Television – Camera – system and detail – Combined image signal generator and general image signal...
Patent
1997-05-14
2000-10-24
Garber, Wendy
Television
Camera, system and detail
Combined image signal generator and general image signal...
348229, H04N 5235, H04N 5228
Patent
active
061375330
ABSTRACT:
A system and method of enhancing dynamic range in images is disclosed that increases the contrast in the resulting image without requiring an increase in the dynamic range of the analog-to-digital converter used to convert the analog image signals to digital information. The system and method disclosed achieve this advantageous result by providing per-pixel gain control circuitry and per-pixel gain selection circuitry. The analog image signal range is segmented into a number (N) of multiple levels, where N is selected to be the desired level of enhancement. Multiple analog gain (G1) levels and multiple digital gain (G2) levels are also provided. The analog gain (G1) is selected for each image pixel based upon the segment in which that pixel falls so that the signal levels may be increased for each segment to utilize the full range (R) of the analog-to-digital converter. Once digitized, a digital gain (G2) is selected for the same pixel so that on a per-pixel basis, the total gain (G1*G2) is kept substantially constant. In this way, the dynamic range of the system is increased without needing to increase the dynamic range of the ADC. The resulting digital information is enhanced by (Log.sub.2 N) bits, and it may be companded down into a smaller bit range for a video output device by any desired transfer function during digital signal processing.
REFERENCES:
patent: 4814864 (1989-03-01), Pritchard
patent: 4851842 (1989-07-01), Iwamatsu
patent: 4911552 (1990-03-01), Kurashige et al.
patent: 5049997 (1991-09-01), Arai
patent: 5053877 (1991-10-01), Kondo et al.
patent: 5065248 (1991-11-01), Homma
patent: 5093716 (1992-03-01), Kondo et al.
patent: 5179528 (1993-01-01), Robertson et al.
patent: 5258848 (1993-11-01), Kondo et al.
patent: 5262849 (1993-11-01), Mimura et al.
patent: 5272539 (1993-12-01), Kondo
patent: 5282043 (1994-01-01), Cochard et al.
patent: 5291276 (1994-03-01), Matsumoto et al.
patent: 5307158 (1994-04-01), Tsuruta et al.
patent: 5319449 (1994-06-01), Saito et al.
patent: 5420635 (1995-05-01), Konishi et al.
patent: 5448293 (1995-09-01), Kogane et al.
patent: 5455685 (1995-10-01), Mori
patent: 5508739 (1996-04-01), Suh
patent: 5512947 (1996-04-01), Sawachi et al.
patent: 5534916 (1996-07-01), Sakaguchi
patent: 5539456 (1996-07-01), Ishii
patent: 5585846 (1996-12-01), Kim
patent: 5712682 (1998-01-01), Hannah
Cirrus Logic Inc.
Garber Wendy
Harrington Alicia
Peterman Brian W.
Violette J. P.
LandOfFree
System and method for enhancing dynamic range in images does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System and method for enhancing dynamic range in images, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System and method for enhancing dynamic range in images will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1969769