Colorspaces and converting them

Let's understand the concept of a colorspace. A colorspace is a mathematical model that is used to represent a set of colors. With colorspaces, we can represent colors with numbers. If you've ever have worked with web programming, then you must have come across various codes for colors since colors are represented in HTML with Hexadecimal numbers. This is a good example of representing colors with a colorspace and allows us to perform numerical and logical computations with them. Representing colors with colorspaces also allows us to reproduce the colors with ease in analog and digital forms.

We will frequently use BGR, RGB, HSV, and grayscale colorspaces throughout this book. In BGR and RGB, B stands for blue, G stands for green, and R stands for red. OpenCV reads and stores a color image in the BGR colorspace. The HSV colorspace represents a set of colors with a component for hue, a component for saturation, and a component for value...