Book Image

Raspberry Pi By Example

By : Arush Kakkar
Book Image

Raspberry Pi By Example

By: Arush Kakkar

Overview of this book

Want to put your Raspberry Pi through its paces right out of the box? This tutorial guide is designed to get you learning all the tricks of the Raspberry Pi through building complete, hands-on hardware projects. Speed through the basics and then dive right in to development! Discover that you can do almost anything with your Raspberry Pi with a taste of almost everything. Get started with Pi Gaming as you learn how to set up Minecraft, and then program your own game with the help of Pygame. Turn the Pi into your own home security system with complete guidance on setting up a webcam spy camera and OpenCV computer vision for image recognition capabilities. Get to grips with GPIO programming to make a Pi-based glowing LED system, build a complete functioning motion tracker, and more. Finally, get ready to tackle projects that push your Pi to its limits. Construct a complete Internet of Things home automation system with the Raspberry Pi to control your house via Twitter; turn your Pi into a super-computer through linking multiple boards into a cluster and then add in advanced network capabilities for super speedy processing!
Table of Contents (22 chapters)
Raspberry Pi By Example
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Retrieving image properties


We can retrieve and use many image properties with OpenCV functions. Take a look at the following code:

import cv2
img = cv2.imread('lena_color_512.tif',1)
print img.shape
print img.size
print img.dtype

The img.shape operation returns the shape of the image, that is, its dimensions and the number of color channels. The output of the previously listed code will be as follows:

(512, 512, 3)
786432
uint8

If the image is colored, then img.shape returns a triplet containing the number of rows, the number of columns, and the number of channels in the image. Usually, the number of channels is three, representing the red, green, and blue channels. If the image is grayscale, then img.shape only returns the number of rows and the number of columns. Try to modify the preceding code to read the image in the grayscale mode and observe the output of img.shape.

The img.size operation returns the total number of pixels, and img.dtype returns the image datatype.