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1
Content available Quality Assessment of Resampled Digital Images by Statistical Metrics
100%
KORNETA W.
Edukacja-Technika-Informatyka
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2017
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tom 8
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nr 3
282-287
EN
The visual degradation of resampled (downsampled and then upsampled to the original size) greyscale digital images is quantified by local luminance, contrast and structure statistical comparison indexes. Spatial distributions of these indexes are shown. The global quality of resampled image is quantifiedby the similarity index defined by median values of local indexes. Parameters of this index consistent with the median opinion score are determined. The dependence of global indexes on the size of downsampled image is presented.
2
Content available Open access resources on motion artifact in adult dentomaxillofacial CBCT: illustrated pictorial review of medical literature
88%
Olszewski R.
Nemesis. Negative Effects in Medical Sciences Oral and Maxillofacial Surgery
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2021
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tom 15
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nr 1
1-37
EN
Objective: to know how much open access/open knowledge reference figures were available on motion artifacts in CBCT dentomaxillofacial imaging, and to describe and to categorize clinical variation of motion artifacts related to diverse types of head motion retrospectively observed during CBCT scanning time. Material and methods: a search equation was performed on Pubmed database. We found 56 articles. The 45 articles were out of scope, and 7 articles were excluded after applying exclusion and inclusion criteria. Only 4 articles were finally freely accessible and selected for this review. Moreover, we retrospectively used our department CBCT database to search examinations with motion artifacts. We also checked retrospectively for radiological protocols as the type of motion artifact was described when occurred during the CBCT scanning time by the main observer. We had obtained the approval from the Ethical committee for this study. Results: The accessibility of free figures on motion artifact in dentomaxillofacial CBCT is limited to 13 figures not annotated, and to one annotated figure presenting a double contour around cortex of bony orbits. We proposed to categorize the motion artifacts into three levels: low, intermediary, and major. Each level was related to: 1) progressive image quality degradation, 2) distortion of anatomy, and 3) potential possibility of performing clinical diagnosis. All 45 figures were annotated. Conclusions: There exists a scarce open access literature on motion artifacts in CBCT. In our pictorial review we found that low level motion artifacts were more related to head rotation in axial plane (rolling). Rolling and lateral translation were responsible of intermediary level motion artifacts. Major level motion artifacts were created by complex motion with multiple rotation axes, multiple translation directions, and by anteroposterior translation. The main limitation of this study is related to retrospectively report empirical observation of patient motion during CBCT scanning and to compare these observations with motion artifacts found on clinical images. More robust methodology should be further developed using a virtual simulation of various types of head movements and associated parameters to consolidate the open knowledge on motion artifacts in dentomaxillofacial CBCT.  
3
Content available remote Reversible Data Hiding Scheme Based on Image Inpainting
88%
Qin C. , Wang Z. H. , Chang C.-C. , Chen K. N.
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2012
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tom Vol. 120, nr 1
59-70
EN
Reversible/lossless image data hiding schemes provide the capability to embed secret information into a cover image where the original carrier can be totally restored after extracting the secret information. This work presents a high performance reversible image data hiding scheme especially in stego image quality control using image inpainting, an efficient image processing skill. Embeddable pixels chosen from a cover image are initialized to a fixed value as preprocessing for inpainting. Subsequently, these initialized pixels are repaired using inpainting technique based on partial differential equations (PDE). These inpainted pixels can be used to carry secret bits and generate a stego image. Experimental results show that the proposed scheme produces low distortion stego images and it also provides satisfactory hiding capacity.
4
The evaluation of the influence comparable digital image spatial shift on the value of the subjective quality criterion universal image quality index and the method of its elimination
75%
Pęksiński J. , Mikołajczak G.
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2009
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tom nr 6
CD-CD
EN
The paper presents the criteria to assess the quality of processed digital images, including a universal measure of quality Q. Identified susceptibility of these factors on the spatial shift of pixels, which can distort the value of measurement. In order to eliminate the impact of shifting the value of the indicators proposed a method based on the correlation signals.
