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97 lines
4.1 KiB
ReStructuredText
97 lines
4.1 KiB
ReStructuredText
Hough Transform
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===============
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.. highlight:: cpp
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gpu::HoughLines
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---------------
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Finds lines in a binary image using the classical Hough transform.
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.. ocv:function:: void gpu::HoughLines(const GpuMat& src, GpuMat& lines, float rho, float theta, int threshold, bool doSort = false, int maxLines = 4096)
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.. ocv:function:: void gpu::HoughLines(const GpuMat& src, GpuMat& lines, HoughLinesBuf& buf, float rho, float theta, int threshold, bool doSort = false, int maxLines = 4096)
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:param src: 8-bit, single-channel binary source image.
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:param lines: Output vector of lines. Each line is represented by a two-element vector :math:`(\rho, \theta)` . :math:`\rho` is the distance from the coordinate origin :math:`(0,0)` (top-left corner of the image). :math:`\theta` is the line rotation angle in radians ( :math:`0 \sim \textrm{vertical line}, \pi/2 \sim \textrm{horizontal line}` ).
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:param rho: Distance resolution of the accumulator in pixels.
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:param theta: Angle resolution of the accumulator in radians.
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:param threshold: Accumulator threshold parameter. Only those lines are returned that get enough votes ( :math:`>\texttt{threshold}` ).
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:param doSort: Performs lines sort by votes.
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:param maxLines: Maximum number of output lines.
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:param buf: Optional buffer to avoid extra memory allocations (for many calls with the same sizes).
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.. seealso:: :ocv:func:`HoughLines`
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gpu::HoughLinesDownload
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-----------------------
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Downloads results from :ocv:func:`gpu::HoughLines` to host memory.
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.. ocv:function:: void gpu::HoughLinesDownload(const GpuMat& d_lines, OutputArray h_lines, OutputArray h_votes = noArray())
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:param d_lines: Result of :ocv:func:`gpu::HoughLines` .
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:param h_lines: Output host array.
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:param h_votes: Optional output array for line's votes.
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.. seealso:: :ocv:func:`gpu::HoughLines`
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gpu::HoughCircles
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-----------------
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Finds circles in a grayscale image using the Hough transform.
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.. ocv:function:: void gpu::HoughCircles(const GpuMat& src, GpuMat& circles, int method, float dp, float minDist, int cannyThreshold, int votesThreshold, int minRadius, int maxRadius, int maxCircles = 4096)
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.. ocv:function:: void gpu::HoughCircles(const GpuMat& src, GpuMat& circles, HoughCirclesBuf& buf, int method, float dp, float minDist, int cannyThreshold, int votesThreshold, int minRadius, int maxRadius, int maxCircles = 4096)
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:param src: 8-bit, single-channel grayscale input image.
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:param circles: Output vector of found circles. Each vector is encoded as a 3-element floating-point vector :math:`(x, y, radius)` .
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:param method: Detection method to use. Currently, the only implemented method is ``CV_HOUGH_GRADIENT`` , which is basically *21HT* , described in [Yuen90]_.
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:param dp: Inverse ratio of the accumulator resolution to the image resolution. For example, if ``dp=1`` , the accumulator has the same resolution as the input image. If ``dp=2`` , the accumulator has half as big width and height.
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:param minDist: Minimum distance between the centers of the detected circles. If the parameter is too small, multiple neighbor circles may be falsely detected in addition to a true one. If it is too large, some circles may be missed.
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:param cannyThreshold: The higher threshold of the two passed to the :ocv:func:`gpu::Canny` edge detector (the lower one is twice smaller).
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:param votesThreshold: The accumulator threshold for the circle centers at the detection stage. The smaller it is, the more false circles may be detected.
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:param minRadius: Minimum circle radius.
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:param maxRadius: Maximum circle radius.
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:param maxCircles: Maximum number of output circles.
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:param buf: Optional buffer to avoid extra memory allocations (for many calls with the same sizes).
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.. seealso:: :ocv:func:`HoughCircles`
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gpu::HoughCirclesDownload
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-------------------------
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Downloads results from :ocv:func:`gpu::HoughCircles` to host memory.
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.. ocv:function:: void gpu::HoughCirclesDownload(const GpuMat& d_circles, OutputArray h_circles)
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:param d_circles: Result of :ocv:func:`gpu::HoughCircles` .
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:param h_circles: Output host array.
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.. seealso:: :ocv:func:`gpu::HoughCircles`
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