Appendix A
Human Visual Perception
A.1 Introduction
The human visual system (HVS) is the final link in the perception of images and video sequences. A clear understanding of its capabilities and limitations can lead to better image and video processing solutions. In applications whose ultimate goal is to improve the image quality for human consumption, this knowledge allows designers to establish objective performance criteria and quality measures. In machine vision systems (MVS) whose goal is to emulate—and ultimately outperform—their human counterpart, it is absolutely necessary that we know how the human visual system works, which performance limits it imposes, and how this knowledge can be factored into the design of MVS.
In this appendix, we will provide a very brief overview of the human visual system with emphasis on aspects that are relevant—some may say essential—to the researcher and practitioner in the field. This is a long, deep, and fascinating topic for which there are almost as many open questions as there are answers. The interested reader may refer to the “Learn More About It” section at the end of the appendix for suggestions on books and other references that will broaden and deepen their understanding of the field of human vision science.
A.2 The Human Eye
The HVS has two main components, the eye (input sensor) and the brain (information processing unit), connected by the optic nerve (transmission path) (Figure A.1). Image perception consists of capturing the ...
