Tone Mapping for High Dynamic Range Cameras

High dynamic range images must be tone mapped before being displayed on devices with low output dynamic range. Two existing global tone mapping operators are evaluated and then a new improved operator using a sigmoid compression curve is proposed. It is then demonstrated through simulation and experimental results that an existing capture device, used previously only for simple logarithmic compression, can be modified such that tone mapping can be performed directly during the capture process. A local tone mapping operator using bilateral filtering is then investigated and shown to outperform global operators. A novel approximation to this operator is devised which is well suited to implementation on a camera integrated circuit. The operator is evaluated and shown to tone map high dynamic range scenes successfully, particularly in the context of car safety applications.