Image analysis – Histogram processing – For setting a threshold
Patent
1986-03-27
1988-03-15
Boudreau, Leo H.
Image analysis
Histogram processing
For setting a threshold
324307, 358168, 382 6, G06K 956
Patent
active
047318651
ABSTRACT:
A two-step smoothing process produces a brightness map of an image. The image is multiplied, pixel by pixel, by the inverse of the brightness map to correct for image brightness variations due to the imaging system and not to the object being imaged. The first smoothing step scans a square multi-pixel window across the image to produce a gross brightness map of the image. The brightness value of the center pixel in the window is ascribed the sum of the values of all pixels in the window. In an alternate embodiment, the center pixel in the window is ascribed the brightness of the brightest pixel in the window. The second smoothing step scans the gross brightness map with a smaller square window to smooth blockiness in the gross brightness map for producing a smoothed brightness map. Smoothing ascribes a value to the center pixel in the window equal to the weighted sum of the remaining pixels in the window. The weight contribution of each pixel in the window is varied according to its distance from the pixel whose value is being calculated. Linear and non-linear weighting may be used. The original image is multiplied, pixel by pixel, by the inverse of the smoothed brightness map to produce a corrected image. The corrected image is normalized to return its values within the dynamic range of a display device.
REFERENCES:
patent: 4217641 (1980-08-01), Naparstek
patent: 4229764 (1980-10-01), Danos
patent: 4290049 (1981-09-01), Sternberg et al.
patent: 4323977 (1982-04-01), Arseneau
patent: 4509074 (1985-04-01), Krauss et al.
patent: 4591789 (1986-05-01), Glover et al.
patent: 4611283 (1986-09-01), Cumelsky
patent: 4644473 (1987-02-01), Kojima et al.
Boudreau Leo H.
General Electric Company
Morrison Thomas R.
LandOfFree
Digital image correction does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Digital image correction, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Digital image correction will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1931068