Temat: Image quality - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Image Quality Assessment Using Edge Correlation
Autorzy:: Ruikar, J.
Sinha, A.
Chaudhury, S.
Tematy:: image quality assessment
image quality metrics
steerable Gaussian filter
subjective assessment; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/226152.pdf Link otwiera się w nowym oknie
Opis:: In literature, oriented filters are used for low-level vision tasks. In this paper, we propose use of steerable Gaussian filter in image quality assessment. Human visual system is more sensitive to multidirectional edges present in natural images. The most degradation in image quality is caused due to its edges. In this work, an edge based metric termed as steerable Gaussian filtering (SGF) quality index is proposed as objective measure for image quality assessment. The performance of the proposed technique is evaluated over multiple databases. The experimental result shows that proposed method is more reliable and outperform the conventional image quality assessment method.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Dose and noise in abdominal computed tomography examinations
Autorzy:: Obrzut, Marzanna
Staniszewska, Maria A.
Cabaj, Anna
Opis:: Background: Dose reduction in computed tomography (CT) examinations was an idea of the Co-rdinated Research Project (CRP) "Dose Reduction in Computed Tomography (CT) while maintaining Diagnostic Confidence", supported by the International Agency of Atomic Energy (IAEA) in the years 2003-2005. Participation in the CRP inspired the authors' attempts to elaborate a method for optimization of CT abdominal procedures allowing reduce a dose to patient with saving diagnostically satisfying image quality. The paper presents the algorithm together with clinical verification of the results of the study. Material/Methods: Two types of single-slice CT scanners were used for the investigations. The images recorded for patients undergoing routine abdomen examinations and then these obtained with modified exposure parameters were analyzed. The influence of the changed tube outputs on image quality was checked using Catphan 424 phantom. Results: As the result no statistically significant difference between the measured noise in clinical images for patients examined at routine and modified settings (within the same weight category) was observed. Conclusions: The conclusion was that at routine (screening) abdomen examinations, the dose may be reduced up to 50% with saving diagnostically satisfying image quality.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 3.

Tytuł:: Quality Assessment of Resampled Digital Images by Statistical Metrics
Autorzy:: KORNETA, WOJCIECH
Tematy:: image quality
image resampling
similarity index; Pokaż więcej
Wydawca:: Uniwersytet Rzeszowski
Powiązania:: https://bibliotekanauki.pl/articles/457632.pdf Link otwiera się w nowym oknie
Opis:: 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.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Prior Image Jpeg-Compression Detection
Autorzy:: Koziel, G.
Tematy:: compression detection
image quality
JPEG; Pokaż więcej
Wydawca:: Polskie Towarzystwo Promocji Wiedzy
Powiązania:: https://bibliotekanauki.pl/articles/117800.pdf Link otwiera się w nowym oknie
Opis:: The paper presents two methods of prior JPEG-compression detection. In the first method the histogram of chrominance is analysed. In JPEG-compressed images the histogram contains significantly more local maxima than in uncompressed files. The second method is based on neighbouring pixel Ø value difference. In JPEG-compressed image the distribution of these values is different than the distribution counted on the edges of compression 8x8 blocks. These differences are summed up to create a classifier that allows to assess if the image was compressed.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Xception-based Architecture with Cross-sampled Training for Image Quality Assessment on KonIQ-10ĸ
Autorzy:: Tomasz, M. Lehmann
Przemyslaw, Rokita
Tematy:: image quality assessment
computer vision
Xception; Pokaż więcej
Wydawca:: Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Instytut Informatyki Technicznej
Powiązania:: https://bibliotekanauki.pl/articles/31339412.pdf Link otwiera się w nowym oknie
Opis:: Image quality assessment is a crucial task in various fields such as digital photography, online content creation, and automated quality control, as it ensures an optimal visual experience and aids in maintaining consistent standards. In this paper, we propose an efficient method for training image quality assessment models on the KonIQ-10ĸ dataset. Our novel approach utilizes a dual-Xception architecture that analyzes both the image content and additional image parameters, outperforming traditional single convolutional models. We introduce cross-sampling methods with random draw sampling of instances from majority classes, effectively enhancing prediction quality in the Mean Opinion Score(MOS) ranges that are underrepresented in the database. This methodology allows us to achieve near state-of-the-art results with limited computing costs and resources. Most importantly, our predictions across the entire spectrum of MOS values maintain consistent quality. Because of using a novel and highly effective method for image sampling, we achieved these results with much lower computational cost, making our approach the most effective way of MOS estimation on the KonIQ-10ĸ database.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Phantom studies as useful method for optimization of CT procedures with single-slice scanners
Autorzy:: Rybka, Krzysztof
Biegański, Tadeusz
Staniszewska, Maria Anna
Opis:: Background: Optimization of X-ray diagnostic procedures requires a selection of exposure parameters adequately for the patient anatomical structure and clinical needs, meanwhile use of the ready software protocols is a daily routine. The paper presents the methods and the results based on phantom studies aimed to optimize the exposure parameters for the examined object in examinations performed using single-slice CT scanners. Material/Methods: The studies were concerned with the significance of particular exposure parameters for image quality and patient doses in routine head procedures. Image quality was evaluated using a Catphan 424 phantom. Dosimetric measures of exposure were evaluated by computed tomography dose index (CTDI), and dose-length-product (DLP) was measured using a Nomex dosimeter. Results/Conclusions: Two single-slice CT scanners were investigated in details: a fourth generation one (Picker PQ-2000) and a third generation one (Siemens Somatom Balance). The dependence of image quality factors on high voltage, anode current, scan time, slice thickness were described and CTDI was evaluated. For both the CT scanners tested, the combinations of exposure parameters were found for which low dose value was accompanied by good image quality. Moreover, the high-contrast resolution was not practically changed with dose reduction, in opposite to low-contrast resolution being related to exposure parameters and the type of CT scanner. Dose reduction possible for the fourth generation scanner is deeper.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 7.

