The focal spot of the image enhancement is to formulate the images supplementary comprehensible so that in this technique, the novel image is processed so that the consequential image is more appropriate than the imaginative for specific applications i. e. the image is enhanced. Before applying further processing on the image, noise should remove from the image. Noise is a accidental deviation of image Intensity and able to be seen as grains in the image. Image enhance is the manipulation of the image data to produce a visually high quality image. This technique may have frequency domain and spatial domain. Further, types of spatial domain techniques are of many types that are explained in this paper. In this paper taken a salt & pepper type noise, various image enhancement filters have been reviewed which are commonly worked under spatial domain technique. These filters are mean filter, median filter, Order statistics filter, Gaussian Blur filter, Dark Frame subtraction filter, Shock filter etc. Images can be enhanced by altering its features of original image and provide more better result as compare to original image.The paper also focuses on testing the functioning of various as well as their linear & non-linear filters for the removal of noise that focused around past studies & compared using Peak Signal to Noise Ratio (PSNR). It explores the effects of applying noise reduction filters having similar properties on noisy images with emphasis on Signal-to-Noise-Ratio (SNR) value and Mean-squared error (MSE) estimation for comparing the results.
Image enhancement, Noise, Spatial Domain, Image Filters, PSNR, SNR, MSE.