiving sensor 6A, and the observation image sensor 7A Is the observation light 1a from the observation target 1.
Only one is to be imaged. That is, the observation light 1a is incident on the optical system condenser lens 3A at an incident angle θ1 = 90.
When the light enters at ゜, the observation light 1a forms an image on the observation image sensor 7A. On the other hand, as the incident angle θ1 to the optical system condenser lens 3A decreases, the image forming position of the incident light moves toward the laser light receiving sensor 6A.

Therefore, by installing the laser light emitting device 5 such that the incident angle θ2 of the laser beam 5a with respect to the optical system condenser lens 3A is smaller than the incident angle θ1 of the observation light 1a, the optical system condenser lens 3A Only the laser beam 5a from the laser beam emitting device 5 can be imaged on the laser beam receiving sensor 6A installed outside the central axis. It should be noted that this is a laser light receiving sensor 6B and an observation image sensor 7B
The same applies to the relationship between
Only the laser light 5a from the laser light emitting device 5 is imaged on B, and only the observation light 1a from the observation target 1 is imaged on the observation imaging element 7B.

FIG. 3 is an explanatory view showing an image forming state of laser light in the laser light receiving sensor 6A. In FIG. 3, a represents a case where the observation image pickup device 7A is at an optimum position.
A reference position indicating an imaging point located at the center on the laser light receiving sensor 6A measured and stored in advance during assembly adjustment on the ground, and b is a laser light receiving sensor measured when the spacecraft is in orbit. 6A is an image forming position on 6A. The light reception data processing unit 8 compares the coordinates indicating the image formation position b output from the laser light reception sensor 6A with the coordinates of the reference position a stored in advance and stores these coordinates in the X-axis and Y-axis directions. The differences Δx and Δy are calculated.

Here, the differences Δx and Δy calculated based on the measurement data from the laser light receiving sensor 6A are pixel shifts in the X-axis direction and the Y-axis direction of the observation image pickup device 7A provided in the same holding mechanism. Since the amount is equal to the amount, it is possible to detect a deviation from the optimum position of the observation imaging element 7A and a pixel deviation between the bands based on the deviation amount. The same applies to the relationship between the laser light receiving sensor 6B and the observation imaging device 7B. The coordinates of the image forming position b output from the laser light receiving sensor 6B and the observation imaging device 7B The deviation from the optimal position of the observation image pickup device 7B and the pixel deviation between the bands are detected from the differences Δx and Δy from the coordinates of the reference position a, which is the image forming position when is at the optimal position.

Next, the details of the detection of a pixel shift will be described with reference to FIGS. FIG. 4 shows a laser light receiving sensor 6A,
FIG. 5 is an explanatory diagram showing a light receiving surface of FIG. 6B, and FIG. 5 is a block diagram showing an example of the light receiving data processing unit 8 of FIG. In FIG. 4, the light receiving surfaces of the laser light receiving sensors 6A and 6B are composed of a large number of n columns × m rows of light receiving elements that are two-dimensionally developed, and each element is sequentially driven at a constant period by surface scanning. Then, a light receiving signal corresponding to each light receiving level is output.

In this case, the order of driving and outputting the light receiving signal is as follows, with the element E1 in the first row shown in FIG. 4 being the first, followed by the elements E2, E3,. Then, the process proceeds to the next row, and the signal of the element En + 1 in the second row is output. Further, the other elements are sequentially driven,
When the signal of the last element m × n of the light receiving surface is output, the operation returns to the beginning and the same operation is repeated from the element E1. As a result, if the arrangement of each element is known in advance, the drive time of each element is constant, and the current drive is performed by counting the drive time from E1 based on the drive start time of element E1. The light receiving element can be recognized.

