MPSCNNSpatialNormalization(3)

NAME
MPSCNNSpatialNormalization -

SYNOPSIS

#import <MPSCNN.h>

Inherits MPSCNNKernel.

  Instance Methods
(nonnull instancetype) - initWithDevice:kernelWidth:kernelHeight:
(nonnull instancetype) - initWithDevice:

  Properties
float alpha
float beta
float delta
NSUInteger kernelWidth
NSUInteger kernelHeight

  Additional Inherited Members

Detailed Description

This depends on Metal.framework Specifies the spatial normalization filter. The spatial normalization for a feature channel applies the filter over local regions which extend spatially, but are in separate feature channels (i.e., they have shape 1 x kernelWidth x kernelHeight). For each feature channel, the function computes the sum of squares of X inside each rectangle, N2(i,j). It then divides each element of X as follows: Y(i,j) = X(i,j) / (delta + alpha/(kw*kh) * N2(i,j))^beta, where kw and kh are the kernelWidth and the kernelHeight. It is the end-users responsibility to ensure that the combination of the parameters delta and alpha does not result in a situation where the denominator becomes zero - in such situations the resulting pixel-value is undefined.

Method Documentation

  - (nonnull instancetype) initWithDevice: (nonnull id< MTLDevice >) NS_DESIGNATED_INITIALIZER
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 MPSKernel.

  - (nonnull instancetype) initWithDevice: (nonnull id< MTLDevice >) device(NSUInteger) kernelWidth(NSUInteger) NS_DESIGNATED_INITIALIZER
Initialize a spatial normalization filter

Parameters:
    device The device the filter will run on
    kernelWidth The width of the kernel
    kernelHeight The height of the kernel

Returns:
    A valid MPSCNNSpatialNormalization object or nil, if failure.

NOTE: For now, kernelWidth must be equal to kernelHeight

Property Documentation

  - alpha [read], [write], [nonatomic], [assign]
The value of alpha. Default is 1.0. Must be non-negative.

  - beta [read], [write], [nonatomic], [assign]
The value of beta. Default is 5.0

  - delta [read], [write], [nonatomic], [assign]
The value of delta. Default is 1.0

  - kernelHeight [read], [nonatomic], [assign]
The height of the filter window

  - kernelWidth [read], [nonatomic], [assign]
The width of the filter window

Author

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