Optical sensors are widely used in different fields for measuring and collecting information from diverse sources. This book attempts to understand the various applications of optical sensors. Some of the important topics elucidated in the book are optical and photonic sensors, signal processing, evaluations and assessments of different applications, etc. The various studies that are constantly contributing towards advancing technologies and evolution of this field are examined in detail. Students, researches and academicians engaged in the field will find this book full of innovative insights and developments in optical sensor technology.