OpenCV is a comprehensive computer vision and machine learning library written primarily in C++ with bindings for Python, Java, JavaScript, Swift, and other languages. Its architecture is modular, with core modules for fundamental data structures (Mat, UMat, Scalar), image processing (imgproc), video I/O (videoio), deep neural network inference (dnn), feature detection (features), object detection (objdetect), camera calibration (calib), 3D geometry (geometry), point cloud processing (ptcloud), and more. The library provides a hardware abstraction layer (HAL) for CPU optimizations (SIMD, IPP, Carotene) and supports GPU acceleration via CUDA, OpenCL, and Vulkan backends. Key entry points include cv::imread/cv::imwrite for image loading, cv::VideoCapture for video streams, and cv::dnn::readNet for model inference. Data flows typically involve reading image or video data, applying processing pipelines (filtering, feature extraction, detection), and outputting results. External dependencies include vendored third-party libraries for image codecs (libjpeg-turbo, libwebp, libtiff, openjpeg), compression (zlib-ng), serialization (protobuf, flatbuffers), text shaping (harfbuzz), and linear algebra (mlas, clapack). The codebase is actively maintained with frequent commits, extensive test and performance benchmarks, and support for multiple platforms including Windows, Linux, macOS, Android, and iOS.

OpenCV Zoo is a curated collection of pre-trained computer vision models optimized for OpenCV's DNN module, accompanied by inference demo scripts (Python and C++), benchmarking harness, evaluation tools, and quantization utilities. The repository serves as a practical resource for deploying models on a wide range of hardware (x86, ARM, RISC-V, NPUs) by providing ready-to-run code for tasks such as face detection/recognition, object detection, segmentation, text detection/recognition, pose estimation, and more. While primarily an application-oriented model zoo, it also includes research-grade evaluation metrics (e.g., LFW, WIDERFace) and quantization workflows, giving it a hybrid character that bridges model deployment and performance characterization. The benchmarking framework and quantization tools are the most architecturally coherent parts; model-specific demos are utilitarian but tightly coupled to their respective ONNX graphs.