Color sensitivity of the multi-exposure HDR imaging process

Abstract

Multi-exposure high dynamic range(HDR) imaging builds HDR radiance maps by stitching together different views of a same scene with varying exposures. Practically, this process involves converting raw sensor data into low dynamic range (LDR) images, estimate the camera response curves, and use them in order to recover the irradiance for every pixel. During the export, applying white balance settings and image stitching, which both have an influence on the color balance in the final image. In this paper, we use a calibrated quasi-monochromatic light source, an integrating sphere, and a spectrograph in order to evaluate and compare the average spectral response of the image sensor. We finally draw some conclusion about the color consistency of HDR imaging and the additional steps necessary to use multi-exposure HDR imaging as a tool to measure the physical quantities such as radiance and luminance.

Collection of papers accepted for the 5th CIE Symposium on Colour and Visual Appearance, April 21–22, 2020, Hong Kong, CN

“…The spectral responsivities originate from a database by Jiang et al (2013). The spectral responsivities of HDR images was considered identical to the camera's raw spectral responsivity (Lenseigne et al, 2013). Additionally, 205 SPDs, as illustrated in Figure 2, of light sources that are commercially available were collected , containing LEDs (117), fluorescents (35), incandescent (17), halogens (31), metal halides ( 4) and sodium pressure lamps (1) from 300 nm to 900 nm with steps of 0,5 nm originating from the LSPDD database by Roby and Aubé (2012).…”

Spectral tuning of luminance cameras: A theoretical model and validation measurements

“…Moreover, Lenseigne et al . 22 showed that the spectral responsivity of the HDR has large similarities, including the effect of white balancing, to the raw spectral responsivity, indicating that the colour space of the HDR image is camera dependent and not necessarily similar to the spectral sRGB responsivity.…”