opencv/modules/gpuimgproc/doc/histogram.rst

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Histogram Calculation
=====================
.. highlight:: cpp
gpu::evenLevels
-------------------
Computes levels with even distribution.
.. ocv:function:: void gpu::evenLevels(GpuMat& levels, int nLevels, int lowerLevel, int upperLevel)
:param levels: Destination array. ``levels`` has 1 row, ``nLevels`` columns, and the ``CV_32SC1`` type.
:param nLevels: Number of computed levels. ``nLevels`` must be at least 2.
:param lowerLevel: Lower boundary value of the lowest level.
:param upperLevel: Upper boundary value of the greatest level.
gpu::histEven
-----------------
Calculates a histogram with evenly distributed bins.
.. ocv:function:: void gpu::histEven(const GpuMat& src, GpuMat& hist, int histSize, int lowerLevel, int upperLevel, Stream& stream = Stream::Null())
.. ocv:function:: void gpu::histEven(const GpuMat& src, GpuMat& hist, GpuMat& buf, int histSize, int lowerLevel, int upperLevel, Stream& stream = Stream::Null())
.. ocv:function:: void gpu::histEven( const GpuMat& src, GpuMat hist[4], int histSize[4], int lowerLevel[4], int upperLevel[4], Stream& stream=Stream::Null() )
.. ocv:function:: void gpu::histEven( const GpuMat& src, GpuMat hist[4], GpuMat& buf, int histSize[4], int lowerLevel[4], int upperLevel[4], Stream& stream=Stream::Null() )
:param src: Source image. ``CV_8U``, ``CV_16U``, or ``CV_16S`` depth and 1 or 4 channels are supported. For a four-channel image, all channels are processed separately.
:param hist: Destination histogram with one row, ``histSize`` columns, and the ``CV_32S`` type.
:param histSize: Size of the histogram.
:param lowerLevel: Lower boundary of lowest-level bin.
:param upperLevel: Upper boundary of highest-level bin.
:param buf: Optional buffer to avoid extra memory allocations (for many calls with the same sizes).
:param stream: Stream for the asynchronous version.
gpu::histRange
------------------
Calculates a histogram with bins determined by the ``levels`` array.
.. ocv:function:: void gpu::histRange(const GpuMat& src, GpuMat& hist, const GpuMat& levels, Stream& stream = Stream::Null())
.. ocv:function:: void gpu::histRange(const GpuMat& src, GpuMat& hist, const GpuMat& levels, GpuMat& buf, Stream& stream = Stream::Null())
:param src: Source image. ``CV_8U`` , ``CV_16U`` , or ``CV_16S`` depth and 1 or 4 channels are supported. For a four-channel image, all channels are processed separately.
:param hist: Destination histogram with one row, ``(levels.cols-1)`` columns, and the ``CV_32SC1`` type.
:param levels: Number of levels in the histogram.
:param buf: Optional buffer to avoid extra memory allocations (for many calls with the same sizes).
:param stream: Stream for the asynchronous version.
gpu::calcHist
------------------
Calculates histogram for one channel 8-bit image.
.. ocv:function:: void gpu::calcHist(const GpuMat& src, GpuMat& hist, Stream& stream = Stream::Null())
:param src: Source image.
:param hist: Destination histogram with one row, 256 columns, and the ``CV_32SC1`` type.
:param stream: Stream for the asynchronous version.
gpu::equalizeHist
------------------
Equalizes the histogram of a grayscale image.
.. ocv:function:: void gpu::equalizeHist(const GpuMat& src, GpuMat& dst, Stream& stream = Stream::Null())
.. ocv:function:: void gpu::equalizeHist(const GpuMat& src, GpuMat& dst, GpuMat& hist, GpuMat& buf, Stream& stream = Stream::Null())
:param src: Source image.
:param dst: Destination image.
:param hist: Destination histogram with one row, 256 columns, and the ``CV_32SC1`` type.
:param buf: Optional buffer to avoid extra memory allocations (for many calls with the same sizes).
:param stream: Stream for the asynchronous version.
.. seealso:: :ocv:func:`equalizeHist`