将Opencv Matrix旋转90,180,270度 [英] Rotate Opencv Matrix by 90, 180, 270 degrees

问题描述

我从网络摄像头捕获图像，我需要旋转它的直角。我发现自己的函数：

1. getRotationMatrix2D - 创建旋转矩阵is）


2. transform - 通过旋转矩阵将一个矩阵转换为另一个矩阵

但是，除了黑色区域，我别无选择。这是我的代码：

  if（rotate_button.click％4> 0）{
 double angle =（rotate_button。点击％4）* 90; //按钮每点击增加1点击
 Mat transform_m = getRotationMatrix2D（Point（cam_frame_width / 2，cam_frame_height / 2），angle，1）; //创建旋转矩阵
 Mat current_frame; 
 transform（cam_frame，current_frame，transform_m）; //将捕获的图像转换为新的图像
 cam_frame = Mat（（int）current_frame.cols，（int）current_frame.rows，cam_frame_type）= Scalar（0,128,0）; //调整捕获的矩阵大小，所以我可以复制调整大小的一个
 current_frame.copyTo（cam_frame）; // Copy size to original 
} 
  

只输出黑屏。

解决方案

使用warpAffine：

尝试：

  Point2f src_center（source.cols / 2.0F，source.rows / 2.0F）; 
 Mat rot_mat = getRotationMatrix2D（src_center，angle，1.0）; 
 Mat dst; 
 warpAffine（source，dst，rot_mat，source.size（））; 
  

dst >

I'm capturing image from webcam and I need to rotate it by right angle. I found myself theese functions:

1. getRotationMatrix2D - to create rotation matrix (whatever it is)
2. transform - transform one matrix to another by rotation matrix

But, I don't get anything but black area. This is my code:

   if(rotate_button.click%4>0) {
       double angle = (rotate_button.click%4)*90;  //button increments its click by 1 per click
       Mat transform_m = getRotationMatrix2D(Point(cam_frame_width/2, cam_frame_height/2), angle, 1);  //Creating rotation matrix
       Mat current_frame;
       transform(cam_frame, current_frame, transform_m);  //Transforming captured image into a new one
       cam_frame = Mat((int)current_frame.cols,(int)current_frame.rows, cam_frame_type) = Scalar(0,128,0);  //resizing captured matrix, so I can copy the resized one on it
       current_frame.copyTo(cam_frame);  //Copy resized to original
   }

Outputs just black screen.

解决方案

Use warpAffine.:

Try:

Point2f src_center(source.cols/2.0F, source.rows/2.0F);
Mat rot_mat = getRotationMatrix2D(src_center, angle, 1.0);
Mat dst;
warpAffine(source, dst, rot_mat, source.size());

dst is the final image

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