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Bachelor's Thesis
Author of thesis: Eliáš Gábor
Acad. year: 2025/2026
Supervisor: prof. Mgr. Pavel Rajmic, Ph.D.
Reviewer: Ing. Peter Balušík
This thesis deals with quantization and dithering when reducing the bit depth of audio signals and the number of colours in images. The theoretical part explains sampling, quantization and quantization noise, including its relation to bit depth and the signal-to-noise ratio. It describes the types of quantizers (mid-tread and mid-riser), the distributions of dither noise (RPDF, TPDF, Gaussian) and its shaping into less audible bands, and, for images, banding artefacts and image dithering methods (random, ordered and error diffusion). The practical part consists of two interactive web applications written in JavaScript, intended as teaching support for signal processing. The audio applet allows changing the signal type, bit depth and dithering; it shows the result in three graphs (the original signal, the quantized signal and the quantization error) and also plays it back, so the difference between quantization with and without dithering can be both seen and heard. The image applet quantizes a selected image to a chosen number of levels and applies random, ordered (Bayer) or Floyd--Steinberg dithering in greyscale as well as in colour, comparing the result with the original. Both applications run directly in the browser.
Audio, bit depth, digital signal processing, dithering, image, JavaScript, quantization, quantization noise, web application
Date of defence
18.06.2026
Result of the defence
Defended (thesis was successfully defended)
Grading
D
Process of defence
Student prezentoval výsledky své práce a komise byla seznámena s posudky. Student obhájil bakalářskou práci s výhradami a odpověděl na otázky členů komise a oponenta. Otázky: 1) Môžete vysvetliť princíp metódy tvarovania šumu (noise shaping) a objasniť, prečo nebola implementovaná vo Vašej demonštračnej audio aplikácii? 2) Skúšali ste pred aplikáciou dithering algoritmov linearizovať sRGB hodnoty pixelov? Aký vplyv by malo zahrnutie tejto linearizácie na výsledné obrázky?
Language of thesis
Slovak
Faculty
Fakulta elektrotechniky a komunikačních technologií
Department
Department of Telecommunications
Study programme
Audio Engineering (BPC-AUD)
Specialization
Audio Production and Recording (AUDB-ZVUK)
Composition of Committee
prof. Mgr. Pavel Rajmic, Ph.D. (předseda) MgA. et Mgr. Ondřej Jirásek, Ph.D. (místopředseda) Ing. Miroslav Balík, Ph.D. (člen) Ing. Richard Ladislav (člen) Ing. Václav Mach, Ph.D. (člen)
Supervisor’s reportprof. Mgr. Pavel Rajmic, Ph.D.
Grade proposed by supervisor: D
Reviewer’s reportIng. Peter Balušík
Grade proposed by reviewer: D
Responsibility: Mgr. et Mgr. Hana Odstrčilová