Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
179 words
A real time histogram modification system in which a recoding strategy of pixels in a digitized input video signal is determined by processing iteratively the number of pixels in respective grey levels of output picture information using a predetermined scene adaptive quantizer comprising: means for compressing the number of grey levels in the input video signal into a predetermined number of grey levels in accordance with an encoding strategy; means, coupled to said compressing means, for counting and storing the number of pixels in the compressed video signal appearing in each of said predetermined number of grey levels; means, coupled to said counting and storing means, for determining whether each of said counts is within, above or below a range of values, called a window, about each of respective predetermined theoretical values, which theoretical values collectively form said scene adaptive quantizer; and means for generating said encoding strategy and for recoding said strategy, when any of said counts are above or below said respective window, by adjusting the number of input grey levels for the respective output grey level.
Claim 2
Dependent Claim
179 words
A real time histogram modification system in which a recoding strategy of pixels in a digitized input video signal is determined by processing iteratively the number of pixels in respective grey levels of output picture information using a predetermined scene adaptive quantizer comprising: means for compressing the number of grey levels in the input video signal into a predetermined number of grey levels in accordance with an encoding strategy; means, coupled to said compressing means, for counting and storing the number of pixels in the compressed video signal appearing in each of said predetermined number of grey levels; means, coupled to said counting and storing means, for determining whether each of said counts is within, above or below a range of values, called a window, about each of respective predetermined theoretical values, which theoretical values collectively form said scene adaptive quantizer; and means for generating said encoding strategy and for recoding said strategy, when any of said counts are above or below said respective window, by adjusting the number of input grey levels for the respective output grey level.
Claim 3
Dependent Claim
38 words
A system as claimed in claim 1, comprising means for forming a pre-positionable keyhole in a frame of the scene to be modified and wherein only the input video signal occurring within the keyhole is subjected to recoding.
Claim 4
Dependent Claim
65 words
A system as claimed in claim 1, in which histogram modification is applied to the information in the entire frame and means are provided for selecting a subset of pixels in the output picture information, which subset of pixels are processed iteratively using the predetermined scene adaptive operator to provide the recoding strategy which is applied to all the pixels in the input video signal.
Claim 5
Dependent Claim
21 words
A system as claimed in claim 1, 2, or 3, further comprising means for forming a plurality of different size windows.
Claim 6
Dependent Claim
18 words
A system as claimed in claim 1, 2 or 3, in which the scene adaptive quantizer is hyperbolic.
Claim 7
Dependent Claim
18 words
A system as claimed in claim 1, 2 or 3, in which the scene adaptive quantizer is exponential.
Claim 8
Dependent Claim
31 words
A system as claimed in claim 4, in which the encoding strategy generating and encoding means comprises a microprocessor and a program memory for storing at least one scene adaptive quantizer.
Claim 9
Dependent Claim
38 words
A system as claimed in claim 7, in which the program memory stores a plurality of non-linear scene adaptive quantizers and the microprocessor is adapted to select and apply any one of the scene adaptive quantizers at will.
Claim 10
Dependent Claim
48 words
A system as claimed in claim 7, in which the microprocessor is programmed to vary the size of an area of a frame to be modified and to recalculate the size of the window and the set of predetermined theoretical values, both of which are area dependent variables.
Claim 11
Dependent Claim
36 words
A system as claimed in claim 7, further comprising a store containing at least two sets of window values, and wherein the microprocessor is adapted to select one of said sets on a time dependent basis.
Claim 12
Dependent Claim
22 words
A system as claimed in claim 7, further comprising a pattern detecting means for modifying a histogram in a scene dependent manner.
Claim 13
Dependent Claim
45 words
A system as claimed in claim 1, 2 or 3, in which the encoding strategy generating and recoding means produces a linear encoding strategy for the first frame of the input video signal, the second and susequent frames being recoded using the scene adaptive quantizer.
Claim 14
Dependent Claim
47 words
A system as claimed in claim 1, 2 or 3, in which the scene adaptive quantizer is histogram equalization in which each of the predetermined theoretical values is the quotient of the total number of pixels divided by the number of grey levels in the output signal.
Claim 15
Dependent Claim
64 words
A system as claimed in claim 1, 2 or 3 in which the scene adaptive quantizer is Gaussian and in which the encoding strategy generating and recoding means is adapted to determine the recoding strategy by starting at the grey levels in the center of the histogram formed in the counting and storing means and working outwards to the black and white levels, respectively.