c++ 基于opencv 识别、定位二维码

目录

• 前言
• 1 二维码特性

• 思考题：

• 1）查找轮廓,筛选出三个二维码顶点
• 2）确定三个二维码顶点的次序
• 3）通过二维码对图片矫正。
• 4）二维码相邻区域定位

int QrParse::FindQrPoint(Mat& srcImg, vector<vector<Point>>& qrPoint) {
	//彩色图转灰度图
	Mat src_gray;
	cvtColor(srcImg, src_gray, CV_BGR2GRAY);
	namedWindow("src_gray");
	imshow("src_gray", src_gray);
	//二值化
	Mat threshold_output;
	threshold(src_gray, threshold_output, 0, 255, THRESH_BINARY | THRESH_OTSU);
	Mat threshold_output_copy = threshold_output.clone();
	namedWindow("Threshold_output");
	imshow("Threshold_output", threshold_output);
	//调用查找轮廓函数
	vector<vector<Point> > contours;
	vector<Vec4i> hierarchy;
	findContours(threshold_output, contours, hierarchy, CV_RETR_TREE, CHAIN_APPROX_NONE, Point(0, 0));
	//通过黑色定位角作为父轮廓，有两个子轮廓的特点，筛选出三个定位角
	int parentIdx = -1;
	int ic = 0;
	for (int i = 0; i < contours.size(); i++) {
		if (hierarchy[i][2] != -1 && ic == 0) {
			parentIdx = i;
			ic++;
		} else if (hierarchy[i][2] != -1) {
			ic++;
		} else if (hierarchy[i][2] == -1) {
			ic = 0;
			parentIdx = -1;
		} {
			bool isQr = QrParse::IsQrPoint(contours[parentIdx], threshold_output_copy);
			//保存找到的三个黑色定位角
			if (isQr)
			qrPoint.push_back(contours[parentIdx]);
			ic = 0;
			parentIdx = -1;
		}
	}
	return 0;
}

bool QrParse::IsQrPoint(vector<Point>& contour, Mat& img)
{
 //最小大小限定
 RotatedRect rotatedRect = minAreaRect(contour);
 if (rotatedRect.size.height < 10 || rotatedRect.size.width < 10)
 return false;
 //将二维码从整个图上抠出来
 cv::Mat cropImg = CropImage(img, rotatedRect);
 int flag = i++;
 //横向黑白比例1:1:3:1:1
 bool result = IsQrColorRate(cropImg, flag);
 return result;
}

//横向和纵向黑白比例判断
bool QrParse::IsQrColorRate(cv::Mat& image, int flag)
{
 bool x = IsQrColorRateX(image, flag);
 if (!x)
 return false;
 bool y = IsQrColorRateY(image, flag);
 return y;
}
//横向黑白比例判断
bool QrParse::IsQrColorRateX(cv::Mat& image, int flag)
{
 int nr = image.rows / 2;
 int nc = image.cols * image.channels();
 vector<int> vValueCount;
 vector<uchar> vColor;
 int count = 0;
 uchar lastColor = 0;
 uchar* data = image.ptr<uchar>(nr);
 for (int i = 0; i < nc; i++)
 {
 vColor.push_back(data[i]);
 uchar color = data[i];
 if (color > 0)
 color = 255;
 if (i == 0)
 {
 lastColor = color;
 count++;
 }
 else
 {
 if (lastColor != color)
 {
 vValueCount.push_back(count);
 count = 0;
 }
 count++;
 lastColor = color;
 }
 }
 if (count != 0)
 vValueCount.push_back(count);
 if (vValueCount.size() < 5)
 return false;
 //横向黑白比例1:1:3:1:1
 int index = -1;
 int maxCount = -1;
 for (int i = 0; i < vValueCount.size(); i++)
 {
 if (i == 0)
 {
 index = i;
 maxCount = vValueCount[i];
 }
 else
 {
 if (vValueCount[i] > maxCount)
 {
 index = i;
 maxCount = vValueCount[i];
 }
 }
 }
 //左边 右边 都有两个值，才行
 if (index < 2)
 return false;
 if ((vValueCount.size() - index) < 3)
 return false;
 //黑白比例1:1:3:1:1
 float rate = ((float)maxCount) / 3.00;
 cout << "flag:" << flag << " ";
 float rate2 = vValueCount[index - 2] / rate;
 cout << rate2 << " ";
 if (!IsQrRate(rate2))
 return false;
 rate2 = vValueCount[index - 1] / rate;
 cout << rate2 << " ";
 if (!IsQrRate(rate2))
 return false;
 rate2 = vValueCount[index + 1] / rate;
 cout << rate2 << " ";
 if (!IsQrRate(rate2))
 return false;
 rate2 = vValueCount[index + 2] / rate;
 cout << rate2 << " ";
 if (!IsQrRate(rate2))
 return false;
 return true;
}
//纵向黑白比例判断 省略
bool QrParse::IsQrColorRateY(cv::Mat& image, int flag)

bool QrParse::IsQrRate(float rate)
{
 //大概比例 不能太严格
 return rate > 0.6 && rate < 1.9;
}

// pointDest存放调整后的三个点，三个点的顺序如下
// pt0----pt1
//
// pt2
bool QrParse::AdjustQrPoint(Point* pointSrc, Point* pointDest) {
	bool clockwise;
	int index1[3] = {
		2,1,0
	}
	;
	int index2[3] = {
		0,2,1
	}
	;
	int index3[3] = {
		0,1,2
	}
	;
	for (int i = 0; i < 3; i++) {
		int *n = index1;
		if(i==0)
		n = index1; else if (i == 1)
		n = index2; else
		n = index3;
		if (angle > 80 && angle < 99) {
			pointDest[0] = pointSrc[n[2]];
			if (clockwise) {
				pointDest[1] = pointSrc[n[0]];
				pointDest[2] = pointSrc[n[1]];
			} else {
				pointDest[1] = pointSrc[n[1]];
				pointDest[2] = pointSrc[n[0]];
			}
			return true;
		}
	}
	return true;
}

//二维码倾斜角度
Point hor(pointAdjust[0].x+300,pointAdjust[0].y); //水平线
double qrAngle = QrParse::Angle(pointAdjust[1], hor, pointAdjust[0], clockwise);
//以二维码左上角点为中心 旋转
 Mat drawingRotation = Mat::zeros(Size(src.cols,src.rows), CV_8UC3);
 double rotationAngle = clockwise? -qrAngle:qrAngle;
 Mat affine_matrix = getRotationMatrix2D(pointAdjust[0], rotationAngle, 1.0);//求得旋转矩阵
 warpAffine(src, drawingRotation, affine_matrix, drawingRotation.size());