Method
VipsImageinvertlut
Declaration [src]
int
vips_invertlut (
VipsImage* in,
VipsImage** out,
...
)
Description [src]
Given a mask of target values and real values, generate a LUT which will map reals to targets.
Handy for linearising images from measurements of a colour chart. All values in [0,1]. Piecewise linear interpolation, extrapolate head and tail to 0 and 1.
Eg. input like this:
4 3
0.1 0.2 0.3 0.1
0.2 0.4 0.4 0.2
0.7 0.5 0.6 0.3
Means a patch with 10% reflectance produces an image with 20% in channel 1, 30% in channel 2, and 10% in channel 3, and so on.
Inputs don’t need to be sorted (we do that). Generate any precision LUT, default to 256 elements.
It won’t work too well for non-monotonic camera responses (we should fix this). Interpolation is simple piecewise linear; we ought to do something better really.
Optional arguments
size: %gint, generate this much
See also
This method is not directly available to language bindings.
Parameters
out-
Type:
VipsImageOutput LUT.
The argument will be set by the function. The caller of the method takes ownership of the returned data, and is responsible for freeing it. ...-
Type:
NULL-terminated list of optional named arguments.