Line detection in pictures - Hough transform

1 canny edge detection edge detection

The effect is as follows:

2. How to use a computer to identify and detect straight lines?

 Note: Not expressed in polar coordinates

1 Formula derivation

and uniquely determine a straight line: (the tangent of is the slope)

Additional knowledge: Trigonometric functions

Tangent_Baidu Encyclopedia (baidu.com)

Function name	official
sine function	sinθ=y/r
cosine function	cosθ=x/r
tangent function	tanθ=y/x
cotangent function	cotθ=x/y
secant function	secθ=r/x
cosecant function	cscθ=r/y

2 Start counting and vote for the straight line

对 和Trial area:

 Calculate the position information (x, y) of the edge point using all angle intervals and vote in the above table.

Complete your vote:

 Each group is a straight line. The more votes it gets, the more likely it is that it is the target straight line.

 3. Code learning

I haven’t learned yet, but I have learned to write.