---
title: "Tracking Module Reference"
description: "API reference for Iris tracking module — MOSSE tracker, KCF/CSRT tracker types, MeanShift tracker, and background subtraction."
keywords: ["tracking", "MOSSE", "KCF", "CSRT", "tracker", "background subtraction", "object tracking", "MeanShift", "MeanShiftTracker"]
---
# Tracking Module Reference
Provides object tracking and background subtraction algorithms.
## Tracker
```rust
pub enum TrackerType {
KCF,
CSRT,
MOSSE,
}
pub struct Tracker<B: Backend> {
pub tracker_type: TrackerType,
pub bbox: Option<Rect<usize>>,
}
impl<B: Backend> Tracker<B> {
pub fn new(tracker_type: TrackerType) -> Self;
pub fn init(&mut self, image: &Image<B>, bbox: Rect<usize>) -> Result<()>;
pub fn update(&mut self, image: &Image<B>) -> Result<Rect<usize>>;
}
```
## BackgroundSubtractor
```rust
pub struct BackgroundSubtractor<B: Backend> {
learning_rate: f32,
threshold: f32,
background: Option<Image<B>>,
}
impl<B: Backend> BackgroundSubtractor<B> {
pub fn new(learning_rate: f32, threshold: f32) -> Self;
pub fn apply(&mut self, frame: &Image<B>) -> Result<Image<B>>;
}
```
## Example
```rust
use iris::prelude::*;
use burn::backend::wgpu::Wgpu;
type Backend = Wgpu;
let device = Default::default();
// Background subtraction
let mut subtractor = BackgroundSubtractor::new(0.1, 0.05);
let mask = subtractor.apply(&frame)?;
// Object tracking
let mut tracker = Tracker::new(TrackerType::MOSSE);
let init_bbox = Rect::new(50, 50, 100, 100);
tracker.init(&frame1, init_bbox)?;
// Track across frames
let bbox = tracker.update(&frame2)?;
println!("Object at: {:?}", bbox);
```
## MeanShift Tracker
Iterative kernel-based tracker that locates the object by shifting the search window toward the peak of the color histogram probability distribution.
```rust
pub struct MeanShiftTracker {
// internal state
}
impl MeanShiftTracker {
pub fn new() -> Self;
pub fn init<B: Backend>(&mut self, image: &Image<B>, roi: Rect<usize>) -> Result<()>;
pub fn update<B: Backend>(&mut self, image: &Image<B>) -> Result<Rect<usize>>;
}
```
### Methods
| `new()` | Creates a new MeanShift tracker with default parameters. |
| `init(image, roi)` | Initializes the tracker with the target region of interest (histogram model). |
| `update(image)` | Performs one MeanShift iteration and returns the updated bounding box. |
### Example
```rust
use iris::prelude::*;
let device = WgpuDevice::default();
let frame1 = Image::<Wgpu>::open("frame1.jpg", &device)?;
let frame2 = Image::<Wgpu>::open("frame2.jpg", &device)?;
let mut tracker = MeanShiftTracker::new();
let roi = Rect::new(120, 80, 64, 64);
tracker.init(&frame1, roi)?;
let bbox = tracker.update(&frame2)?;
println!("Tracked object at: {:?}", bbox);
```