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VCX score

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VCX Score
VCX
Area served
Global
Websitevcx-forum.org

VCX score is a smartphone camera benchmarking score described as "designed to reflect the user experience regarding the image quality and the performance of a camera in a mobile device".[1][2] developed by a non-profit organization - VCX-Forum.[3]

VCX scores[4] are used by specialist media[5] and by VCX-Forum members to showcase the benchmarking of smartphones,[6] as well as market photography[7] technology.

VCX scoring methodology has been cited in various published books and independent imaging organizations:

  • Book: Camera image quality benchmarking ISBN 978-1-119-05449-8[8]

Service Provider

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VCX-Forum (where VCX is an acronym for Valued Camera eXperience) is an independent, non-governmental, standard-setting organization for image quality measurement and benchmarking (VCX score). Its members are drawn from mobile phone manufacturers, mobile operators, imaging labs, mobile and computer chipset manufacturers, sensor manufacturers, device manufacturers, software companies, equipment providers, and camera & accessory manufacturers among others.[11]

VCX-Score methodology

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Tenets

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VCX score methodologies are based on the 5 Tenets:

  • VCX-Forum test measurements shall ensure the out-of-the-box experience
  • VCX-Forum shall remain 100% objective
  • VCX-Forum shall remain open and transparent
  • VCX-Forum shall employ an independent imaging lab for testing
  • VCX-Forum shall seek continuous improvement

Parameters

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To ensure the test results accurately reflect the user experience, the image quality is evaluated for five parameters:

  • Spatial Resolution
  • Texture loss – the ability of the device to reproduce low contrast, fine details
  • Sharpening – the ability of the device to sharpen with minimum distracting artifacts
  • Noise – the ability of the device to suppress noise while minimizing obfuscation of details
  • Dynamic range – the ability of the device to capture maximum contrast in a scene
  • Color Reproduction – the ability of the device to capture colors closely matching the original scene

Setup

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  • The device under test is mounted on a tripod on rails to keep the reproduction scale constant between devices under test
  • The entire lab is temperature-controlled to standard room temperature (23 °C ± 2 °C)
  • The device under test is expected to:
    1. reproduce reflective test targets like the "TE42-LL" (TE42-LL target in A1066 and A 460 (Selfie) in 4:3 and 16:9);
    2. reproduce transmissive TE269B test target (for dynamic range measurements); and
    3. reproduce test charts while mounted on a hand simulation device (a device which simulates the movement of the human hand to measure the motion stabilization apparatus of the device, based on ISO 20954-2).
  • The device under test is then used to capture a series of images and video in various controlled lighting conditions

A detailed description of the setup and procedure is available as a whitepaper on the VCX-Forum website.[12] as well as in the book, Camera Image Quality Benchmarking,[13] page 318, section 9.4.3

Labs and testing

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Tests and benchmarks are conducted by independent labs. The test procedure, metrics, and weighting are dictated by the standard developed by VCX-Forum.

Benchmark publication

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VCX scores are published on the VCX-Forum website. Parts of this publication are often reproduced in specialist media and smartphone vendor social media channels as part of their marketing campaign.

Criticism

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Metrics and weighting

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VCX-Forum claims that all test measurements must ensure the out-of-the-box experience (Tenet 1 of VCX-Forum) but does not specify what happens when the devices are updated later on.

VCX-Forum claims to be objective (Tenet 2 of VCX-Forum) but uses subjective components for the formation of the weighting itself. This subjective base is claimed to have come from blind tests for which no evidence has been provided on the website.

Despite the claim that VCX is an open and transparent standard (Tenet 3 of VCX-forum), the details of weighting and scoring are only visible to members of the VCX-Forum.

Most measurements are done with the device on a tripod[14] and aimed at test charts. This does not reflect the common user scenario that VCX-Forum claims to reflect.

References

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  1. ^ Wueller, Dietmar; Artmann, Uwe; Vijay, Rao; Reif, Guenter; Kramer, Joerg (January 2018). "VCX: An industry initiative to create an objective camera module evaluation for mobile devices". Society for Imaging Science and Technology. 30. doi:10.2352/ISSN.2470-1173.2018.05.PMII-172.
  2. ^ Artmann, Uwe (January 2021). "VCX Version 2020 - Further development of a transparent and objective evaluation scheme for mobile phone cameras". Society for Imaging Science and Technology. 33 (9). doi:10.2352/ISSN.2470-1173.2021.9.IQSP-204. S2CID 237965411.
  3. ^ "VCX Forum". vcx-forum.org. Retrieved 2018-08-20.
  4. ^ "VCX score". vcx-forum.org/score/version-2020. Retrieved 2020-08-26.
  5. ^ *Sebastian, Sonntag (June 2020). "Smartphone Kameras im test – Smarte Kameras". pp. 22–29.
  6. ^ "Samsung Electronics promotion". Retrieved 2022-03-22.
  7. ^ "ISOCELL". Retrieved 2018-05-03.
  8. ^ Jonathan B., Phillips & Henrik, Eliasson (January 1, 2001) [1st pub. November 17, 2017]. "Chapter 9.4.3". Camera Image Quality Benchmarking. Wiley. ISBN 978-1-119-05449-8.
  9. ^ Wueller, Dietmar; Artmann, Uwe; Vijay, Rao; Reif, Guenter; Kramer, Joerg (January 2018). "VCX: An industry initiative to create an objective camera module evaluation for mobile devices". Society for Imaging Science and Technology. 30. doi:10.2352/ISSN.2470-1173.2018.05.PMII-172.
  10. ^ Artmann, Uwe (January 2021). "VCX Version 2020 – Further development of a transparent and objective evaluation scheme for mobile phone cameras". Society for Imaging Science and Technology. 33 (9). doi:10.2352/ISSN.2470-1173.2021.9.IQSP-204. S2CID 237965411.
  11. ^ "VCX Forum members". vcx-forum.org/about/members. Retrieved 2021-09-26.
  12. ^ "VCX white paper". vcx-forum.org/standard/white-paper. Retrieved 2020-08-26.
  13. ^ Jonathan B., Phillips & Henrik, Eliasson (January 1, 2001) [1st pub. November 17, 2017]. "Chapter 9.4.3". Camera Image Quality Benchmarking. Wiley. ISBN 978-1-119-05449-8.
  14. ^ "Test Laboratory". Image Engineering. Retrieved March 1, 2022.
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