Facsimile and static presentation processing – Facsimile – Recording apparatus
Patent
1990-05-11
1992-02-04
Britton, Howard W.
Facsimile and static presentation processing
Facsimile
Recording apparatus
35821318, H04N 314, H04N 5335
Patent
active
050863436
ABSTRACT:
A correction circuit processes digitized signals from an image sensor and generates gain correction values to compensate for variations in the output of the sensor. While imaging a gain calibration object, the sensor is operated in a calibration mode in which a plurality of calibration values are generated that pertain to each photosite. The digitized calibration values are transformed into log space for processing by a gain level averaging circuit. The log calibration signals are first subtracted from a reference corresponding to a maximum expected signal value. The difference signals are serially accumulated by means of pair of registers and an adder, and the sum is stored in a gain memory. In a subsequent normal operating mode, the summed signals for each photosite are retrieved from the gain memory and bit-shifted to form an average correction value for each photosite. The correction values are applied to an adder in synchronism with sensor signals from like photosites and added therewith in log space to provide gain compensation.
REFERENCES:
patent: 3800078 (1974-03-01), Cochran et al.
patent: 4216503 (1980-08-01), Wiggins
patent: 4343021 (1982-08-01), Frame
patent: 4486781 (1984-12-01), Wilmer et al.
patent: 4602277 (1986-07-01), Guichard
patent: 4602291 (1986-07-01), Temes
patent: 4698685 (1987-10-01), Beaverson
patent: 4731661 (1988-03-01), Nagano
patent: 4760464 (1988-07-01), Sakano
patent: 4839729 (1989-06-01), Ando et al.
patent: 4903316 (1990-02-01), Hongo et al.
patent: 4912558 (1990-03-01), Easterly et al.
patent: 4970598 (1990-11-01), Vogel
patent: 4979042 (1990-12-01), Vogel
Cook William A.
D'luna Lionel J.
Parulski Kenneth A.
Britton Howard W.
Eastman Kodak Company
Greening Wendy R.
Woods David M.
LandOfFree
Method and apparatus for compensating for sensitivity variations does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for compensating for sensitivity variations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for compensating for sensitivity variations will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-350169