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libuvc iris and exposure have no effect

asked 2015-09-01 08:46:48 -0500

Roque gravatar image

Hello folks,

I am using libuvc paired with a Logitech C270 camera for some vision processing. I need to change exposure and iris parameters in order to reduce over-exposure.

I've got the suggested launch file from here and changed the auto_exposure to 0. This produced a constant image on the camera. But, changing exposure_absolute and iris_absolute produced no effect on the viewed image. Also, I have no errors while running

Here is my launch file:

<launch>
  <group ns="camera">
    <node pkg="libuvc_camera" type="camera_node" name="mycam">
      <!-- Parameters used to find the camera -->
      <param name="vendor" value="0x046d"/>
      <param name="product" value="0x0825"/>
      <param name="serial" value=""/>
      <!-- If the above parameters aren't unique, choose the first match: -->
      <param name="index" value="0"/>

      <!-- Image size and type -->
      <param name="width" value="640"/>
      <param name="height" value="480"/>
      <!-- choose whichever uncompressed format the camera supports: -->
      <param name="video_mode" value="uncompressed"/> <!-- or yuyv/nv12/jpeg -->
      <param name="frame_rate" value="30"/>

      <param name="timestamp_method" value="start"/> <!-- start of frame -->
      <param name="camera_info_url" value="file:///home/roque/ROS/cal.yml"/>

      <param name="auto_exposure" value="3"/> <!-- use aperture_priority auto exposure -->
      <param name="auto_white_balance" value="false"/>
      <param name="auto_focus" value="false" />
      <param name="auto_hue" value="false"/>

      <param name="exposure_absolute" value="0.01"/>
      <param name="iris_absolute" value="1" />
      <param name="focus_absolute" value="1"/>
      <param name="brightness" value="1000"/>
      <param name="contrast" value="0"/>
      <param name="gain" value="0"/>
      <param name="saturation" value="0"/>
      <param name="sharpness" value="0"/>
    </node>
    <node name="image_view" pkg="image_view" type="image_view" respawn="false" output="screen">
      <remap from="image" to="/camera/image_raw"/>
      <param name="autosize" value="true" />
    </node>
  </group>
</launch>

Thank you in advance!

With my best regards,

Pedro

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answered 2015-09-01 08:55:17 -0500

AFAIK not all cameras support all controls specified in the UVC spec. You could try if other tools allow changing the controls. You could try the guvcview tool for instance (just start guvcview or sudo guvcview in a terminal). If the controls work there, it's a issue with the ROS driver. If they don't, the camera might not support the controls.

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guvcview works!

Roque gravatar image Roque  ( 2015-09-01 17:44:28 -0500 )edit

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Asked: 2015-09-01 08:46:48 -0500

Seen: 338 times

Last updated: Sep 01 '15