Evaluation of changes in image appearance with changes in displayed image size

Park, J.Y. 2014. Evaluation of changes in image appearance with changes in displayed image size. PhD thesis University of Westminster Faculty of Media, Arts and Design

TitleEvaluation of changes in image appearance with changes in displayed image size
TypePhD thesis
AuthorsPark, J.Y.
Abstract

This research focused on the quantification of changes in image appearance when images are displayed at different image sizes on LCD devices. The final results provided in calibrated Just Noticeable Differences (JNDs) on relevant perceptual scales, allowing the prediction of sharpness and contrast appearance with changes in the displayed image size.

A series of psychophysical experiments were conducted to enable appearance predictions. Firstly, a rank order experiment was carried out to identify the image attributes that were most affected by changes in displayed image size. Two digital cameras, exhibiting very different reproduction qualities, were employed to capture the same scenes, for the investigation of the effect of the original image quality on image appearance changes. A wide range of scenes with different scene properties was used as

a test-set for the investigation of image appearance changes with scene type. The outcomes indicated that sharpness and contrast were the most important attributes for the majority of scene types and original image qualities. Appearance matching experiments were further conducted to quantify changes in perceived sharpness and contrast with respect to changes in the displayed image size.

For the creation of sharpness matching stimuli, a set of frequency domain filters were designed to provide equal intervals in image quality, by taking into account the system’s Spatial Frequency Response (SFR) and the observation distance. For the creation of contrast matching stimuli, a series of spatial domain S-shaped filters were designed to provide equal intervals in image contrast, by gamma adjustments. Five displayed image sizes were investigated. Observers were always asked to match the appearance of the smaller version of each stimulus to its larger reference. Lastly, rating experiments were conducted to validate the derived JNDs in perceptual quality for both sharpness and contrast stimuli. Data obtained by these experiments finally converted into JND scales for each individual image attribute.

Linear functions were fitted to the final data, which allowed the prediction of image appearance of images viewed at larger sizes than these investigated in this research.

Year2014
FileJae_PARK_2014.pdf
Publication dates
Completed2014

Related outputs

Just noticeable differences in perceived image contrast with changes in displayed image size
Triantaphillidou, S., Park, J.Y. and Jacobson, R.E. 2014. Just noticeable differences in perceived image contrast with changes in displayed image size. SPIE Proceedings 9016, Image Quality and System Performance XI. San Francisco, USA

Evaluation of perceived image sharpness with changes in the displayed image size
Park, J.Y., Triantaphillidou, S., Jacobson, R.E. and Gupta, G. 2012. Evaluation of perceived image sharpness with changes in the displayed image size. in: SPIE proceedings: Electronic Imaging: Image Quality & System Performance IX, 82930J SPIE.

Visual scene busyness measures through a region growing spatial segmentation
Gupta, G., Psarrou, A., Triantaphillidou, S. and Park, J.Y. 2012. Visual scene busyness measures through a region growing spatial segmentation. in: Lewis, C. and Burgess, D. (ed.) Optics and Photonics for Counterterrorism, Crime Fighting, and Defence VIII SPIE.

Identification of image attributes that are most affected with changes in displayed image size
Park, J.Y., Triantaphillidou, S. and Jacobson, R.E. 2009. Identification of image attributes that are most affected with changes in displayed image size. in: Farnand, S.P. and Gaykema, F. (ed.) Image quality and system performance VI : 19-21 January 2009, San Jose, California, USA IS&T - The Society for Imaging and Science and Technology and SPIE.

Permalink - https://westminsterresearch.westminster.ac.uk/item/8yv3x/evaluation-of-changes-in-image-appearance-with-changes-in-displayed-image-size


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