user1968818
Reputation: 67
Getting the correct polygon to show in image
really need your help now
I have some detection results.
and i wish to show this result on this un-rotated image(please ignore the blue boxes)
My logic for my algorithm is as follows
Given that the coordinates for the yellow box are with reference to the frame of reference(top left hand corner of Image 1), I am trying to find the coordinates for the yellow box with reference to the frame of reference of the top left hand corner of the inner image within Image 1.
So i used basic trigno(right-angled triangle at the bottom right corner of Image 1, to obtain the coordinates of the top left hand corner of the inner image and find the coordinates of the yellow box with reference to this point.
After which i use since i want to show the results on Image 2, i used the centre of the inner image as my rotation point and translate the coordinate of the yellow box with respect to this centre to the origin of the inner image(top left hand corner) and rotate using this matrix:
[x,y] where [x,y] are for my points
My resultant polygon on the image is this:
which my prof took a look at it and said it was wrong.
I have lost count how many times i went through the logic and implementation...it seems correct to me. Can any kind soul help me out here?
Here's part of my code:
//code for rotated image at 135 deg
else if(nameForcompare.equals("135")){
angle = 225;
minPoint.set_y(catYmin); minPoint.set_x(catXmin); maxPoint.set_y(catYmax); maxPoint.set_x(catXmax);
//Show detection results of rotated image
g5.setColor(Color.YELLOW);
g5.drawRect((int)minPoint.get_x(), (int)minPoint.get_y(), (int)(maxPoint.get_x()-minPoint.get_x()), (int)(maxPoint.get_y()-minPoint.get_y()));
rotatedX = Double.parseDouble(originalWidth)*Math.cos(Math.toRadians((int)45));
if(catXmin < rotatedX){
o = imageHeight - catYmin;
a = rotatedX - catXmin;
theta = Math.atan(o/a);
h = (o/Math.sin(theta));
if(theta >= Math.toRadians((int)45)){
thetaZ = theta - Math.toRadians((int)45);
oZ = h*Math.sin(thetaZ); //ycoordinate
aZ = h*Math.cos(thetaZ); //xcoordinate
varX = checkPointsBeforeRotationX(aZ);
varY = checkPointsBeforeRotationY(oZ);
}
else{
thetaZ = Math.toRadians((int)45) - theta;
oZ = 0; //ycoordinate
aZ = h*Math.cos(thetaZ); //xcoordinate
varX = checkPointsBeforeRotationX(aZ);
varY = checkPointsBeforeRotationY(oZ);
}
minPoint.set_x(varX);
minPoint.set_y(varY);
}
else if(catXmin == rotatedX){
theta = Math.toRadians((int)45);
h = imageHeight - catYmin;
o = h*Math.sin(theta); //ycoordinate
a = h*Math.cos(theta); //xcoordinate
varX = checkPointsBeforeRotationX(a);
varY = checkPointsBeforeRotationY(o);
minPoint.set_y(varY);
minPoint.set_x(varX);
}
else if(catXmin > rotatedX){
a = imageHeight - catYmin;
o = catXmin - rotatedX;
theta = Math.atan(o/a);
h = (o/Math.sin(theta));
if(theta <= Math.toRadians((int)45)){
thetaZ = theta + Math.toRadians((int)45);
oZ = h*Math.sin(thetaZ); //ycoordinate
aZ = h*Math.cos(thetaZ); //xcoordinate
varX = checkPointsBeforeRotationX(aZ);
varY = checkPointsBeforeRotationY(oZ);
}
else{
thetaZ = Math.toRadians((int)45) - theta;
oZ = 0; //xcoordinate
aZ = h*Math.cos(thetaZ); //ycoordinate
varX = checkPointsBeforeRotationX(oZ);
varY = checkPointsBeforeRotationY(aZ);
}
minPoint.set_x(varX);
minPoint.set_y(varY);
}
if(catXmax < rotatedX){
o = imageHeight - catYmax;
a = rotatedX - catXmax;
theta = Math.atan(o/a);
h = (o/Math.sin(theta));
if(theta >= Math.toRadians((int)45)){
thetaZ = theta - Math.toRadians((int)45);
oZ = h*Math.sin(thetaZ); //ycoordinate
aZ = h*Math.cos(thetaZ); //xcoordinate
