[mawen1250]

Thanks for your report.
This is the correct result for MSRCP. It indicates that there's a bluish color cast in the original image, which is amplified after the Retinex with *chromaticity preservation*. Under this circumstance the color cast itself is unwanted chromatic information, so the plain MSRCP result is not suitable.

possible solutions:
1. Use MSRCR(MSR with color restoration) instead, which will eliminate color cast. Currently it's not implemented yet.
2. Do some modification to the MSRCP algorithm, such as adding a threshold to attenuate chroma adjustment for very dark area.
3. For now, this may be a good solution: use std.Lut to build a mask guided by luma, and apply std.MaskedMerge to blend the value of source and retinex for chroma planes.