Kovačević, Sandra (2020) Provjera autentičnosti računalno generiranih holograma tiskanih standardnim grafičkim CtF (Computer to Film) postupkom. Master's thesis - Graduate Programme. Grafički fakultet. [Mentor: Modrić, Damir].
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Abstract
Fokus ovog rada su prethodno računalno generirani hologrami otisnuti CtF (Computer to Film) standardnom grafičkom tehnikom ispisa u svrhu provjere mogućnosti kopiranja istih. Nad prikupljenim podacima provodila se analiza i usporedba interferentnih uzoraka u svrhu detektiranja deformacija prilikom kopiranja na visokim rezolucijama. Obrada podataka sastajala se od dvije faze. Optička rekonstrukcija kopiranih interferentnih uzoraka programom Adobe Photoshop CC 2015 (korištenje alata za uređivanje razine osvjetljenja slike i pretvaranje slike u tonovima sive u crno-bijele s visokim kontrastom) i numerička rekonstrukcija primjenom specifičnog programa ImageJ. Korišteni program koristi opciju FFT (Fast Fourier Transform) i omogućava brzu obradu informacija. Analizom rezultata interferiranih uzoraka pri kopiranju na visokim rezolucijama potvrdili smo da se računalno generirani hologrami ne mogu kopirati navedenim metodama, odnosno nije moguće generirati kvalitetnu repliku.
| Item Type: | Master's thesis - Graduate Programme |
|---|---|
| Mentor name: | Modrić, Damir |
| Thesis Committee: | Budimir, Ivan and Modrić, Damir and Petric Maretić, Katja |
| Defence date: | 22 September 2020 |
| Abstract in english: | The focus of this paper are previously computer-generated holograms printed in CtF (Computer to Film) technology in order to check the possibility of their fabrication. The collected data were analysed and compared for the purpose of detecting deformations when copying at high resolutions. Data processing consisted of two phases. Optical reconstruction of copied patterns with Adobe Photoshop CC 2015 (using tools to edit the brightness of the image and convert the image in grayscale to black and white with high contrast) and numerical reconstruction using a specific program ImageJ. Used program gives the possibility of the FFT (Fast Fourier Transform) option and enables fast information processing. By analysing the results of known samples when copying at high resolutions, we confirmed that computer-generated holograms cannot be copied by the mentioned methods, therefore it is not possible to generate a quality replica. |
| Uncontrolled Keywords: | CGH, holografija, interferencija, optička rekonstrukcija, numerička rekonstrukcija, CtF postupak |
| Keywords in english: | CGH, holography, interference, optical reconstruction, numerical reconstruction, CtF printing process |
| Subjects: | TECHNICAL SCIENCES > Graphic Technology |
| Institution: | Grafički fakultet |
| City: | Zagreb |
| Number of Pages: | 52 |
| Callnumber: | MOD 2020 KOV |
| Inventory number: | DB892 |
| Depositing User: | Nina Jelača |
| Status: | Unpublished |
| Date Deposited: | 16 Dec 2020 10:37 |
| Last Modified: | 16 Dec 2020 10:37 |
| URI: | http://eprints.grf.unizg.hr/id/eprint/3277 |
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