> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/opencv/opencv/llms.txt
> Use this file to discover all available pages before exploring further.

# OpenCV Modules Overview

> Comprehensive overview of OpenCV's modular architecture and core functionality modules

OpenCV is organized into a set of modules, each providing specific functionality for computer vision tasks. Understanding this modular structure helps you choose the right tools for your applications.

## Core Modules

<CardGroup cols={2}>
  <Card title="core" icon="cube" href="/modules/core">
    Fundamental data structures (Mat), basic operations, and utilities
  </Card>

  <Card title="imgproc" icon="image" href="/modules/imgproc">
    Image processing functions including filtering, transforms, and feature detection
  </Card>

  <Card title="imgcodecs" icon="file-image" href="/modules/imgcodecs">
    Image file reading and writing with support for multiple formats
  </Card>

  <Card title="videoio" icon="video" href="/modules/videoio">
    Video capture and writing interfaces for cameras and video files
  </Card>

  <Card title="highgui" icon="window-maximize" href="/modules/highgui">
    High-level GUI functions for window management and user interaction
  </Card>

  <Card title="video" icon="film" href="/modules/video">
    Video analysis including motion tracking and background subtraction
  </Card>

  <Card title="calib3d" icon="camera" href="/modules/calib3d">
    Camera calibration and 3D reconstruction algorithms
  </Card>
</CardGroup>

## Module Dependencies

OpenCV modules are designed with clear dependencies to maintain modularity:

```mermaid theme={null}
graph TD
    core[core]
    imgproc[imgproc]
    imgcodecs[imgcodecs]
    videoio[videoio]
    highgui[highgui]
    video[video]
    calib3d[calib3d]
    
    imgproc --> core
    imgcodecs --> core
    videoio --> core
    highgui --> core
    highgui -.-> imgcodecs
    highgui -.-> videoio
    video --> core
    video --> imgproc
    calib3d --> core
    calib3d --> imgproc
```

<Note>
  The **core** module is the foundation - all other modules depend on it for basic data structures and operations.
</Note>

## Module Descriptions

### Core Module

The backbone of OpenCV providing:

* **Mat** class for n-dimensional arrays
* Basic array operations (add, subtract, multiply)
* Mathematical functions
* XML/YAML persistence
* Utility functions and system information

### Image Processing (imgproc)

Comprehensive image processing capabilities:

* Linear and non-linear filtering
* Geometric transformations
* Color space conversions
* Histograms
* Structural analysis and shape descriptors
* Motion analysis and object tracking
* Feature detection

### Image Codecs (imgcodecs)

Image I/O operations:

* Support for JPEG, PNG, TIFF, WebP, AVIF, and more
* Image reading with `imread()`
* Image writing with `imwrite()`
* Animation support (GIF, AVIF, APNG)
* Metadata handling (EXIF, XMP, ICC)

### Video I/O (videoio)

Video capture and writing:

* **VideoCapture** class for reading from cameras or files
* **VideoWriter** class for creating video files
* Multiple backend support (FFmpeg, GStreamer, DirectShow)
* Audio stream support
* Hardware acceleration options

### High-Level GUI (highgui)

User interface utilities:

* Window creation and management
* Image display with `imshow()`
* Keyboard and mouse event handling
* Trackbars for interactive parameter adjustment
* OpenGL integration support

### Video Analysis (video)

Advanced video processing:

* Optical flow (Lucas-Kanade, Farneback)
* Object tracking (MeanShift, CamShift)
* Background subtraction (MOG2, KNN)
* Motion analysis algorithms

### Camera Calibration (calib3d)

3D vision and calibration:

* Camera calibration (intrinsic and extrinsic parameters)
* Stereo calibration and rectification
* 3D reconstruction
* Pose estimation
* Homography computation

## Choosing the Right Module

<Tabs>
  <Tab title="Image Processing">
    Use **imgproc** for:

    * Filtering and smoothing images
    * Edge detection
    * Color transformations
    * Geometric transformations (resize, rotate)
    * Contour detection
  </Tab>

  <Tab title="Video Analysis">
    Use **video** and **videoio** for:

    * Reading from cameras or video files
    * Tracking moving objects
    * Detecting motion
    * Background/foreground segmentation
    * Writing processed video
  </Tab>

  <Tab title="3D Vision">
    Use **calib3d** for:

    * Camera calibration
    * Stereo vision
    * 3D reconstruction
    * AR/VR applications
    * Depth estimation
  </Tab>

  <Tab title="I/O Operations">
    Use **imgcodecs** and **videoio** for:

    * Loading and saving images
    * Capturing from cameras
    * Recording video
    * Format conversion
  </Tab>
</Tabs>

## Getting Started

To use OpenCV modules in your code:

```cpp theme={null}
#include <opencv2/core.hpp>        // Core functionality
#include <opencv2/imgproc.hpp>     // Image processing
#include <opencv2/imgcodecs.hpp>   // Image I/O
#include <opencv2/highgui.hpp>     // GUI functions
#include <opencv2/videoio.hpp>     // Video I/O
#include <opencv2/video.hpp>       // Video analysis
#include <opencv2/calib3d.hpp>     // Calibration and 3D

using namespace cv;
```

## Next Steps

<CardGroup cols={2}>
  <Card title="Explore Core Module" href="/modules/core">
    Learn about Mat and fundamental operations
  </Card>

  <Card title="Image Processing" href="/modules/imgproc">
    Discover filtering and transformation functions
  </Card>

  <Card title="Quick Start Guide" href="/quickstart">
    Build your first OpenCV application
  </Card>

  <Card title="API Reference" href="/api-reference">
    Browse the complete API documentation
  </Card>
</CardGroup>