PL
W pracy przedstawiono stosowane kryteria oceny jakości przetwarzanych obrazów cyfrowych, w tym uniwersalną miarę jakości Q. Stwierdzono podatność tych współczynników na przesunięcie pikseli, co może zafałszować wartość miary. W celu eliminacji wpływu przesunięcia na wartość wskaźników zaproponowano metodę opartą na korelacji sygnałów.
5
Content available remote Wpływ promieniowania rozproszonego na jakość obrazu na radiogramie
75%
Słania J. , Sołtys K.
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2012
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tom R. 84, nr 8
35-40
PL
Przedstawiono wpływ promieniowania rozproszonego na jakość obrazu na radiogramie. Omówiono zjawiska fizyczne towarzyszące promieniowaniu rozproszonemu oraz jego praktyczne skutki. Zaprezentowano przykłady badania wpływu promieniowania rozproszonego na jakość obrazu na radiogramie dla różnych obiektów, uwzględniając wpływ promieniowania rozproszonego od obiektów znajdujących się poza błoną oraz niezgodności w obliczeniach czasów ekspozycji.
EN
The influence of scattered radiation on the image quality of the radiograph was presented in the paper. Physical phenomena accompanying scattered radiation and its practical results were shown. The authors discussed practical examples of research on the influence of scattered radiation on the image quality of radiograph for different objects, including the influence of scattered radiation from objects situated behind the X-ray film and incompatibility in exposition time calculating.
6
Accelerated image quality estimation based on the Monte Carlo approach for various types of image distortions
75%
Okarma K.
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2010
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tom No. 63
157-165
EN
In the paper the application of the Monte Carlo method for the fast estimation of image quality is investigated. Taking into account the variety of possible distortions present in the images, probably the largest publicly available database of 1700 images with 17 types of distortions has been used for the practical verification of the proposed approach. The analysis has been performed for some of the "state-of-the-art" image quality metrics as an alternative to the classical ones together with the comparison to well known Peak Signal to Noise Ratio.
7
Content available Benchmarking image codecs by assessment of coded test images: the development of test images and new objective quality metrics
63%
Punchihewa A. , Bailey D. G. , Hodgson R. M.
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2006
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tom nr 1
11-16
EN
Objective quality measures are required for benchmarking codec performance. Our aim was to develop a simple, accurate method capable of rapidly measuring the degree of blockiness, edge-blur and ringing due to image compression. Two test images were designed to emphasise these artefacts. The efficacy of the new metrics is demonstrated using a JPEG codec at a range of compression levels.
8
Ocena jakości obrazów generowanych przez algorytmy demosaicingu
51%
Mantiuk R.
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2010
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tom nr 1 (22)
113-123
PL
W artykule zaprezentowane i przetestowane zostały techniki oceny spadku jakości obrazów spowodowanego przez algorytmy demosaicingu. Pod uwagę wzięto trzy metryki: CIE76, S-CIELAB oraz HDR-VDP służące do automatycznego szacowania różnic w wyglądzie pomiędzy obrazem wzorcowym a obrazem po demosaicingu. Najlepsze wyniki uzyskano dla metryki HDR-VDP, która generuje rezultaty spójne z percepcyjnym widzeniem zniekształceń przez człowieka. Metryka HDR-VDP może być z powodzeniem stosowana do oceny jakości algorytmów demosaicingu.
EN
Most of the modern digital cameras capture color images based on the CFA (Color Filter Array) pattern. Each point of the sensor matrix acquires one of the R,G, or B values. The demosaicing algorithms convert mosaic consisted of these points to a standard digital image representation with three RGB values for each color channel. The quality of the demosaicing algorithms is measured as a level of deformation in an image after demosaicing comparing to original appearance of a scene. In particular, unfavorable are artifacts that are well seen by a man, like object blurring or color halos. In the paper the metrics of difference between a scene and an image of a scene after demosaicing are analyzed. We test the following difference metrics: CIE76 (E ab), S-CIELAB, and HDR-VDP and suggest the one which is the most suitable for estimation of demosaicing algorithms fidelity.
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