To make computers "see", we need more than just clever algorithms. A complete computer vision (CV) system relies on a combination of hardware and software working together. Think of it like human vision: our eyes (hardware) capture light, and our brain (processing and "software") interprets what we see.
The Building Blocks
At a high level, a CV system generally consists of these parts:
- Input Device: Something to capture the visual information. This is usually a camera or sensor.
- Processing Unit: The hardware that runs the calculations needed to analyze the visual data.
- Software: The algorithms and programs that perform the actual vision tasks.
- Output: A way to present or use the results of the analysis.
A simplified view of how components interact in a computer vision system.
Let's examine each component more closely.
Input Devices: Capturing the Visual Scene
The first step is always acquiring the image or video data.
- Cameras: The most common input device. This could be anything from a simple webcam built into your laptop to sophisticated industrial cameras or the camera on your smartphone. Standard cameras capture light in the visible spectrum, often storing it in familiar color formats like RGB (Red, Green, Blue).
- Specialized Sensors: Depending on the application, other types of sensors might be used. Examples include:
- Depth Sensors (e.g., Kinect, LiDAR): These measure distance, providing 3D information about the scene.
- Thermal Cameras: These detect infrared radiation (heat) instead of visible light.
- Multi-spectral Cameras: Capture information across broader or different ranges of the electromagnetic spectrum.
For this introductory course, we'll primarily work with standard digital images captured by conventional cameras. The input device provides the raw pixel data that the rest of the system will analyze.
Processing Hardware: The Computational Engine
Analyzing images requires significant computation. Pixels need to be processed, patterns identified, and calculations performed.
- Central Processing Unit (CPU): Every computer has a CPU. It's the general-purpose workhorse that runs the operating system and most applications. CPUs are great for sequential tasks and managing the overall system. Many basic CV tasks can run perfectly well on a modern CPU.
- Graphics Processing Unit (GPU): Originally designed for rendering graphics in video games, GPUs have become essential for more demanding CV tasks, especially those involving deep learning. Why? Because image processing often involves performing the same simple calculation on many pixels simultaneously. GPUs excel at this kind of parallel processing, containing thousands of simpler cores designed to work together. This makes them much faster than CPUs for many CV algorithms.
- Specialized Hardware (Advanced): For specific, high-performance applications (like running complex models on mobile devices or in real-time systems), specialized hardware like TPUs (Tensor Processing Units), FPGAs (Field-Programmable Gate Arrays), or dedicated AI accelerators might be used. These are designed to be extremely efficient at the specific mathematical operations common in machine learning and computer vision, but are outside the scope of this introductory course.
Your development environment, which we'll set up shortly, will typically use your computer's CPU, but libraries like OpenCV are often optimized to take advantage of a GPU if one is available and properly configured.
Software: The Intelligence Behind the System
Hardware alone can't interpret images. Software provides the instructions and logic.
- Operating System (OS): The foundation (like Windows, macOS, Linux) that manages the hardware resources and allows other software to run.
- Programming Languages: We need a language to write the instructions. Python is currently the most popular language for computer vision due to its ease of use and extensive library support. Other languages like C++ are also widely used, particularly where performance is critical.
- Computer Vision Libraries: These are collections of pre-written code that provide ready-to-use functions for common CV tasks. Instead of writing code from scratch to load an image, apply a filter, or detect edges, you can use functions provided by a library. The most prominent library we'll use is OpenCV (Open Source Computer Vision Library). Others include scikit-image, Pillow (for basic image manipulation), and deep learning frameworks like TensorFlow and PyTorch (which have extensive CV capabilities).
- Algorithms/Applications: This is the specific code you might write (or use) to solve a particular problem, like detecting faces, recognizing characters, or tracking objects. This code utilizes the functions provided by the CV libraries to process the input images and generate results.
Output: Presenting the Findings
Once the analysis is complete, the system needs to present the results in a useful way. This could be:
- Displaying the image with detected objects highlighted by bounding boxes.
- Outputting text, such as the classification of an object ("cat", "dog").
- Generating numerical data, like the coordinates of features or the size of an object.
- Triggering an action in another system (e.g., stopping a robot if an obstacle is detected).
Our Focus
In this course, while acknowledging the importance of hardware, our primary focus will be on the software components. You'll learn to use Python and the OpenCV library to load, manipulate, and analyze images using the processing power of your own computer (CPU primarily, though the concepts apply equally if you have a GPU). We will start by setting up this software environment in the next section.
