Over the years, many optical principles that have the potential for metrological applications have been found, and many related techniques and devices have been invented. On the basis of these principles and techniques, numerous interesting applications have been reported in academic communities. In addition, a number of optical equipment and systems have already been commercialized.
So we may ask, “What are the features of optical metrology?” First of all, that it is a “noncontact approach” in metrological applications should be cited. This feature causes neither deformation nor damage to the specimen due to the measuring force. Also, flexibility in setting up measuring systems is also brought by this noncontact arrangement. Moreover, “full-field measurement” is possible. We are not limited to “point-wise measurement.” This feature, essentially inherent to optical methods such as photography and video, is currently summarized as “imaging.” Full-field data with abundant information can be instantly captured by imaging devices at a single moment and then analyzed by computational processing in a short time.
Furthermore, compatibility of light with electricity is another important factor for incorporating optical techniques to practical applications. “Light” is easily converted into an electrical quantity (electric current, voltage, etc.) using various detectors and sensing devices, and this means computational analysis of captured data is easily attainable due to recent remarkable advances in electronic devices and computer technology. Optical metrology can thus be seen to offer a variety of advantages.
Because of these superior and attractive features of light and/or optical methods, many research papers and technical reports on a wide range of applications have appeared over the years. However, this does not mean that compiling these results in a book on optical metrology is easy. With due consideration to recent trends in optical metrology, the title Handbook of Optical Metrology: Principles and Applications was chosen. The editor’s fundamental concept for this handbook was inspired by the following phrase found in the book Zen of Vegetable Roots (written by Zicheng Hong) published around 1600: “An academic learning is just like a daily meal necessary for our life. However, at the same time, it should be practically useful when needed.”
When the editorial work for this book started, some people suggested solicitously that a few similar books might have been published already. However, as far as I checked, there are no comparable books that have been compiled with the same intention as ours. Admittedly, some books titled Optical Metrology do exist, but most of them are focused on a specified area or restricted topic. In this book, we ensure that a wide range of applications using optical methods are included, in addition to the fundamental principles and techniques.
This book is basically written for beginners, but, in addition to introductory description, each chapter contains further suggestions, carefully prepared by the contributor to meet the needs of people with advanced knowledge.
I am pleased and relieved that I could accomplish the goal we set through the collaboration of many people.
I thank all contributors and other people who supported the publication of this book, especially Dr. Michael Shribak with whom the fundamental concept was discussed at a restaurant in Boston, Dr. Natalia Dushkina who made a tremendous effort to cover two fundamental chapters, and Dr. Peter Hall who warmly encouraged the editor through his English sense of humor. Kind suggestions by Dr. Toshiyuki Takatsuji, editorial secretary, were helpful for editing chapters relating to dimensional metrology. Dr. Toshitaka Wakayama, research associate, and Megumi Asano, private secretary, are also warmly appreciated for their editorial assistance.
I hope this handbook will be useful for researchers and engineers in industrial fields, as well as for academicians and students.
Toru Yoshizawa