Systems linearity considerations for digital photography

End-to-end system studies in digital photography inevitably lead to the question of setting goals in order to achieve overall linearity. But this itself poses the specific question of which key print/display variables should, in ideal circumstances, be linear with which key scene-acquisition parameters. Within the digital context, intuitive answers gleaned from traditional analog approaches to this question can vary from the confusing to the misleading, and digital attempts at direct emulation of analog systems may in fact off-set the potential advantages implicit in the newer digital technologies. The author has used a digital end-to-end signal-to-noise ratio model to consider some aspects of this linearity question, and to offer solutions based on the appropriate combination of SNR optimization and the human visual-response characteristics. Some results and conclusions are discussed here, especially those relating to the optimum digital strategy for scene-acquisition.