如何根据XY坐标计算旋转角度？ [英] How to calculate angle of rotation based on XY coordinates?

问题描述

我正在制作一种用于计算旋转角度的图像处理方法。我为获得每个边框像素的X和Y坐标做了另一个。

我需要一些指示我可以开始。

Exmaple image

我想找出图像的问号角度来计算它，但我还无法找出任何东西。

有些代码会很好。

解决方案

假设你有

 --- ---------------------------------- 
 
 | P2 = {X2，Y2} 
 | / 
 | / 
 | / 
 | / 
 | / 
 | / alpha 
 | / ............. 
 | P1 = {X1，Y1} 
 | 
 

然后 math.atan2（Y2-Y1，X2-X1）为您提供 alpha 角度。然后简单计算所有其他的。

如果你有每个边框的X和Y，那么你就得到了构成正方形的四条线中每条线的X和Y.



因此计算角度很简单：学校级几何学。

取一个角度 - 在你的例子的右上角。

你知道作为方形一部分的线的坐标：P1和P2，所以你知道X坐标的差异：P2.X - P1.X

这允许你制作一个直角三角形，你知道斜边（从P1和P2的毕达哥拉斯）和相邻的线长度（X合作的差异）。

所以你可以锻炼角度简单：



Theta = Cos ^-1 （A / H）



当你是什么时，你在数学课上涵盖了所有这些？ 12？ ：笑：

I am making a image processing method for calculating the angle of rotation. I made another for getting the X and Y coordinates of each border pixel.
I need some directions where I can start.
Exmaple image
I want to find out the question mark angles of the image to calculate it but I cant figure out anything yet.
Some code will be nice.

解决方案

Suppose you have

     -------------------------------------

|                     P2={X2,Y2}
|                   /
|                  /
|                 /
|                /
|               /
|              /  alpha
|             / .............
|              P1={X1,Y1}
|

Then math.atan2(Y2-Y1,X2-X1) gives you the alpha angle. All the other ones are then simply computed.

If you have the X and Y of each border, then you have the X and Y of each of the four lines that makes up the square.

So working out the angle is easy: school level geometry.
Take one of the angles - the top right in your example.
You know the coordinates of the line that is part of the square: P1, and P2, so you know the difference in X coordinates: P2.X - P1.X
That allows you to make a right angle triangle, where you know the Hypotenuse (from Pythagoras on P1 and P2) and Adjacent line lengths ( the difference in X co-ords).
So you can work out the angle simply:

Theta = Cos^-1(A/H)

You covered all this in Maths class when you were what? 12? :laugh:

这篇关于如何根据XY坐标计算旋转角度？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！