How to Do Basic Image Processing with Raspberry Pi
By Nauman Shakir
Image processing is the process of performing some mathematical functions and operations on an image, images or video. The output that we get after image processing is a set of parameters or some altered image, images or videos.
Due to the low price of the Raspberry Pi, it is being used for image processing and video processing in many projects.
You need to have these components for getting started with basic image processing.
- 16GB Micro SD Card. You can buy them with Raspbian installed or you can learn How to Install Raspbian on a Raspberry Pi’s SD Card here.
- HDMI cable for display or you can learn how to connect a Raspberry Pi to a laptop display.
- A USB camera that is compatible with Raspberry Pi.
Installing the Image Processing Program
Plug in all the components and open the Linux terminal in Raspbian and run the following commands:
- sudo apt-get install update
- sudo apt-get upgrade
- sudo apt-get install python-pygame
- wget http://www.cl.cam.ac.uk/projects/raspberrypi/tutorials/robot/resources/imgproc.zip
- unzip imgproc.zip
- cd library
- sudo make install
Now we’re ready to program the Raspberry Pi for image processing!
Programming a Raspberry Pi for Image Processing
- Make sure that you have connected the USB camera to Raspberry Pi
- Open Python 3 and press CTRL+N to open a new window. In this window write the following code.
from imgproc import * # open the webcam my_camera = Camera(320, 240) # grab an image from the camera my_image = my_camera.grabImage() # open a view, setting the view to the size of the captured image my_view = Viewer(my_image.width, my_image.height, "Basic image processing") # display the image on the screen my_view.displayImage(my_image) # wait for 5 seconds, so we can see the image waitTime(5000)
- Save this code somewhere on the desktop and run it.
- The code will capture an image and will display it on the screen.
Turning Red Pixels to Blue with Raspberry Pi
Now we are going to turn all red pixels in the image to blue. Write this snippet of code below the code shown in the section above.
# iterate over ever pixel in the image by iterating over each row and each column for x in range(0, my_image.width): for y in range(0, my_image.height): # get the value of the current pixel red, green, blue = my_image[x, y] # check if the red intensity is greater than the green if red > green: # check if red is also more intense than blue if red > blue: # this pixel is predominantly red # let's set it to blue my_image[x, y] = 0, 0, 255
You now know how to do basic image processing on your Raspberry Pi! For more details and functions, check out this Youtube tutorial: