Computer Vision on Browser — Using OpenVC & Emscripten

scan a barcode on the browser

How to use OpenCV with WebAseembly on a browser?

OpenCV, a popular C++ computer vision library, can be reused in a web browser environment with WebAssembly, allowing for high-performance image processing applications in the browser.

Emscripten is a toolchain for compiling C and C++ code to WebAssembly, which is a low-level bytecode format that can be executed in web browsers. To compile OpenCV with Emscripten, you first need to configure the Emscripten environment by setting up the necessary system paths and environment variables.

After the build process is complete, you can generate the WebAssembly module and supporting JavaScript code by running the Emscripten compiler on the OpenCV library. This generates a WebAssembly module that contains the compiled OpenCV code, as well as a JavaScript file that provides a wrapper around the WebAssembly module and exposes a JavaScript API for interfacing with the OpenCV library.

To configure Emscripten to compile OpenCV, you need to follow these steps:

1. Install Emscripten: Download and use the latest version of the Emscripten Docker version from the official website, and configure your environment by following the installation instructions.
2. Download and extract OpenCV: Download the source code for OpenCV and extract it to a directory on your system.
3. Create a build directory: Create a directory for building OpenCV, and navigate to it using a terminal or command prompt.
4. Specify the Emscripten toolchain: Set the CMake toolchain file to use the Emscripten toolchain by specifying the path to the Emscripten toolchain file.
5. Compile OpenCV: Run the make command to compile OpenCV with the Emscripten toolchain. This generates the object files and libraries for OpenCV in the build directory.
6. Generate WebAssembly module and JavaScript wrapper: Use the Emscripten compiler to generate the WebAssembly module and the JavaScript wrapper code. This creates the files necessary for interfacing with OpenCV in a web browser.
7. Once these steps are completed, you can use the generated WebAssembly module and JavaScript wrapper code to interface with OpenCV in your web application.

The following bash script utilizes the Emscripten Docker Image to create a Docker environment for compiling OpenCV into WebAssembly.

glyclt-cv for Computer Vision

The upcoming post will provide a detailed explanation of the process for building a WebAssembly environment to compile the OpenCV processing library for use in a web browser.