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Moved image transformation (deskew) functions to its own class

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This commit is contained in:
Matt Hill
2014-10-26 09:31:41 -04:00
parent db232f5ec9
commit c175342169
5 changed files with 162 additions and 71 deletions
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89
src/openalpr/licenseplatecandidate.cpp
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@@ -20,6 +20,8 @@
#include <opencv2/core/core.hpp>
#include "licenseplatecandidate.h"
#include "edges/edgefinder.h"
#include "transformation.h"
using namespace std;
using namespace cv;
@@ -65,6 +67,8 @@ void LicensePlateCandidate::recognize()
PlateCorners cornerFinder(pipeline_data->crop_gray, &plateLines, pipeline_data);
vector<Point> smallPlateCorners = cornerFinder.findPlateCorners();
EdgeFinder edgeFinder(pipeline_data);
if (cornerFinder.confidence > 0)
{
@@ -74,11 +78,16 @@ void LicensePlateCandidate::recognize()
Mat originalCrop = pipeline_data->crop_gray;
pipeline_data->plate_corners = transformPointsToOriginalImage(this->pipeline_data->grayImg, pipeline_data->crop_gray, expandedRegion, smallPlateCorners);
Transformation imgTransform(this->pipeline_data->grayImg, pipeline_data->crop_gray, expandedRegion);
pipeline_data->plate_corners = imgTransform.transformSmallPointsToBigImage(smallPlateCorners);
Size cropSize = getCropSize(pipeline_data->plate_corners);
Mat transmtx = imgTransform.getTransformationMatrix(pipeline_data->plate_corners, cropSize);
pipeline_data->crop_gray = imgTransform.crop(cropSize, transmtx);
Size outputImageSize = getOutputImageSize(pipeline_data->plate_corners);
Mat transmtx = getTransformationMatrix(pipeline_data->plate_corners, outputImageSize);
pipeline_data->crop_gray = deSkewPlate(this->pipeline_data->grayImg, outputImageSize, transmtx);
if (this->config->debugGeneral)
displayImage(config, "quadrilateral", pipeline_data->crop_gray);
@@ -87,16 +96,14 @@ void LicensePlateCandidate::recognize()
vector<TextLine> newLines;
for (uint i = 0; i < pipeline_data->textLines.size(); i++)
{
vector<Point2f> textArea = transformPointsToOriginalImage(this->pipeline_data->grayImg, originalCrop, expandedRegion,
pipeline_data->textLines[i].textArea);
vector<Point2f> linePolygon = transformPointsToOriginalImage(this->pipeline_data->grayImg, originalCrop, expandedRegion,
pipeline_data->textLines[i].linePolygon);
vector<Point2f> textArea = imgTransform.transformSmallPointsToBigImage(pipeline_data->textLines[i].textArea);
vector<Point2f> linePolygon = imgTransform.transformSmallPointsToBigImage(pipeline_data->textLines[i].linePolygon);
vector<Point2f> textAreaRemapped;
vector<Point2f> linePolygonRemapped;
perspectiveTransform(textArea, textAreaRemapped, transmtx);
perspectiveTransform(linePolygon, linePolygonRemapped, transmtx);
textAreaRemapped = imgTransform.remapSmallPointstoCrop(textArea, transmtx);
linePolygonRemapped = imgTransform.remapSmallPointstoCrop(linePolygon, transmtx);
newLines.push_back(TextLine(textAreaRemapped, linePolygonRemapped));
}
@@ -123,31 +130,13 @@ void LicensePlateCandidate::recognize()
}
}
// Re-maps the coordinates from the smallImage to the coordinate space of the bigImage.
vector<Point2f> LicensePlateCandidate::transformPointsToOriginalImage(Mat bigImage, Mat smallImage, Rect region, vector<Point> corners)
{
vector<Point2f> cornerPoints;
for (uint i = 0; i < corners.size(); i++)
{
float bigX = (corners[i].x * ((float) region.width / smallImage.cols));
float bigY = (corners[i].y * ((float) region.height / smallImage.rows));
bigX = bigX + region.x;
bigY = bigY + region.y;
cornerPoints.push_back(Point2f(bigX, bigY));
}
return cornerPoints;
}
Size LicensePlateCandidate::getOutputImageSize(vector<Point2f> corners)
Size LicensePlateCandidate::getCropSize(vector<Point2f> areaCorners)
{
// Figure out the approximate width/height of the license plate region, so we can maintain the aspect ratio.
LineSegment leftEdge(round(corners[3].x), round(corners[3].y), round(corners[0].x), round(corners[0].y));
LineSegment rightEdge(round(corners[2].x), round(corners[2].y), round(corners[1].x), round(corners[1].y));
LineSegment topEdge(round(corners[0].x), round(corners[0].y), round(corners[1].x), round(corners[1].y));
LineSegment bottomEdge(round(corners[3].x), round(corners[3].y), round(corners[2].x), round(corners[2].y));
LineSegment leftEdge(round(areaCorners[3].x), round(areaCorners[3].y), round(areaCorners[0].x), round(areaCorners[0].y));
LineSegment rightEdge(round(areaCorners[2].x), round(areaCorners[2].y), round(areaCorners[1].x), round(areaCorners[1].y));
LineSegment topEdge(round(areaCorners[0].x), round(areaCorners[0].y), round(areaCorners[1].x), round(areaCorners[1].y));
LineSegment bottomEdge(round(areaCorners[3].x), round(areaCorners[3].y), round(areaCorners[2].x), round(areaCorners[2].y));
float w = distanceBetweenPoints(leftEdge.midpoint(), rightEdge.midpoint());
float h = distanceBetweenPoints(bottomEdge.midpoint(), topEdge.midpoint());
@@ -163,37 +152,3 @@ Size LicensePlateCandidate::getOutputImageSize(vector<Point2f> corners)
return Size(width, height);
}
Mat LicensePlateCandidate::getTransformationMatrix(vector<Point2f> corners, Size outputImageSize)
{
// Corners of the destination image
vector<Point2f> quad_pts;
quad_pts.push_back(Point2f(0, 0));
quad_pts.push_back(Point2f(outputImageSize.width, 0));
quad_pts.push_back(Point2f(outputImageSize.width, outputImageSize.height));
quad_pts.push_back(Point2f(0, outputImageSize.height));
// Get transformation matrix
Mat transmtx = getPerspectiveTransform(corners, quad_pts);
return transmtx;
}
Mat LicensePlateCandidate::deSkewPlate(Mat inputImage, Size outputImageSize, Mat transformationMatrix)
{
Mat deskewed(outputImageSize, this->pipeline_data->grayImg.type());
// Apply perspective transformation to the image
warpPerspective(inputImage, deskewed, transformationMatrix, deskewed.size(), INTER_CUBIC);
if (this->config->debugGeneral)
displayImage(config, "quadrilateral", deskewed);
return deskewed;
}