//程序功能：利用最小二乘法拟合直线
//输入：二维点
//输出：拟合直线
line calLine(LinkedList <myPair> input)
{
matrix A = new matrix(input.Count, 2);
matrix AT = new matrix(2, input.Count);
matrix B = new matrix(input.Count, 1);
for (int i = 0; i < input.Count; ++i)
{
myPair cur = input.ElementAt(i);
A.a[i, 0] = cur.x;
A.a[i, 1] = cur.y;
AT.a[0, i] = cur.x;
AT.a[1, i] = cur.y;
B.a[i, 0] = 100;
}
matrix coef = AT.doMul(A);
matrix b = AT.doMul(B);
matrix mat = new matrix(2, 3);
for (int i = 0; i < 2; ++i)
{
for (int j = 0; j < 2; ++j)
{
mat.a[i, j] = coef.a[i, j];
}
}
mat.a[0, 2] = b.a[0, 0];
mat.a[1, 2] = b.a[1, 0];
double BB = (mat.a[0, 0] * mat.a[1, 2] - mat.a[1, 0] * mat.a[0, 2]) / (mat.a[1, 1] * mat.a[0, 0] - mat.a[0, 1] * mat.a[1, 0]);
double AA = (mat.a[0, 2] - mat.a[0, 1] * BB) / mat.a[0, 0];
return(new line(AA, BB, -100));
}
//输出找到的最小刻度线的点
public myPair FindLeft()
{
myPair ret = new myPair(-1, -1);
int max1 = 0;
for (int i = height - 1; i * 3 >= 2 *height; i--)
{
int sum = 0;
for (int j = 0; j < 100; j++)
{
if (gray[j, i] == 255)
{
if (gray[j + 1, i - 1] == 255 && gray[j + 2, i - 2] == 255 && gray[j + 3, i - 3] == 255 && gray[j + 4, i - 4] == 255)
{
//return new node(circle_x - (int)Math.Sqrt(radius * radius - (circle_y - i) * (circle_y - i)),i);
sum = (j - circle_x) * (j - circle_x) + (i - circle_y) * (i - circle_y);
if (Math.Sqrt(max1) + 10 < Math.Sqrt(sum))
{
ret.x = j;
ret.y = i;
max1 = sum;
}
break;
}
else if (gray[j + 1, i] == 255 && gray[j + 2, i - 1] == 255 && gray[j + 3, i - 2] == 255 && gray[j + 4, i - 3] == 255)
{
sum = (j - circle_x) * (j - circle_x) + (i - circle_y) * (i - circle_y);
if (Math.Sqrt(max1) + 10 < Math.Sqrt(sum))
{
ret.x = j;
ret.y = i;
max1 = sum;
}
break;
}
}
}
}
return(ret);
}
//根据直线的两个端点P，Q进行初始化
public line(myPair P, myPair Q)
{
if (P.x == Q.x)
{
A = 1;
B = 0;
C = -P.x;
return;
}
if (P.y == Q.y)
{
A = 0;
B = 1;
C = -P.y;
return;
}
B = 1;
A = 1.0 * (Q.y - P.y) / (P.x - Q.x);
C = -(A * P.x + B * P.y);
}
//输出找到的最大刻度线的点
public myPair FindRight()
{
myPair ret = new myPair(0, 0);
int max1 = 0;
for (int i = height - 1; i * 3 >= 2 *height; i--)
{
int sum = 0;
for (int j = width - 1, k = 0; k < 100; k++, j--)
{
if (gray[j, i] == 255)
{
if (gray[j - 1, i - 1] == 255 && gray[j - 2, i - 2] == 255 && gray[j - 3, i - 3] == 255 && gray[j - 4, i - 4] == 255)
{
sum = (j - circle_x) * (j - circle_x) + (i - circle_y) * (i - circle_y);
if (Math.Sqrt(max1) + 10 < Math.Sqrt(sum))
{
ret.x = j;
ret.y = i;
max1 = sum;
}
break;
}
else if (gray[j - 1, i] == 255 && gray[j - 2, i - 1] == 255 && gray[j - 3, i - 2] == 255 && gray[j - 4, i - 3] == 255)
{
sum = (j - circle_x) * (j - circle_x) + (i - circle_y) * (i - circle_y);
if (Math.Sqrt(max1) + 10 < Math.Sqrt(sum))
{
ret.x = j;
ret.y = i;
max1 = sum;
}
break;
}
}
}
}
return(ret);
}
//函数功能：利用RANSAC算法从图像中提取直线，RANSAC对噪声敏感度小
//输入：二值化图像input，目标直线的一个端点center
//输出：目标直线方程
public line doRANSAC(myPicture input, myPair center)
{
LinkedList <myPair> arr = new LinkedList <myPair>();
for (int i = 0; i < input.width; ++i)
{
