Скачать или смотреть How to Successfully Crosscompile OpenCV for Aarch64 on Linux

Learn how to troubleshoot common issues while `cross-compiling OpenCV for Aarch64` on Linux, including library dependencies and solutions.
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Troubleshooting Crosscompilation of OpenCV for Aarch64 on Linux

Crosscompiling can be a challenging task, especially when working with libraries like OpenCV for different architectures. For developers looking to build OpenCV for the Aarch64 architecture on Linux, encountering issues during the build process is not uncommon. One user faced difficulties when trying to crosscompile OpenCV after successfully building it for x86_64. Let's break down the common problems, particularly focusing on missing dependencies, and how to resolve them.

The Problem

When trying to crosscompile OpenCV, the user executed the cmake command but received the following error message: "Configuring incomplete, errors occurred!" along with several warnings indicating that vital libraries such as ZLIB, JPEG, and others could not be found. This indicates a common issue—missing dependencies that are required for the Aarch64 build.

Understanding the Error Messages

The output from the cmake command revealed a series of "Could NOT find xxx" messages. These messages suggest that certain libraries indispensable for building OpenCV cannot be located. Let's explore the details of the error messages and their implications:

Common Missing Libraries

ZLIB: Required for compression libraries.

JPEG: Essential for handling JPEG image formats.

PNG: Necessary for handling PNG image formats.

OpenBLAS: Needed for optimized linear algebra computations.

LAPACK: A library needed for advanced numerical computations.

These errors indicate that your build environment lacks the Aarch64 versions of these libraries. This situation typically arises when these dependencies are either not installed or cannot be located by CMake.

Steps to Resolve Missing Dependencies

To successfully crosscompile OpenCV for Aarch64, you need to ensure that the required libraries are available for that architecture. Here’s how you can navigate through the process:

1. Check Installed Packages

First, verify whether your package manager has pre-built versions of the required libraries for Aarch64. Use commands such as:

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The actual command may vary based on your package manager, so refer to its documentation.

2. Install Missing Libraries

If the libraries are not present or cannot be found, consider installing them using your package manager. You might find commands like the following useful:

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Remember to append :arm64 or the relevant architecture suffix to ensure you're fetching the correct version.

3. Build Libraries from Source

If your package manager does not have Aarch64 versions for these libraries, you will need to build them from source. Follow these steps for each missing library:

Download the source code from the library's official repository.

Set up the build environment for Aarch64 (you may need to configure a toolchain).

Run the build commands and install them to your desired location.

Examples commands may look like this:

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4. Update CMake Files or Use CMake Options

Ensure that the /usr/local/opencv/platforms/linux/aarch64-gnu.toolchain.cmake file is properly configured. This toolchain file tells CMake where to look for the Aarch64 versions of libraries and compilers. You might also want to specify additional CMake options like PKG_CONFIG_LIBDIR to point to the sysroot.

5. Re-run the CMake Command

Once all required libraries have been installed and CMake is properly configured, re-run the cmake command followed by the make command to commence the build.

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Conclusion

Crosscompiling OpenCV for Aarch64 on Linux can pre