Geometrical transformations of images

Here we consider the different kinds of geometrical transformations that change the position of the image's pixel. OpenCV does operations such as image resizing and warping using interpolation that suppress the aliasing effect. Hence, using OpenCV operations is more preferable than custom pixel-by-pixel implementation, except when you implement your own transformation algorithm with antialiasing (which can be tricky), or maybe when you need the aliasing effect. The following is a list of geometrical transformations that are applicable to ofxCv images:

• The resize( w, h ) function changes the image size to w × h pixels. For example:

  image2 = image;
  image2.resize( image2.width * 0.5, image2.height * 0.5 );

  This code transforms image to image2 with a size that equals 50 percent of the size of image. Such a procedure decreases the number of pixels four times, so the speed of processing increases 4 times. However, object localization accuracy in x and y axes...