Pučić, Ivan (2021) Promjene vrijednosti boja digitalnih slika pri prijenosu međuspremnikom = Changes in colour values of digital images during clipboard transfer. Dissertation (PhD) thesis. Grafički fakultet. [Mentor: Matijević, Mile].
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Abstract
Zbog razlike između oblika zapisa pojedinih grafičkih alata dolazi do prilagođavanja podataka prilikom njihovog prijenosa. Ovaj rad istražuje promjene koje nastaju prijenosom piksel grafika između različitih grafičkih alata korištenjem međuspremnika kroz određivanje sličnosti fotografija prije i nakon prijenosa te mjerenje razlika u vrijednostima boja koje su nastale tijekom prijenosa. U prvom ispitivanju od 132 planirana smjera prijenosa piksel grafika uspješno je provedeno njih 91. Određivana sličnost fotografija prije i nakon prijenosa, izračunata po SSIM algoritmu, pokazala je da je u 11 slučajeva izvršen savršeni prijenos, odnosno prijenosom nije došlo do izmjene strukturnih informacija fotografije. Nadalje, u većini slučajeva (79,34%) prijenosom je nastala fotografija s malim odstupanjima u strukturi u odnosu na početnu fotografiju (SSIM indeks iznosi 0,9 do 0,99). Analizom rezultata drugog ispitivanja pokazalo se da su evidentirane visoke vrijednosti u razlikama boja nastalih tijekom prijenosa dobivene za boje koje na fotografijama zauzimaju malu površinu te time nemaju veliki utjecaj na vidljivu kvalitetu prijenosa. U trećem ispitivanju, usporedbom dobivenih razlika u vrijednostima boja kod prijenosa grafika u RGB i CMYK prostoru boja, pokazalo se da korišteni prostor boja utječe na kvalitetu prijenosa, na način da se promjene u vrijednostima boja događaju manje pri korištenju RGB nego CMYK prostora boja. Na temelju dobivenih rezultata moguće je potvrditi hipotezu da su promjene u vrijednostima boja u piksel grafikama nastale prijenosom međuspremnikom uzrokovane nekompatibilnošću operativnog sustava i grafičkih alata. Nadalje, potvrđeno je da, unatoč evidentiranim promjenama u vrijednostima boja, transformirane datoteke udovoljavaju kriterijima i prikladne su za svakodnevnu uporabu. Naposljetku, na temelju dobivenih rezultata moguće je vrednovanje sustava za upravljanje bojom na razini operativnog sustava te definiranje preporuka za korištenje međuspremnika. Preporuke idu u smjeru da je opravdano korištenje međuspremnika za svakodnevnu uporabu, no za profesionalnu uporabu preporučuje se izbjegavanje prijenosa međuspremnikom. Također, zbog manjih promjena vrijednosti boja, preporučuje se korištenje RGB umjesto CMYK prostora boja za prijenos piksel grafika međuspremnikom.
| Item Type: | Dissertation (PhD) thesis |
|---|---|
| Mentor name: | Matijević, Mile |
| Thesis Committee: | Bolanča Mirković, Ivana and Modrić, Damir and Hajdek, Krunoslav |
| Defence date: | 23 September 2021 |
| Abstract in english: | The difference in clipboard file formats of the used graphic programs causes the adaptation of image data during transfer. The transfer of pixel graphics causes the change in the color values of the pixels. This leads to a visible change in the whole pixel graphics. This paper researches the changes created during the transfer of pixel graphics between different graphic programs using the clipboard. The level of changes was determined through image similarity of the original image and created copies, and the application of color difference equations of selected color values was also transferred as pixel graphics. The research showed it was not possible to complete all planned pixel data transfers due to the incompatibility of the used programs. In the first part, the transfers were completed successfully in 91 out of 132 planned transfer directions. The similarity measurement of photographs was calculated with the SSIM algorithm. The perfect transfer was completed in 11 out of 91 transfer directions, implying that there was no change in the structural information of the images. A small shift in the structure of the processed pixel graphics in comparison to the original pixel graphics appeared in 79.34% of the cases. A small shift is perceived as an index range 0.9 to 0.99. The analysis of the results in the second part of the research showed a high difference between colors before and after the transfer for the colors that appear on a small surface percentage of the photos. This reduces that effect on the color perception of the photo to a small influence. The comparison of calculated color differences of the transferred pixel graphic in CMYK color space (color chart 201101) and RGB color space (color chart 201102) was performed in the third part. The comparison showed that there is a difference in the shift of the color values in relation to the used document color space. The shifts in color values are smaller when RGB color space is used than CMYK-based color space images. The results show that it is possible to confirm the hypothesis that the changes in color values of the tested pixel graphics appear during clipboard transfer. They are caused by the incompatibility of the color management systems of the operating system and usedprograms. Furthermore, it is confirmed that despite the evident changes in color values, the transformed pixel graphics concur with the quality criteria and can be used in everyday operations. The obtained results enable the evaluation of the existing color management systems on the operating system level. They also enable the definition of recommendations for the use of a clipboard. The use of a clipboard is recommended in standard everyday use. However, it is not recommended for professional use where color preservation is essential. The use of RGB color space is recommended due to the smaller shift in color values during the clipboard transfer of pixel graphics. |
| Uncontrolled Keywords: | grafički alati, međuspremnik, sustavi boja, operativni sustavi |
| Keywords in english: | graphic tools, clipboard, color systems, operating system |
| Subjects: | TECHNICAL SCIENCES > Graphic Technology |
| Institution: | Grafički fakultet |
| City: | Zagreb |
| Number of Pages: | 176 |
| Callnumber: | 655:004:535.6 PUČ p |
| Inventory number: | 10428 |
| Depositing User: | Nina Jelača |
| Status: | Unpublished |
| Date Deposited: | 25 Apr 2022 09:38 |
| Last Modified: | 25 Apr 2022 09:40 |
| URI: | http://eprints.grf.unizg.hr/id/eprint/3354 |
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