Specifications

Color Space Conversion
9-23
9
ColorTwistFP
Applies a color-twist
matrix to an image with
floating-point pixel values.
IPLStatus iplColorTwistFP (const IplImage* src , IplImage*
dst , float* cTwist )
src Thesourceimage.
dst The resultant image.
cTwist The array containing color-twist matrix elements.
Discussion
The function iplColorTwistFP() applies the color-twist matrix stored in
the array cTwist to each of the first three color channels.
Mathematically, the function performs the following operation:
R ’ = t
00
· R + t
01
· G + t
02
· B + t
03
G ’ = t
10
· R + t
11
· G + t
12
· B + t
13
B ’ = t
20
· R + t
21
· G + t
22
· B + t
23
Here ( R ’, G ’, B ’) are the output values of the first three channels, and
(
R , G , B ) are the input values of these channels. The array cTwist should
contain the color-twise matrix elements in this order:
t
00
t
01
t
02
t
03
t
10
t
11
t
12
t
13
t
20
t
21
t
22
t
23
Both src and dst images must contain 32-bit floating-point pixel data.
Tiling and rectangular ROIs are supported; masking and COIs are not.
The function returns
IPL_StsOk on success, or an error status code on
failure (if the application passes invalid arguments or if there is insufficient
memory to perform the operation).