Patent ID: 8144252

Claim:
A noise reduction apparatus comprising: an input section which inputs an image signal; a plurality of first high pass filters which receive the image signal input to the input section and which have different passing frequency bands; a plurality of level histogram generation sections which are provided so as to correspond to the plurality of first high pass filters and each of which generates a level histogram representing the number of pixels of the image signal counted for each amplitude level thereof; a detection section which detects one of the level histograms generated by the plurality of level histogram generation sections that satisfy a predetermined threshold value; a first selection section which selects the output of the first high pass filter that has supplied its output to the level histogram generation section that has generated the level histogram detected by the detection section; a first noise reduction section which applies high frequency component noise reduction processing to the output of the first high pass filter selected by the first selection section; a first subtractor which subtracts the output of the first high pass filter selected by the first selection section from the image signal input to the input section; a second noise reduction section which applies low frequency component noise reduction processing to the output of the first subtracter; and an adder which adds outputs of the first and second noise reduction sections.