Jan P. Allebach

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Atkins, C. Brian. Ph.D., Purdue University, December 1998. Classification-Based Methods in Optimal Image Interpolation. Major Professors: Charles A. Bouman and Jan P. Allebach. In this thesis, we introduce two new approaches to optimal image interpolation which are based on the idea that image data falls into different categories or classes, such as edges(More)
In this paper, we present the adaptive bilateral filter (ABF) for sharpness enhancement and noise removal. The ABF sharpens an image by increasing the slope of the edges without producing overshoot or undershoot. It is an approach to sharpness enhancement that is fundamentally different from the unsharp mask (USM). This new approach to slope restoration(More)
We present an enhanced error diffusion halftoning algorithm for which the filter weights and the quantizer thresholds vary depending on input pixel value. The weights and thresholds are optimized based on a human visual system model. Based on an analysis of the edge behavior, a tone dependent threshold is designed to reduce edge effects and start-up delay.(More)
A model for the human visual system (HVS) is an important component of many halftoning algorithms. Using the iterative direct binary search (DBS) algorithm, we compare the halftone texture quality provided by four different HVS models that have been reported in the literature. Choosing one HVS model as the best for DBS, we then develop an approximation to(More)
In today’s digital world securing different forms of content is very important in terms of protecting copyright and verifying authenticity. Many techniques have been developed to protect audio, video, digital documents, images, and programs (executable code). One example is watermarking of digital audio and images. We believe that a similar type of(More)
We investigate the display of color image sequences using a model-based approach to mul-tilevel error diiusion. We extend Bouman and Kolpatzik's technique 1] for design of an optimal lter to the temporal dimension. Our model for the human visual system accounts for the spatial and temporal frequency dependence of the contrast sensitivity of the luminance(More)
We incorporate models for printer dot interactions within the iterative direct binary search (DBS) halftoning algorithm. Monochrome electro-photographic printers are considered. Both analytical and stochastic models are studied. In the analytical model it is assumed that the printer can generate a circular spot with constant absorptance at each printer(More)
We introduce a new approach to optimal image scaling called Resolution Synthesis (RS). In RS, the pixel being interpolated is £rst classi£ed in the context of a window of neighboring pixels; and then the corresponding high-resolution pixels are obtained by £ltering with coef£cients that depend upon the classi£cation. RS is based on a stochastic model(More)