UNCOOLED DRIVER VIEWER ENHANCEMENT SYSTEM

• US 20010045516A1
• Filed: 02/10/1999
• Published: 11/29/2001
• Est. Priority Date: 10/09/1998
• Status: Active Grant

• Current Assignee: Thomson-CSF Optronics Canada Inc.
• Original Assignee: Thomson-CSF Optronics Canada Inc.
• Inventors: CARON, HUBERT, WROBEL, LESLIE, FAINA-CHERKAOUI, MARCELA, KOVACEVIC, BRANISLAV, EMANUEL, MICHAEL
• Granted Patent: US 6,521,892 B2
• Time in Patent Office: Days
• US Class Current: 250/332
• CPC Class Codes: B60R 1/00 Optical viewing arrangements; Real-time viewing arrangements for drivers or passengers using optical image capturing systems, e.g. cameras or video systems specially adapted for use in or on vehicles
• CPC Class Codes: B60R 1/24 in front of the vehicle
• CPC Class Codes: B60R 1/30 providing vision in the non-visible spectrum, e.g. night or infrared vision
• CPC Class Codes: B60R 11/04 Mounting of cameras operative during drive; Arrangement of controls thereof relative to the vehicle
• CPC Class Codes: B60R 2300/106 using night vision cameras
• CPC Class Codes: B60R 2300/8053 for bad weather conditions or night vision
• CPC Class Codes: G01J 5/20 using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices
• 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 thermal imager system for use in a vehicle utilizes an uncooled microbolometer detector array (19), optics (13) for conducting scene radiation to the array within a sensor module (12) which is separate from an image processing and display unit (39), to provide a small, direct view sensor module (12) that may be oriented for forward viewing. The sensor module (12) is mounted external to the vehicle and the image processing and display unit (39) is mounted internal to the vehicle, and the two are connected by a noise immune bidirectional digital communication path or harness (37). The optics (13) consist exclusively of refractive optical components (14, 16) providing a straight line radiation path from the scene to the array (19).

Claims

1. A thermal imager system, comprising an uncooled microbolometer detector array and optics of a sensor module separate from an image processing and display unit, thereby providing a small, direct view sensor module that may be oriented for forward viewing.

2. The system in accordance with

claim 1

, wherein the sensor module is mounted externally of a vehicle and the image processing and display unit is mounted internally of the vehicle.

3. The system in accordance with

claim 2

, further including a noise immune bidirectional digital communication path coupling the sensor module and image processing and display unit.

4. The system in accordance with

claim 1

, wherein the optics consist exclusively of refractive optical components.

5. The system in accordance with

claim 1

, wherein each element of the array of infrared sensitive elements is calibrated to obtain analog signal correction factors at two distinct uniform temperature levels and data indicative of the correction factors are stored.

6. The system in accordance with

claim 5

, wherein each digital representation of an infrared radiation level indicative analog signal is corrected in accordance with the corresponding stored correction factors and the corrected digital representations energize the corresponding display elements.

7. The system in accordance with

claim 1

, wherein each element of the array of infrared sensitive elements is periodically calibrated to obtain an element analog signal correction factor at a uniform temperature level near ambient temperature and data indicative of the correction factors are stored.

8. The system in accordance with

claim 7

, wherein the each digital representation of an infrared radiation level indicative analog signal is corrected in accordance with the corresponding stored correction factor and the corrected digital representations energize the corresponding display elements.

9. The system in accordance with

claim 7

, wherein a shutter of the sensor module at ambient temperature repeatedly and automatically temporarily blocks an optical path from the scene to the array for a very short time interval.

10. The system in accordance with

claim 1

, in combination with a vehicle, wherein sensor module is external of the vehicle and the display unit is within the vehicle.

11. The system in accordance with

claim 1

, wherein digital representations of infrared radiation level indicative analog signals for each element are periodically sampled, a histogram of all representations is maintained, the maintained histogram is equalized, stored, and utilized to interpret subsequently received digital representations and to energize appropriately the correspondingly located element of the display device.

12. The system in accordance with

claim 11

, wherein the histogram is periodically updated.

