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purecv

PureCV reimplements the core, imgproc, features2d, video and calib3d modules of OpenCV in pure Rust. There is no C++ binding and no C++ toolchain: it is memory-safe, can use several cores and SIMD, and runs from desktops and WebAssembly down to no_std microcontrollers.

Install

Section titled “Install”

In a Rust project (the minimum supported Rust version is 1.88):

[dependencies]
purecv = "0.11"

Cargo features:

Feature Default What it does
std yes Standard library. Turn it off for no_std
parallel yes Multi-core parallelism with Rayon
simd no SIMD with pulp: x86 SSE and AVX, ARM NEON, WebAssembly simd128
ndarray no Interoperability with the ndarray crate
wasm no WebAssembly-specific optimisations

For SIMD and threads together: purecv = { version = "0.11", features = ["parallel", "simd"] }.

First steps

Section titled “First steps”
use purecv::core::{Matrix, Scalar};


fn main() {
    // A 480x640 matrix with 3 channels, filled with ones
    let mat = Matrix::<f32>::ones(480, 640, 3);


    // Another one, filled with a constant value
    let mut gray = Matrix::<f32>::zeros(480, 640, 3);
    gray.set_to(Scalar::all(128.0f32));


    println!("{}x{}", mat.cols, mat.rows);
}

The repository has runnable examples for filters, thresholds, histograms, FAST and ORB keypoints, feature matching, optical flow, solve_pnp and camera undistortion: cargo run --example <name>.

In the browser and Node.js

Section titled “In the browser and Node.js”
Terminal window
npm install @webarkit/purecv-wasm

The package has two builds, standard (dist-std) for maximum compatibility and SIMD (dist-simd) for browsers with WebAssembly simd128. It covers most of core and imgproc, and has started on video (optical flow) and calib3d (solve_pnp, find_homography, rodrigues).

import init, { Mat, gaussian_blur, CV_8UC3, BORDER_DEFAULT } from '@webarkit/purecv-wasm/dist-std/purecv_wasm.js';


await init();


const mat = Mat.new(480, 640, CV_8UC3);
// ... fill `mat` with your image data
const blurred = gaussian_blur(mat, 5, 5, 0.0, 0.0, BORDER_DEFAULT);


// JavaScript doesn't free WebAssembly memory for you
mat.free();
blurred.free();

no_std and microcontrollers

Section titled “no_std and microcontrollers”

Build with default-features = false to run without the standard library, for example on an ESP32. core, imgproc, calib3d and video work this way; features2d still needs std. See the ESP32 examples.

See also

Section titled “See also”