MPSImageGaussianBlur(3)

NAME

       MPSImageGaussianBlur

SYNOPSIS

       #import <MPSImageConvolution.h>

       Inherits MPSUnaryImageKernel.

   Instance Methods
       (nonnull instancetype) - initWithDevice:sigma:
       (nullable instancetype) - initWithCoder:device:
       (nonnull instancetype) - initWithDevice:

   Properties
       float sigma

   Additional Inherited Members

Detailed Description

       The MPSImageGaussianBlur convolves an image with gaussian of given
       sigma in both x and y direction.

                   The MPSImageGaussianBlur utilizes a very fast algorith that typically runs at approximately
                   1/2 of copy speeds. Notably, it is faster than either the tent or box blur except perhaps
                   for very large filter windows. Mathematically, it is an approximate gaussian. Some
                   non-gaussian behavior may be detectable with advanced analytical methods such as FFT.
                   If a analytically clean gaussian filter is required, please use the MPSImageConvolution
                   filter instead with an appropriate set of weights. The MPSImageGaussianBlur is intended
                   to be suitable for all common image processing needs demanding ~10 bits of precision or
                   less.

Method Documentation

   - (nullable instancetype) initWithCoder: (NSCoder *__nonnull)
       aDecoder(nonnull id< MTLDevice >) device
       NSSecureCoding compatability  While the standard
       NSSecureCoding/NSCoding method -initWithCoder: should work, since the
       file can't know which device your data is allocated on, we have to
       guess and may guess incorrectly. To avoid that problem, use
       initWithCoder:device instead.

       Parameters:
           aDecoder The NSCoder subclass with your serialized MPSKernel
           device The MTLDevice on which to make the MPSKernel

       Returns:
           A new MPSKernel object, or nil if failure.



       Reimplemented from MPSUnaryImageKernel.

   - (nonnull instancetype) initWithDevice: (nonnull id< MTLDevice >) device
       Standard init with default properties per filter type

       Parameters:
           device The device that the filter will be used on. May not be NULL.

       Returns:
           a pointer to the newly initialized object. This will fail,
           returning nil if the device is not supported. Devices must be
           MTLFeatureSet_iOS_GPUFamily2_v1 or later.



       Reimplemented from MPSUnaryImageKernel.

   - (nonnull instancetype) initWithDevice: (nonnull id< MTLDevice >)
       device(float) sigma
       Initialize a gaussian blur filter for a particular sigma and device

       Parameters:
           device The device the filter will run on
           sigma The standard deviation of gaussian blur filter. Gaussian
           weight, centered at 0, at integer grid i is given as w(i) =
           1/sqrt(2*pi*sigma) * exp(-i^2/2*sigma^2) If we take cut off at 1%
           of w(0) (max weight) beyond which weights are considered 0, we have
           ceil (sqrt(-log(0.01)*2)*sigma) ~ ceil(3.7*sigma) as rough estimate
           of filter width

       Returns:
           A valid object or nil, if failure.

Property Documentation

   - sigma [read],  [nonatomic],  [assign]
       Read-only sigma value with which filter was created

Author

       Generated automatically by Doxygen for
       MetalPerformanceShaders.framework from the source code.





Version MetalPerformanceShaders-Thu2Jul 13 2017        MPSImageGaussianBlur(3)


Mac OS X 10.13.1 - Generated Tue Nov  7 06:13:02 CST 2017