A collision avoidance system is an automobile safety system designed to reduce the severity of an accident. It uses a combination of radar, laser and camera to detect the obstacles and avoid an imminent crash. Being relatively cheap, and capable of giving depth information stereo camera pair alone can be used for obstacle detection. Prime step in obstacle detection by stereo camera system is the generation of disparity map which gives the relative distance for all the obstacles in the scenario. But the accuracy and reliability of the disparity map is decided by quality of stereo images which might vary with external lighting conditions. Images captured under low light or night time conditions will have very poor quality and thereby affecting the reliability of the disparity map. In this paper, pre-processing the stereo images using histogram based enhancement techniques along with filtering is proposed to improve the reliability of the disparity map. The enhancement techniques like histogram equalization with the combination of low pass and median filter is used to process the stereo images before disparity map creation. Simulation results indicate the improvement in the disparity map accuracy and scene visibility with the proposed enhancement technique for the stereo image captured in low light.

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In this digital world, encryption plays an important role in various domains. Securing the information is the main goal when transfer of information takes place. Image encryption is a very important part of this as it applies to various domains like medical, multimedia, defence etc. A new method for image encryption is proposed here taking into account the “confusion-diffusion” structure. While working with secure data, requirements like fast computation, compression and processing are important issues. Deoxyribonucleic Acid (DNA) encoding has the capability to cope up with this requirement. In this paper a new algorithm is proposed based on composite chaos map for pixel scrambling and hence image encryption. First the algorithm takes the image and XORs with a composite chaotic map which further goes into dynamic DNA encoding followed by pixel scrambling which results in the image being very random thus it becomes less prone to attacks. The method discussed performs efficiently as shown in the experimental results.

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