This document reviews and compares several techniques for enhancing mammogram images to aid in the early detection of breast cancer. It discusses methods such as wavelet-based enhancement, iterative smoothing and sharpening, dyadic wavelet processing using gradient and Laplacian filters, and particle swarm optimization combined with contrast limited adaptive histogram equalization. The techniques aim to highlight subtle features like masses and microcalcifications, reduce noise, and maximize contrast to assist radiologists in cancer diagnosis. Evaluation of the methods suggests they can improve detection rates compared to traditional techniques.