Sources of Error in HDRI for Luminance Measurement: A Review of the Literature

ABSTRACT

Compared to the use of conventional spot luminance meters, high dynamic range imaging (HDRI) offers significant advantages for luminance measurements in lighting research. Consequently, the reporting of absolute luminance data based on HDRI measurements has rapidly increased in technical lighting literature, with researchers using HDRI to address topics such as daylight distribution and discomfort glare. However, questions remain about the accuracy of luminance data derived from HDRI. This article reviewed published papers that reported potential sources of error in deriving absolute luminance values from high dynamic range imaging (HDRI) using a consumer grade digital camera, along with application papers that included an analysis of errors in HDRI-derived luminance values. Four sources of significant error emerged from the literature review: lens vignetting, lens flare, luminous overflow, and sensor spectral responsivity. The cause and magnitude for each source of error is discussed using the relevant findings from previous research and any available correction methods are presented. Based on the review, a set of recommendations was developed for minimizing the possible errors in HDRI luminance measurements as well as recommendations for future research using HDRI.

KEYWORDS:

• High dynamic range imaging
• luminance
• measurement

Disclosure statement

No potential conflict of interest was reported by the authors.

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Notes

1. Photosphere and raw2hdr are software tools available for combining multiple LDR images into a HDR image. raw2hdr accepts RAW image formats and operates from the command line. Photosphere accepts JPEG image formats and has a user interface. See Stanley (2016) for a more comprehensive comparison of available software tools used for HDRI creation and analysis. Both tools were created by Ward with the free versions limited to macOS. A Windows version of Photosphere can be purchased from Ward (2018a). Photosphere. http://www.anyhere.com/.

Additional information

Funding

This work was supported by the Solid-State Lighting Program of the U.S. Department of Energy; Office of Energy Efficiency and Renewable Energy.