ComputeThreshold_Otsu
Computes the value of the Otsu threshold.
Syntax
IppStatus ippiComputeThreshold_Otsu_8u_C1R
(
const Ipp8u*
pSrc
,
int
srcStep
,
IppiSize
roiSize
,
Ipp8u*
pThreshold
);
Include Files
ippi.h
Domain Dependencies
Headers:
ippcore.h
,
ippvm.h
,
ipps.h
Libraries:
ippcore.lib
,
ippvm.lib
,
ipps.lib
Parameters
- pSrc
- Pointer to the source image ROI.
- srcStep
- Distance in bytes between starts of consecutive lines in the source image.
- roiSize
- Size of the image ROI in pixels.
- pThreshold
- Pointer to the Otsu threshold value.
Description
This function operates with ROI (see
Regions of Interest in Intel IPP
).
This function calculates the Otsu threshold (
[Otsu79]
) for the source image
pSrc
in accordance with the following formula:
where 0
≤
x
<
roiSize.width
, 0
≤
y
<
roiSize.height
, and
T
is the Otsu threshold.
where
The computed Otsu threshold can be used in the thresholding functions described above.
For example, the following figures shows how the Otsu threshold can be used for background/foreground selection. The figure a) below shows the initial image, the figure b) shows the histogram of the initial image with the red line indicating the computed Otsu threshold. The figure c) demonstrates the resulting image obtained by applying the function
ippiThreshold_8u_C1R
with a computed Otsu threshold value to the source image.
Using Otsu Threshold for Background/Foreground Selection
Return Values
- ippStsNoErr
- Indicates no error. Any other value indicates an error.
- ippStsNullPtrErr
- Indicates an error condition if one of the specified pointer isNULL.
- ippStsSizeErr
- Indicates an error condition ifroiSizehas a field with zero or negative value.
- ippStsStepErr
- Indicates an error condition ifsrcStepis less than or equal to 0.