OpenCV Cooking

 I like to make various effects using OpenCV. If I knew how to use image processing programs such as video editing programs and Photoshop, I would probably have used these programs. But I am a programmer and I can hardly use these programs. So I enjoy using OpenCV to implement the effects I want. Zoom in Suppose you want to zoom in to a specific area in the original high-resolution image as shown below.   The final image area is marked with a box. And the display will use images of this box size. If you zoom in while maintaining the original resolution of image, the resolution will be much lower because you will need to zoom in on the gradually smaller image. This method is also possible, but I don't want the image resolution to be lowered. So at first, we will start zooming in by reducing the original image to the size of the box image. During zoom-in, the size of the image will gradually become similar to the size of the box, and the final image will be the box image. Therefore,

 I often work with OpenCV in Raspberry Pi or the Jetson series. In the NVidia Jetson series, OpenCV is optimized and comes with the Jetpack installation. As a result, you do not need to install OpenCV separately. However, because Raspberry Pi OS is not installed with OpenCV, users must install it themselves. Unlike the Jetson series, Raspberry Pi has no GPU to use Cuda. The Mali GPU, used by Raspberry Pi, is used only for graphics and is difficult to use in OpenCV to speed up the OpenCV processing speed. Therefore, OpenCV used by Raspberry Pi does not require special optimization. Therefore, it is less necessary to build and use the source code. The case of building the source code is probably when you need the latest version of OpenCV. If you want to use an already verified version rather than the latest version, you can easily install it by following the steps below. Install Raspberry Pi OS on the Rpi4B I will use Raspberry Pi 4 B+ 2GB memory model and the OS will use Raspberry Pi OS