Breast a tumor [1]. Breast cancer is one

Breast cancer becoming the most occurring forms
of cancer in women, especially in developing countries as well as in developed
countries. Mammogram is accepted as best radiographic method to clinical
examination in the early stages of illnesses for breast cancer. Diagnostic
features such as cysts and masses may be small or ill-defined, so mammogram
image quality is extremely important when used for interpretation and
diagnosis. Pre-processing is an important
part of any imaging modalities to bring the image to that quality where it is
suitable for analysis and extraction of significant data. This paper talks
about, six denoising techniques which have great significance in mammographic image analysis due to poor
quality of mammograms and with the help of mini-MIAS database, results were evaluated using many
image metrics.  Cancer is abnormal change, in the genes which are
responsible for regulating the growth of cells and keeping them healthy, where
genes in each cell’s nucleus, which acts as the “control room” of each cell.
Normally, the process of cell growth like old cells in our bodies replaces themselves
through a healthy new. Sometimes changed cell gains the ability to keep
dividing without control or order, producing more and forming a tumor 1. Breast
cancer is one of the most occurring forms of cancer in women, especially in India.
Breast Cancer detection at initial stage is the only solution, to reduce the
death rate among the women’s, so regular screening of mammograms for detection
of masses is essential, so wide range of treatment options can be available at early
stages  like less-aggressive surgery and
adjuvant therapy. 2Mammography is a medical imaging
which uses a low-dose x-ray system to analyze inside the breasts. A mammography
examination is known as mammogram, which aids in the early
detection and diagnosis of breast diseases in women. Mammogram is accepted as an important
adjunct to clinical examination in the care of patients with many common
illnesses for breast cancer.  It provides
the complete information about shape, structure and pathologies of breast which
helps out in diagnosing breast cancer.  Mostly mammograms are found with five abnormalities which
require further examination to classify it as benign or malign. The
mammograms are confirmed as abnormal after the clinical diagnosis mammography which
is divided into two classes: benign (noncancerous) and malignant (cancerous). The abnormalities are Asymmetric
breast tissue, Mass, Micro calcification, Asymmetric density and Architectural
distortion. Except for mass and micro calcification all the other abnormalities
are found in very rare cases known as invasive breast cancer.3 Diagnostic features such as a benign or
malignant tumor, or non-masses are exclusively normal tissues which may be small or ill-defined, so
mammogram image quality is extremely important when used for interpretation and
diagnosis.4In digital imaging, systems
introduce various noises and artifacts which are to be removed. The noise like low contrast of the small
tumors to the background can be hardly detected in mammography. For this an
image preprocessing techniques are adopted to reduce the noise level of the
image, preserving the mammography structures and features. Also denoising is
more significant in image processing, analysis and applications; by reserving
the details of an image and removing the random noise as far as possible is the
goal of image denoising approaches. In this work, a comparative study of several denoising techniques for mammogram
is presented. The filters considered are: 
1) median filter, 2) adaptive median filter, 3) frost filter, 4) wavelet
filter, 5) histogram equalization, 6) Contrast
Limited Adaptive Histogram Equalization.