We propose an algorithm in which a sequence of digital halftone images is efficiently transmitted using encoding compatible with conventional facsimile devices. To enhance the CCITT standardized coding schemes for Group 3 and Group 4 facsimile apparatus, pre-encoding is done on each image in the sequence: The image is either pre-encoded as a combination of bit representation of block means and ...

This paper addresses an optimal design problem of dynamic quantizers for a class of 2D systems with discrete-valued control input. First, we derive a closed form expression of the performance of a class of dynamic quantizers. Next, based on that, an optimal dynamic quantizer is provided. Finally, we apply the optimal dynamic quantizer to generate binary halftone images.

A new digital halftone resolution technique, based on a neural network with connection strengths derived from stochastic power spectra, is proposed. Ulichney's "blue noise" spectrum is used as a basis; alternative spectra are also examined. The new technique is compared with standard resolution techniques, ordered dither, Floyd-Steinberg, and dot diffusion. The new technique appears to offer re...

Visual Cryptography (VC), proposed by Naor and Shamir, has numerous uses, including visual authentication and identification, image encryption and steganography for security purpose, and. In this paper Contrast the visual information based on pseudo randomization and pixel reversal using sigmoid function is also proposed. Keywords— Information hiding, Information Security, Halftone image, Visua...

Hexagonal dot packing seems to offer benefits for halftone printing compared to conventional square dot packing, but little practical experience has been reported. Taking advantage of recent refinements in digital electrophotographic (EP) printer technology, the authors conducted experiments on a commercially deployable system to assess whether the potential advantages of hexagonal dot packing ...

The direct binary search algorithm is a powerful heuristic for generating high quality halftone images that account for the characteristics of both the output device and viewer. With a hard circular dot overlap model, it yields enhanced detail rendition, suppression of aliasing artifacts, and improved tonal gradation in shadow areas.