Lithuanian Journal of Physics article / Lietuvos fizikos žurnalo straipsnis

INVESTIGATION OF BLUR KERNEL OF TERAHERTZ IMAGES
Viktoriia Abramova^a,b, Sergey Abramov^a, Vladimir Lukin^a, Ignas Grigelionis^b, Linas Minkevičius^b, and Gintaras Valušis^b
^aDepartment of Information-Communication Technologies, National Aerospace University,
Chkalova 17, 61070 Kharkiv, Ukraine
^bDepartment of Optoelectronics, Center for Physical Sciences and Technology, Saulėtekio 3, 10257 Vilnius, Lithuania
Email: viktoriia.abramova@ftmc.lt

Received 5 October 2023; accepted 6 October 2023

The paper discusses issues of digital processing of terahertz images. It is shown that despite the improvement of the hardware part of imaging setups, the acquired images still often have a low resolution and suffer from noise and blurring effects. Thus, to improve their visual quality, it is advisable to use special digital processing methods. While some progress has already been made in terms of denoising of terahertz images, the research of their deblurring is only at the very early stage. Therefore, this paper attempts to analyze the properties of blur functions for real terahertz images to further use them while designing a corresponding deblurring technique. For this purpose, the phase-only image method has been used. A study of blur properties for the three most common blur types (defocus, motion and Gaussian blur) has shown that for test images they can be distinguished and their main parameters can be assessed. However, the application of this method to real terahertz images has shown that the blur characteristics in them are very different from the ones obtained for modelled examples. The real blur demonstrates a quite complex behaviour and estimating its kernel requires additional research.
Keywords: terahertz imaging, image deblurring, blur kernel estimation

KAUKIŲ, LEMIANČIŲ TERAHERCINIŲ VAIZDŲ SULIEJIMĄ, TYRIMAS
Viktoriia Abramova^a,b, Sergey Abramov^a, Vladimir Lukin^a, Ignas Grigelionis^b, Linas Minkevičius^b, Gintaras Valušis^b

^aNacionalinio aerokosmoso universiteto Informacijos ir komunikacijos technologijų departamentas, Charkivas, Ukraina
^bFizinių ir technologijos mokslų centro Optoelektronikos skyrius, Vilnius, Lietuva

Šiame darbe aptariamos skaitmeninio terahercinių vaizdų apdorojimo problemos. Nepaisant vis tobulinamos aparatūrinės terahercinių vaizdų užrašymo dalies, jų kokybė vis tiek nukenčia dėl žemos skyros ar vaizdo suliejimo. Norint padidinti vaizdų kokybę galima naudoti tam tikrus skaitmeninius duomenų apdorojimo metodus. Didelis dėmesys skiriamas triukšmo filtravimo metodų vystymui, tačiau norint apčiuopiamai pagerinti vaizdų kokybę nemažiau svarbūs yra gerokai mažiau tyrinėti suliejimo mažinimo metodai. Todėl šiame darbe tiriamos ir analizuojamos suliejimo funkcijų savybės bei konstruojamas suliejimo pašalinimo iš terahercinių vaizdų mechanizmas. Tam šiuo atveju yra naudojami faziniai vaizdai. Trijų dažniausiai pasitaikančių (išfokusavimo, judėjimo, Gauso) suliejimo mechanizmų tyrimai su testinėmis matomos šviesos nuotraukomis atskleidė galimybę nustatyti suliejimo mechanizmų prigimtį bei jų parametrus. Tačiau eksperimente užrašytų terahercinių vaizdų atveju pastebėta, kad suliejimo mechanizmai yra visiškai kiti nei testiniuose vaizduose, o norint pagrįsti sudėtingą jų prigimtį reikalingi papildomi tyrimai.

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