varX = checkPointsBeforeRotationX(aZ);
varY = checkPointsBeforeRotationY(oZ);
}
else{
thetaZ = Math.toRadians((int)45) - theta;
oZ = 0; //ycoordinate
aZ = h*Math.cos(thetaZ); //xcoordinate
varX = checkPointsBeforeRotationX(aZ);
varY = checkPointsBeforeRotationY(oZ);
}
maxPoint.set_x(varX);
maxPoint.set_y(varY);
}
else if(catXmax == rotatedX){
theta = Math.toRadians((int)45);
h = imageHeight - catYmin;
o = h*Math.sin(theta); //ycoordinate
a = h*Math.cos(theta); //xcoordinate
varX = checkPointsBeforeRotationX(a);
varY = checkPointsBeforeRotationY(o);
maxPoint.set_y(varY);
maxPoint.set_x(varX);
}
else if(catXmax > rotatedX){
a = imageHeight - catYmax;
o = catXmax - rotatedX;
theta = Math.atan(o/a);
h = (o/Math.sin(theta));
if(theta <= Math.toRadians((int)45)){
thetaZ = theta + Math.toRadians((int)45);
oZ = h*Math.sin(thetaZ); //ycoordinate
aZ = h*Math.cos(thetaZ); //xcoordinate
varX = checkPointsBeforeRotationX(aZ);
varY = checkPointsBeforeRotationY(oZ);
}
else{
thetaZ = Math.toRadians((int)45) - theta;
oZ = 0; //xcoordinate
aZ = h*Math.cos(thetaZ); //ycoordinate
varX = checkPointsBeforeRotationX(oZ);
varY = checkPointsBeforeRotationY(aZ);
}
maxPoint.set_y(varX);
maxPoint.set_x(varY);
}
getCorners();
checkPointsAfterRotation(angle);
checkCornerPointsAfterRotation(angle);
g2.setColor(Color.MAGENTA);
g2.drawPolygon(xPoints, yPoints, nPoints);
Corners1 =0; Corners2 =0;
public static void rotate2(Point originForRotation, Point pointForRotation, Double angle){
double cos=Math.cos(angle);
double sin=Math.sin(angle);
double oX =originForRotation.get_x();
double oY =originForRotation.get_y();
double x=pointForRotation.get_x();
double y=pointForRotation.get_y();
x = x-oX; y = y-oY;
pointForRotation.set_x((cos*x-sin*y)+oX);
pointForRotation.set_y((sin*x+cos*y)+oY);
pointForRotation.show();
}
public static void getCorners(){
if((minPoint.get_x() > maxPoint.get_x()) && (minPoint.get_y() < maxPoint.get_y())){
topleftPoint.set_x(maxPoint.get_x()); bottomrightPoint.set_x(minPoint.get_x());
topleftPoint.set_y(minPoint.get_y()); bottomrightPoint.set_y(maxPoint.get_y());
Corners1 = 1;
}
else if((minPoint.get_x() > maxPoint.get_x()) && (minPoint.get_y() > maxPoint.get_y())){
toprightPoint.set_x(minPoint.get_x()); bottomleftPoint.set_x(maxPoint.get_x());
toprightPoint.set_y(maxPoint.get_y()); bottomleftPoint.set_y(minPoint.get_y());
Corners2 = 1;
}
else if((minPoint.get_x() < maxPoint.get_x()) && (minPoint.get_y() < maxPoint.get_y())){
toprightPoint.set_x(maxPoint.get_x()); bottomleftPoint.set_x(minPoint.get_x());
toprightPoint.set_y(minPoint.get_y()); bottomleftPoint.set_y(maxPoint.get_y());
Corners2 = 1;
}
else if((minPoint.get_x() < maxPoint.get_x()) && (minPoint.get_y() > maxPoint.get_y())){
topleftPoint.set_x(minPoint.get_x()); bottomrightPoint.set_x(maxPoint.get_x());
topleftPoint.set_y(maxPoint.get_y()); bottomrightPoint.set_y(minPoint.get_y());
Corners1 = 1;
}
}
public static Double checkPointsBeforeRotationX(Double pointX){
if(pointX > (Double.parseDouble(originalWidth))){
pointX = Double.parseDouble(originalWidth);
}
return pointX;
}
public static Double checkPointsBeforeRotationY( Double pointY){
if(pointY > (Double.parseDouble(originalHeight))){
pointY = Double.parseDouble(originalHeight);
}
return pointY;
}
public static void checkPointsAfterRotation(int angle){
rotate2(origin, minPoint, Math.toRadians((int)angle));
rotate2(origin, maxPoint, Math.toRadians((int)angle));
//check for out of bound points after rotation
if(minPoint.get_y()< 0){
minPoint.set_y(0);
}
else if(minPoint.get_y() > Double.parseDouble(originalHeight)){
minPoint.set_y(Double.parseDouble(originalHeight));