Tytuł:: Measuring the effective coverage of the image databases
Autorzy:: Buczkowski, M.
Tematy:: image quality assessment
coverage analysis
image characteristic analysis; Pokaż więcej
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Powiązania:: https://bibliotekanauki.pl/articles/114262.pdf Link otwiera się w nowym oknie
Opis:: The paper presents new methods for estimating effective coverage of the image databases in spatial information (SI) vs. colorfulness (CF) space. Existing and commonly used metrics are vulnerable to databases containing very different images in terms of SI and CF, which can maximize the relative ranges, while preserving, in specific cases, high uniformity. The area covered by convex hull created on SI × CF space can be large, but the interior of the convex envelope might be poorly filled. To overcome this flaw, a fill factor is proposed, which determines how well the convex hull area is utilized. In the paper the method is described in details and presented on a few existing databases, as well as on artificial, non-existing databases to prove its robustness in different scenarios. Provided results show that new metric is closer to the actual coverage than existing methods.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: On the optimisation of nonlinear mapping functions towards high correlation of full-reference image quality metrics and their combinations with subjective evaluations
Autorzy:: Okarma, K.
Tematy:: image quality
VQEG
state of the art; Pokaż więcej
Wydawca:: Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Powiązania:: https://bibliotekanauki.pl/articles/97539.pdf Link otwiera się w nowym oknie
Opis:: One of the most relevant problems related to most of the objective full-reference image and video quality assessment methods is their correlation with subjective perception of various types of distortions. Since the relation between the subjective scores, typically expressed as Mean Opinion Scores (MOS) or Differential MOS, and most of the metrics is nonlinear, various mapping functions are used in order to linearize this relation e.g. logistic function recommended by the Video Quality Experts Group (VQEG). Such compensation can also be conducted using some other function e.g. polynomial or exponential ones. Nevertheless, the results obtained for each of available datasets differ and such approach cannot be considered as universal. One of possible solutions, proposed in some earlier papers, is the use of combined metrics, which have significantly higher linear correlation with MOS or DMOS values without the necessity of nonlinear mapping. The comparative analysis of the optimisation results for some “state-of-the-art” metrics and proposed combined ones is also provided in the paper.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Assessment of the spatio-temporal vector median filtering algorithms using colour video quality metrics
Autorzy:: Okarma, K.
Tematy:: Vector Median Filter
VMF
video quality
image quality; Pokaż więcej
Wydawca:: Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Powiązania:: https://bibliotekanauki.pl/articles/97449.pdf Link otwiera się w nowym oknie
Opis:: In this paper the application of the combined video quality assessment method as well as some other recently developed objective metrics for the analysis of the results of the nonlinear colour video filtering is discussed. The spatio-temporal versions of colour image filtering methods, including the Vector Median Filter, can be obtained using frame-by-frame approach but the proper choice of the spatio-temporal kernel weights and the colour space used during filtration should be based on a reliable video quality assessment. In some earlier papers the combined video quality assessment method has been proposed, which has a highly linear correlation with subjective quality scores and can be extended into the colour version. As the illustration of the problem, some results of the colour video denoising using the spatio-temporal VMF, also in a weighted version, together with the quality assessment results have been presented in the paper.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Irreversible medical image compression: conditions of acceptability
Autorzy:: Przelaskowski, A.
Tematy:: irreversible compression
medical image compression
diagnostic accuracy
diagnostic image quality; Pokaż więcej
Wydawca:: Politechnika Gdańska
Powiązania:: https://bibliotekanauki.pl/articles/1965779.pdf Link otwiera się w nowym oknie
Opis:: Acceptance of irreversible image compression applicable to medical imagery is controversial in the medical community. The influence of this irreversible process on degradation of diagnostic image features is considered and how to preserve diagnostic accuracy. Fears, doubts, the disadvantages of the data distortion process and the advantages of safe and efficient irreversible compression for image information storage and interchange are discussed. The effects of compression on various image exams are analysed. The conclusion is that irreversible compression is not to be afraid of, but its characteristics should be well understood before implementing it in current practice.
Dostawca treści:: Biblioteka Nauki

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