Histogram equalization is a popular technique for enhancing image contrast. However, it tends to change the brightness of an image and hence, this technique is not very well suited to be implemented in consumer electronics, where preserving the original brightness is essential to avoid annoying artifacts. This paper proposes a novel extension of bi-histogram equalization referred to as Range Li...

Histogram equalization is one of the most popular techniques in image enhancement. However, due to the shifting of the mean brightness, the quality of the output image is deteriorated with great amount of information loss. This paper proposes a novel modification of the adaptive histogram equalization algorithm to improve its abilities in preserving information entropy, maintaining the mean bri...

This paper considers the problem of estimating the brightness of visual stimuli. A number of physical asymmetries are seen to permit determination of brightness that is invariant to certain manipulations of the sensor responses, such as inversion. In particular, the light-dark range asymmetry is examined and is shown to result, over a certain range, in increased variability of sensor responses ...

This paper exploits physical models of time-varying brightness in image sequences to estimate optical flow and physical parameters of the scene. Previous approaches handled violations of brightness constancy with the use of robust statistics or with generalized brightness constancy constraints that allow generic types of contrast and illumination changes. Here, we consider models of brightness ...

This work presents an eye-tracking and pupil size-measuring device that interfaces with a computer for applications useful in psychometry, ophthalmology, physiology and virtual reality (VR) systems. This system utilizes a change-coupled device (CCD) camera, appropriate lenses, PC with frame grabber and a DSP unit with various types of VR equipment, i.e., HMD, simulator or LCD projection device....

In low light environment, the surveillance video image has lower contrast, less information and uneven brightness. To solve this problem, this paper puts forward a contrast resolution compensation algorithm based on human visual perception model. It extracts Y component from the YUV video image acquired by camera originally to subtract contrast feature parameters, then makes a proportional inte...

Image segmentation is one of the most important steps before the image data analysis, which divided the image into several areas that have strong similarity. With the more and more widely application of the mesh fabric, the quality requirements are more stringent. As the impact of uneven illumination, the image brightness is inconsistent, which bring a great difficulty to the image segmentation...

Contrast enhancement is an important factor in the image preprocessing step. One of the widely accepted contrast enhancement method is the histogram equalization. Although histogram equalization achieves comparatively better performance on almost all types of image, global histogram equalization sometimes produces excessive visual deterioration. A new extension of bi-histogram equalization call...

Image enhancement aims at improving the quality of image for better visualization. This paper presents three methods of image enhancement: GHE, LHE and DSIHE that improve the visual quality of images. In this paper, we implement and examine the effect of above mentioned techniques based on objective and subjective image quality parameters (like PSNR, NAE, SC, AE and MOS) to measure the quality ...