20.500.12556/RUL-152942 Izboljšava stresanja barv nizkoresolucijskih slik z omejeno barvno paleto Improving color dithering in low resolution images with a limited color palette V delu se ukvarjamo s problematiko pretvorbe barvnih slik nizke resolucije v slike z omejeno, vnaprej določeno barvno paleto. Za čim boljše rezultate se za takšne probleme uporablja stresanje. Stresanje je koncept namernega dodajanja šuma, s katerim zmanjšamo prisotnost artefaktov in v splošnem dosežemo boljše rezultate. Predlagamo štiri nove tehnike stresanja, ki temeljijo na zaznavanju robov na sliki in jih podrobneje analiziramo. Dve izmed njih poleg dveh uveljavljenih metod stresanja primerjamo v anketi. Poleg različnih tehnik stresanja v anketi primerjamo tudi stresanje slik v štirih različnih barvnih prostorih — sRGB, CIELAB, ICtCp in Oklab. Iz rezultatov ankete prikažemo, da nove predlagane tehnike stresanja v večini primerov niso boljše od obstoječih. Pokažemo tudi, da je v veliki večini primerov stresanje v Oklab prostoru znatno boljše od stresanja v ostalih treh primerjanih prostorih. Rezultate ankete primerjamo z rezultati metrik DSCSI in FLIP in pokažemo visok nivo korelacije, kar kaže na primernost uporabe omenjenih metrik za analizo stresenih slik, kot tudi na primernost uporabe teh metrik za analizo slik, ki so stresene v barvnih prostorih, ki niso sRGB ali CIELAB, ki sta najpogosteje uporabljena. Na koncu predlagamo več potencialnih sprememb predlaganih algoritmov, ki bi lahko prinesle napredek v kakovosti stresenih slik. In this thesis, we deal with the problem of converting low-resolution color images into images of a limited, predetermined, color palette. To achieve the best results, dithering is used for such problems. Dithering is a concept of intentionally adding noise to reduce the presence of artifacts and generally achieve better results. We propose four new dithering techniques that are based on edge detection and analyze them in detail. Two of them, alongside two established dithering methods, are compared in a survey. In addition to different dithering techniques, we also compare images dithered in four different color spaces — sRGB, CIELAB, ICtCp, and Oklab. Survey results show that the new proposed dithering techniques are not better than the existing ones in most cases. They also show that in the vast majority of cases, dithering in Oklab space is significantly better than dithering in any of the other three spaces we compared. By comparing the survey results with the outputs of DSCSI and FLIP metrics we show a high level of correlation, indicating the suitability of using these metrics for analyzing dithered images, as well as the suitability of using these metrics for analyzing images that are dithered in color spaces other than sRGB or CIELAB, which are most commonly used. Finally, we propose several potential changes to the proposed algorithms that could bring progress in the quality of dithered images. stresanje barv nizkoresolucijsko paleta barvni prostor detekcija robov anketa sRGB CIELAB ICtCp Oklab Floyd Steinberg Burkes Bayer color dithering low resolution palette color space edge detection survey sRGB CIELAB ICtCp Oklab Floyd Steinberg Burkes Bayer true false false Slovenski jezik Angleški jezik Magistrsko delo/naloga 2023-12-13 08:05:00 2023-12-13 08:05:08 2023-12-22 11:18:01 0000-00-00 00:00:00 2023 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 35449 178665987 Svigelj_Mihael_-_Izboljsava_stresanja_barv_nizkoresolucijskih_slik_z_omejeno_barvno_paleto.pdf Svigelj_Mihael_-_Izboljsava_stresanja_barv_nizkoresolucijskih_slik_z_omejeno_barvno_paleto.pdf 1 C91AA0559D7152A258484A6BBCADDE57 032192cc51f4103d3635794f9fba99bcc2d3fecefc2cac528d97cf558c5f7d20 f354fdbe-9985-11ee-9499-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=178689 Fakulteta za računalništvo in informatiko 0 0 0