P‐31: A Statistical Paradigm for Assessment of Subjective Image Quality Results

Cutone, Matthew; Dalecki, Marc; Goel, James; Wilcox, Laurie M.; Allison, Robert S.

doi:10.1002/sdtp.12154

Cited by 6 publications

(2 citation statements)

References 8 publications

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“…The rationale for bypassing the color conversion was that it would improve the compression performance and produce fewer visible artefacts. To assess this hypothesis, the VDC-M and DSC data were separately fitted using a Generalized Linear Mixed Model (GLMM) (11) (12). The analysis showed that there was no overall effect of bypassing color conversion for either codec.…”

Section: Resultsmentioning

confidence: 99%

75‐2: The Effect of Chromatic Aberration Correction on Visually Lossless Compression

Mohona

Wilcox

et al. 2022

Symp Digest of Tech Papers

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In augmented and virtual reality (AR/VR), magnifying display lenses typically introduce pincushion distortion and transverse chromatic aberration. These distortions are corrected by pre‐processing, one side‐effect of which is disruption of the spatial correlation between color channels. As a result, the standard practice of performing color space conversion prior to image compression may introduce undesirable, visible artefacts. To assess this, we evaluated the performance of two low impairment display stream codecs on distortion corrected stereoscopic images based on converting to YCoCg color space or bypassing the color conversion.

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Section: Resultsmentioning

confidence: 99%

75‐2: The Effect of Chromatic Aberration Correction on Visually Lossless Compression

Mohona

Wilcox

et al. 2022

Symp Digest of Tech Papers

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“…To test the two hypotheses, the flicker paradigm data was fitted using a Generalized Linear Mixed Model (GLMM) 32 following the approach described by Cutone et al 33 for the analysis of 2D image quality assessment data. GLMM analysis was performed using the R statistical software environment (R Core Team 2017) and maximum likelihood estimation was used for fitting data using lme4's “glmer.” Before fitting GLMM, control data were excluded because these are unrelated to the experimental hypotheses and including control data can cause convergence failure as the correct response proportions were typically 1.0 for control data.…”

Section: Resultsmentioning

confidence: 99%

Subjective assessment of display stream compression for stereoscopic imagery

2021

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High‐resolution display bandwidth requirements often now exceed the capacity of display link channels necessitating compression. The goal of visually lossless compression codecs such as VESA DSC 1.2 is that viewers perceive no difference between the compressed and uncompressed images, maintaining long‐standing expectations of a lossless display link. Such low impairment performance is difficult to validate as artifacts are at or below sensory threshold. We have developed a 3D version of the ISO/IEC 29170‐2 flicker paradigm and used it to compare the effects of image compression in flat images presented in the plane of the screen (2D) to compression in flat images with a disparity offset from the screen (3D). We hypothesized that differences in the location and size of the compression errors between the disparate images in the 3D case would affect their visibility. The results showed that artifacts were often less visible in 3D compared to 2D viewing. These findings have practical applications with respect to codec performance targets and algorithm development for 3D movie, animation, and virtual reality content. In particular, higher compression should be attainable in stereoscopic compared to equivalent 2D images because of increased tolerance to artifacts that are binocularly unmatched or have disparity relative to the screen.

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Subjective assessment of visual fidelity: Comparison of forced‐choice methods

Au,

Mohona,

Wilcox

et al. 2024

J Soc Info Display

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Increases in display resolution, frame rate, and bit depth, particularly with advances in stereoscopic 3D (S3D) displays, have increased demand for efficient compression throughout the imaging pipeline. To meet such requirements, typically the aim is to reduce bandwidth while presenting content that is visually indistinguishable from the original uncompressed versions. Subjective image quality assessment is essential and multiple methods have been proposed. Of these, the ISO/IEC 29170‐2 flicker paradigm is a rigorous method used to define visually lossless performance. However, it is possible that the enhanced sensitivity to artifacts in the presence of flicker does not predict visibility under natural viewing conditions. Here, we test this prediction using high‐dynamic range S3D images and video under flicker and non‐flicker protocols. As hypothesized, sensitivity to artifacts was greater when using the flicker paradigm, but no differences were observed between the non‐flicker paradigms. Results were modeled using the Pyramid of Visibility, which predicted artifact detection driven by moderately low spatial frequencies. Overall, our results confirm the flicker paradigm is a conservative estimate of visually lossless behavior; it is highly unlikely to miss artifacts that would be visible under normal viewing. Conversely, artifacts identified by the flicker protocol may not be problematic in practice.

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P‐31: A Statistical Paradigm for Assessment of Subjective Image Quality Results

Cited by 6 publications

References 8 publications

75‐2: The Effect of Chromatic Aberration Correction on Visually Lossless Compression

75‐2: The Effect of Chromatic Aberration Correction on Visually Lossless Compression

Subjective assessment of display stream compression for stereoscopic imagery

Subjective assessment of visual fidelity: Comparison of forced‐choice methods

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