13. The process of acquiring an image of a scene based on the infrared radiation emanating from the scene and displaying the scene image at a display location removed from the site of image acquisition, comprising:

projecting the scene infrared radiation onto an array of infrared sensitive elements;

deriving an infrared radiation level indicative analog signal from each element;

converting each analog signal into a digital representation thereof, wherein the steps of projecting, deriving and converting are performed by a unit connected to a noise immune bidirectional digital communication path;

transmitting via the path each digital representation to the display location; and

utilizing each digital representation to energize at least one correspondingly located display element of a display device, wherein the step of utilizing is performed in a unit connected to the path.

14. The process of

claim 13

, including the initial step of calibrating each element of the array of infrared sensitive elements to obtain analog signal correction factors at two distinct uniform temperature levels and storing data indicative of the correction factors.

15. The process of

claim 14

, wherein the step of utilizing includes correcting each digital representation in accordance with the corresponding stored correction factors and using the corrected digital representations for energizing the corresponding display elements.

16. The process of

claim 13

, including the step of periodically and automatically calibrating each element of the array of infrared sensitive elements to obtain an element analog signal correction factor at a uniform temperature level near ambient temperature and storing data indicative of the correction factors.

17. The process of

claim 16

, wherein the step of utilizing includes correcting each digital representation in accordance with the corresponding stored correction factor and using the corrected digital representations for energizing the corresponding display elements.

18. The process of

claim 16

, wherein the step of periodically calibrating includes repeatedly and automatically temporarily blocking the optical path from the scene to the array for a very short time interval with an ambient temperature shutter.

19. The process of

claim 13

, wherein the step of projecting comprises a plurality of exclusively refractive steps.

20. The process of

claim 13

, for providing a view of an external scene to an occupant of a vehicle, wherein the steps of projecting, deriving and converting are performed external of the vehicle and the step of utilizing is performed within the vehicle.

21. The process of

claim 13

, wherein the step of utilizing includes periodically sampling the digital representations for each element, maintaining a histogram of the magnitude of the representations, equalizing the maintained histogram, storing the equalized histogram, and utilizing the stored equalized histogram to interpret subsequently received digital representations and energize appropriately the correspondingly located element of the display device.

22. The process of

claim 21

, including the additional step of periodically updating the historgram.

23. A thermal imager system comprising:

an array of infrared radiation detector cells;

an optical system for projecting infrared radiation emanating from a scene onto the array of infrared radiation detector cells;

a sensor module housing containing the array of cells and the optical system;

an image processing and display module spaced from the sensor module for displaying an image of the scene; and

a noise immune bidirectional digital communication path coupling the sensor module and the image processing and display module.

24. The system in accordance with

claim 23

, for use in a vehicle, wherein the sensor module is mounted external of the vehicle and the image processing and display module is mounted internal of the vehicle.

25. The system in accordance with

claim 23

, wherein the optical system consists exclusively of refractive optical components.

26. The system in accordance with

claim 23

, wherein each element of the array of infrared sensitive elements is calibrated to obtain analog signal correction factors at two distinct uniform temperature levels and data indicative of the correction factors are stored.

27. The system in accordance with

claim 26

, wherein each digital representation of an infrared radiation level indicative analog signal is corrected in accordance with the corresponding stored correction factors and the corrected digital representations energize the corresponding display elements.

28. The system in accordance with

claim 23

, wherein each element of the array of infrared sensitive elements is periodically and automatically calibrated to obtain an element analog signal correction factor at a uniform temperature level near ambient temperature and data indicative of the correction factors are stored.

29. The system in accordance with

claim 28

, wherein the each digital representation of an infrared radiation level indicative analog signal is corrected in accordance with the corresponding stored correction factor and the corrected digital representations energize the corresponding display elements.

30. The system in accordance with

claim 28

, wherein, at an ambient temperature, a shutter of the sensor module repeatedly and automatically temporarily blocks the optical path from the scene to the array for a very short time interval.

31. The system in accordance with

claim 23

, in combination with a vehicle, wherein sensor module is external of the vehicle and the display unit is within the vehicle.

32. The system in accordance with

claim 23

, wherein digital representations of infrared radiation level indicative analog signals for each element are periodically sampled, a histogram of the representations is maintained, the maintained histogram is equalized, stored, and utilized to interpret subsequently received digital representations and to energize appropriately the correspondingly located element of the display device.

33. The system in accordance with

claim 32

, wherein the histogram for each cell is periodically updated.