The article compares different techniques for improving the contrast of images by analyzing their histograms. The researchers tested Bi-Histogram Equalization, Recursive Mean Seperated Histogram Equalization, Multipeak Histogram Equalization, and Brightness Preserving Dynamic Histogram Equalization on standard images. Each technique has its own way of enhancing contrast while maintaining image brightness. The results were compared using metrics like absolute mean Brightness error and peak signal to noise ratio.