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This paper describes the design and implementation of intra-pulse polyphase codes for a weather radar system. Algorithms to generate codes with good correlation properties are discussed. Thereafter, a new design framework is described, which optimizes the polyphase code and corresponding mismatched filter, using a cost/error function, especially for weather radars. It establishes the performance of these intra-pulse techniques with specific application towards second trip removal. The developed code is implemented on NASA D3R, which is a dual-frequency, dual-polarization, Doppler weather radar system.

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Steganography is the art of secret communication between two parties that not only conceals the contents of a message but also its existence. Steganalysis attempts to detect the existence of embedded data in a steganographically altered cover file. Many algorithms have been proposed, but so far each has some weakness that has allowed its effects to be detected, usually through statistical analysis of the image. In this paper, we propose a different approach to JPEG steganography that provides high embedding capacity with zero-deviant histogram restoration. Our algorithm, named J3, uses stop points in its header structure that allows it to restore the histogram completely, making its detection impossible by any first order steganalysis. It gives better results with higher order steganalysis when compared to F5, Outguess and Steghide. As far as we know, there is no existing algorithm that can provide as high an embedding payload with complete histogram restoration.