Pixel-wise Multiplication

Detailed Description

Performs element-wise multiplication between two images and a scalar value.

Pixel-wise multiplication is performed between the pixel values in two VX_DF_IMAGE_U8 or VX_DF_IMAGE_S16 images and a scalar floating-point number scale. The output image can be VX_DF_IMAGE_U8 only if both source images are VX_DF_IMAGE_U8 and the output image is explicitly set to VX_DF_IMAGE_U8. It is otherwise VX_DF_IMAGE_S16. If one of the input images is of type VX_DF_IMAGE_S16, all values are converted to VX_DF_IMAGE_S16.

The scale with a value of \( {1}/{2^n} \), where n is an integer and \( 0 \le n \le 15 \), and 1/255 (0x1.010102p-8 C99 float hex) must be supported. The support for other values of scale is not prohibited. Furthermore, for scale with a value of 1/255 the rounding policy of VX_ROUND_POLICY_TO_NEAREST_EVEN must be supported whereas for the scale with value of \( {1}/{2^n} \) the rounding policy of VX_ROUND_POLICY_TO_ZERO must be supported. The support of other rounding modes for any values of scale is not prohibited.

The rounding policy VX_ROUND_POLICY_TO_ZERO for this function is defined as:

\[ reference(x,y,scale) = truncate(((int32_t)in1(x,y)) * ((int32_t)in2(x,y)) * (double)scale) \]

The rounding policy VX_ROUND_POLICY_TO_NEAREST_EVEN for this function is defined as:

\[ reference(x,y,scale) = round_to_nearest_even(((int32_t)in1(x,y)) * ((int32_t)in2(x,y)) * (double)scale) \]

The overflow handling is controlled by an overflow-policy parameter. For each pixel value in the two input images:

\[ out(x,y) = in_1(x,y) in_2(x,y) scale \]

Functions
vx_node	vxMultiplyNode (vx_graph graph, vx_image in1, vx_image in2, vx_scalar scale, vx_enum overflow_policy, vx_enum rounding_policy, vx_image out)
	[Graph] Creates an pixelwise-multiplication node. More...
vx_status	vxuMultiply (vx_context context, vx_image in1, vx_image in2, vx_float32 scale, vx_enum overflow_policy, vx_enum rounding_policy, vx_image out)
	[Immediate] Performs elementwise multiplications on pixel values in the input images and a scale. More...

Function Documentation

vx_node vxMultiplyNode	(	vx_graph	graph,
		vx_image	in1,
		vx_image	in2,
		vx_scalar	scale,
		vx_enum	overflow_policy,
		vx_enum	rounding_policy,
		vx_image	out
	)

[Graph] Creates an pixelwise-multiplication node.

Parameters

[in]	graph	The reference to the graph.
[in]	in1	An input image, VX_DF_IMAGE_U8 or VX_DF_IMAGE_S16.
[in]	in2	An input image, VX_DF_IMAGE_U8 or VX_DF_IMAGE_S16.
[in]	scale	A non-negative VX_TYPE_FLOAT32 multiplied to each product before overflow handling.
[in]	overflow_policy	A VX_TYPE_ENUM of the vx_convert_policy_e enumeration.
[in]	rounding_policy	A VX_TYPE_ENUM of the vx_round_policy_e enumeration.
[out]	out	The output image, a VX_DF_IMAGE_U8 or VX_DF_IMAGE_S16 image.

Returns

vx_node.

Return values

0	Node could not be created.
*	Node handle.

vx_status vxuMultiply	(	vx_context	context,
		vx_image	in1,
		vx_image	in2,
		vx_float32	scale,
		vx_enum	overflow_policy,
		vx_enum	rounding_policy,
		vx_image	out
	)

[Immediate] Performs elementwise multiplications on pixel values in the input images and a scale.

Parameters

[in]	context	The reference to the overall context.
[in]	in1	A VX_DF_IMAGE_U8 or VX_DF_IMAGE_S16 input image.
[in]	in2	A VX_DF_IMAGE_U8 or VX_DF_IMAGE_S16 input image.
[in]	scale	The scale value.
[in]	overflow_policy	A vx_convert_policy_e enumeration.
[in]	rounding_policy	A vx_round_policy_e enumeration.
[out]	out	The output image in VX_DF_IMAGE_U8 or VX_DF_IMAGE_S16 format.

Returns

A vx_status_e enumeration.

Return values

VX_SUCCESS	Success
*	An error occurred. See vx_status_e.