How does CV_CHAIN_APPROX_SIMPLE work?
From the documentation of Imgproc.findContours
:
CV_CHAIN_APPROX_SIMPLE
compresses horizontal, vertical, and diagonal segments and leaves only their end points. For example, an up-right rectangular contour is encoded with 4 points.
How does this work exactly? Does this use the Douglas-Peucker algorithm?
I'm interpreting it wrong I think, it just ignores points if they're on a horizontal/diagonal/vertical line but doesn't do anything too fancy? ApproxPolyDP uses Douglas-Peucker.
take a look at the code
i can say it uses a simple method not Douglas-Peucker algorithm