Detailed Description

Defines the Kernel Object and Interface.

A Kernel in OpenVX is the abstract representation of an computer vision function, such as a “Sobel Gradient” or “Lucas Kanade Feature Tracking”. A vision function may implement many similar or identical features from other functions, but it is still considered a single unique kernel as long as it is named by the same string and enumeration and conforms to the results specified by OpenVX. Kernels are similar to function signatures in this regard.

In each of the cases, a client of OpenVX could request the kernels in nearly the same manner. There are two main approaches, which depend on the method a client calls to get the kernel reference. The first uses enumerations.

vx_kernel kernel = vxGetKernelByEnum(context, VX_KERNEL_SOBEL_3x3);

vx_node node = vxCreateGenericNode(graph, kernel);

The second method depends on using strings to get the kernel reference.

vx_kernel kernel = vxGetKernelByName(context, "org.khronos.openvx.sobel_3x3");

vx_node node = vxCreateGenericNode(graph, kernel);

Modules
	The list of available libraries
	The standard list of available libraries [R00400].

	The list of available kernels
	The standard list of available vision kernels.

Data Structures
struct	vx_kernel_info_t
	The Kernel Information Structure. This is returned by the Context to indicate which kernels are available in the OpenVX implementation. More...

Macros
#define	VX_MAX_KERNEL_NAME (256)
	Defines the length of a kernel name string to be added to OpenVX, including the trailing zero [R01652].

Typedefs
typedef struct _vx_kernel *	vx_kernel
	An opaque reference to the descriptor of a kernel. More...

Functions
vx_kernel VX_API_CALL	vxGetKernelByEnum (vx_context context, vx_enum kernel)
	Obtains a reference to the kernel [R00656]. More...

vx_kernel VX_API_CALL	vxGetKernelByName (vx_context context, const vx_char *name)
	Obtains a reference to a kernel using a string to specify the name [R00650]. More...

vx_status VX_API_CALL	vxQueryKernel (vx_kernel kernel, vx_enum attribute, void *ptr, vx_size size)
	This allows the client to query the kernel to get information about the number of parameters, enum values, etc [R00661]. More...

vx_status VX_API_CALL	vxReleaseKernel (vx_kernel *kernel)
	Release the reference to the kernel [R00667]. The object may not be garbage collected until its total reference count is zero. More...

Data Structure Documentation

◆ vx_kernel_info_t

struct vx_kernel_info_t

The Kernel Information Structure. This is returned by the Context to indicate which kernels are available in the OpenVX implementation.

Definition at line 1635 of file vx_types.h.

Data Fields
vx_enum	enumeration	The kernel enumeration value from `The list of available kernels` (or an extension thereof). See also vxGetKernelByEnum
vx_char	name[VX_MAX_KERNEL_NAME]	The kernel name in dotted hierarchical format. e.g. "org.khronos.openvx.sobel_3x3". See also vxGetKernelByName

Typedef Documentation

◆ vx_kernel

typedef struct _vx_kernel* vx_kernel

An opaque reference to the descriptor of a kernel.

See also: vxGetKernelByName; vxGetKernelByEnum

Definition at line 198 of file vx_types.h.

Function Documentation

◆ vxGetKernelByName()

vx_kernel VX_API_CALL vxGetKernelByName	(	vx_context	context,
		const vx_char *	name
	)

Obtains a reference to a kernel using a string to specify the name [R00650].

User Kernels follow a "dotted" heirarchical syntax. For example: "com.company.example.xyz". The following are strings specifying the kernel names:

