An ISO standard for measuring low light performance

To measure the low light performance of today's cameras has become a challenge [1]. The increasing quality for noise reduction algorithms and other steps of the image pipe make it necessary to investigate the balance of image quality aspects. The first step to define a measurement procedure is to capture images under low light conditions using a huge variety of cameras and review the images as well as the metadata of these images. Image quality parameters that are known to be affected by low light levels are noise, resolution, texture reproduction, color fidelity, and exposure. For each of the parameters thresholds below which the images get unacceptable need to be defined. Although this may later on require a real psychophysical study to increase the precision of the thresholds the current project tries to find out whether each parameter can be viewed as an independent one or if multiple parameters need to be grouped to differentiate acceptable images from unacceptable ones. Another important aspect is the definition of camera settings. For example the longest acceptable exposure time and how this is affected by image stabilization. Cameras on a tripod may produce excellent images with multi second exposures. After this ongoing analysis the question is how the light level gets reported? All these aspects are currently collected and will be incorporated into the upcoming ISO 19093 Standard that defines the measurement procedure for the low light performance of cameras.