Updated Camera Spatial Frequency Response for ISO 12233

D., Burns Peter; Masaoka, Kenichiro; Kenneth, Parulski; Wueller, Dietmar

doi:10.2352/ei.2022.34.9.iqsp-357

Cited by 11 publications

(9 citation statements)

References 13 publications

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“…This latest standard will come with many improvements to the ISO12233 to increase the and precision of the measured e-SFR. Once released, these advances in the ISO12233 [10] would benefit future revisions of the NS-SFR and system e-SFR estimation methodology. Such advantages would include the following:…”

Section: Discussionmentioning

confidence: 99%

A tool for deriving camera spatial frequency response from natural scenes (NS-SFR)

Zwanenberg¹,

Triantaphillidou²,

Jenkin³

2023

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Recent research on digital camera performance evaluation introduced the Natural Scene Spatial Frequency Response (NS-SFR) framework, shown to provide a comparable measure to the ISO12233 edge SFR (e-SFR) but derived outside laboratory conditions. The framework extracts step-edges captured from pictorial natural scenes to evaluate the camera SFR. Comprising two parts, the first utilizes the ISO12233 slanted-edge algorithm to produce an 'envelope' of NS-SFRs. The second estimates the system e-SFR from this NS-SFR data.One current drawback of this proposed methodology has been the computation time. Although successful in e-SFR estimation, the process was not optimized; it derived NS-SFRs from all suitable step-edges before statistically treating the results to estimate the e-SFR.This paper presents changes to the framework processes, aiming to optimize the computation time for real-world implementation while maintaining e-SFR estimation accuracy. The developments include an improved framework structure and an edge isolation step that is easier to compute. The resulting code has been incorporated into a self-executable user-interface prototype, available on GitHub, allowing users to select images for e-SFR camera estimation, for different radial annuli and camera orientations.

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Section: Discussionmentioning

confidence: 99%

A tool for deriving camera spatial frequency response from natural scenes (NS-SFR)

Zwanenberg¹,

Triantaphillidou²,

Jenkin³

2023

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“…Matlab analysis source code is listed in a new Annex M. The details of these improvements are reported in a companion paper presented at this conference. 22 Another significant addition in the 4 th edition of ISO 12233 is an informative annex which describes how to compute an acutance value from either the e-SFR or the s-SFR data. This provides a "single number" resolution metric which can be correlated with perceived sharpness.…”

Section: Th Edition Of Iso 12233mentioning

confidence: 99%

“…The acutance is computed by summing the SFR, weighted by the visual Contrast Sensitivity Function (CSF). 22,23 𝐶𝑆𝐹(𝑓) =…”

Section: Acutance Calculationmentioning

confidence: 99%

Creation and evolution of ISO 12233, the international standard for measuring digital camera resolution

Ken¹,

Wueller²,

Peter³

et al. 2022

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Thirty years ago, ISO/TC42 WG18, a newly created ISO working group on digital photography, began developing a standard to measure the spatial resolution of digital cameras. After years of proposals, testing, and analysis, consensus was reached on a test chart with tilted edge features for measuring spatial frequency response (SFR) and hyperbolic wedges for measuring visual and limiting resolution. The group ensured that the test chart and analysis software would be available internationally. First published in 2000, ISO 12233 is now used to measure cameras in a wide range of applications. It was revised in 2014 to define three new charts, a sine-wave modulated target in polar format, a low contrast e-SFR target, and the CIPA chart with software which computes a "human equivalent visual resolution" value. ISO 12233 is now being revised to provide improved results in challenging applications. This paper describes early resolution measurement approaches, and work in the 1990s to standardize the SFR method. It also describes enhancement made in later editions, including the 4th edition which is nearing publication.

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“…To suppress the effect of noise on the measured results, A Hamming Window for smoothing the sampling signal is proposed in the third edition of ISO 12233 slanted-edge method published in 2017 [4]. A Tukey Window may be used to further enhance the smoothing effect in the fourth edition of the ISO 12233 slanted-edge method, which is being drafted [5][6]. However, there is still no better solution for reducing the effect of image sharpening but using a sampling efficiency [4][5][6][7][8][9] to express the magnitude of sharpening.…”

Section: Introductionmentioning

confidence: 99%

“…A Tukey Window may be used to further enhance the smoothing effect in the fourth edition of the ISO 12233 slanted-edge method, which is being drafted [5][6]. However, there is still no better solution for reducing the effect of image sharpening but using a sampling efficiency [4][5][6][7][8][9] to express the magnitude of sharpening. Image sharpening is a necessary image processing procedure in all image processing software for image input devices.…”

Section: Introductionmentioning

confidence: 99%

An improved slanted-edge method for measuring modulation transfer function based on edge-preserving filter

Nie¹,

Ruan²,

Cui³

et al. 2023

Fourteenth International Conference on Graphics and Image Processing (ICGIP 2022)

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ISO 12233 provides a method for measuring Modulation Transfer Function (MTF) of digital input devices based on a slanted-edge method. However, the results measured by the method are greatly affected by image processing procedures, especially sharpening, and false MTF is often given. In this article, an improved slanted-edge method is proposed where an edge-preserving filter with optimal parameters is introduced to smooth the image before implementing ISO 12233 method. Particularly, three edge-preserving filters, bilateral filter, guided filter and adaptive weighted least square filter, and one general filter, Gaussian filter, are compared in mitigating the effect of sharpening algorithm on the measurement of digital camera MTF. The experimental results indicate that the effect of sharpening algorithm on the measured MTF can be effectively reduced by using an edge-preserving filter, and significantly improvement on the MTF accuracy at Nyquist frequency is achieved. Especially, the slanted-edge method based on the guided filter and the weighted least squares filter can give more real MTF for a digital camera.

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Updated Camera Spatial Frequency Response for ISO 12233

Cited by 11 publications

References 13 publications

A tool for deriving camera spatial frequency response from natural scenes (NS-SFR)

A tool for deriving camera spatial frequency response from natural scenes (NS-SFR)

Creation and evolution of ISO 12233, the international standard for measuring digital camera resolution

An improved slanted-edge method for measuring modulation transfer function based on edge-preserving filter

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