Kurt Demaagd - Practical Computer Vision with SimpleCV: The Simple Way to Make Technology See

Copyright 2012 Ingenuitas

O'Reilly Media

Computer Vision The analyzing and processing of images. These concepts can be applied to a wide array of applications, such as medical imaging, security, autonomous vehicles, etc. It often tries to duplicate human vision by using computers and cameras. Machine Vision The application of computer vision concepts, typically in an industrial setting. These applications are used for quality control, process control, or robotics. These are also generally considered the solved problems. However, there is no simple dividing line between machine vision and computer vision. For example, some advanced machine vision applications, such as 3D scanning on a production line, may still be referred to as computer vision. Tuple A list with a pair of numbers. In Python, it is written enclosed in parentheses. It is often used when describing (x, y) coordinates, the width and height of an object, or other cases where there is a logical pairing of numbers. It has a slightly more technical definition in mathematics, but this definition covers its use in this book. NumPy Array or Matrix NumPy is a popular Python library used in many scientific computing applications, known for its fast and efficient algorithms. Since an image can also be thought of as an array of pixels, many bits of processing use NumPys array data type. When an array has two or more dimensions, it is sometimes called a Matrix. Although intimate knowledge of NumPy is not needed to understand this book, it is useful from time to time. Blob Blobs are contiguous regions of similar pixels. For example, in a picture detecting a black cat, the cat will be a blob of contiguous black pixels. They are so important in computer vision that they warrant their own chapter. They also pop up from time to time throughout the entire book. Although covered in detail later, it is good to at least know the basic concept now. JPEG, PNG, GIF or other image formats Images are stored in different ways, and SimpleCV can work with most major image formats. This book primarily uses PNGs, which are technically similar to GIFs. Both formats use non-lossy compression, which essentially means the image quality is not changed in the process of compressing it. This creates a smaller image file without reducing the quality of the image. Some examples also use JPEGs. This is a form of lossy compress, which results in even smaller files, but at the cost of some loss of image quality. PyGame PyGame appears from time to time throughout the book. Like NumPy, PyGame is a handy library for Python. It handles a lot of window and screen management work. This will be covered in greater detail in the Drawing chapter. However, it will also pop up throughout the book when discussing drawing on the screen.