Machine vision camera and video preprocessing system

• US 5,745,173 A
• Filed: 11/15/1994
• Issued: 04/28/1998
• Est. Priority Date: 09/08/1992
• Status: Expired due to Fees

• Current Assignee: Active Motion Systems LLC
• Original Assignee: Active Motion Systems LLC
• Inventors: Edwards, Michael Kenneth, Mayeaux, Paul Howard
• Primary Examiner(s): Faile, Andrew
• Assistant Examiner(s): Vu, Ngoc-Yen, VU, NGOC YEN T
• Application Number:
  US08/340,053
• Time in Patent Office: 1,260 Days
• Field of Search: 382/132, 382/169, 382/270, 382/273, 382/274, 348/207, 348/208, 348/222, 348/223, 348/234, 348/237, 348/266, 348/272, 348/273, 348/33, 348/47, 348/48, 348/143
• US Class Current: 348/208.4
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 23/6811 based on the image signal
• CPC Class Codes: H04N 23/683 performed by a processor, e.g. controlling the readout of an image memory
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof

Abstract

An improved camera system intended for a machine vision system which produces an image output that is specially adapted to be received by a machine vision system. In one embodiment, the camera system receives components from three portions of the electromagnetic spectrum, these being infrared, visible, and ultraviolet, and then combines these three portions essentially as expanded colors in an expanded version of an RGB "red/green/blue" video system. This provides a better image in all types of weather and visibility conditions. In addition, the camera system includes dynamic range transform logic which selectively compresses the dynamic range of the respective pixel values comprising the image to extract the most useful information from the extended dynamic range of the image. This reduces the amount of information required to be processed while retaining a quality image. The camera system also includes motion compensation logic that removes the motion or jitter caused by the camera system being subject to vibration from various environmental influences. The system also optionally removes stationary background features from the output image.

Claims

1. A video preprocessing system for use in machine vision systems, comprising:

receiving means for receiving electromagnetic radiation of varying frequencies from a scene and for producing infrared, visible, and ultraviolet signals corresponding to the infrared, visible, and ultraviolet portions, respectively, of said electromagnetic radiation;

first, second, and third dynamic range transform means receiving said infrared, visible, and ultraviolet signals, respectively, for companding the dynamic range of said received infrared, visible and ultraviolet signals to produce dynamic range companded infrared, visible, and ultraviolet signals; and

means receiving said dynamic range companded infrared, visible, and ultraviolet signals for producing a composite output image using each of said companded infrared, visible, and ultraviolet signals.

2. The video preprocessing system of claim 1, wherein each of said dynamic range transform means expands a portion of the dynamic range of said received infrared, visible, and ultraviolet signals into a first portion of the dynamic range of said companded signals and compresses the remainder of the dynamic range of said received infrared, visible, and ultraviolet signals into a second portion of the dynamic range of said companded signals.

3. The video preprocessing system of claim 2, wherein said received infrared, visible, and ultraviolet signals comprise incoming pixel values, wherein each of said dynamic range transform means maps incoming pixel values below a pixel value knee level to higher pixel value levels according to a first gain and maps incoming pixel values above said pixel value knee level to pixel values according to a second incremental gain, wherein said first gain is greater than said second incremental gain.

4. The video preprocessing system of claim 3, wherein said incoming pixel values below said pixel value knee level have a first range and said incoming pixel values above said pixel value knee level have a second range, wherein each of said dynamic range transform means expands the first range of pixel values below said pixel value knee level according to said first gain and compresses the second range of said pixel values above said pixel value knee level by said second incremental gain.

5. The video preprocessing system of claim 1, further comprising:

motion compensation means receiving portions of said output image for adjusting said output image to compensate for jitter caused by environmental influences on the system.

6. A video preprocessing system for use in machine vision systems, comprising:

a charge coupled device grid receiving electromagnetic radiation of varying frequencies from a scene and for producing infrared, visible, and ultraviolet signals corresponding to the infrared, visible, and ultraviolet portions, respectively, of said electromagnetic radiation;

first, second, and third dynamic range transform adjusters receiving said infrared, visible, and ultraviolet signals, respectively, for companding the dynamic range of said received infrared, visible and ultraviolet signals to produce dynamic range companded infrared, visible, and ultraviolet signals; and

wherein said dynamic range companded infrared, visible, and ultraviolet signals are used to produce a composite output image using each of said infrared, visible, and ultraviolet companded signals.

