/*******************************************************************************
* Function: doubleThresholdByValue
* Description: performs double local thresholding using Otsu's method
* Arguments:
percentage - parameter for amount of lowering Otsu threshold
roiMask - ROI binary mask
* Returns: void
* Comments:
* Revision:
*******************************************************************************/
void
FGExtraction::doubleThresholdByValue(double percentage, Mat roiMask)
{
int u = 0;
int thresh = getOtsuThreshold(0, 255, &u, roiMask);
int highThresh = thresh - int(percentage*(thresh - u));
int lowThresh = thresh - int(1.4*percentage*(thresh - u));
#ifdef DEBUG
//cout << "th_H = " << highThresh << "; th_L = " << lowThresh << "; \n";
#endif
Mat maskedFG;
bitwise_and(_inImg, roiMask, maskedFG);
// generate high and low look-up tables
Mat highLUT(1, 256, CV_8U);
Mat lowLUT(1, 256, CV_8U);
uchar* highData = highLUT.data;
uchar* lowData = lowLUT.data;
for(int i = 0; i < 256; ++i){
highData[i] = i <= highThresh ? 0 : 255;
lowData[i] = i <= lowThresh ? 0 : 255;
}
// threshold by using look-up tables
LUT(maskedFG, highLUT, _highMask);
LUT(maskedFG, lowLUT, _lowMask);
bitwise_or(_fgHighImg, _highMask, _fgHighImg, roiMask);
bitwise_or(_fgLowImg, _lowMask, _fgLowImg, roiMask);
}
int ImageProcessor::getHigherThreshold()
{
switch (thresholdPolicy) {
case ImagePolicy::OTSU:
return getOtsuThreshold();
case ImagePolicy::ENTROPY:
return getEntropyThreshold();
case ImagePolicy::COSTUMED:
return higherThreshold;
}
return 0;
}