FIG. 5 is a block diagram showing a light receiving data processing unit 8 for detecting a pixel shift based on such a principle. In FIG. 5, reference numeral 11 denotes a reference clock which is output and a laser beam is output based on the reference clock. A light-receiving element driving driver for sequentially driving the respective light-receiving elements on the light receiving sensors 6A and 6B, 10 is a preamplifier circuit for amplifying signals from the laser light receiving sensors 6A and 6B, and 12 and 13 are light-receiving element driving drivers 11. X-axis counter and Y-axis which output the X-axis and Y-axis coordinate values of the currently driven light receiving element by counting the driving time based on the reference clock of
Axis counters 14 are arithmetic circuits for calculating differences Δx and Δy between coordinate outputs from the X-axis counter 12 and the Y-axis counter 13 and reference coordinate data stored in the memory 15 in advance.

The light-receiving element driving driver 11 starts driving from the element E1 (see FIG. 4) of the laser light receiving sensors 6A and 6B, and the X-axis counter 12 and the Y-axis counter 13 operate when the light-receiving element is driven. The counting of the driving time is started from the time of driving the element E1 based on the reference clock output from. Here, when each element is driven in order and the light receiving element that spot receives the laser light from the laser light emitting device 5 is driven, a light receiving signal corresponding to the light receiving level of the laser light is output, After being amplified by the preamplifier circuit 10, it is output to the X-axis counter 12 and the Y-axis counter 13 to stop the counting operation of the X-axis counter 12 and the Y-axis counter 13.

Therefore, from the X-axis counter 12 and the Y-axis counter 13, the coordinate position of the light receiving element that spot-receives the laser light, that is, the laser light receiving sensor 6 A on which the laser light from the laser light emitting device 5 forms an image. , 6B, the coordinate data indicating the image forming position b (see FIG. 3) is output. The arithmetic circuit 14 outputs the coordinate data and the reference coordinates in the memory 15, that is, the reference position a (see FIG. 3). The differences Δx and Δy are calculated and output as pixel shift amounts.

As described above, the laser light from the laser emitting device 5 is transmitted from outside the range of the observation viewing angle α to the optical system condenser lens 3A.
And the laser light is received by laser light receiving sensors 6A and 6B disposed near the observation image pickup elements 7A and 7B, and the observation image pickup element is detected based on the light receiving position of the laser light in the laser light reception sensors 6A and 6B. By calculating the pixel shift amounts of 7A and 7B by the light receiving laser processing unit 8, it is possible to detect the shift of each band element of the optical camera from the optimum position and the pixel shift between the bands.

In this case, as a configuration for detecting a pixel shift, a laser beam emitting device 5, a laser beam receiving sensor 6
Since only the A, 6B and the light receiving laser processing unit 8 need to be provided, it is possible to detect a pixel shift without increasing the number of components. Also, since the laser light from the laser light emitting device 5 is irradiated to the optical system condenser lens 3A from outside the range of the observation viewing angle α, the observation imaging element 7A,
Pixel shift can be detected without obstructing the observation in 7B. Further, the detection of the pixel shift can be performed to the degree of the measurement accuracy of the laser light receiving sensors 6A and 6B, and the pixel shift can be accurately detected even during the observation without requiring a complicated configuration. Become.

[0023]

As described above, according to the present invention, the irradiating means for irradiating the observation optical system with laser light at a predetermined angle, and the irradiating means provided near the observation image pickup device and irradiated from the irradiating means. A light-receiving sensor that spot-receives the laser light on the light-receiving surface; a calculating unit that measures a light-receiving position of the laser light on the light-receiving surface of the light-receiving sensor; Detects deviation from the optimal position of the observation image sensor provided for each band of the observation optical system and pixel deviation between bands without increasing the number of components mounted on the spacecraft It is possible to do.

Further, the irradiating means irradiates the observation optical system with laser light at a predetermined angle from outside the observation viewing angle of the observation optical system, so that observation by the observation image pickup devices 7A and 7B is not hindered. Pixel shift can be detected. In addition, the light receiving data processing means determines the position of the laser beam on the light receiving surface of the light receiving sensor and the light receiving surface of the light receiving sensor of the observation image sensor measured in advance according to the positional relationship between the observation image sensor and the light receiving sensor. Since the pixel shift amount of the observation image pickup device is calculated based on the reference position, the difference from the reference position of the observation image pickup device installed on the spacecraft on the ground can be directly and accurately obtained.

