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We model a degraded image as an original image that has been subject to linear frequency distortion and additive noise injection. Since the psychovisual effects of frequency distortion and noise injection are independent, we decouple these two sources of degradation and measure their effect on the human visual system. We develop a distortion measure (DM) of(More)
Grayscale digital image halftoning quantizes each pixel to one bit. In error diffusion halftoning, the quantization error at each pixel is filtered and fed back to the input in order to diffuse the quantization error among the neighboring grayscale pixels. Error diffusion introduces nonlinear distortion (directional artifacts), linear distortion(More)
Error diffusion halftoning is a popular method of producing frequency modulated (FM) halftones for printing and display. FM halftoning fixes the dot size (e.g., to one pixel in conventional error diffusion) and varies the dot frequency according to the intensity of the original grayscale image. We generalize error diffusion to produce FM halftones with(More)
Halftones and other binary images are difficult to process with causing several degradation. Degradation is greatly reduced if the halftone is inverse halftoned (converted to grayscale) before scaling, sharpening, rotating, or other processing. For error diffused halftones, we present (1) a fast inverse halftoning algorithm and (2) a new multiscale gradient(More)
We consider the problem of rendering high-resolution images on a display composed of multiple superimposed lower-resolution projectors. A theoretical analysis of this problem in the literature previously concluded that the multi-projector superimposition of low resolution projectors cannot produce high resolution images. In our recent work, we showed to the(More)
Multi-projector super-resolution is the dual of multi-camera super-resolution. The goal of projector super-resolution is to produce a high resolution frame via superimposition of multiple low resolution subframes. Prior work claims that it is impossible to improve resolution via superimposed projection except in specialized circumstances. Rigorous analysis(More)
We present a fast, non-iterative technique for producing grayscale images from error diiused and dithered halftones. The rst stage of the algorithm consists of a Gaussian l-ter and a median lter, while the second stage consists of a bandpass lter, a thresholding operation, and a median lter. The second stage enhances the rendering of edges in the inverse(More)
| We present an inverse halftoning algorithm for error diiused halftones. At each pixel, the algorithm applies a separable 7 7 FIR lter parameterized by the horizontal and vertical edge strengths computed from the local gradients. The algorithm requires entirely local operations, storage of 7 rows, and fewer than 300 arithmetic operationsspixel. The(More)
— This paper presents an extensible framework for designing analog filters that exhibit several desired behavioral properties after being realized in circuits. In the framework, we model the constrained nonlinear optimization problem as a sequential quadratic programming (SQP) problem. SQP requires real-valued constraints and objective functions that are(More)
This thesis is dedicated to my parents, and to the memory of my w onderful Gran. Acknowledgments First of all, I would very much like to thank my advisors, Al Bovik and Brian Evans in alphabetical order for all their help during my time in graduate school. I believe that their complementary styles have given this work a unique character. They have broadened(More)