Lossless JPEG

About: Lossless JPEG is a research topic. Over the lifetime, 2415 publications have been published within this topic receiving 51110 citations. The topic is also known as: Lossless JPEG & .jls.

Evaluation of JPEG and JPEG2000 compression algorithms for dermatological images

Abstract: Background Some image compression methods are used to reduce the disc space needed for the image to store and transmit the image efficiently. JPEG is the most frequently used algorithm of compression in medical systems. JPEG compression can be performed at various qualities. There are many other compression algorithms; among these, JPEG2000 is an appropriate candidate to be used in future. Objective To investigate perceived image quality of JPEG and JPEG2000 in 1 : 20, 1 : 30, 1 : 40 and 1 : 50 compression rates. Methods In total, photographs of 90 patients were taken in dermatology outpatient clinics. For each patient, a set which is composed of eight compressed images and one uncompressed image has been prepared. Images were shown to dermatologists on two separate 17-inch LCD monitors at the same time, with one as compressed image and the other as uncompressed image. Each dermatologist evaluated 720 image couples in total and defined whether there existed any difference between two images in terms of quality. If there was a difference, they reported the better one. Among four dermatologists, each evaluated 720 image couples in total. Results Quality rates for JPEG compressions 1 : 20, 1 : 30, 1 : 40 and 1 : 50 were 69%, 35%, 10% and 5% respectively. Quality rates for corresponding JPEG2000 compressions were 77%, 67%, 56% and 53% respectively. Conclusion When JPEG and JPEG2000 algorithms were compared, it was observed that JPEG2000 algorithm was more successful than JPEG for all compression rates. However, loss of image quality is recognizable in some of images in all compression rates.

Optimal bit allocation for full-frame DCT coding schemes: application to cardiac angiography

Abstract: This paper reports on a lossy compression method applicable to cardiac angiography. Full frame DCT coding has been investigated, using an optimized bit allocation and quantization scheme. We compared it to the standard JPEG method in the environment of a cardiac angiography system with dedicated visualization devices and post-processing. At a compression ratio 12:1, the image quality appeared to be better than the JPEG base-line compression. Owing to the principle of our method, no blocking effect is induced, whereas this is a critical drawback of the JPEG algorithm. Furthermore, the sharpness of fine details is better preserved.

JPEG and Sequential Search Algorithm applied on Low- Frequency Sub- Band for Image Compression (JSS)

Abstract: In this research we introduce and idea for image compression, based on JPEG technique and Sequential Search Algorithm, at first using Discrete Wavelet Transform (DWT) to obtain LL sub-band, then apply JPEG technique on the LL sub-band. JPEG technique consist of; JPEG Transformation, and JPEG Coding. The LL sub-band transformed by JPEG transformation for obtaining more compression ratio. Before apply JPEG coding, our algorithm used feedbacks system for inverse JPEG transformation to get decoded LL sub-band, and then the difference between decoded LL and original LL are stored in a new matrix called D- Matrix, finally the D-Matrix compressed by Sequential Search Algorithm. The Decompression algorithm consists of; Inverse JPEG transformation to get decoded LL, Sequential Search Algorithm to find D-Matrix, Add D-Matrix with the decoded LL and apply inverse DWT to get decompressed image. Our algorithm tested on two different gray level images and compared with JPEG and JPEG2000.

Watermarking for JPEG image using error correction coding

Abstract: Compression is the most common process that limits the robustness of watermarking We propose a watermarking method for JPEG compressed color images in the semi-decompression domain, using Reed-Solomon (RS) codes The watermark embedding and recovery processes can be applied without decompressing the compressed file completely There is no perceptible degradation between the watermarked image and the original image Experimental results show that the scheme is robust against some distortion attacks and JPEG lossy compression with different compression rates

Lossless Jpeg-Base Compression of Transmultiplexed Images

Abstract: A transmultiplexer assigned to combine images into one image to be sent through a single communication channel is presented. The considered system can be equipped with integer-to-integer filters to enable the lossless compression. The efficiency of lossless JPEG compression applied to transmultiplexed signals has been verified.