H - Electricity – 04 – N
Patent
H - Electricity
04
N
350/47, 350/83
H04N 5/14 (2006.01) G06K 9/38 (2006.01) H04N 1/403 (2006.01) H04N 5/235 (2006.01)
Patent
CA 1099401
Abstract of the Disclosure Method and device for eliminating the background brightness vari- ation of a video signal, in which the background brightness in each line of the frame of a video signal has its low frequency brightness signal a(t) limited, as well as being limited by its deviation from the limited bright- ness of the preceding line of frame. This can be expressed mathematically by stating that ¦V(t-) - ?(t)¦ is minimized by means of ?(t) on the marginal conditions ¦ ?(t) - ?(t - T)¦ ? .epsilon. and ¦ ?(t) - ?(t - .DELTA.)¦ ? .epsilon., in which V(t) = the video signal V at the moment t; a(t) = an estimation of the background brightness variation a(t); T = the duration of a line; .DELTA. = h/b T/k, in which h/b = the height/width ratio of the image and k = the number of lines per frame, and .epsilon. = the maximum value of the derivative of a(t) multipled by .DELTA.. Thus the device of this invention comprises a device for limiting the rate of the build-up of the video signal current during each line by means of a slope limiter comprising a current limiter and condensor connected to the video signal, a delay circuit for delaying the resulting limited current for the duration of one line of the frame comprising a delay and a one-to-one amplifier so that the difference between the limited variation can be limited with respect to the preceding line in the frame, and a subtracting device for subtracting this difference from that of each line of the original video signal. Since the first line of each frame has no preceding line by which to be limited, a separate prolongation device is provided responsive to the frame synchronization pulse for inactivating the difference limiting device for the first line of each frame. In known methods, use is made only of a small length of the line that is being scanned at a certain moment unlike the present invention.
303555
Van Der Houwen Derk
Wilcke Robert
Fetherstonhaugh & Co.
Telegrafie En Telefonie de Staat Der Nederlanden Te Dezen Vertegenwoordigd Door de Direc
LandOfFree
Method and device for eliminating the background brightness... 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 device for eliminating the background brightness..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and device for eliminating the background brightness... will most certainly appreciate the feedback.
Profile ID: LFCA-PAI-O-931921