chapter 12, Optics in Our World

Excerpt

12.1 Introduction

Throughout this book we have discussed many facets of the field of optics and optical engineering. It is my hope that this exposure will encourage some readers to further pursuits and studies, perhaps leading to a career in this field. For others this has merely been an excursion into an area of general interest and nothing more. I believe this final chapter will be of interest to all of these readers. It will deal with the optical aspects of several phenomena and devices that we all might encounter in our daily lives. It is my hope that this will increase our awareness, appreciation, and understanding of them all.

We have seen in several earlier chapters how the human eye is closely related to the optical design of certain instruments. This chapter will touch on the concept of the complete visual system, including the eyes, the mind, and our lifetime of visual experiences. These experiences tend to program the mind, allowing it to interpret what is seen by the eye and imaged onto the retina.

Also in this chapter, we will deal with a number of technological advances of the day, with special emphasis on their optical content. In order to keep this presentation at a reasonable comfort level (for the author as well as the reader), this section will be limited to the most fundamental concepts and principles.

12.2 Optical Illusions: Size

Many times what we actually see, and what we think we see, are two very different matters. This phenomenon results when the mind, based on earlier experience, adds information to what is collected and delivered by the eye, leading us to a conclusion that may not always be correct.

In Fig. 12.1, for example, the diagram on the left represents a common optical illusion known as the Ponzo illusion. Here we see two rectangular blocks (A and B) that are exactly the same size. It follows that the images of blocks A and B on our retina are also the same size.