The techniques of digital image improvement are to improve the visual quality of the images. The main purpose of image enhancement is to process an image so that the result is more convenient than the original image for the specific application. This paper presents real-time hardware image enhancement techniques using field programmable gate array (FPGA). This work focuses on the implementation of image enhancement algorithms such as brightness control, stretch contrast, negative transformation, thresholds, Fpga filtering techniques that have become a competitive alternative for digital signal processing applications high performance. These algorithms were successfully implemented in retinal images in Verilog HDL using Xilinx ISE, MATLAB and MODELSIM. The objective of this work is to simulate and implement these algorithms using verilog HDL. The device selected here for its implementation is Xilinx (Spartan-3E).
Digital image processing plays a vital role in the analysis and interpretation of remote sensing data. Especially the data obtained from Medical and Satellite Remote Sensing, which is in digital form, can be best used with the help of digital image processing. Image enhancement and information extraction are two important components of digital image processing. Image enhancement techniques help improve the visibility of any portion or feature of the image.
Image enhancement processes have different techniques for improving the visual appearance of an image. Meanwhile, the term image enhancement is medium like enhancing an image appearance by increasing the dominance of some features or decreasing ambiguity between different regions of the image.
The improvement methods can be divided into two categories:
1. Methods of spatial domain
2. Frequency Domain Methods
The underwater environment is rich in underwater cultural heritage. Underwater archaeology is concerned with studying this rich cultural heritage. Underwater image practices to harness data such as coral reefs, detection of oil pipeline lines as well as telecommunication cables, shipwrecks, etc. Hence the investigations are being carried out in the deep water regions. The sea was the main route for commercial activities in antiquity. Much of the trade has been in spite of the ships. Shipwrecks were often common in those times because of the ever-changing and unexpected storms in these regions. Hence light shipwrecks to ancient culture and therefore the archaeologist are interested in this. Shipwrecks can be called as moments in time, which gives a lot of information about people and culture. Even scientific methods of archaeology can force controlled destruction. The underwater image is quite difficult due to bad lighting. Light rays traveling through water undergo dispersion attenuation and are sometimes absorbed by water molecules and other suspended particles in underwater water. As the depth of the ocean increases, it in turn results in visually degraded images. Due to the light scattering effect on the aquatic environment, the artificial light source must be provided for adequate illumination. Disastrously, these artificial lightnings tend to illuminate the scene in a non-uniform way. Each sensor that produces spatially distributed intensity values of electromagnetic radiation that can be digitized and stored in RAM is suitable for capturing images. [2] Depending on the application, image capture systems are varied, differing in acquisition mode and speed, spectral and dynamic range of spatial resolution, sensor systems, etc.