Blurry image quality from cameras

[sbrodeur]

The images from the cameras seems anomaly blurry:

We may need to check the configuration here about exposure and gain: https://github.com/sbrodeur/ros-icreate-bbb/blob/master/scripts/ros.sh#L19 The cameras also have auto-focus capability, but this is not configured. To disable autofocus:

v4l2-ctl --device=/dev/video6 --set-ctrl focus_auto=0
v4l2-ctl --device=/dev/video7 --set-ctrl focus_auto=0

To set the focus to a fixed value:

v4l2-ctl --device=/dev/video6 --set-ctrl focus_absolute=30
v4l2-ctl --device=/dev/video7 --set-ctrl focus_absolute=30

We may need to play with these options to see if there is any effect on the image quality. The exposure was set to a high value to avoid having blurry images during movement. A high gain may also cause more noise in the images. The quality can also depend on the amount of lighting in the room, which is not particularly great for the image above.

[sgcarrier]

Commands dont seem to be recognized due to the focus_auto and focus_absolute keywords. Also, the gain and exposure commands, while work in command line seem to have no effect when changed in the ros.sh file

[sbrodeur]

The ros.sh file is called when the ros service is started, so it requires to run the following command for changes to take effect:

service ros restart

[sgcarrier]

Was able to set focus, exposure and manual mode in startup script (ros.sh), but the gain parameter is overwritten somewhere in the code. I suspect capturev4l2.cpp. Will continue to investigate.

[sbrodeur]

We should be able to set exposure from the capture node: http://stackoverflow.com/questions/26084794/v4l2-help-in-camera-settings

[sbrodeur]

Here is some code example to integrate here: https://github.com/sbrodeur/ros-icreate-bbb/blob/master/src/camera/src/capturev4l2.cpp#L158

        // Manual exposure control
        // See: https://linuxtv.org/downloads/v4l-dvb-apis/extended-controls.html
        struct v4l2_control stream_control_exposure;
        stream_control_exposure.id = V4L2_CID_EXPOSURE_AUTO;
        stream_control_exposure.value = V4L2_EXPOSURE_MANUAL;
        if(xioctl(_fd, VIDIOC_S_CTRL, &stream_control_exposure) != 0)
        {
            perror("Couldn't set camera exposure to manual");
            return 1;
        }

        // Manual exposure absolute value
        struct v4l2_control stream_control_exposure_value;
        stream_control_exposure_value.id = V4L2_CID_EXPOSURE_ABSOLUTE;
        stream_control_exposure_value.value = _exposure;
        if(xioctl(_fd, VIDIOC_S_CTRL, &stream_control_exposure_value) != 0)
        {
            perror("Couldn't set camera exposure absolute value");
            return 1;
        }

        // Manual focus
        struct v4l2_control stream_control_focus;
        stream_control_focus.id = V4L2_CID_FOCUS_AUTO;
        stream_control_focus.value = false;
        if(xioctl(_fd, VIDIOC_S_CTRL, &stream_control_focus) != 0)
        {
            perror("Couldn't set autofocus to manual");
            return 1;
        }

        // Manual focus absolute value
        struct v4l2_control stream_control_focus_value;
        stream_control_focus_value.id = V4L2_CID_FOCUS_ABSOLUTE;
        stream_control_focus_value.value = _focus;
        if(xioctl(_fd, VIDIOC_S_CTRL, &stream_control_focus_value) != 0)
        {
            perror("Couldn't set camera focus absolute value");
            return 1;
        }

[sbrodeur]

See commit 92ffa7d for the integration (as above) of exposure and focus control. It needs to be tested on the robot.

[sbrodeur]

I'm not sure if we can flip the image by the camera, since it doesn't seem supported:

root@beaglebone:~# v4l2-ctl --device=/dev/video6 --set-ctrl horizontal_flip=1
unknown control 'horizontal_flip'

[sgcarrier]

So far, gain adjustment isn't working. The culprit seems to be in initMmap(), when we start the capture. If we try to change setting after that it gives errors , and if done before they seem to be reset. So far the best solution seems to be adding a script that runs 30 sec after the end of ros.sh that will run the settings command line.

[sbrodeur]

See relevant discussion here: http://www.linuxquestions.org/questions/linux-software-2/camera-settings-in-linux-v4l2-or-uvc-drivers-4175525260/

"I finally solved the issue. The thing is that I had to change the Exposure and the Gain settings after I started the photo capturing not before (all other settings are to be set before). In addition Gain can only be set when Exposure is set to manual."

[sbrodeur]

It is possible to create a cron job to periodically (e.g. every minute) set the camera configuration:

* * * * * /root/work/ros-icreate-bbb/scripts/ros-cron.sh >> /root/work/ros-icreate-bbb/scripts/ros-cron.log 2>&1

This will currently execute every minute automatically on the robot.

Compared to the previous camera image, now the output is much more clear and still not blurry during movement: The cameras seem also to have similar (albeit not perfectly equal) color balance output under the same configuration (e.g. check the wall color).

[sbrodeur]

See commit 10e4455 for the cron job implementation.