Secure Access Camera and Method for Camera Control

• US 20080062278A1
• Filed: 05/29/2007
• Published: 03/13/2008
• Est. Priority Date: 05/09/2001
• Status: Active Grant

• Current Assignee: SSK Virtualimage Corporation
• Original Assignee: SSK Virtualimage Corporation
• Inventors: Khan, Shahid, Khan, Sal, Levine, Martin
• Granted Patent: US 7,800,687 B2
• Time in Patent Office: Days
• US Class Current: 348/231.3
• CPC Class Codes: H04N 23/70 Circuitry for compensating brightness variation in the scene
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means
• CPC Class Codes: H04N 5/76 Television signal recording
• CPC Class Codes: H04N 7/186 Video door telephones

Abstract

A camera and a method for controlling the camera. Also a face recognition secure access camera and a method of capturing an image that is not saturated or too dark.

Claims

1. A video camera for capturing and exposure correcting a video stream comprising human facial images for subsequent processing by facial recognition software, said camera comprising a body for housing:

a. an image detector for capturing said human facial images from said video stream, wherein;

i. said image detector is operated by a software program comprising an operating system stored within a first memory;

ii. a target image comprising a single human facial image is selected from the video stream; and

,

iii. said target image is digitized by said software program as a first half facial image and a second half facial image for digital signal output as a first and a second image file respectively for storage within a second memory;

b. a digital signal processor connected said first memory and the image detector and operable by the software program, wherein the software program is adapted for virtual control of the target image in respect of at least tilt, pan, zoom and focus; and

,

c. a second memory communicating with the digital signal processor for selective retrieval of said first and second image files by the software program for processing, wherein the software program includes;

i. a control loop for exposure correction of the first and second image files;

ii. means for merging exposure corrected first and second image files into an exposure corrected target facial image for processing by;

iii. said facial recognition software for authentication of said exposure corrected target facial image.

2. The camera of claim 1 wherein the camera is further connected to a video display terminal and the target facial image is displayed thereon.

3. The camera of claim 2 further comprising a universal asynchronous transmitter/receiver connected to the digital signal processor for connecting to a bit-serial communications network so that said the video stream can be transmitted over a computer network to a remote location for facial recognition processing.

4. The camera of claim 3 wherein said means for exposure correction includes an exposure level control loop and a gain control loop, wherein said gain control loop is operative only when said exposure level control loop is at a maximum value.

5. The camera of claim 4 wherein said exposure control loop comprises a first exposure control sub-loop and a second exposure control sub-loop.

6. The camera of claim 5 wherein said first exposure control sub-loop corrects the image exposure of said first half target facial image and said second exposure control sub-loop corrects the image exposure of said second target half facial image.

7. The camera of claim 6 wherein the first exposure control sub-loop comprises:

a. a first set point representing a desired exposure intensity for the camera, wherein said desired exposure intensity is adapted for ambient light conditions;

b. the first half target facial image at a first exposure intensity comprising a first plurality of pixels;

c. means for calculating an first average exposure intensity of said first plurality of pixels;

d. a comparator for calculating a difference value between said first average exposure intensity and said desired exposure intensity;

e. means for calculating a second camera exposure intensity for the first half target facial image based on said difference value;

f. means for adjusting the camera exposure to said second camera exposure intensity; and

,

g. iterative means for repeating steps c to f until the camera exposure intensity for the first half target facial image is at the first set point thereby creating a first half exposure corrected target facial image.

8. The camera of claim 7 wherein the second control sub-loop comprises:

a. the first set point;

b. the second half target facial image at the first exposure intensity comprising a second plurality of pixels;

c. means for calculating a second average exposure intensity of said second plurality of pixels;

d. a comparator for calculating a second difference value between said second average exposure intensity and the desired exposure intensity;

e. means for calculating a third camera exposure intensity for the second half target facial image based on said second difference value;

f. means for adjusting the camera to said third camera exposure intensity; and

,

g. iterative means for repeating steps c to f until the camera exposure for the second half target facial image is adapted to the first set point thereby creating a second half exposure corrected target facial image.

9. The camera of claim 8 further comprising means for merging said first and said second half exposure corrected target facial images into a complete exposure corrected target facial image for subsequent facial recognition processing.

10. The camera of claim 9 wherein said means for merging the first and second half exposure corrected target facial images comprises:

a. means for averaging the exposure intensity of the first and second half target facial images; and

,

b. a compression factor for compressing said complete exposure corrected target facial image into an at least 8-bit image.

11. The camera of claim 10 wherein the means for merging the first and second half exposure corrected target facial images further comprises Gamma Correction.

12. The camera of claim 11 wherein said gain control loop comprises a first gain control sub-loop and a second gain control sub-loop.

13. The camera of claim 12, wherein said first gain control sub-loop comprises:

a. a gain set point representing a desired exposure intensity for the camera;

b. the first half target facial image having a first gain value comprising the first plurality of pixels;

c. means for calculating an average exposure intensity of the first plurality of pixels;

d. a comparator for calculating a first difference value between said average exposure intensity and said desired exposure intensity;

e. means for calculating a second gain value based on said first difference value;

f. means for adjusting the camera to said second gain value; and

,

g. iterative means for repeating steps c to f until the camera gain value is equal to said gain set point thereby creating a first half exposure corrected target facial image.

14. The camera of claim 13, wherein said second gain control sub-loop comprises:

a. the gain set point;

b. the second half target facial image having said first gain value comprising the second plurality of pixels;

c. means for calculating the average exposure intensity of the second plurality of pixels;

d. a comparator for calculating a second difference value between said average exposure and the desired exposure intensity;

e. means for calculating a third gain value for the second half target facial image based on said second difference value;

f. means for adjusting the camera to said third gain value; and

,

g. iterative means for repeating steps b to f until the camera gain value for the second half target facial image is equal to the gain set point thereby creating a second half exposure corrected target facial image.

15. The camera of claim 14 further comprising means for merging said first half exposure corrected target facial image and said second half exposure corrected target facial image into complete exposure corrected target facial image for subsequent facial recognition processing.

16. The camera of claim 15 wherein said means for merging the first half and second half exposure corrected target facial image comprises Gamma Correction.