for (int j = 0; j < input.height; ++j)
{
if (input.grayDegree[i, j] == 255)
{
arr.AddLast(new myPair(i, j));
}
}
}
Random rd = new Random(13);
line ret = new line(0, 0, 0);
double besterror = 1000000000000;
int bound = (int)(0.07 * arr.Count);
for (int iter = 0; iter < 100; ++iter)
{
int sampleIndex = rd.Next() % arr.Count;
myPair sample = arr.ElementAt(sampleIndex);
line cur = new line(center, sample);
LinkedList <myPair> alsoinliers = new LinkedList <myPair>();
foreach (myPair p in arr)
{
double d = cur.distance(p);
if (d <= 4)
{
alsoinliers.AddLast(p);
}
}
if (alsoinliers.Count >= bound)
{
alsoinliers.AddLast(sample);
line better = calLine(alsoinliers);
double thiserror = 0;
foreach (myPair p in alsoinliers)
{
double dis = better.distance(p);
thiserror += dis * dis;
}
thiserror /= alsoinliers.Count;
if (thiserror < besterror)
{
besterror = thiserror;
ret = better;
}
}
}
return(ret);
/*
* for (int i = 0; i < input.width; ++i)
* {
* for (int j = 0; j < input.height; ++j)
* {
* double val = Math.Abs(ret.A * i + ret.B * j + ret.C);
* if (val <= 1)
* {
* input.picture.SetPixel(i, j, Color.FromArgb(255, 0, 0));
* }
* }
* }
*/
//return input;
}
//计算该直线到点P的距离
public double distance(myPair P)
{
return(Math.Abs(A * P.x + B * P.y + C) / Math.Sqrt(A * A + B * B));
}
//函数功能：对main.cs传入的图像进行处理，并将结果传递到ans.cs显示
public void domain()
{
//处理输入
double low = 0.0;
double high = 1.0;
try
{
low = Convert.ToDouble(smallInput.Text);
high = Convert.ToDouble(largeInput.Text);
}
catch
{
return;
}
OTSU B = new OTSU();
//锐化、二值化
myPicture ret = B.doOTSU(sharp4.doSharp(Pic));
myPicture res = ret;
//找圆心之前的预处理
findCircleInit circle = new findCircleInit();
ret = circle.init(ret);
ret = sharp4.doSharp(ret);
ret = circle.doHough(ret);
//找圆心
circle o = new findCircleCenter().doFind(ret);
//找指针
ret = new findLineInit().doFind(Pic, o);
myPicture tmp = sharp1.doSharp(ret);
tmp = smooth2.doSmooth(tmp);
tmp = B.doOTSU(tmp);
RANSAC R = new RANSAC();
myPair L = R.doFind(smooth2.doSmooth(B.doOTSU(sharp4.doSharp(Pic))), R.doRANSAC(tmp, new myPair((int)o.x, (int)o.y)), o);
//找刻度线的预处理
eraseCircleElement ECE = new eraseCircleElement(res, (int)o.r, (int)o.x, (int)o.y);
int r = ECE.solve();
res = ECE.erase(r - 1);
//找到左右两端的刻度线
findTick ticks = new findTick(res, r - 1, (int)o.x, (int)o.y);
myPair left = ticks.FindLeft(), right = ticks.FindRight();
//求角度
double thta = 2 * Math.PI - angle(left, right, o);
double alpha;
if (L.x <= o.x)
{
alpha = angle(left, L, o);
}
else
{
alpha = thta - angle(L, right, o);
}
double ans = low + (high - low) * (alpha + Math.PI / 180) / thta;
Form newForm = new ans(ans);
newForm.ShowDialog();
newForm.Dispose();
}
private double angle(myPair left, myPair right, circle o)
{
return(Math.Acos(((left.x * right.x - o.x * (left.x + right.x) + o.x * o.x) + (left.y * right.y - o.y * (left.y + right.y) + o.y * o.y)) / (Math.Sqrt((left.x - o.x) * (left.x - o.x) + (left.y - o.y) * (left.y - o.y)) * Math.Sqrt((right.x - o.x) * (right.x - o.x) + (right.y - o.y) * (right.y - o.y)))));
}