org.khronos.openvx.color_convert

org.khronos.openvx.channel_extract

org.khronos.openvx.channel_combine

org.khronos.openvx.sobel_3x3

org.khronos.openvx.magnitude

org.khronos.openvx.phase

org.khronos.openvx.scale_image

org.khronos.openvx.table_lookup

org.khronos.openvx.histogram

org.khronos.openvx.equalize_histogram

org.khronos.openvx.absdiff

org.khronos.openvx.mean_stddev

org.khronos.openvx.threshold

org.khronos.openvx.integral_image

org.khronos.openvx.dilate_3x3

org.khronos.openvx.erode_3x3

org.khronos.openvx.median_3x3

org.khronos.openvx.box_3x3

org.khronos.openvx.gaussian_3x3

org.khronos.openvx.custom_convolution

org.khronos.openvx.gaussian_pyramid

org.khronos.openvx.accumulate

org.khronos.openvx.accumulate_weighted

org.khronos.openvx.accumulate_square

org.khronos.openvx.minmaxloc

org.khronos.openvx.convertdepth

org.khronos.openvx.canny_edge_detector

org.khronos.openvx.and

org.khronos.openvx.or

org.khronos.openvx.xor

org.khronos.openvx.not

org.khronos.openvx.multiply

org.khronos.openvx.add

org.khronos.openvx.subtract

org.khronos.openvx.warp_affine

org.khronos.openvx.warp_perspective

org.khronos.openvx.harris_corners

org.khronos.openvx.fast_corners

org.khronos.openvx.optical_flow_pyr_lk

org.khronos.openvx.remap

org.khronos.openvx.halfscale_gaussian

org.khronos.openvx.laplacian_pyramid

org.khronos.openvx.laplacian_reconstruct

org.khronos.openvx.non_linear_filter

Parameters

[in]	context	The reference to the implementation context [R00651].
[in]	name	The string of the name of the kernel to get [R00652].

Returns: A kernel reference [R00653]. Any possible errors preventing a successful completion of the function should be checked using vxGetStatus [R00654].

Precondition: vxLoadKernels if the kernel is not provided by the OpenVX implementation.

Note: User Kernels should follow a "dotted" hierarchical syntax [R00655]. For example: "com.company.example.xyz".

◆ vxGetKernelByEnum()

vx_kernel VX_API_CALL vxGetKernelByEnum	(	vx_context	context,
		vx_enum	kernel
	)

Obtains a reference to the kernel [R00656].

Enum values above the standard set are assumed to apply to loaded libraries.

Parameters

[in]	context	The reference to the implementation context [R00657].
[in]	kernel	A value from `The list of available kernels` or a vendor or client-defined value [R00658].

Returns: A vx_kernel reference [R00659]. Any possible errors preventing a successful completion of the function should be checked using vxGetStatus [R00660].

Precondition: vxLoadKernels if the kernel is not provided by the OpenVX implementation.

◆ vxQueryKernel()

vx_status VX_API_CALL vxQueryKernel	(	vx_kernel	kernel,
		vx_enum	attribute,
		void *	ptr,
		vx_size	size
	)

This allows the client to query the kernel to get information about the number of parameters, enum values, etc [R00661].

Parameters

[in]	kernel	The kernel reference to query [R00662].
[in]	attribute	The attribute to query. Use a `The Kernel Attribute Constants` [R00663].
[out]	ptr	The pointer to the location at which to store the resulting value [R00664].
[in]	size	The size of the container to which ptr points [R00665].

Returns: A The vx_status Constants value.

Return values

VX_SUCCESS	No errors; any other value indicates failure [R00666].
VX_ERROR_INVALID_REFERENCE	kernel is not a valid `vx_kernel` reference.
VX_ERROR_INVALID_PARAMETERS	If any of the other parameters are incorrect.
VX_ERROR_NOT_SUPPORTED	If the attribute value is not supported in this implementation.

◆ vxReleaseKernel()

vx_status VX_API_CALL vxReleaseKernel ( vx_kernel * kernel )

Release the reference to the kernel [R00667]. The object may not be garbage collected until its total reference count is zero.

Parameters

[in] kernel The pointer to the kernel reference to release [R00668].

Postcondition: After returning from this function the reference is zeroed [R00669].

Returns: A The vx_status Constants value.

Return values

VX_SUCCESS	No errors; any other value indicates failure [R00670].
VX_ERROR_INVALID_REFERENCE	kernel is not a valid `vx_kernel` reference.

Detailed Description

Modules

Data Structures

Macros

Typedefs

Functions

Data Structure Documentation

◆ vx_kernel_info_t

Typedef Documentation

◆ vx_kernel

Function Documentation

◆ vxGetKernelByName()

◆ vxGetKernelByEnum()

◆ vxQueryKernel()

◆ vxReleaseKernel()