Improving High Dynamic Range Image Based Light Measurement

This study proposes a fast high dynamic range imaging (HDRI) technique for light measurement to shorten the long capturing time of current camera-aided computational photography widely used in lighting practice. In comparison with the conventional meter measurement, HDRI-assisted lighting measurement is a remote, efficient, affordable yet time-consuming method. The fast HDRI technique increases the film speed (ISO) to speed up the process taking a sequence of low dynamic range images. Since increasing camera's film speed may introduce more image noise, the possible error rate of the proposed method is evaluated by applying Gaussian noise estimation and impulsive noise detection on the image with different film speeds. In addition, a new per-pixel calculation process is developed to retrieve the illuminance of a target scene with selected regions of interest, which can be used to assist human-centric lighting tasks. Extensive comparative experiments are also conducted to verify the accuracy and efficiency of the proposed method.