Browsing by Subject "Quantization errors"

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Open Access
QR-RLS algorithm for error diffusion of color images
(SPIE, 2000) Unal, G. B.; Yardimci, Y.; Arıkan, Orhan; Çetin, A. Enis
Printing color images on color printers and displaying them on computer monitors requires a significant reduction of physically distinct colors, which causes degradation in image quality. An efficient method to improve the display quality of a quantized image is error diffusion, which works by distributing the previous quantization errors to neighboring pixels, exploiting the eye's averaging of colors in the neighborhood of the point of interest. This creates the illusion of more colors. A new error diffusion method is presented in which the adaptive recursive least-squares (RLS) algorithm is used. This algorithm provides local optimization of the error diffusion filter along with smoothing of the filter coefficients in a neighborhood. To improve the performance, a diagonal scan is used in processing the image.
Open Access
Quantization errors in overlapped block digital filtering methods
(IARIA, 2013) Daloğlu, Mustafa; Serpedin, E.
In digital signal processing applications involving filtering long sequences, block filtering methods like overlapsave and overlap-add are widely used. Like all finite-precision applications, overlap-save and overlap-add methods are also affected by quantization errors. The goal of this paper is to calculate and make a quantitative comparison of the overall quantization noise resulting from the two methods in terms of power (variance) of the quantization noise. Multiple quantization noise sources are taken into consideration in the computation of the variances. The calculations reveal that the overlap-add approach is more prone to quantization noise compared to the overlap-save approach due to the addition of overlapping sections between overlap-add output blocks. Copyright © 2013 IARIA.