Raspberry Pi是什么？
引用维基百科的一句话：
The Raspberry Pi is a credit card sized single-board computer developed in the UK by the Raspberry Pi Foundation with the intention of stimulating the teaching of basic computer science in schools.
简单地说，它就是一个基于ARM CPU的、信用卡那么大的迷你计算机。
In short, Pi is an ARM-based mini computer which has a credit card size.
前段时间公司举行hackathon比赛，我做了一套如题所示的系统，整个过程太累了，连续30个小时没睡，简直要了我半条命，现在我打算把它的主要实现记下来。
Raspberry Pi是什么？
引用维基百科的一句话：
The Raspberry Pi is a credit card sized single-board computer developed in the UK by the Raspberry Pi Foundation with the intention of stimulating the teaching of basic computer science in schools.
简单地说，它就是一个基于ARM CPU的、信用卡那么大的迷你计算机。
我曾经写过一篇教程，展示了如何调用OpenCV，来控制摄像头拍照。在那篇文章的末尾，我提到了一个遗留问题，即把抓取图像的尺寸设置得稍高一点的时候，那个程序就很容易崩溃；在图像尺寸设置得很低的时候，有时候也会崩溃，我一直没弄明白为什么。
但是在前段时间，由于参赛原因，被迫在很短的时间内解决这个棘手的问题。真可谓是搜了无数网页，最后采取了一种折衷的方式“在很大程度上”解决了这个问题——毕竟还不完美。
For non-Chinese readers:
I'm a software engineer in Shanghai, China. Since I bought a Raspberry Pi, I spent some spare time on it and I'm glad to share something with Pi users all over the world, so this article has two languages: Chinese & English, and I try to translate the Chinese to English as accurately as possible, but, there might be some translation mistakes, so if you don't know what I mean in the article, just leave a comment, and I'll reply when I get an answer. Also welcome to contact me via Email.
Raspberry Pi是什么？简单地说，它就是一个基于ARM CPU的、信用卡那么大的迷你计算机。
In short, Pi is an ARM-based mini computer which has a credit card size.
本文主要内容：
在Raspberry Pi上，通过调用OpenCV库，自己写一个简单的C程序来控制摄像头拍照，并保存图片。
在阅读本文之前，请确保你已经阅读过我的另一篇配置Pi的文章，因为本文是在它的基础上进行的。
The main content of this article:
Write a simple C program by invoking the OpenCV library on Raspberry Pi to control a webcam to take photos & save them.
Before reading this article, please make sure that you've read my another article about Pi configuration, because this article is based on that.