magickHoughLineImage method

Future<bool> magickHoughLineImage(int width, int height, int threshold)

MagickHoughLineImage() can be used in conjunction with any binary edge extracted image (we recommend Canny) to identify lines in the image. The algorithm accumulates counts for every white pixel for every possible orientation (for angles from 0 to 179 in 1 degree increments) and distance from the center of the image to the corner (in 1 px increments) and stores the counts in an accumulator matrix of angle vs distance. The size of the accumulator is 180x(diagonal/2). Next it searches this space for peaks in counts and converts the locations of the peaks to slope and intercept in the normal x,y input image space. Use the slope/intercepts to find the endpoints clipped to the bounds of the image. The lines are then drawn. The counts are a measure of the length of the lines.

This method runs inside an isolate different from the main isolate.

• width: find line pairs as local maxima in this neighborhood.
• height: find line pairs as local maxima in this neighborhood.
• threshold: the line count threshold.

Implementation

Future<bool> magickHoughLineImage(
        int width, int height, int threshold) async =>
    await _magickCompute(
      _magickHoughLineImage,
      _MagickHoughLineImageParams(
        _wandPtr.address,
        width,
        height,
        threshold,
      ),
    );