Algorithms for approximately optimal quantization of color images are discussed. The distortion measure used is the distance in RGB space. These algorithms are used to compute the color map for low-depth frame buffers in order to allow high-quality static images to be displayed. It is demonstrated that most color images can be very well displayed using only 256 or 512 colors. Thus frame buffers...

The quality of the watermarked images is considered as one of the most important requirements of any watermarking system. In most applications, the watermarking algorithm embeds the watermark without affecting the quality of the host media. In this study, a comparison of watermarking image quality was performed between two existing methods: Dual Intermediate Significant Bit (DISB) and Genetic A...

Stego-images are often contaminated by interchannel noise or active attack when communicating on the Web. And it is challenging to restore embedded image from corrupted stego-image. This paper studies a k NN-bit approximation algorithm remove noises in image. The proposed distinguishes reliable bits extracted bits, and estimates pixel values keeping unchanged correcting unreliable bits. ...

We describe a digital holographic storage system for the study of noise sources and the evaluation of modulation and error-correction codes. A precision zoom lens and Fourier transform optics provide pixel-to-pixel matching between any input spatial light modulator and output CCD array over magnifications from 0.8 to 3. Holograms are angle multiplexed in LiNbO(3):Fe by use of the 90 degrees geo...

A new method is introduced for the least significant bit (LSB) image steganography in spatial domain providing the capacity of one bit per pixel. Compared to the recently proposed image steganography techniques, the new method called onethird LSB embedding reduces the probability of change per pixel to one-third without sacrificing the embedding capacity. This improvement results in a better im...

In this paper a novel spatial domain LSB based watermarking scheme for color Images is proposed. The proposed scheme is of type blind and invisible watermarking. Our scheme introduces the concept of storing variable number of bits in each pixel based on the actual color value of pixel. Equal or higher the color value of channels with respect to intensity of pixel stores higher number of waterma...

-Steganography is a skill to convey the secret data in the digital images without getting any unexpected notices to attackers. LSB replacement, the simplest method, directly replaces the secret bits with LSB bit plane. Unfortunately, it is insecure because it cannot resist against the visual attacks and statistic detection. The original work was proposed by Chang et al. in 2010, and their work ...

We compare a variety of lossless image compression methods on a large sample of astronomical images and show how the compression ratios and speeds of the algorithms are affected by the amount of noise (that is, entropy) in the images. In the ideal case where the image pixel values have a randomGaussian distribution, the equivalent number of uncompressible noise bits per pixel is given byNbits =...

■ Many factors govern the design of image-coding systems, ranging from the sensor type through storage and transmission limitations to the imagery end use. Image-compression performance depends on the costs of storage or transmission bandwidth (in bits per pixel), computational burden (in operations per second), information loss (utility), and artifacts that may change the receiver operating ch...