Developer Reference

  • 2020
  • 10/21/2020
  • Public Content
Contents

Threshold

Performs thresholding of pixel values in an image buffer.

Syntax

Case 1: Not-in-place operation on one-channel data
IppStatus ippiThreshold_<mod>
(
const Ipp<datatype>*
pSrc
,
int
srcStep
,
Ipp<datatype>*
pDst
,
int
dstStep
,
IppiSize
roiSize
,
Ipp<datatype>
threshold
,
IppCmpOp
ippCmpOp
);
Supported values for
mod
:
8u_C1R
16u_C1R
16s_C1R
32f_C1R
Case 2: Not-in-place operation on multi-channel data
IppStatus ippiThreshold_<mod>
(
const Ipp<datatype>*
pSrc
,
int
srcStep
,
Ipp<datatype>*
pDst
,
int
dstStep
,
IppiSize
roiSize
,
const Ipp<datatype>
threshold
[3]
,
IppCmpOp
ippCmpOp
);
Supported values for
mod
:
8u_C3R
16u_C3R
16s_C3R
32f_C3R
8u_AC4R
16u_AC4R
16s_AC4R
32f_AC4R
Case 3: In-place operation on one-channel data
IppStatus ippiThreshold_<mod>
(
Ipp<datatype>*
pSrcDst
,
int
srcDstStep
,
IppiSize
roiSize
,
Ipp<datatype>
threshold
,
IppCmpOp
ippCmpOp
);
Supported values for
mod
:
8u_C1IR
16u_C1IR
16s_C1IR
32f_C1IR
Case 4: In-place operation on multi-channel data
IppStatus ippiThreshold_<mod>
(
Ipp<datatype>*
pSrcDst
,
int
srcDstStep
,
IppiSize
roiSize
,
const Ipp<datatype>
threshold
[3]
,
IppCmpOp
ippCmpOp
);
Supported values for
mod
:
8u_C3IR
16u_C3IR
16s_C3IR
32f_C3IR
8u_AC4IR
16u_AC4IR
16s_AC4IR
32f_AC4IR
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.
pDst
Pointer to the destination image ROI.
dstStep
Distance in bytes between starts of consecutive lines in the destination image.
pSrcDst
Pointer to the source and destination image ROI (for the in-place operation).
srcDstStep
Distance in bytes between starts of consecutive lines in the source and destination image buffer (for the in-place operation).
roiSize
Size of the source and destination ROI in pixels.
threshold
The threshold level value to use for each pixel. In case of multi-channel data, an array of threshold values for each color channel is used.
ippCmpOp
The operation specified for comparing pixel values and the
threshold
. Comparison for either “less than” or “greater than” can be used.
Description
This function operates with ROI (see Regions of Interest in Intel IPP).
This function thresholds pixels in the source image
pSrc
using the specified level
threshold
. Pixel values in the source image are compared to the
threshold
value according to the type of comparison operation specified in the
ippCmpOp
. The following values for
ippCmpOp
are possible:
  • ippCmpLess
    specifies the “less than” comparison and defines the
    threshold
    value as a lower bound. Comparison is performed by the following formula:
  • ippCmpGreater
    specifies the “greater than” comparison and defines the
    threshold
    value as an upper bound. Comparison is performed by the following formula:
If the result of comparison is true, the corresponding output pixel is set to the
threshold
value. Otherwise, it is set to the source pixel value.
Return Values
ippStsNoErr
Indicates no error. Any other value indicates an error or a warning.
ippStsNullPtrErr
Indicates an error condition if one of the specified pointer is
NULL
.
ippStsSizeErr
Indicates an error condition if
roiSize
has a field with zero or negative value.
ippStsStepErr
Indicates an error condition if
srcStep
,
dstStep
, or
srcDstStep
has a zero or negative value
ippStsNotSupportedModeErr
Indicates an error if the comparison mode is not supported.

Example

The code example below shows how to use the
ippiThreshold_8u_C1R
function.
void func_threshold() { IppiSize ROI = {5,4}; Ipp8u src[9*4] = {1, 2, 4, 8, 16, 8, 4, 2, 1, 1, 2, 4, 8, 16, 8, 4, 2, 1, 1, 2, 4, 8, 16, 8, 4, 2, 1, 1, 2, 4, 8, 16, 8, 4, 2, 1}; Ipp8u dst[9*4]; Ipp8u threshold = 6; ippiThreshold_8u_C1R(src, 9, dst, 9, ROI, threshold, ippCmpGreater); }
Result:
dst 1 2 4 6 6 8 4 2 1 1 2 4 6 6 8 4 2 1 1 2 4 6 6 8 4 2 1 1 2 4 6 6 8 4 2 1

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804