Recent trends in pixel-based image enhancement techniques using VLSI cores – a review

• Image enhancement techniques were explored. • Enhancement techniques incorporating VLSI cores were explored. • Few state-of-art techniques were implemented in Xilinx ISE. • Area, power and delay were calculated in Xilinx ISE for the enhancement techniques. • Performance analysis of Pixel-based techniques was carried out in MATLAB. Image processing is widely used in biometrics, medicine, agriculture, robotics, computer vision and other domain applications. Based on recent trends, the need for obtaining good-quality images with standalone architecture is in demand. Image enhancement techniques are applied to low-contrast or degraded images to improve their quality, while VLSI serves as a processing platform for real-time images as they are more speed-efficient. This paper meticulously studies various state-of-the-art pixel-based image enhancement techniques, including studies incorporating VLSI cores. Experimental research and implementation of pixel-based enhancement techniques are carried out in Xilinx ISE, along with their power, area and delay analysis. The techniques were implemented using the Spartan6 FPGA device in Xilinx ISE 14.7 design tool. The enhancement techniques were tested, and the results from MATLAB are included to provide a better understanding of these techniques. It is observed that Histogram Sliding achieves better area utilization. In terms of delay, Histogram Stretching proves more efficient. Histogram Equalization and its variants prove more power efficient than other state-of-the-art methods. This paper highlights the importance of VLSI in image processing.