Detailed Description

Compares an image template against overlapped image regions.

The detailed equation to the matching can be found in vx_comp_metric_e. The output of the template matching node is a comparison map. The output comparison map should be the same size as the input image. The template image size (width*height) shall not be larger than 65535. If the valid region of the template image is smaller than the entire template image, the result in the destination image is implementation-dependent.

Enumerations
enum	vx_comp_metric_e { VX_COMPARE_HAMMING = ((( VX_ID_KHRONOS ) << 20) \| ( VX_ENUM_COMP_METRIC << 12)) + 0x0, VX_COMPARE_L1 = ((( VX_ID_KHRONOS ) << 20) \| ( VX_ENUM_COMP_METRIC << 12)) + 0x1, VX_COMPARE_L2 = ((( VX_ID_KHRONOS ) << 20) \| ( VX_ENUM_COMP_METRIC << 12)) + 0x2, VX_COMPARE_CCORR = ((( VX_ID_KHRONOS ) << 20) \| ( VX_ENUM_COMP_METRIC << 12)) + 0x3, VX_COMPARE_L2_NORM = ((( VX_ID_KHRONOS ) << 20) \| ( VX_ENUM_COMP_METRIC << 12)) + 0x4, VX_COMPARE_CCORR_NORM = ((( VX_ID_KHRONOS ) << 20) \| ( VX_ENUM_COMP_METRIC << 12)) + 0x5 }
	comparing metrics. More...

Functions
vx_node VX_API_CALL	vxMatchTemplateNode (vx_graph graph, vx_image src, vx_image templateImage, vx_enum matchingMethod, vx_image output)
	[Graph] The Node Compares an image template against overlapped image regions. More...

vx_status VX_API_CALL	vxuMatchTemplate (vx_context context, vx_image src, vx_image templateImage, vx_enum matchingMethod, vx_image output)
	[Immediate] The function compares an image template against overlapped image regions. More...

Enumeration Type Documentation

enum vx_comp_metric_e

comparing metrics.

In all the equations below w and h are width and height of the template image respectively. \( R \) is the compare map. \( T \) is the template image. \( I \) is the image on which the template is searched.

Enumerator
VX_COMPARE_HAMMING	hamming distance \( R(x,y) = \frac{1}{w*h}\sum_{\grave{x},\grave{y}}^{w,h} XOR(T(\grave{x},\grave{y}),I(x+\grave{x},y+\grave{y}))\)
VX_COMPARE_L1	L1 distance \( R(x,y) = \frac{1}{w*h}\sum_{\grave{x},\grave{y}}^{w,h} ABS(T(\grave{x},\grave{y}) - I(x+\grave{x},y+\grave{y}))\).
VX_COMPARE_L2	L2 distance normalized by image size \( R(x,y) = \frac{1}{w*h}\sum_{\grave{x},\grave{y}}^{w,h} (T(\grave{x},\grave{y}) - I(x+\grave{x},y+\grave{y}))^2\).
VX_COMPARE_CCORR	cross correlation distance \( R(x,y) = \frac{1}{wh}\sum_{\grave{x},\grave{y}}^{w,h} (T(\grave{x},\grave{y})I(x+\grave{x},y+\grave{y}))\)
VX_COMPARE_L2_NORM	L2 normalized distance \( R(x,y) = \frac{\sum_{\grave{x},\grave{y}}^{w,h} (T(\grave{x},\grave{y}) - I(x+\grave{x},y+\grave{y}))^2} {\sqrt{\sum_{\grave{x},\grave{y}}^{w,h} T(\grave{x},\grave{y})^2 * I(x+\grave{x},y+\grave{y})^2}} \).
VX_COMPARE_CCORR_NORM	cross correlation normalized distance \( R(x,y) = \frac{\sum_{\grave{x},\grave{y}}^{w,h} T(\grave{x},\grave{y}) * I(x+\grave{x},y+\grave{y})2^{15}} {\sqrt{\sum_{\grave{x},\grave{y}}^{w,h} T(\grave{x},\grave{y})^2 I(x+\grave{x},y+\grave{y})^2}} \)

Definition at line 1447 of file vx_types.h.

Function Documentation

vx_node VX_API_CALL vxMatchTemplateNode	(	vx_graph	graph,
		vx_image	src,
		vx_image	templateImage,
		vx_enum	matchingMethod,
		vx_image	output
	)

[Graph] The Node Compares an image template against overlapped image regions.

The detailed equation to the matching can be found in vx_comp_metric_e. The output of the template matching node is a comparison map as described in vx_comp_metric_e. The Node have a limitation on the template image size (width*height). It should not be larger then 65535. If the valid region of the template image is smaller than the entire template image, the result in the destination image is implementation-dependent.

Parameters

[in]	graph	The reference to the graph.
[in]	src	The input image of type `VX_DF_IMAGE_U8`.
[in]	templateImage	Searched template of type `VX_DF_IMAGE_U8`.
[in]	matchingMethod	attribute specifying the comparison method `vx_comp_metric_e`. This function support only `VX_COMPARE_CCORR_NORM` and `VX_COMPARE_L2`.
[out]	output	Map of comparison results. The output is an image of type VX_DF_IMAGE_S16

Returns: vx_node.

Return values

vx_node A node reference. Any possible errors preventing a successful creation should be checked using vxGetStatus

vx_status VX_API_CALL vxuMatchTemplate	(	vx_context	context,
		vx_image	src,
		vx_image	templateImage,
		vx_enum	matchingMethod,
		vx_image	output
	)

[Immediate] The function compares an image template against overlapped image regions.