The light receiving sensor comprises a large number of light receiving elements constituting a two-dimensionally expanded light receiving surface, and the light receiving element driving means scans each light receiving element of the light receiving sensor based on a predetermined reference clock. The scanning position calculating means outputs scanning coordinate data indicating the scanning position of the light receiving element which spot-receives the laser beam from the irradiating means based on the reference clock based on the reference clock. The pixel shift amount is calculated based on the reference coordinate data indicating the reference position at which the spot light is received in the case of the above and the scanning coordinate data from the scanning position calculating means. Therefore, it is possible to accurately detect the pixel shift without requiring a complicated configuration.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a pixel shift detecting device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an image forming state in a laser light receiving sensor and an observation image sensor.

FIG. 3 is an explanatory diagram showing an image forming state of laser light in a laser light receiving sensor.

FIG. 4 is an explanatory diagram showing a light receiving surface of a laser light receiving sensor.

FIG. 5 is a block diagram showing a light reception data processing unit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Observation target, 2 ... Optical camera main body, 3A, 3B ... Optical system condensing lens, 4 ... Optical system spectral lens, 5 ... Laser beam emitting device, 6A, 6B ... Laser beam receiving sensor, 7A, 7B
... Observation imaging element, 8 ... Light receiving data processing unit, 10 ... Preamplifier circuit, 11 ... Light receiving element drive driver, 12 ... X axis counter, 13 ... Y axis counter, 14 ... Operation circuit.

Claims (4)

(57) [Claims] 1. An observation optical system for observing an object to be photographed, an observation image pickup device for photographing an image within an observation field of view of the observation optical system, and a laser beam to the observation optical system at a predetermined angle. Irradiating means for irradiating a laser beam, the light receiving means being disposed in the vicinity of the observation imaging device and having a two-dimensionally expanded light receiving surface, and receiving a spot of laser light emitted from the irradiating means on the light receiving surface A light receiving data processing unit that measures a light receiving position of the laser light on a light receiving surface of the light receiving sensor and calculates a pixel shift amount of the observation imaging element based on the measured light receiving position. Pixel shift detector for optical cameras. 2. The pixel shift detecting device for an optical camera according to claim 1, wherein the irradiating unit irradiates the observation optical system with a laser beam at a predetermined angle from outside the observation viewing angle of the observation optical system. A pixel shift detecting device for an optical camera, wherein 3. The pixel shift detecting device for an optical camera according to claim 1, wherein the light receiving data processing unit is arranged on a light receiving surface of the light receiving sensor according to a positional relationship between the observation imaging element and the light receiving sensor. A pixel shift amount of the observation imaging element is calculated based on a laser light reception position and a reference position on the light receiving surface of the light reception sensor of the observation imaging element measured in advance during adjustment. Pixel shift detector for optical cameras. 4. The pixel shift detecting device for an optical camera according to claim 1, wherein the light receiving sensor constitutes a two-dimensionally expanded light receiving surface and outputs a light receiving signal indicating a light receiving level according to driving. A plurality of light-receiving elements for outputting, the light-receiving data processing means outputs a predetermined reference clock, and based on this reference clock, light-receiving element driving means for driving each light-receiving element of the light-receiving sensor by surface scanning; A scanning position on the light receiving sensor is sequentially calculated based on a reference clock, and scanning of the light receiving element is performed based on a light receiving signal output when a light receiving element that spot receives laser light from the irradiation unit is driven. Scanning position calculation means for outputting scanning coordinate data indicating a position, and the measurement is performed in advance when the observation imaging device is at an optimum position. A memory for storing reference coordinate data indicating a reference position at which a laser beam from the emitting unit is spot-received; and calculating a pixel shift amount based on the scanning coordinate data from the scanning position calculating unit and the reference coordinate data in the memory. A pixel shift detecting device for an optical camera, comprising: