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Fix Sobel Filtering

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This commit is contained in:
Lukas Moungos
2023-05-18 17:57:02 +02:00
parent 7ffa5e29ea
commit 9e834679b7
4 changed files with 74 additions and 45 deletions
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12
src/Detector.cpp
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@@ -36,16 +36,16 @@ void Detector::detect(Mat thresholdFrame, Mat &output){
//DEBUG
//rectangle(filteredFrame, r, Scalar(0,0,255),4);
drawRectangle(output, approx_contour);
drawRectangle(output, thresholdFrame, approx_contour);
}
}
void Detector::drawRectangle(Mat &output, contour_t contour){
void Detector::drawRectangle(Mat &output, Mat threshold, contour_t contour){
// -> Cleaning done!
//polylines(output, contour, true, Scalar(0,0,255), THICKNESS_VALUE);
// 1 -> 1 contour, we have a closed contour, true -> closed , 4 ->
// thickness
polylines(output, contour, true, Scalar(0,0,255), THICKNESS_VALUE);
// -----------------------------
@@ -59,6 +59,9 @@ void Detector::drawRectangle(Mat &output, contour_t contour){
double dx = (double)(contour[(i+1)%4].x - contour[i].x) / 7;
double dy = (double)(contour[(i+1)%4].y - contour[i].y) / 7;
SampleStrip strip = sobelFilter.getSampleStrip(dx, dy);
// First point already rendered, now the other 6 points
for (size_t j = 1; j < 7; j++) {
// Position calculation
@@ -70,9 +73,8 @@ void Detector::drawRectangle(Mat &output, contour_t contour){
p.x = (int)px;
p.y = (int)py;
cv::Point2d correction;
correction = sobelFilter.getSubPixelPoint(dx, dy, contour.at(i), p, output);
correction = sobelFilter.getSubPixelPoint(p, strip, threshold);
correction.x += p.x;
correction.y += p.y;

2
src/Detector.hpp
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@@ -14,5 +14,5 @@ class Detector{
typedef std::vector<cv::Point> contour_t;
// List of contours
typedef std::vector<contour_t> contour_vector_t;
void drawRectangle(cv::Mat &output, contour_t contour);
void drawRectangle(cv::Mat &output, cv::Mat threshold ,contour_t contour);
};

95
src/SobelFilter.cpp
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@@ -1,33 +1,11 @@
#include "SobelFilter.hpp"
cv::Point2d SobelFilter::getSubPixelPoint(float dx, float dy, cv::Point edge, cv::Point delimiter,cv::Mat input){
SampleStrip sample;
cv::Point2d SobelFilter::getSubPixelPoint(cv::Point delimiter, SampleStrip sample,cv::Mat input){
double diffLength = sqrt ( dx*dx+dy*dy );
int stripeLength = (int)(0.8* diffLength);
if (stripeLength < 5)
stripeLength = 5;
sample.length = stripeLength;
cv::Point2f p1;
cv::Point2f p2;
p1.x = dx / diffLength;
p1.y = dy / diffLength;
p2.x = p1.y;
p2.y = -p1.x;
sample.vecX = p1;
sample.vecY = p2;
int nStop = stripeLength / 2;
int nStart = -nStop;
cv::Size size(3,stripeLength);
cv::Mat iplStripe(size, CV_8UC1);
int nStart = sample.nStart;
int nStop = sample.nStop;
int stripeLength = sample.length;
cv::Mat iplStripe = sample.iplStripe;
for (int m = -1; m <= 1; ++m) {
for (int n = nStart; n <= nStop; ++n) {
@@ -46,11 +24,52 @@ cv::Point2d SobelFilter::getSubPixelPoint(float dx, float dy, cv::Point edge, cv
}
}
cv::Sobel(iplStripe, iplStripe, CV_8U, 1, 0);
cv::Mat grad_y;
cv::Sobel(iplStripe, grad_y, CV_8U, 1,0);
return findSubPixelPoint(iplStripe, sample);
return findSubPixelPoint(grad_y, sample);
}
SampleStrip SobelFilter::getSampleStrip(float dx, float dy){
SampleStrip sample;
double diffLength = sqrt ( dx*dx+dy*dy );
int stripeLength = (int)(0.8* diffLength);
if (stripeLength < 5)
stripeLength = 5;
if(stripeLength % 2 == 0){
stripeLength++;
}
cv::Point2f p1;
cv::Point2f p2;
p1.x = dx / diffLength;
p1.y = dy / diffLength;
p2.x = p1.y;
p2.y = -p1.x;
int nStop = stripeLength / 2;
int nStart = -nStop;
cv::Size size(3,stripeLength);
cv::Mat iplStripe(size, CV_8UC1);
sample.length = stripeLength;
sample.vecX = p1;
sample.vecY = p2;
sample.nStart = nStart;
sample.nStop = nStop;
sample.iplStripe = iplStripe;
return sample;
}
int SobelFilter::samplePixel(const cv::Mat &pSrc, const cv::Point2f &p){
int x = int( floorf ( p.x ) );
int y = int( floorf ( p.y ) );
@@ -68,7 +87,7 @@ int SobelFilter::samplePixel(const cv::Mat &pSrc, const cv::Point2f &p){
return a + ( ( dy * ( b - a) ) >> 8 );
}
cv::Point2d SobelFilter::findSubPixelPoint(cv::Mat iplStripe, SampleStrip strip){
cv::Point2d SobelFilter::findSubPixelPoint(cv::Mat input, SampleStrip strip){
double maxIntensity = -1;
@@ -76,8 +95,8 @@ cv::Point2d SobelFilter::findSubPixelPoint(cv::Mat iplStripe, SampleStrip strip)
// Finding the max value
for (size_t i = 0; i < iplStripe.cols; ++i) {
uchar intensity = iplStripe.at<uchar>(i,1);
for (size_t i = 0; i < input.cols - 2; ++i) {
uchar intensity = input.at<uchar>(i,1);
if(intensity > maxIntensity){
maxIntensity = intensity;
maxIntensityIndex = i;
@@ -90,10 +109,10 @@ cv::Point2d SobelFilter::findSubPixelPoint(cv::Mat iplStripe, SampleStrip strip)
unsigned int max1 = maxIntensityIndex - 1, max2 = maxIntensityIndex + 1;
// TASK: Why do we need this if statement?
y0 = (maxIntensityIndex <= 0) ? 0 : iplStripe.at<uchar>(max1,1);
y1 = iplStripe.at<uchar>(maxIntensityIndex,1);
y0 = (maxIntensityIndex <= 0) ? 0 : input.at<uchar>(max1,1);
y1 = input.at<uchar>(maxIntensityIndex,1);
// TASK: Why do we need this if statement?
y2 = (maxIntensityIndex >= strip.length - 3) ? 0 : iplStripe.at<uchar>(max2,1);
y2 = (maxIntensityIndex >= strip.length - 3) ? 0 : input.at<uchar>(max2,1);
// Formula for calculating the x-coordinate of the vertex of a parabola, given 3 points with equal distances
// (xv means the x value of the vertex, d the distance between the points):
@@ -109,8 +128,10 @@ cv::Point2d SobelFilter::findSubPixelPoint(cv::Mat iplStripe, SampleStrip strip)
return edgeCenter;
}
edgeCenter.x = pos + (strip.vecX.x + strip.vecY.x);
edgeCenter.y = pos + (strip.vecX.y + strip.vecY.y);
int maxIndexShift = maxIntensityIndex - (strip.length >> 1);
edgeCenter.x = ((double)maxIndexShift + pos) * strip.vecX.x;
edgeCenter.y = ((double)maxIndexShift + pos) * strip.vecY.y;
return edgeCenter;
}

10
src/SobelFilter.hpp
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@@ -2,16 +2,22 @@
#include <opencv2/opencv.hpp>
struct SampleStrip{
float length;
int length;
cv::Point2f vecX;
cv::Point2f vecY;
int nStart;
int nStop;
cv::Mat iplStripe;
};
class SobelFilter{
public:
void drawStrips(cv::Mat output);
cv::Point2d getSubPixelPoint(float dx, float dy,const cv::Point edge, cv::Point delimiter,cv::Mat input);
cv::Point2d getSubPixelPoint(cv::Point delimiter, SampleStrip sample,cv::Mat input);
SampleStrip getSampleStrip(float dx, float dy);
private:
int samplePixel(const cv::Mat &pSrc, const cv::Point2f &p);