Adaptive Wavelet Fusion based Color Image Enhancement by Scaling the DC Coefficients

Abstract-Usually the images taken by digital cameras are different from the original true color image in terms of color and brightness of the scene captured. Various factors like non uniform illumination, color of ambient light, low or high contrast, and over exposure or under exposure of some specific regions may leads to poor contrast which is annoying to human visual system. Thus, enhancement methods are required for color images. In this paper An image fusion is used to improve the performance of DC coefficient scaling method in the compressed DCT domain for enhancing the contrast of colour images. Using the multi resolution wavelet fusion preserves the brightness of the enhanced image. This improves the entropy of standard DCT based DC coefficient scaling method. For comparing the performance along with SNR and the absolute standard deviation difference is also used as parameters. The methods are tested on various true colour images from different environmen

Low contrast detection factor based contrast enhancement and restoration for underwater images

Marine ecosystem is the largest of earth’s aquatic ecosystems. It includes salt marshes, coral reefs, deep sea, sea floor, etc. To learn deep about the activities taking place inside, underwater imaging is a tool. But these images lack in contrast and brightness leading to the lack of information in the ocean activities. To enhance such low contrast underwater images, Low Contrast Detection Factor (LCDF) is proposed in this study. It uses the value, saturation and hue to enhance the low contrast regions and to restore the color.  Quality assessment is done to substantiate the proposed algorithm. It is found that the entropy gives an average of 7.3. No-reference Quality Metrics such as Natural Image Quality Evaluator and Blind/ Referenceless Image Spatial Quality Evaluator shows an average value of 3.6 and 22.5, respectively. The blur metrics shows a value of 0.21. The quality metrics indicates that the naturalness of the underwater image is maintained while the contrast of the underwater image has increased

Low contrast detection factor based contrast enhancement and restoration for underwater images

7-13Marine ecosystem is the largest of earth’s aquatic ecosystems. It includes salt marshes, coral reefs, deep sea, sea floor, etc. To learn deep about the activities taking place inside, underwater imaging is a tool. But these images lack in contrast and brightness leading to the lack of information in the ocean activities. To enhance such low contrast underwater images, Low Contrast Detection Factor (LCDF) is proposed in this study. It uses the value, saturation and hue to enhance the low contrast regions and to restore the color. Quality assessment is done to substantiate the proposed algorithm. It is found that the entropy gives an average of 7.3. No-reference Quality Metrics such as Natural Image Quality Evaluator and Blind/ Referenceless Image Spatial Quality Evaluator shows an average value of 3.6 and 22.5, respectively. The blur metrics shows a value of 0.21. The quality metrics indicates that the naturalness of the underwater image is maintained while the contrast of the underwater image has increased