Project Description

About: "Detecting Color and using colored marker to draw virtually."

It is an OpenCV application that can track an object’s movement, using which a user can draw on the screen by moving the object around — I call it Webcam Paint.

Code Explanation

Step 1: Initialize Some Stuff

Firstly, I need to import the necessary libraries.

Then I initialize variables that are used in the following steps.

The lower and the upper numpy arrays help us in finding the colored cap. The myColors and myColorValues are used to create list of colors. The myPoints helps to set the coordinates of each of the color.

Step 2: Start Reading The Video (Frame by Frame)

Now I use the OpenCV function cv2.VideoCapture() method to read a video, frame by frame (using a while loop), either from a video file or from a webcam in real-time. In this case, I pass 0 to the method to read from a webcam.

Step 3: Find The Contour-Of-Interest

Once I start reading the webcam feed, I constantly look for a color object in the frames with the help of cv2.inRange() method and use the upper and lower variables initialized in Step 1. Once I find the contour(the if condition passes when a contour is found), I do a series of image operations and make it smooth. I use the center of the contour to draw on the screen as it moves. The cv2.circle() method draws a circle around it.

Step 4: Start Drawing And Store The Drawings

Now I start tracking coordinates of each and every point the center of the contour touches on the screen, along with its color.

I have created a drawOnCanvas() function to store the points in its respective color.

Step 5: Show The Drawings On The Screen

So far I stored all the points in their respective color. Now I just join all the points in each and every frame with a line and put it on a window we created using cv2.imshow() method and it all fits perfectly to work!

That’s it! I have successfully used a bunch of basic image processing tools and operations in OpenCV!