# Interfaces

## Compile and incorporate OpenCV 4.5.5 into your framework

1. Use the Yocto workflow to sync and build the latest Qualcomm Linux software release as described in the
[Qualcomm Linux Build Guide](https://docs.qualcomm.com/bundle/publicresource/topics/80-70015-254/) .

Note

Prior to running an SSH command, ensure that you enable SSH in Permissive mode by following the steps in the [How to SSH](https://docs.qualcomm.com/bundle/publicresource/topics/80-70015-254/how_to.html#use-ssh)
Section of the [Qualcomm Linux Build Guide](https://docs.qualcomm.com/bundle/publicresource/topics/80-70015-254/)
2. Flash the latest Qualcomm Linux software release as described in the
[Qualcomm Linux Build Guide](https://docs.qualcomm.com/bundle/publicresource/topics/80-70015-254/).
3. To enable the **tests** package, include `tests` in
`PACKAGECONFIG` in the
`<workspace>/layers/meta-openembedded/meta-oe/recipes-support/opencv/opencv_4.5.5.bb`
recipe file as follows.

PACKAGECONFIG ??= "gapi python3 eigen jpeg png tiff v4l libv4l samples tbb gphoto2 tests \
        ${@bb.utils.contains("DISTRO_FEATURES", "x11", "gtk", "", d)} \
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**Libraries and test applications**

By default, only libraries shown in the compiled build as test bins are cleaned up.

1. To retain test bins, include the following code in the
`<workspace>/meta-openembedded/meta-oe/recipes-support/opencv/opencv_4.5.5.bb` recipe file:

RM_WORK_EXCLUDE += "opencv"
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2. When the build is already compiled, OpenCV must be cleaned before compilation.
To clean OpenCV, run the following command:

bitbake -fc cleanall opencv
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    During compilation no code is modified; so a direct compilation does not generate the corresponding bins.
3. To compile OpenCV, run the following command:

bitbake opencv
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The path to the libraries is `/tmp-glibc/sysroots-components/armv8-2a/opencv/usr/lib/`.

The path to the bins is `/tmp-glibc/work/armv8-2a-qcom-linux/opencv/4.5.5-r0/build/bin/`.

## Testing

To invoke the OpenCV API, native OpenCV test examples can reference sample applications. Use the following procedure to invoke applications on the Snapdragon target.
Compile the full build image to ensure that all libraries are part of the application images.

1. Flash the images on the device as described in the [Qualcomm Linux Build Guide](https://docs.qualcomm.com/bundle/publicresource/topics/80-70015-254/).

    OpenCV libraries are on the device at `/usr/lib`.
2. For test data, Git clone the projects at [https://github.com/opencv/opencv_extra/tree/4.5.5](https://github.com/opencv/opencv_extra/tree/4.5.5).
3. To avoid read only errors while trying to push test data and bins to the device, use the device IP address to log in to an SSH terminal and run the following command to remount the device.

mount -o remount,rw /
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4. Use the `scp` command to push the test data to a preferred host location.

    For example: `scp -r [file] root@[IP-ADDR]:/tmp`
5. Use the `scp` command to push the required test bin to `/usr/bin`.

    For example: `scp -r [test] root@[IP-ADDR]:/usr/bin/`
6. Execute the following commands on the host.

scp -r tmp-glibc/sysroots-components/armv8-2a/opencv/usr/lib/libopencv_ts.so root@[IP-ADDR]:/usr/lib/
        scp -r tmp-glibc/sysroots-components/armv8-2a/opencv/usr/lib/libopencv_ts.so.4.5.5 root@[IP-ADDR]:/usr/lib/
        scp -r tmp-glibc/sysroots-components/armv8-2a/opencv/usr/lib/libopencv_ts.so.405 root@[IP-ADDR]:/usr/lib/
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7. Log in to an SSH terminal and run the following commands.

chmod 777 /usr/bin/<opencv_test_bin>
        root@qcm6490:~# cd /usr/bin
        export OPENCV_LOG_LEVEL=DEBUG
        export OPENCV_VIDEOIO_DEBUG=1
        export OPENCV_TEST_DATA_PATH=/tmp
        ./<opencv_test_bin> --gtest_output=json:/tmp/results.json --gtest_also_run_disabled_tests
        exit
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    Results are stored in `/tmp/results.json`.
To change the results filename, modify the
`--gtest_output=json:/tmp/results.json` argument.

Last Published: Oct 15, 2024

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