7. The video preprocessing system of claim 6, wherein each of said dynamic range transform adjusters expands a portion of the dynamic range of said received infrared, visible, and ultraviolet signals into a first portion of the dynamic range of said companded signals and compresses the remainder of the dynamic range of said received infrared, visible, and ultraviolet signals into a second portion of the dynamic range of said companded signals.

8. The video preprocessing system of claim 7, wherein said received infrared, visible, and ultraviolet signals comprise incoming pixel values, wherein each of said dynamic range transform adjusters maps incoming pixel values below a pixel value knee level to higher pixel value levels according to a first gain and maps incoming pixel values above said pixel value knee level to pixel values according to a second incremental gain, wherein said first gain is greater than said second incremental gain.

9. The video preprocessing system of claim 8, wherein said incoming pixel values below said pixel value knee level have a first range and said incoming pixel values above said pixel value knee level have a second range, wherein each of said dynamic range transform adjusters expands the first range of pixel values below said pixel value knee level according to said first gain and compresses the second range of said pixel values above said pixel value knee level by said second incremental gain.

10. The video preprocessing system of claim 6, further comprising:

a motion compensator receiving portions of said output image for adjusting said image to compensate for jitter caused by environmental influences on the system.

11. A method for performing video preprocessing, comprising:

receiving electromagnetic radiation of varying frequencies from a scene;

producing infrared, visible, and ultraviolet signals corresponding to the infrared, visible, and ultraviolet portions, respectively, of said electromagnetic radiation;

separately companding the dynamic range of each of said infrared, visible and ultraviolet signals to produce dynamic range companded infrared, visible and ultraviolet signals; and

producing a composite output image using each of said companded infrared, visible, and ultraviolet signals.

12. The method claim of claim 11, wherein said infrared, visible, and ultraviolet signals comprise incoming pixel values and said separately companding comprises mapping incoming pixel values below a pixel value knee level to higher pixel value levels according to a first gain and mapping incoming pixel values above said pixel value knee level to pixel values according to a second incremental gain, wherein said first gain is greater than said second incremental gain.

13. The method of claim 12, wherein said incoming pixel values below said pixel value knee level have a first range and said incoming pixel values above said pixel value knee level have a second range, wherein said separately companding comprises expanding the first range of pixel values below said pixel value knee level according to said first gain and compressing the second range of said pixel values above said pixel value knee level by said second incremental gain.

14. A video preprocessing system for use in machine vision systems, comprising:

video source means for receiving electromagnetic radiation of varying frequencies from a scene and for producing signals representing an image, wherein said signals have a dynamic range, wherein said signals correspond to two or more of the infrared, visible, and ultraviolet portions of said electromagnetic radiation;

dynamic range transform means receiving said signals and for companding the dynamic range of said signals and for producing dynamic range companded signals, wherein said dynamic range transform means expands a portion of the dynamic range of said signals into a first portion of the dynamic range of said companded signals and compresses the remainder of the dynamic range of said signals into a second portion of the dynamic range of said companded signals; and

means for receiving said companded signals and for producing a composite output image based on said companded signals.

15. The video preprocessing system of claim 14, further comprising:

motion compensation means receiving said companded signals for adjusting said image to compensate for jitter caused by environmental influences on the system.

16. A video preprocessing system for use in machine vision systems, comprising:

a charge coupled device grid for receiving electromagnetic radiation of varying frequencies from a scene and for producing signals corresponding to two or more of the infrared, visible, and ultraviolet portions of said electromagnetic radiation, said signals having a dynamic range;

a dynamic range transform adjuster receiving said signals for companding the dynamic range of said signals and for producing dynamic range companded signals, wherein said dynamic range transform adjuster expands a portion of the dynamic range of said signals into a first portion of the dynamic range of said companded signals and compresses the remainder of the dynamic range of said signals into a second portion of the dynamic range of said companded signals; and

wherein said companded signals are used to produce a composite output image based on said companded signals.

17. A method for performing video preprocessing, comprising:

receiving electromagnetic radiation of varying frequencies from a scene and producing signals corresponding to two or more of the infrared, visible, and ultraviolet portions of said electromagnetic radiation, said signals having a dynamic range;

companding the dynamic range of said signals to produce dynamic range companded signals after said step of receiving, wherein said step of companding expands a portion of the dynamic range of said signals into a first portion of the dynamic range of said companded signals and compresses the remainder of the dynamic range of said signals into a second portion of the dynamic range of said companded signals; and

producing a composite output image based on said companded signals.