Even after the development in the data transfer rates and bandwidths the transfer has become very costly in the applications has the image contains a lot of information. So there is need for compression techniques where the image will be encoded in a format and is transmitted over the network. The image will be decoded by a decryption process by which the original image will be obtained. There are various image compression techniques available. In this paper we will look into JPEG image compression technique and how the encryption and decryption algorithms for transmitted the image.
Brief on JPEG compression algorithm:
Image which carries information in the form of rectangular array of dots called as pixels. Depending on the pixel value the color of it is identified. Here in JPEG image compression method the encoding process is done over where the original image is divided into 8X8 size blocks of sub images. Here DCT is performed on each image separately and the resultant is divided with the quantization matrix.
The obtained value is made into one dimensional data for obtaining this we can apply zig zag coding, arithmetic or a by applying Huffman coding algorithm. To obtain the original image the reverse mechanism is applied in the decoder. Here we use a source encoder in the image compression model so as to reduce the redundancy present in the input image. If any data loss occurs we can measure the data loss by using fidelity criterion and apply it the algorithm to obtain the image.
Conclusions:
By using image compression the transmitted data gets decreased by which we can transmit the data by using a low frequency signal. By using JPEG compression technique the image gets encrypted which occupies less space and it does not vary the quality of the image when the original image is restored.
Download Electronics and Communication Project Report on JPEG Image Compression.