Patent ID: 7576711

Claim:
A contrast compensating apparatus for a PDP module, comprising: an APL (Average Picture Level) calculating unit for calculating an APL of a video signal; a sustain pulse generating unit for generating and providing sustain pulses the number of which corresponds to an output of the APL calculating unit to the PDP module; a histogram analyzing unit for calculating a maximum value M of brightness repeating numbers of the video signal, a minimum brightness value W 1 and a maximum brightness value W 2 of a brightness repetition distribution area that includes the maximum value M of the brightness repeating numbers; a comparing unit for comparing the output of the APL calculating unit with at least one brightness section threshold value and outputting a result of comparison; a contrast compensating unit for comparing an output of the comparing unit with a first setting value, comparing the maximum value of the brightness repeating numbers from the histogram analyzing unit with a second setting value, and calculating a contrast compensation value using the minimum brightness value W 1 and the maximum brightness value W 2 according to results of comparison; and a mixer for feeding an output of the contrast compensating unit back to an input terminal of the video signal, wherein the contrast compensating unit calculates the contrast compensation value in a manner that the contrast compensating unit calculates a brightness difference between the minimum brightness value W 1 and the maximum brightness value W 2 , reads a brightness compensation value corresponding to the calculated brightness difference with reference to a pre-stored brightness difference / compensation value table, and calculates brightness level increase/decrease values of corresponding pixels so that a brightness distribution area that includes the minimum brightness value W 1 and the maximum brightness value W 2 is shifted to a brightness repetition distribution area having a minimum value W 1 ′ and a maximum value W 2 ′,the minimum value W 1 ′ and the maximum value W 2 ′ being values reduced from the minimum brightness value W 1 and the maximum brightness value W 2 by as much as the brightness compensation value, respectively.