The Variance object finds variance values
in an input or sequence of inputs.

Construction

H = vision.Variance returns
a System object, H, that computes the variance of
an input or a sequence of inputs.

H = vision.Variance(Name,Value) returns
a variance System object, H, with each specified
property set to the specified value. You can specify additional name-value
pair arguments in any order as (Name1, Value1,...,NameN,ValueN).

Enable calculation over successive calls to step method

Set this property to true to enable the calculation
of the variance over successive calls to the step method.
The default is false.

ResetInputPort

Enable resetting via an input in running variance mode

Set this property to true to enable resetting
the running variance. When the property is set to true,
a reset input must be specified to the step method
to reset the running variance. This property applies when you set
the RunningVariance property
to true. The default is false.

ResetCondition

Reset condition for running variance mode

Specify the event to reset the running variance as Rising
edge, Falling edge, Either edge,
or Non-zero. This property applies when you set
the ResetInputPort property
to true. The default is Non-zero.

CustomDimension

Numerical dimension to operate along

Specify the dimension (one-based value) of the input signal,
over which the variance is computed. The value of this property cannot
exceed the number of dimensions in the input signal. This property
applies when you set the Dimension property to Custom.
The default is 1.

Dimension

Numerical dimension to operate along

Specify how the variance calculation is performed over the data
as All, Row, Column, or Custom.
This property applies only when you set the RunningVariance property
to false. The default is All.

ROIForm

Type of region of interest

Specify the type of region of interest as Rectangles, Lines, Label
matrix, or Binary mask. This property
applies when you set the ROIProcessing property
to true. Full ROI processing support requires a Computer Vision System Toolbox™ license.
If you only have the DSP System Toolbox™ license, the ROIForm property
value options are limited to Rectangles. The default
is Rectangles.

ROIPortion

Calculate over entire ROI or just perimeter

Specify the region over which to calculate the variance as Entire
ROI, or ROI perimeter. This property
applies when you set the ROIForm property
to Rectangles. The default is Entire ROI.

ROIProcessing

Enable region of interest processing

Set this property to true to enable calculating
the variance within a particular region of each image. This property
applies when you set the Dimension property
to All and the RunningVariance property
to false. Full ROI processing support requires
a Computer Vision System Toolbox license. If you only have the DSP System Toolbox license,
the ROIForm property
value options are limited to Rectangles. The default
is false.

ROIStatistics

Statistics for each ROI, or one for all ROIs

Specify what statistics to calculate as Individual
statistics for each ROI , or Single statistic for
all ROIs. This property does not apply when you set the ROIForm property
to Binary mask. The default isIndividual
statistics for each ROI.

ValidityOutputPort

Output flag indicating if any part of ROI is outside input image

Set this property to true to return the validity
of the specified ROI as completely or partially inside of the image.
This applies when you set the ROIForm property
to Lines or Rectangles.

Set this property to true to return the validity
of the specified label numbers. This applies when you set the ROIForm property
to Label matrix.

Specify the rounding method as one of Ceiling | Convergent | Floor | Nearest | Round | Simplest | Zero.
The default is Floor.

OverflowAction

Overflow action for fixed-point operations

Specify the overflow action as Wrap or Saturate.
The default is Wrap.

InputSquaredProductDataType

Input squared product and fraction lengths

Specify the input-squared product fixed-point data type as Same
as input or Custom. The default is Same as input.

CustomInputSquaredProductDataType

Input squared product word and fraction lengths

Specify the input-squared product fixed-point type as a scaled numerictype object. This property
applies when you set the InputSquaredProductDataType property
to Custom. The default is numerictype(true,32,15).

InputSumSquaredProductDataType

Input-sum-squared product and fraction lengths

Specify the input-sum-squared product fixed-point data type
as Same as input-squared product or Custom.
The default is Same as input-squared product.

CustomInputSumSquaredProductDataType

Input sum-squared product and fraction lengths

Specify the input-sum-squared product fixed-point type as a
scaled numerictype object.
This property applies when you set the InputSumSquaredProductDataType property
to Custom. The default is numerictype(true,32,23).

AccumulatorDataType

Data type of the accumulator

Specify the accumulator fixed-point data type as Same
as input, or Custom. The default is Same
as input.

CustomAccumulatorDataType

Accumulator word and fraction lengths

Specify the accumulator fixed-point type as a scaled numerictype object. This property
applies when you set the AccumulatorDataType property
to Custom. The default is numerictype(true,32,30).

OutputDataType

Data type of output

Specify the output fixed-point data type as Same as
accumulator, Same as input, or Custom.
The default is Same as accumulator.

CustomOutputDataType

Output word and fraction lengths

Specify the output fixed-point type as a scaled numerictype object.

This property applies when you set the OutputDataType property
to Custom. The default is numerictype(true,32,30).