从变换矩阵中寻找角度 [英] Finding Angle from transform matrix
本文介绍了从变换矩阵中寻找角度的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有一个像这样的值的变换矩阵。
I have a transform matrix with values like this.
分别变换:xx,xy,yx,yy,tx和ty。
Transform: xx, xy, yx, yy, tx, and ty respectively.
如何从上面的给定值集中找到角度。
How can I find the angle from the above set of gives values.
推荐答案
如果是只有旋转,可以使用给定的矩阵变换矢量(1,0),并计算结果矢量和x轴之间的角度,如原始问题的评论中已经提到的那样
If it's only about the rotation, one can transform the vector (1,0) using the given matrix, and compute the angle between the resulting vector and the x-axis, as already mentioned in the comment to the original question
import java.awt.Point;
import java.awt.geom.AffineTransform;
import java.awt.geom.Point2D;
import java.util.Random;
public class ExtractRotation
{
public static void main(String[] args)
{
for (int i=0; i<=180; i++)
{
double angleRad = Math.toRadians(i);
AffineTransform at = createRandomTransform(angleRad);
double extractedAngleRad = extractAngle(at);
System.out.println(
"In: "+Math.toDegrees(angleRad)+ " " +
"Out "+Math.toDegrees(extractedAngleRad));
}
}
private static double extractAngle(double m[])
{
return extractAngle(new AffineTransform(m));
}
private static double extractAngle(AffineTransform at)
{
Point2D p0 = new Point();
Point2D p1 = new Point(1,0);
Point2D pp0 = at.transform(p0, null);
Point2D pp1 = at.transform(p1, null);
double dx = pp1.getX() - pp0.getX();
double dy = pp1.getY() - pp0.getY();
double angle = Math.atan2(dy, dx);
return angle;
}
private static Random random = new Random(0);
private static AffineTransform createRandomTransform(double angleRad)
{
AffineTransform at = new AffineTransform();
double scale = 1.0;
at.translate(randomDouble(), randomDouble());
scale = Math.abs(randomDouble());
at.scale(scale, scale);
at.rotate(angleRad);
at.translate(randomDouble(), randomDouble());
scale = Math.abs(randomDouble());
at.scale(scale, scale);
return at;
}
private static double randomDouble()
{
return -5.0 + random.nextDouble() * 10;
}
}
这篇关于从变换矩阵中寻找角度的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文