In the area of medicine, storing medical images of the patient in a very secure manner becomes to be toughest challenge. As the development in the digitalization of medicine, medical images security becomes critical issues for providing the secure transmission of data and images over unsecured channels. To overcome such issues, visual cryptography has been introduced using cryptographic mechani...

Yanling Ju Ph.D., Purdue University, May 2015. Black-Box Printer Models and their Applications. Major Professor: Jan P. Allebach. In the electrophotographic printing process, the deposition of toner within the area of a given printer addressable pixel is strongly influenced by the values of its neighboring pixels. The interaction between neighboring pixels, which is commonly referred to as dot-...

The Yule-Nielsen modified spectral Neugebauer model enhanced for accounting for ink spreading in the different ink superposition conditions (EYNSN) requires measuring the reflectances of halftone calibration patches in order to compute the ink spreading curves mapping nominal ink surface coverages to effective ink surface coverages. Spectral measurements of dozens of halftone patch reflectance ...

Now in use on x-ray beamlines worldwide, shearing interferometry and Hartmann wavefront sensing provide effective feedback for measuring optimizing high-quality beams. Conventionally, both approaches spatially modulate the beam properties (amplitude or phase) using two-tone, binary patterns, leading to deleterious diffraction effects that must be mitigated. In shearing, presence of multiple ord...

One of the main challenges for the characterization of printing systems consists, for a given substrate, in establishing the relationship between surface coverages of the selected set of inks and the spectral reflectances of the printed ink halftones. Knowledge of print halftone spectral reflectances enables deducing their colors. Models enabling the prediction of spectral reflectances as a fun...

Visual secret sharing is the technique that divide the secret image into n multiple shares. Each share constitutes some information and when k shares out of n stack together the secret will reveal. However; less than k shares are not work. The beauty of the visual secret sharing scheme is its decryption process i.e. to decrypt the secret using Human Visual System (HVS) without any computation. ...

We conducted a monitor-based subjective study on multilevel halftone. Observers in a halftone preference experiment selected stimuli in a paired comparison design. Images were halftoned using multilevel stochastic screening and multilevel error diffusion. Stimuli were presented on a calibrated monitor from distances equivalent to viewing 300 and 600 dpi prints. We applied Thurstone's law of com...

3D printing is becoming increasingly popular around the world today. By utilizing 3D printing technology, customized products can be manufactured much more quickly and efficiently with much less cost. However, 3D printing still suffers from low quality surface reproduction compared with 2D printing. One effective approach to improve it is to develop an advanced halftoning algorithm for 3D print...

Experimental results of fiber Bragg gratings fabricated with halftone amplitude transmission masks and 10-cm-long phase masks are presented for the first time to our knowledge. The performance of the devices is evaluated in terms of their spectral characteristics and deviation from linear group delay. Good out-of-band sidelobe suppression of -27 dB and group-delay ripple of ?9.5 ps is achieved ...