OpenCV  4.7.0-dev Open Source Computer Vision
Changing Colorspaces

## Goal

• In this tutorial, you will learn how to convert images from one color-space to another, like RGB $$\leftrightarrow$$ Gray, RGB $$\leftrightarrow$$ HSV etc.
• You will learn following functions : cv.cvtColor(), cv.inRange() etc.

## cvtColor

There are more than 150 color-space conversion methods available in OpenCV. But we will look into the most widely used one: RGB $$\leftrightarrow$$ Gray.

We use the function: cv.cvtColor (src, dst, code, dstCn = 0)

Parameters
 src input image. dst output image of the same size and depth as src code color space conversion code(see cv.ColorConversionCodes). dstCn number of channels in the destination image; if the parameter is 0, the number of the channels is derived automatically from src and code.

For RGB $$\rightarrow$$ Gray conversion we use the code cv.COLOR_RGBA2GRAY.

## inRange

Checks if array elements lie between the elements of two other arrays.

We use the function: cv.inRange (src, lowerb, upperb, dst)

Parameters
 src first input image. lowerb inclusive lower boundary Mat of the same size as src. upperb inclusive upper boundary Mat of the same size as src. dst output image of the same size as src and cv.CV_8U type.