Mean and Standard Deviation

Detailed Description

Computes the mean pixel value and the standard deviation of the pixels in the input image (which has a dimension width and height).

The mean value is computed as:

\[ \mu = \frac{\left(\sum_{y=0}^h \sum_{x=0}^w src(x,y) \right)} {(width * height)} \]

The standard deviation is computed as:

\[ \sigma = \sqrt{\frac{\left(\sum_{y=0}^h \sum_{x=0}^w (\mu - src(x,y))^2 \right)} {(width * height)}} \]

Functions
vx_node	vxMeanStdDevNode (vx_graph graph, vx_image input, vx_scalar mean, vx_scalar stddev)
	[Graph] Creates a mean value and standard deviation node. More...
vx_status	vxuMeanStdDev (vx_context context, vx_image input, vx_float32 *mean, vx_float32 *stddev)
	[Immediate] Computes the mean value and standard deviation. More...

Function Documentation

vx_node vxMeanStdDevNode	(	vx_graph	graph,
		vx_image	input,
		vx_scalar	mean,
		vx_scalar	stddev
	)

[Graph] Creates a mean value and standard deviation node.

Parameters

[in]	graph	The reference to the graph.
[in]	input	The input image. VX_DF_IMAGE_U8 is supported.
[out]	mean	The VX_TYPE_FLOAT32 average pixel value.
[out]	stddev	The VX_TYPE_FLOAT32 standard deviation of the pixel values.

Returns

vx_node.

Return values

0	Node could not be created.
*	Node handle.

vx_status vxuMeanStdDev	(	vx_context	context,
		vx_image	input,
		vx_float32 *	mean,
		vx_float32 *	stddev
	)

[Immediate] Computes the mean value and standard deviation.

Parameters

[in]	context	The reference to the overall context.
[in]	input	The input image. VX_DF_IMAGE_U8 is supported.
[out]	mean	The average pixel value.
[out]	stddev	The standard deviation of the pixel values.

Returns

A vx_status_e enumeration.

Return values

VX_SUCCESS	Success
*	An error occurred. See vx_status_e.