The camera images turned permanently grey and black

[Jendker]

Unfortunately after using the video_stream_opencv in docker all the cameras turned grey and black and restarting the machine does not solve it. This effect persists also when using other apps (Zoom etc.). If we plug in another camera, it works fine.

I wanted to ask what is the reason behind setting all the different device settings in the subscribe function. https://github.com/ros-drivers/video_stream_opencv/blob/68cde068bed55488a9d452ee12a9158838843589/src/video_stream.cpp#L293 I am considering if the failed call of these functions could have a permanent effect on the hardware? I'm not sure what otherwise could have caused it.

The image below presents how the output of the cameras looks now.

[awesomebytes]

Hello @Jendker. In this package we set a reasonable set of defaults. Which now that I think about it, maybe they should not be touched up until a user changes them. I may give a go to implementing that.

Anyways, to solve your issue, I propose you use v4l2-ctl (sudo apt-get install v4l-utils) to discover the defaults of your camera, and then you set them. I must say I'm surprised your camera remembers them after losing power. It works like:

v4l2-ctl --all

Driver Info (not using libv4l2):
    Driver name   : uvcvideo
    Card type     : Integrated_Webcam_HD: Integrate
    Bus info      : usb-0000:00:14.0-7
    Driver version: 5.4.94
    Capabilities  : 0x84A00001
        Video Capture
        Metadata Capture
        Streaming
        Extended Pix Format
        Device Capabilities
    Device Caps   : 0x04200001
        Video Capture
        Streaming
        Extended Pix Format
Priority: 2
Video input : 0 (Camera 1: ok)
Format Video Capture:
    Width/Height      : 640/480
    Pixel Format      : 'YUYV'
    Field             : None
    Bytes per Line    : 1280
    Size Image        : 614400
    Colorspace        : sRGB
    Transfer Function : Default (maps to sRGB)
    YCbCr/HSV Encoding: Default (maps to ITU-R 601)
    Quantization      : Default (maps to Limited Range)
    Flags             : 
Crop Capability Video Capture:
    Bounds      : Left 0, Top 0, Width 640, Height 480
    Default     : Left 0, Top 0, Width 640, Height 480
    Pixel Aspect: 1/1
Selection: crop_default, Left 0, Top 0, Width 640, Height 480
Selection: crop_bounds, Left 0, Top 0, Width 640, Height 480
Streaming Parameters Video Capture:
    Capabilities     : timeperframe
    Frames per second: 30.000 (30/1)
    Read buffers     : 0
                     brightness 0x00980900 (int)    : min=-64 max=64 step=1 default=0 value=0
                       contrast 0x00980901 (int)    : min=0 max=95 step=1 default=0 value=0
                     saturation 0x00980902 (int)    : min=0 max=100 step=1 default=64 value=64
                            hue 0x00980903 (int)    : min=-2000 max=2000 step=1 default=0 value=-1200
 white_balance_temperature_auto 0x0098090c (bool)   : default=1 value=1
                          gamma 0x00980910 (int)    : min=100 max=300 step=1 default=100 value=100
                           gain 0x00980913 (int)    : min=1 max=8 step=1 default=1 value=1
           power_line_frequency 0x00980918 (menu)   : min=0 max=2 default=2 value=1
      white_balance_temperature 0x0098091a (int)    : min=2800 max=6500 step=10 default=4600 value=4600 flags=inactive
                      sharpness 0x0098091b (int)    : min=1 max=7 step=1 default=2 value=2
         backlight_compensation 0x0098091c (int)    : min=0 max=3 step=1 default=3 value=3
                  exposure_auto 0x009a0901 (menu)   : min=0 max=3 default=3 value=3
              exposure_absolute 0x009a0902 (int)    : min=10 max=625 step=1 default=166 value=166 flags=inactive

There you can see the different parameters, like brigthness and contrast.

Then you set them to the default you read there like:

v4l2-ctl --set-ctrl brightness=0

[Jendker]

That has helped, thank you!

[awesomebytes]

You can set the desired camera size in the launch file settings of this package, they will be attempted to be set via the opencv API.

Some cameras do ignore it, though

On Sat, Apr 24, 2021, 00:54 zoombinis @.***> wrote:

@awesomebytes https://github.com/awesomebytes Can you clarify how to correct the config?

For instance, using v4l2 it is showing my camera image dimensions as:

Priority: 2 Video input : 0 (Camera 1: ok) Format Video Capture: Width/Height : 1024/720

But actually I have configured the camera to display 640x480

But video_stream_opencv logs the image size as 640x320, which I think is compromising my camera calibration I'm trying to perform.

How can I force the correct image height, or does this not really make any impact?

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[ghost]

@awesomebytes unfortunately the launch file setting is not working for me. I filed a new issue for this. Is there no way to correctly set the width? I haven't seen this issue before with other ros nodes consuming this camera stream.

https://github.com/ros-drivers/video_stream_opencv/issues/99

[machinekoder]

The actual problem is that OpenCV switched away from normalizing the properties: https://github.com/opencv/opencv/blob/master/modules/videoio/src/cap_v4l.cpp#L1994 This property should be set in the node.

[dhgarcia]

I was having this same problem so thanks @Jendker and @awesomebytes, and thanks to @machinekoder for highlighting the OpenCV change that creates the issue.

If it helps to anybody I found a solution. After reading through https://github.com/opencv/opencv/blob/master/modules/videoio/src/cap_v4l.cpp#L379 This behaviour can be solved by just setting the environment variable OPENCV_VIDEOIO_V4L_RANGE_NORMALIZED to true.