#genicam #camera #usb3 #gige #uvc


cameleon is a safe, fast, and flexible library for GenICam compatible cameras

4 releases

0.1.3 Jun 13, 2021
0.1.2 Jun 9, 2021
0.1.1 Jun 4, 2021
0.1.0 Jun 4, 2021

#14 in Video

MPL-2.0 license

19K SLoC

cameleon is a safe, fast, and flexible library for GenICam compatible cameras

Crates.io Documentation MPL-2.0 Build Status

cameleon is a safe, fast, and flexible library for GenICam compatible cameras.


cameleon is a library for operating on GenICam compatible cameras. Our main goal is to provide safe, fast, and flexible library for GenICam cameras.

Currently, cameleon supports only USB3 Vision cameras, but it's planned to support other protocols including GigE Vision. See Roadmap for more details.


USB3 Vision cameras

First, you need to install libusb to communicate with U3V cameras. Then add the following to your Cargo.toml:

cameleon = { version = 0.1, features = 'libusb'}

You can enumerate all cameras connected to the host, and start streaming.

use cameleon::u3v;

// Enumerates all cameras connected to the host.
let mut cameras = u3v::enumerate_cameras().unwrap();

if cameras.is_empty() {
    println!("no camera found");

let mut camera = cameras.pop().unwrap();

// Opens the camera.
// Loads `GenApi` context. This is necessary for streaming.

// Start streaming. Channel capacity is set to 3.
let payload_rx = camera.start_streaming(3).unwrap();

let mut payload_count = 0;
while payload_count < 10 {
    match payload_rx.try_recv() {
        Ok(payload) => {
                "payload received! block_id: {:?}, timestamp: {:?}",
            if let Some(image_info) = payload.image_info() {
                println!("{:?}\n", image_info);
                let image = payload.image();
                // do something with the image.
                // ...
            payload_count += 1;

            // Send back payload to streaming loop to reuse the buffer. This is optional.
        Err(_err) => {

// Closes the camera.

More examples can be found here.

Project Layout

Cameleon consists of several crates.

  • cameleon: Provides high-level APIs to control cameras. This is the primary crate.
  • cameleon-genapi: Provides parser and interpreter of GenApi XML.
  • cameleon-device: Provides device specific protocol decoder and basic I/O operations for devices, also provides emulators.
  • cameleon-gentl: Provides GenTL interfaces as a C library.
  • cameleon-impl: Provides internal APIs for other crates. cameleon-impl is intended to be used only by cameleon project.
  • cameleon-impl-macros: Provides procedural macros for other crates. cameleon-impl-macros is intended to be used only by cameleon project.


USB3 Vision

Why isn't a camera found even though it is connected to the host?

It's probably due to permission issue for USB devices. You could add permissions by editing udev rules, a configuration example is found here.

Why is frame rate so low?

Frame rate can be affected by several reasons.

  1. Parameter settings of the camera

AcquisitionFrameRate and ExposureTime directly affect frame rate. So you need to setup the parameters first to improve frame rate. Also, if DeviceLinkThroughputLimitMode is set to On, you would need to increase the value of DeviceLinkThroughputLimit.

  1. Many devices are streaming simultaneously on the same USB host controller

In this case, it's recommended to allocate the equal throughput limit to the connected cameras, making sure that the total throughput does not exceed the maximum bandwidth of the host controller.

  1. usbfs_memory_mb is set to low value

If you use Linux, you may need to increase usbfs_memory_mb limit. By default, USB-FS on Linux systems only allows 16 MB of buffer memory for all USB devices. This is quite low for high-resolution image streaming. We recommend you to set the value to 1000MB. You could set the value as following:

echo 1000 > /sys/module/usbcore/parameters/usbfs_memory_mb



  • Add support for GigE cameras
  • Impelment emulator
  • Add support for saving and loading camera parameters


  • Implement payload chunk parser
  • Add support for GenTL


  • Add support for UVC cameras

Release cycle

We continuously update the minor version every four weeks, until the version reaches 1.0.0.


Thank you for your interest in contributing to Cameleon! We are so happy to have you join the development.
To start developing, please refer to CONTRIBUTING.md.


This project is licenced under MPL 2.0.


~155K SLoC