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add exact bilinearResize

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This commit is contained in:
uvos 2021-07-01 14:03:29 +02:00
parent b5249be51e
commit d6bacdae62
2 changed files with 64 additions and 2 deletions
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59
src/matutils.cpp
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@ -351,3 +351,62 @@ void removeEmptyFrontBackCols(cv::Mat& mat)
if(frontRej || backRej) removeEmptyFrontBackCols(mat);
}
static float linInterpolate(float A, float B, float x)
{
return A * (1.0f - x) + B * x;
}
template <typename Type> static Type resizePointBilinear(const cv::Mat& inImage, float scaledX, float scaledY,
float xFrac, float yFrac)
{
int u0 = static_cast<int>(scaledX);
int v0 = static_cast<int>(scaledY);
int u1 = std::min(inImage.cols-1, static_cast<int>(scaledX+1));
int v1 = v0;
int u2 = u0;
int v2 = std::min(inImage.rows-1, static_cast<int>(scaledY+1));
int u3 = std::min(inImage.cols-1, static_cast<int>(scaledX+1));
int v3 = std::min(inImage.rows-1, static_cast<int>(scaledY+1));
float col0 = linInterpolate(inImage.at<Type>(v0, u0), inImage.at<Type>(v1, u1), xFrac);
float col1 = linInterpolate(inImage.at<Type>(v2, u2), inImage.at<Type>(v3, u3), xFrac);
float value = linInterpolate(col0, col1, yFrac);
return cv::saturate_cast<Type>(value);
}
template <typename Type> static void resize(const cv::Mat& inImage, cv::Mat& outImage)
{
float scaleY = (inImage.rows - 1) / static_cast<float>(outImage.rows - 1);
float scaleX = (inImage.cols - 1) / static_cast<float>(outImage.cols - 1);
for (int y = 0; y < outImage.rows; ++y)
{
float scaledY = y * scaleY;
float yFrac = scaledY - static_cast<int>(scaledY);
for (int x = 0; x < outImage.cols; x++)
{
float scaledX = x * scaleX;
float xFrac = scaledX - static_cast<int>(scaledX);
outImage.at<Type>(y, x) = resizePointBilinear<Type>(inImage, scaledX, scaledY, xFrac, yFrac);
}
}
}
bool bilinearResize(const cv::Mat& inImage, cv::Mat& outImage, const cv::Size size)
{
if (!(inImage.type() == CV_8U || inImage.type() == CV_32F) ||
size.width < 2 || size.height < 2 || inImage.cols < 2 || inImage.rows < 2)
return false;
outImage = cv::Mat::zeros(size.height, size.width, inImage.type());
if(inImage.type() == CV_8U)
resize<uint8_t>(inImage, outImage);
else if(inImage.type() == CV_32F)
resize<float>(inImage, outImage);
return true;
}

7
src/matutils.h
View file

@ -30,8 +30,8 @@ std::vector<cv::Point2f>::iterator getBottomRight(std::vector<cv::Point2f>& poin
double distance(const cv::Point2f& a, const cv::Point2f& b);
bool findClosest(size_t& xIndex, size_t& yIndex,
const cv::Point2f point, const std::vector< std::vector<cv::Point2f> >& array,
float xTolerance, float yTolerance);
const cv::Point2f point, const std::vector< std::vector<cv::Point2f> >& array,
float xTolerance, float yTolerance);
bool findClosest(size_t& index, const cv::Point2f point, const std::vector<cv::Point2f>& array, float xTolerance, float yTolerance);
@ -47,4 +47,7 @@ bool deleteEmptyCols(cv::Mat& mat);
void removeEmptyFrontBackCols(cv::Mat& mat);
bool bilinearResize(const cv::Mat& inImage, cv::Mat& outImage, cv::Size size);