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Pantheios 1.0.1 beta 104 (Default branch)
03-08-2008
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MPSCNNSpatialNormalizationGradient(3) MetalPerformanceShaders.framework MPSCNNSpatialNormalizationGradient(3) NAME
MPSCNNSpatialNormalizationGradient SYNOPSIS
#import <MPSCNNNormalization.h> Inherits MPSCNNGradientKernel. Instance Methods (nonnull instancetype) - initWithDevice:kernelWidth:kernelHeight: (nullable instancetype) - initWithCoder:device: 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 gradient 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. T(i,j) = (delta + alpha/(kw*kh) * N2(i,j)) N = kw * kh OutputGradient: dZ/dX(i,j) = T(i,j)^(-beta) * ( dZ/dY(i,j) - (2*alpha*beta*X(i,j)/T(i,j)) * (sum_{l,k in L(i),K(j)} dZ/dY(l,k)*X(l,k)) ) N is the kernel size. The window R(k) itself is defined as: L(i) = [i-floor((kw-1)/2), i+floor(kw/2] K(j) = [j-floor((kh-1)/2), j+floor(kh/2] For correct gradient computation all parameters must be the same as the original normalization filter. 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 MPSCNNGradientKernel. - (nonnull instancetype) initWithDevice: (nonnull id< MTLDevice >) device(NSUInteger) kernelWidth(NSUInteger) kernelHeight 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 Generated automatically by Doxygen for MetalPerformanceShaders.framework from the source code. Version MetalPerformanceShaders-100 Thu Feb 8 2018 MPSCNNSpatialNormalizationGradient(3)