line-follower

This code uses image recognition to:

• See which direction a red line is pointing
• See if there's any blue line
  • If there is, measure it and figure out how big it is in inches

How it works

Line following

• The image is converted to HSV and converted to a red mask.
• Using the mask, the top, bottom, left, and right are checked to see if the line goes through that respective side.
• With the knowledge of what sides are passed through, we know where the line is going. Context tells us what it means: for example, a horizontal line means either 'keep going left' or 'keep going right', knowing if we're going right or left at the moment answers that question.

Line measuring

• The image is converted to HSV and made into a blue mask.
• goodFeaturesToTrack() is used to pick out corners. If no corners are found, then there's nothing to measure and we're done here.
• If corners are found, we pick out two opposing corners and find the difference between them. This produces the dimension of the blue rectangle in pixels.
• The rules tell us the width of the tape is 3/4". With this information, and the dimensions in pixels, a ratio allows the length of the unknown side to be calculated.