This paper presents an adaptive contrast enhancement technique based on a hierarchical image representation. First a linear multi-scale image decomposition is obtained by computing a ratio of low-pass pyramid. Thereafter the input image is reconstructed by non-linear multiplication of successive pyramid layers. The recombination process adaptively stretches local image contrast at all levels of...

An experimentally supported model of cortical background activity is used to investigate the role of such activity in neural gain control. The model demonstrates the feasibility of a scheme for contrast enhancement where by the overall intensity of an input pattern adjusts the dynamic range of a neuron such that it remains sensitive to contrast over a wide range of overall intensities. keywords...

This paper discusses the image brightness enhancement of the natural and unnatural images using Continuous Genetic Algorithm. Image contents play a vital role in various images. In this paper, Genetic Algorithm has been investigated for the enhancement of the brightness of the images. The algorithm was effective as the brightness of the image got enhanced with the successive iterations as compa...

In this paper, we will discuss the development of the image enhancement techniques and their application in the field of image processing .The principle objective of image enhancement techniques is to process an input image so that the resultant image is more suitable than the original image for specific application. Traditional global histogram equalization usually causes excessive contrast en...

Now days applications require various kinds of images as sources of information for interpretation and inspection. Image enhancement is method of applying different alterations to an input image to make the resultant image more pleasing or to provide a better transform presentation for future automated image processing techniques. Many images like medical images, images of satellites, and even ...

-Contrast enhancement is an important factor in the gray scale images. One of the widely accepted contrast enhancement method is the Histogram equalization (HE). HE achieves comparatively better performance on almost all types of image but sometimes produces excessive visual deterioration. The proposed Contrast Enhancement using Brightness Preserving Histogram Plateau Limit (CEBPHPL) method pro...

In this paper Finger print Image Enhancement method in spatial domain and frequency domain using filter is discussed. The state-of-art in the literature is reviewed to provide a foundation for the evaluation of the proposed approaches. Fingerprint enhancement can be conducted on either binary ridge images or gray-scale images. Different techniques for gray-level fingerprint images enhancement h...

A histogram is a graphical representation of the distribution of data in an image. It is an estimate of the probability distribution of a continuous variable (quantitative variable). Histogram Equalization is a contrast enhancement technique in the image processing which uses the histogram of image. However histogram equalization is not the best method for contrast enhancement because the mean ...

In speech enhancement, noise power spectral density (PSD) estimation plays a key role in determining appropriate de-nosing gains. In this paper, we propose a robust noise PSD estimator for binaural speech enhancement in timevarying noise environments. First, it is shown that the noise PSD can be numerically obtained using an eigenvalue of the input covariance matrix. A simplified estimator is t...

This paper proposes a speech signal enhancement method in which the wavelet transform scales and thresholds both are adaptive depending on the input noisy signal affected by Additive White Gaussian Noise (AWGN). The proposed Estimated Noise and Adaptive Threshold Bionic Wavelet Transform (ENAT-BWT) method analyses the incoming noisy speech signal at 22 scales, from 7 to 28, of the BWT for negat...