Korelacija med objektivno in subjektivno ovrednoteno vizualno kakovostjo digitalnih fotografij ter njihovo sporočilnostjo

Ahtik, Jure (author), Starešinič, Marica (mentor)

Sodobna komunikacija vse bolj in bolj vključuje fotografijo in dobra sporočilnost fotografije je tista, ki lahko pomeni razliko med uspešno in neuspešno komunikacijo. V raziskavi smo se določitve sporočilnosti lotili z vizualno kakovostjo fotografij, ki smo jo izvedli s subjektivno metodo (spletna aplikacija, množicanje), objektivno metodo sledenja očesnim premikom in matematičnimi objektivnimi metodami (RMSE, PSNR in SSIM), ki smo jim dodali še določitev barvnih razlik. Določitev vizualne kakovosti je temeljila na testni bazi fotografij, ki smo jo definirali v ta namen. Testna baza vsebuje 30 fotografij z 38 različnimi popačenji, ki so posledica apliciranja izbranih parametrov vizualne kakovosti. Ugotovili smo, da od parametrov vizualne kakovosti na vizualno kakovost in posledično sporočilnost najmanj vplivajo povišana ostrina, nižji kontrast in zmanjšana nasičenost, medtem ko višji kontrast, sprememba svetlosti in zmanjšana ostrina na vizualno kakovost vplivajo najbolj. Izračunali smo zelo močno korelacijo med rezultati, pridobljenimi s subjektivno metodo, in tistimi, dobljenimi z objektivno metodo sledenja očesnim premikom, medtem ko je korelacija z drugimi objektivnimi metodami slabša. Rezultat raziskovalnega dela sta tudi dve metodi: metoda za določanje vizualne kakovosti po subjektivni poti in metoda analize rezultatov, dobljenih z metodo sledenja očesnim premikom.

• Language: Slovenian
• Keywords: določitev vizualne kakovosti. fotografija, množicanje, parametri vizualne kakovosti, sledenje očesnim premikom, sporočilnost
• Work type: Doctoral dissertation
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2017
• PID: 20.500.12556/RUL-92679
• COBISS.SI-ID: 292038656
• Publication date in RUL: 27.06.2017

Secondary language

• Language: English
• Title: The correlation between objective and subjective digital photography quality assessment and its communication value

Abstract

Photography is involved in modern communication more than ever and good communication value of photography has a deciding influence on successful communication. In our research we determined communication value with the help of image quality assessment, that was based on subjective method (web application, crowdsourcing), objective method of eye tracking, mathematical objective measures (RMSE, PSNR, SSIM) and colour differences. Assessment was based on a testing image database that we developed for this purpose. Database includes 30 photographs with 28 different manipulations that are based on different visual quality parameters. We determined that higher sharpness, lower contrast and lower saturation have little influence on image quality and on the other hand, higher contrast, change of lightness and lower sharpness have big influence on it. We calculated strong correlation between results gathered with subjective method and ones gathered with an eye tracking method, but the correlation with other objective methods is less significant. In our research we also developed two new methods, one is for subjective quality assessment and the other for analysing data gathered with the method of eye tracking.

• Keywords: visual quality assessment, photography, crowdsourcing, parameters of visual quality, eye tracking, communication value