JPH0258481A - Picture distortion correcting device for movable type ccd image pickup device - Google Patents

Abstract

PURPOSE:To correct the distortion of a picture due to alignment and the tilt of a spin axis generated or changed after satellite launching by rotating a CCD in optical axis rotation. CONSTITUTION:In movable type CCD(charge coupled device) image pickup device 1, when it becomes an upward abnormal locus for an angle theta, a detecting part 4 detects a drift angle theta by a picture data output (c) of the CCD 1 and outputs a correcting requesting signal (d) to rotate the CCD 1 for the angle thetacounterclockwise to eliminate the drift angle theta to a control part 5. The control part 5 impresses a control voltage on piezo elements 3a to 3d corresponding to the correcting requesting signal (d), rotates the CCD 1 with expanding or shrinking and eliminates the drift angle. Thus, the distortion of a picture due to alignment and the tilt of a spin axis generated or changed after satellite launching can be corrected.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a movable CCD (charge couple).
ed device) relates to an image distortion correction device for an image pickup device.

In particular, TDI (Time
Regarding the image correction of the Dela7 and Integration) method stellar sensor, image distortion due to alignment error and tilt of the satellite spin axis can be corrected by changing the alignment around the optical axis of the CCD using a piezo element. The present invention relates to a correction device.

[Prior art] As shown in Fig. 2, the TDI method uses the charge a of the CCD's vixel to move in the direction of an arrow in synchronization with a star image moving in the V direction (the moving direction of the stellar image) on the CCD l. In this method, the image data is acquired by moving the object as shown in the figure.

Conventionally, the CCD section of a star sensor for a spin satellite using such a TDI method has been fixed with respect to an axis perpendicular to the chip surface of the COD, that is, the optical axis.

[Problems to be solved] The conventional TDI type star sensor for spin satellites described in E.
When installing a satellite on a satellite, alignment is sometimes adjusted, but it is impossible to reduce the alignment error below a certain value due to restrictions on alignment measurement methods, measurement devices, etc.

Furthermore, since there is no gravity after launch, alignment errors may be magnified.

Furthermore, regarding the satellite's spin axis, the spin axis during a spin test on the ground does not necessarily match the spin axis after launch, and errors include tilt.

If there is such an alignment error and a tilt of the spin axis, the TDI method, as described above, moves the charge of the vixel in synchronization with the moving direction of the stellar image on the CCD (direction V in Figure 2). Since this is a method of acquiring image data, images of stars moving through the CCD do not pass along the same line in the V direction of the COD, but instead move diagonally. The image data obtained in this way distorts one image into an egg-like shape, and when an image of a large celestial body such as the moon is obtained, one image becomes blank.

In the conventional TDI type star sensor for spin satellites, CC6
Since this is fixed, there is a problem in that it is not possible to correct image distortion due to alignment and spin axis tilt that occurs or changes after hitting the J-2.

The present invention has been made in view of the problems mentioned above.
The object of the present invention is to provide an image distortion capture device for a +lrf dynamic CCD imager capable of compensating for image distortion caused by alignment and spin axis tilt that occurs or changes after a second shot.

[! 1 problem solving stage], 1 Iir dynamic type C to be developed to achieve the above 11 objectives
An image distortion correction device for a CD imager includes a piezoelectric bracket that is located between a CCD and a COD support and supports the CCD rotatably about the optical axis of the CCD with respect to the support;
A detection unit that detects the deviation angle of the CCD based on the image data J, ti from D and outputs a correction request signal, and a supplementary i1E request signal from this detection unit), ';, to eliminate the deviation angle. The apparatus further includes a control section that controls a voltage applied to the piezoelectric element in order to rotate the CCD.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of an image distortion correction device for a movable CCD imager according to the present invention.

1 is a CCD and 2 is a COD support.

3a, 3b, 3c, and 3d are piezo elements.

These piezo elements 3a, 3b, 3c, 3d are CCD
1 and the CCD support 2, and are arranged at approximately the four corners of the CCD 1, and support the CCD 1 rotatably around the optical axis 0 of the CCD with respect to the support 2.

4 is a detection unit which detects the deviation angle 0 of the CCD l based on the image data output C from the CGDI and outputs a correction request signal d.
Output.

Reference numeral 5 denotes a control section, which includes a piezo element 3a for rotating the CCD 1 to eliminate the deviation angle 0 based on the correction request signal d from the detection section 4.

6 for controlling the voltage applied to 3b, 3c, and 3d, for example,
To rotate the CCDI counterclockwise in Figure 1,
A control voltage that causes the piezo elements 3a and 3d to expand is applied, and a control -1t pressure that causes the piezo elements 3b and 3c to contract is applied to each of the piezo elements 3b and 3c.

In the image distortion prevention system of the movable CCD imager as described above, if an abnormal trajectory is now directed upward by an angle of 0 as shown in FIG. Detects the deviation angle Q, and outputs the deviation angle d to the control unit 5 to eliminate this deviation angle 0 (requires rounding correction by rotating the CCDI counterclockwise around f1 by an angle θ).

Then, in response to the correction request signal d, the control unit 5 applies a control voltage Jl to the piezo elements 3a and 3d to expand them, and applies a control voltage Jl to the piezo elements 3b and 3c to cause them to contract. Apply control voltages respectively.

Due to the expansion or contraction of these piezo elements, C
The CD l rotates, the deviation angle disappears, and the image distortion is eliminated.

In addition, when the normal ltILgA is in the f direction, a control section /E that contracts the piezo elements T-3a and 3d is similarly applied to the piezo elements T-3a and 3d, and the piezo elements T-3b and 3d are
A control voltage is applied to c to expand it, so that the CCD 1 rotates clockwise and the deviation angle disappears.

[Effects of R, il] As explained above, the present invention corrects image distortion caused by alignment and spin axis tilt that occurs or changes after launch by rotating the CCD around the optical axis even after launch. Because you can
This has the effect of further increasing the accuracy and resolution of image data.

In addition, since there is no need to require high accuracy than the 7 line/meter accuracy on the ground, there are fewer visits to the alignment measurement method and measurement equipment, and the distance between surfaces required for alignment can be shortened. effective.

Furthermore, the tilt angle of the spin axis after launch can be increased, which loosens constraints on the attitude control of the satellite, making it possible to shorten the attitude control development schedule and reduce development costs. There is an effect.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of an image distortion correction device for a movable CC04A1 imager according to the present invention, and FIG. 2 is an enlarged view of a CCD for explaining the TDI method. 1: CCD 2: CCD support 3a to 3d: Piezo element 4: Detection section 5: Control section Agent Patent attorney Kihei Watanabe

Claims (1)

[Scope of Claims] A piezo element that is located between a CCD and a CCD support and supports the CCD rotatably about the optical axis of the CCD with respect to the support, and a piezo element that is configured to shift the CCD based on image data from the CCD. a detection unit that detects the angle and outputs a correction request signal; and a control unit that controls a voltage applied to the piezo element in order to rotate the CCD so as to eliminate the deviation angle based on the correction request signal from the detection unit. An image distortion correction device for a movable CCD imager, comprising: