ROLLING-SHUTTER IMAGING SYSTEM WITH SYNCHRONIZED SCANNING ILLUMINATION AND METHODS FOR HIGHER-RESOLUTION IMAGING

• US 20130021474A1
• Filed: 07/20/2011
• Published: 01/24/2013
• Est. Priority Date: 07/20/2011
• Status: Abandoned Application

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Taylor, Byron B., Rinker, Robert, Lynch, Ted, Stein, Robert A.
• Application Number:
  US13/186,582
• Publication Number:
  US 20130021474A1
• Time in Patent Office: Days
• US Class Current: 348/144
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/481 Constructional features, e.g. arrangements of optical elements
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: H04N 23/20 for generating image signals from infrared radiation only
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means
• CPC Class Codes: H04N 25/531 by controlling rolling shutters in CMOS SSIS
• 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

Embodiments of a rolling-shutter imaging system with synchronized scanning illumination and methods for higher-resolution imaging are generally described herein. In some embodiments, the imaging system includes a focal plane array (FPA) and a read-out integrated circuit (ROIC) configured to activate only a portion of the FPA during an integration time. The imaging system also includes a scanner synchronized with the ROIC to illuminate only a portion of a sensor field-of-view (FOV) of the FPA within a scene that corresponds to at least the activated portion of the FPA. The imaging system may also include beamforming optics to generate a beam of light to illuminate the portion of the sensor FOV corresponding to portion of the FPA that is activated.

Claims

1. An imaging system comprising:

a read-out integrated circuit (ROIC) configured to activate only a portion of a focal plane array (FPA) during an integration time; and

a scanner synchronized with the ROIC to illuminate only a portion of a sensor field-of-view (FOV) of the FPA within a scene that corresponds to at least the activated portion of the FPA.

2. The imaging system of claim 1 wherein the portion of the sensor FOV that is illuminated by scanner is less than an entire sensor FOV, and

wherein the scanner is configured to illuminate the portion of the sensor FOV with a beam of light having a shape that corresponds substantially to the activated portion of the FPA in the sensor FOV.

3. The imaging system of claim 2 further comprising beamforming optics to generate the beam of light to provide to the scanner, the beam of light provided by the scanner having a width of substantially the sensor FOV and a height in the sensor FOV of substantially the portion of the FPA that are activated,

wherein the beamforming optics is configured to provide a beam of light having a beam divergence that is matched to the activated portion of the FPA.

4. The imaging system of claim 3 wherein the FPA comprises a plurality of rows,

wherein the ROIC is configured to activate one or more rows of the FPA during an integration time in a row-by-row fashion, and

wherein the scanner is configured to synchronously illuminate at least the portion of the sensor FOV that corresponds to the one or more activated rows and not illuminate at least some portions of the sensor FOV that correspond to inactive rows.

5. The imaging system of claim 4 wherein the ROIC is configured to generate an integrator line-sync signal, and

wherein the scanner is synchronized with the integrator line-sync signal and configured to scan the sensor FOV to illuminate the portion of the sensor FOV corresponding to at least the currently active one or more rows of the FPA in a row-by-row fashion.

6. The imaging system of claim 4 wherein the scanner is configured to generate a synchronization signal for the ROIC,

wherein the ROIC is synchronized with the synchronization signal and configured to activate one or more rows of the FPA for the integration time in a row-by-row fashion in response to the synchronization signal, and

wherein the scanner is synchronized with the synchronization signal and configured to scan the sensor FOV to illuminate the portion of the sensor FOV corresponding to at least the currently active one or more rows of the FPA in a row-by-row fashion.

7. The imaging system of claim 3 wherein the portion of the FPA that is illuminated comprises one or more rows of unit cells or pixel elements,

wherein when a row is activated, the pixel elements or unit cells of the row are configured integrate photons of light, and

wherein after the integration time, the ROIC is configured deactivate the row and to read out values of each of the unit cells or pixel elements for subsequent image generation.

8. The imaging system of claim 3 wherein the ROIC and the FPA are configured to operate in accordance with a rolling-shutter image acquisition and generation technique,

wherein the scanner and ROIC are synchronized so that the scanner illuminates the portion of the sensor FOV that corresponds to at least the portion of the FPA that is activated by the ROIC in a row-by-row fashion.

9. The imaging system of claim 3 further comprising a controller 112 to perform an initial synchronization between the scanner and the ROIC,

wherein the initial synchronization is to synchronize the portion of the sensor FOV that is illuminated by the scanner with to the one or more rows of the FPA to be activated.

10. The imaging system of claim 3 wherein the scanner comprises a galvometric scanner comprising one or more moving mirrors.

11. The imaging system of claim 3 wherein the scanner comprises a polygon scanner comprising a polygon configured to rotate or spin.

12. The imaging system of claim 3 wherein the scanner comprises a Risely set scanner comprising a prism configured to rotate.

13. The imaging system of claim 3 wherein the scanner comprises a rotating grating scanner comprising a diffraction grating configured to rotate.

14. The imaging system of claim 3 wherein the scanner comprises an optical phased array.

15. The imaging system of claim 3 wherein the scanner comprises a disk scanner comprising a holographic disk configured to rotate or spin.

16. The imaging system of claim 3 further comprising an illuminator configured to generate light for the beamforming optics, and

wherein the illuminator comprises one of a near infrared (NIR) light source, a short-wave infrared (SWIR) light source, a Laser light source, and a visible light source.

17. A method of generating an image comprising:

activating only a portion of focal plane array (FPA) during an integration time; and

synchronously illuminating only a portion of a sensor field-of-view (FOV) of the FPA within a scene that corresponds to at least the activated portion of the FPA.

18. The method of claim 17 wherein the portion of the sensor FOV that is illuminated is less than an entire sensor FOV, and

wherein the method further comprises generating beam of light having a width of substantially the sensor FOV and a height in the sensor FOV of substantially one or more rows of the FPA that are activated.

19. The method of claim 18 further comprising synchronizing a scanner with a read-out integrated circuit (ROIC) that is coupled to the FPA to allow the scanner to synchronously illuminate only the portion of the sensor FOV that corresponds to at least the activated portion of the FPA.

20. A gimbaled imaging system comprising:

a focal plane array (FPA);

a read-out integrated circuit (ROIC) configured to activate only a portion of the FPA during an integration time;

a scanner synchronized with the ROIC to illuminate only a portion of a sensor field-of-view (FOV) of the FPA within a scene that corresponds to at least the activated portion of the FPA;

beamforming optics to generate a beam of light to provide to the scanner to illuminate the portion of the sensor FOV corresponding to portion of the FPA that is activated; and

an illuminator configured to generate light for the beamforming optics,

wherein at least the FPA, the ROIC, the scanner, and the beamforming optics are located on-gimbal.

21. The gimbaled imaging system of claim 20 wherein the illuminator is located on a gimbal.

22. The gimbaled imaging system of claim 20 wherein the illuminator is located off-gimbal and light generated by the illuminator is provided via the Coudé

path through gimbal axes, and

wherein the gimbaled imaging system further includes an optical fiber path to carry the light generated by the illuminator through the Coudé

path.

23. An air-based platform comprising:

a gimbaled imaging system; and

a propulsion system to propel the air-based platform,

wherein the gimbaled imaging system comprises a read-out integrated circuit (ROIC) configured to activate only a portion of a focal plane array (FPA) during an integration time, a scanner synchronized with the ROIC to illuminate only a portion of a sensor field-of-view (FOV) of the FPA that corresponds to at least the activated portion of the FPA, beamforming optics to generate a beam of light to provide to the scanner to illuminate the portion of the sensor FOV corresponding to portion of the FPA that is activated, and an illuminator configured to generate light for the beamforming optics, and

wherein at least the FPA, the ROIC, the scanner, and the beamforming optics are located on-gimbal.

24. The air-based platform of claim 23 wherein the air-based platform is a missile, the illuminator is a short-wave infrared (SWIR) illuminator and the gimbaled imaging system is part of a seeker configured target imaging.

25. The air-based platform of claim 23 wherein the air-based platform is an unmanned aerial vehicle (UAV) and the gimbaled imaging system is configured for imaging and surveillance.

26. An imaging system comprising:

a read-out integrated circuit (ROIC) configured to activate only a portion of a focal plane array (FPA) during an integration time; and

a vertical-cavity surface-emitting laser (VCSEL) comprising an array of laser diode synchronized with the ROIC to illuminate a portion of a sensor field-of-view (FOV) of the FPA that corresponds to at least the activated portion of the FPA,

wherein rows of the laser diodes are configured to be activated to generate light to illuminate the portion of the sensor FOV that corresponds to one or more active rows of the FPA.

27. The imaging system of claim 26 wherein the portion of the sensor FOV that is illuminated by scanner is less than an entire sensor FOV, and

wherein the system includes beamforming optics configured to provide a beam of light having a beam divergence that is matched to the activated portion of the FPA.