vcm

Hist

The function call is:-

vcm.Hist(clip [, clip clipm, int mf = 0][,int type=1][,int table=[int,int,.....] ][ ,int window = 0][,int limit = 0] )

clip: YUV or Gray format only.
clipm: frame on this clip to be matched with. Must specify if type = 2.
mf: Frame number of clipm to be used for matching.
type: 1. Equalization, 2.Match with frame fm of clipm, 3. Match with given table of luma %age, and population %age values and 4. match with a table of luma %age and cummulative population %age.
table: If type = 3, array of pairs of integer values giving Luma as %age and %age of occurance.Luma should be in ascending order. If type = 4, Luma as %age and cummulative population as %age. Luma and cummulative %age should increase monotonously 0 to 100. Minimum 2 pairs and maximum 20 pairs can be specified.
window: 0. for full frame and 1 for windowed processing. If the frame dimensions are not large enough for windowed process, reverts to full frame process.
limit: if set to 0, No limit to change.Otherwise %age change in value to be allowed.

Hist works with Histogram and can equalize whole frame or with moving window (slow) or match entire clip with a given frame or match with specified Histogram. Equalization may be severe for certain inputs, so use parameter limit.