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SubtractImages_Signed

Header:	FIL.h
Namespace:	fil
Module:	FoundationLite

Subtracts two images pixel by pixel. The result is signed.

Syntax

void fil::SubtractImages_Signed
(
	const fil::Image& inImage1,
	const fil::Image& inImage2,
	ftl::Optional<const fil::Region&> inRoi,
	float inScale,
	fil::Image& outImage
)

Parameters

Name	Type	Default	Description
inImage1	const Image&		First input image
inImage2	const Image&		Second input image
inRoi	Optional<const Region&>	NIL	Range of pixels to be processed
inScale	float	1.0f	Output image scaling factor
outImage	Image&		Output image

Description

Operation subtracts two images. Each outImage pixel is equal to the difference of corresponding pixels of the input images. The result is signed.

The result of the operation is multiplied by inScale factor, which may be used to avoid clipping when the produced values exceed the range of correct pixel values. However it should be noted that when the value of inScale is other than 1.0, the filter uses a slower, not SSE-optimized implementation.

Whenever the resulting value exceeds the range of pixel values, it is clipped to the nearest proper value. In multichannel (color) images each pixel channel is processed separately.

The operation requires that the images being processed have equal format and dimensions, otherwise an error with appropriate description occurs. To obtain an image of desired dimensions one can use ResizeImage or CropImage filter. To alter the pixel type of an image one can use ConvertPixelType filter. ConvertToMultichannel and AverageChannels filters allow to alter the number of image channels.

Examples

Compare SubtractImages_Signed and SubtractImages performed on the sample images.

Hardware Acceleration

This operation is optimized for SSE2 technology for pixels of types: UINT8, SINT16, REAL, SINT8(for inScale=1), UINT16(for inScale=1).

This operation is optimized for SSE41 technology for pixels of types: UINT16(for inScale!=1).

This operation is optimized for AVX2 technology for pixels of types: UINT8, SINT16, UINT16, REAL, SINT8(for inScale=1).

This operation is optimized for NEON technology for pixels of types: UINT8, SINT8, UINT16, SINT16, SINT32.

This operation supports automatic parallelization for multicore and multiprocessor systems.

Errors

List of possible exceptions:

Error type	Description
DomainError	Image formats are not the same in SubtractImages_Signed.
DomainError	Image sizes are not equal in SubtractImages_Signed.
DomainError	Region exceeds an input image in SubtractImages_Signed.