Sensor system having nonuniformity suppression with image preservation

• US 5,323,334 A
• Filed: 12/04/1992
• Issued: 06/21/1994
• Est. Priority Date: 12/04/1992
• Status: Expired due to Term

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Meyers, Franklin J., Johnston, W. Scott
• Primary Examiner(s): Harvey, Jack B.
• Assistant Examiner(s): PEESO, THOMAS R
• Application Number:
  US07/985,724
• Time in Patent Office: 564 Days
• Field of Search: 364/571.01, 364/413.24, 364/571.02, 364/571.05, 250/363.07, 250/557, 250/330, 250/332, 250/334, 382/14, 382/23, 382/28, 382/45
• US Class Current: 702/94
• CPC Class Codes: H04N 25/48 Increasing resolution by shifting the sensor relative to the scene
• CPC Class Codes: H04N 25/63 applied to dark current
• CPC Class Codes: H04N 25/683 by defect estimation performed on the scene signal, e.g. real time or on the fly detection
• CPC Class Codes: H04N 5/33 Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

A sensor system includes a sensor (20) having an array (22) of detector elements (24), a movable sensor positioner (32) in which the sensor (20) is mounted, a signal processor (30) that progressively corrects the intensities of the pixels of a sensor output array for detector element nonuniformity, an electronic scene position corrector (40), and a motion controller (36) that provides a movement command (34) to the sensor positioner (32), and transmits the substance of the movement command to the scene position corrector (40). An image array signal is furnished from the sensor (20) to the signal processor (30), while the sensor positioner (32) is controllably moved under command of the motion controller (36). A nonuniformity-compensated output signal (38) of the signal processor (30) is provided to the scene position corrector (40), wherein the position of the image is corrected for the motion of the sensor positioner (32). The resulting sensor output signal (44) has sensor element nonuniformity selectively compensated, but objects in the field of view of the sensor (20) are not suppressed.

Claims

1. Apparatus for processing an image produced by a sensor having an array of sensor elements, comprising:

controller means for providing a movement command to a sensor positioner to cause a sensor to physically move;

compensation means for correcting for detector element nonuniformity in an image array of pixels produced by the sensor, to form a nonuniformity-compensated image; and

repositioning means for electronically correcting the indicated position of the nonuniformity-compensated image for the movement of the sensor, responsive to an inverse of the movement command received from the controller means.

2. The apparatus of claim 1, wherein the compensation means includes a scene-based nonuniformity calculator.

3. The apparatus of claim 1, wherein the controller means provides the movement command to the compensation means.

4. The apparatus of claim 1, wherein, the compensation means provides the movement command to the controller means.

5. The apparatus of claim 1, further including

a sensor positioner and a sensor supported therein.

6. The apparatus of claim 5, wherein the sensor positioner includes a gimbal in which the sensor is mounted.

7. The apparatus of claim 5, wherein the sensor is an infrared sensor formed of a plurality of detector elements.

8. A method of producing a sensor output signal, comprising the steps of:

furnishing an image array signal from a sensor having an array of detector elements mounted in a physically movable sensor positioner;

controllably moving the sensor positioner;

processing the image array signal to progressively correct pixel intensities of the signal for detector element nonuniformity; and

electronically correcting the indicated position of the processed image array signal for the movement of the sensor positioner to provide a sensor output signal having sensor element nonuniformity selectively compensated but objects in the field of view of the sensor not suppressed.

9. The method of claim 8, wherein the step of processing is accomplished by a scene-based nonuniformity compensator.

10. The method of claim 8, wherein the steps of controllably moving, processing, and electronically correcting all operate responsive to a movement command.

11. The method of claim 8, wherein the sensor positioner includes a gimbal in which the sensor is mounted.

12. The method of claim 8, wherein the sensor is an infrared sensor formed of a plurality of infrared detector elements.

13. The method of claim 8, wherein the step of electronically correcting includes the step of

determining the movement of the sensor positioner from a motion command sent to the sensor positioner.

14. The method of claim 8, wherein the step of electronically correcting includes the step of

determining the movement of the sensor positioner from a measurement of the movement of the sensor.

15. A method of producing a sensor output signal, comprising the steps of:

providing

a sensor having an array of detector elements,

a movable sensor positioner in which the sensor is mounted,

a signal processor that progressively corrects the intensities of the pixels of a sensor output array for detector element nonuniformity,

an electronic scene position corrector, and

a motion controller that provides a movement command to the sensor positioner, and transmits the substance of the movement command to the scene position corrector;

furnishing an image array signal from the sensor to the signal processor, while controllably moving the sensor positioner under command of the motion controller; and

furnishing a nonuniformity-compensated output signal of the signal processor to the scene position corrector, wherein the position of the image is corrected for the motion of the sensor positioner to provide a sensor output signal having sensor element nonuniformity selectively compensated but objects in the field of view of the sensor not suppressed.

16. The method of claim 15, wherein the signal processor includes a scene-based nonuniformity calculator.

17. The method of claim 15, wherein the motion controller provides the movement command to the signal processor.

18. The method of claim 15, wherein the signal processor provides the movement command to the controller.

19. The method of claim 15, wherein the sensor is an infrared sensor formed of a plurality of infrared detector elements.