Improve contrast when image has a flood of white balancing
Histogram equalization is a global operation which can result in some areas being adversely effected at the cost of the rest of the image looking better. Consider using the Retinex algorithm. It works very well at improving both local and global contrast enhancement. There's a flurry of papers on this topic and the algorithm is somewhat straightforward to implement. The most challenging part is the selection of parameters.

Here's a list of papers and here's one that's very useful.