}
if(minPoint.get_x()< 0){
minPoint.set_x(0);
}
else if(minPoint.get_x() > Double.parseDouble(originalWidth)){
minPoint.set_x(Double.parseDouble(originalWidth));
}
if(maxPoint.get_y()< 0){
maxPoint.set_y(0);
}
else if(maxPoint.get_y() > Double.parseDouble(originalHeight)){
maxPoint.set_y(Double.parseDouble(originalHeight));
}
if(maxPoint.get_x()< 0){
maxPoint.set_x(0);
}
else if(maxPoint.get_x() > Double.parseDouble(originalWidth)){
maxPoint.set_x(Double.parseDouble(originalWidth));
}
xPoints[0] = (int)minPoint.get_x();
xPoints[2] = (int)maxPoint.get_x();
yPoints[0] = (int)minPoint.get_y();
yPoints[2] = (int)maxPoint.get_y();
}
public static void checkCornerPointsAfterRotation(int angle){
if(Corners1 == 0 && Corners2 == 1){
rotate2(origin, toprightPoint, Math.toRadians((int)angle));
rotate2(origin, bottomleftPoint, Math.toRadians((int)angle));
if(toprightPoint.get_y()< 0){
toprightPoint.set_y(0);
}
else if(toprightPoint.get_y() > Double.parseDouble(originalHeight)){
toprightPoint.set_y(Double.parseDouble(originalHeight));
}
if(toprightPoint.get_x()< 0){
toprightPoint.set_x(0);
}
else if(toprightPoint.get_x() > Double.parseDouble(originalWidth)){
toprightPoint.set_x(Double.parseDouble(originalWidth));
}
if(bottomleftPoint.get_y()< 0){
bottomleftPoint.set_y(0);
}
else if(bottomleftPoint.get_y() > Double.parseDouble(originalHeight)){
bottomleftPoint.set_y(Double.parseDouble(originalHeight));
}
if(bottomleftPoint.get_x()< 0){
bottomleftPoint.set_x(0);
}
else if(bottomleftPoint.get_x() > Double.parseDouble(originalWidth)){
bottomleftPoint.set_x(Double.parseDouble(originalWidth));
}
xPoints[1] = (int)toprightPoint.get_x(); xPoints[3] = (int)bottomleftPoint.get_x();
yPoints[1] = (int)toprightPoint.get_y(); yPoints[3] = (int)bottomleftPoint.get_y();
}
else if(Corners1 == 1 && Corners2 == 0){
rotate2(origin, topleftPoint, Math.toRadians((int)angle));
rotate2(origin, bottomrightPoint, Math.toRadians((int)angle));
if(topleftPoint.get_y()< 0){
topleftPoint.set_y(0);
}
else if(topleftPoint.get_y() > Double.parseDouble(originalHeight)){
topleftPoint.set_y(Double.parseDouble(originalHeight));
}
if(topleftPoint.get_x()< 0){
topleftPoint.set_x(0);
}
else if(topleftPoint.get_x() > Double.parseDouble(originalWidth)){
topleftPoint.set_x(Double.parseDouble(originalWidth));
}
if(bottomrightPoint.get_y()< 0){
bottomrightPoint.set_y(0);
}
else if(bottomrightPoint.get_y() > Double.parseDouble(originalHeight)){
bottomrightPoint.set_y(Double.parseDouble(originalHeight));
}
if(bottomrightPoint.get_x()< 0){
bottomrightPoint.set_x(0);
}
else if(bottomrightPoint.get_x() > Double.parseDouble(originalWidth)){
bottomrightPoint.set_x(Double.parseDouble(originalWidth));
}
xPoints[1] = (int)topleftPoint.get_x(); xPoints[3] = (int)bottomrightPoint.get_x();
yPoints[1] = (int)topleftPoint.get_y(); yPoints[3] = (int)bottomrightPoint.get_y();
}
}
Upvotes: 0
Views: 164
Answers (1)
Ted Hopp
Reputation: 234795
That's too much code to trace through in detail, but I'll assume that your code faithfully implements the math you described. I think the problem is that you are applying a pure rotation matrix. The transformation from rotated kitty to rotated yellow box is a composition of a translation and a rotation. You need to first translate kitty (and the yellow box) from (x,y) to (0,0) (so the rotated kitty image is position with kitty's top left at the top left of figure 1). Then you need to rotate everything clockwise by 135 degrees.
Using homogeneous coordinates and matrix multiplication will make your code a lot simpler.
Upvotes: 1
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