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2017-10-12 12:57:42 -0500 answered a question GUI opens but is not drawn

I think i see the problem here. Through my own trials i observed that the symptoms you are describing occur when the ima

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2017-10-12 11:05:54 -0500 commented question GUI opens but is not drawn

I'm having the exact same issue after installing 16,04 fresh. Did you ever resolve this issue? Would be very interested

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2016-05-09 16:05:44 -0500 asked a question Getting Frame Transform With Shared Parent

Because ROS (python indigo at least) does not like reverse traversing the TF tree it won't perform a transform between two frames that share a parent. For example if you have a parent frame Base which has two child frames Left_Wheel and Right_Wheel, ROS will happily find the transform between Base and either child, but cannot find the transform between Left_Wheel and Right_Wheel.

I have a convoluted workaround for this which involves setting up a local transformer, inverting one of the the child transforms and setting it as the parent of the shared parent. This is super unpleasant and has to be done every single time I want to perform this transform. Is there a smarter way to do this?


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2016-04-11 16:21:58 -0500 answered a question Combine position estimates from Lidar SLAM and PTAM

Not sure about this situation specifically, but in general robot localization is a great tool for fusing pose estimates

2016-04-07 09:46:43 -0500 asked a question Can't launch libuvc_camera

I'm trying to use libuvc_camera to get my usb camera working on a nodelet to reduce CPU usage, but I'm having a lot of trouble. I've brute-forced my way through most of my problems, but now I'm stonewalled. Every time I try to boot the launch file I just get

unsupported descriptor subtype: 3
unsupported descriptor subtype: 3
uvc_get_stream_ctrl_format_size: Invalid mode (-51)

Here's my launch file:

  <group ns="camera">
    <node pkg="libuvc_camera" type="camera_node" name="mycam">
      <!-- Parameters used to find the camera -->
      <param name="vendor" value="0x2560"/>
      <param name="product" value="0xc110"/>
      <param name="serial" value="32C0D5400"/> 
      <!-- If the above parameters aren't unique, choose the first match: -->
      <param name="index" value="0"/>

      <!-- Image size and type -->
      <param name="width" value="1280"/>
      <param name="height" value="960"/>
      <!-- choose whichever uncompressed format the camera supports: -->
      <param name="video_mode" value="yuyv"/> <!-- uncompressed/yuyv/nv12/jpeg -->
      <param name="frame_rate" value="10"/>

      <param name="timestamp_method" value="start"/> <!-- start of frame -->
      <param name="camera_info_url" value="file:///home/usr/.ros/camera_info/calibration.txt"/>

      <param name="auto_exposure" value="1"/> <!-- use aperture_priority auto exposure -->
      <param name="auto_white_balance" value="false"/>

And here is the error:

process[camera/mycam-1]: started with pid [22107]
unsupported descriptor subtype: 3
unsupported descriptor subtype: 3
uvc_get_stream_ctrl_format_size: Invalid mode (-51)
[ERROR] [1460040590.634224143]: check video_mode/width/height/frame_rate are available
[camera/mycam-1] process has died [pid 22107, exit code -11, cmd /home/davelkan/locus/babbage/devel/lib/libuvc_camera/camera_node __name:=mycam __log:=/home/davelkan/.ros/log/48edeb92-fc35-11e5-9a05-0862664a2a25/camera-mycam-1.log].
log file: /home/davelkan/.ros/log/48edeb92-fc35-11e5-9a05-0862664a2a25/camera-mycam-1*.log
all processes on machine have died, roslaunch will exit
shutting down processing monitor...
... shutting down processing monitor complete

And here's the relevant data from lsusb -v

Bus 004 Device 013: ID 2560:c110  
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               3.00
  bDeviceClass          239 Miscellaneous Device
  bDeviceSubClass         2 ?
  bDeviceProtocol         1 Interface Association
  bMaxPacketSize0         9
  idVendor           0x2560 
  idProduct          0xc110 
  bcdDevice            0.00
  iManufacturer           1 e-con Systems
  iProduct                2 e-con's 1MP Monochrome Camera
  iSerial                 3 2C0D5400


  • I have confirmed my device is uvc compliant

  • I have confirmed uvc is correctly installed

  • I have successfully gotten this camera working with usb_cam

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2016-02-17 13:56:54 -0500 answered a question What are x and y in map_msgs/OccupancyGridUpdate?

Figured it out through testing. X and Y refer to the corner of the occupancy grid update in the occupancy grid frame

2016-02-17 13:42:31 -0500 asked a question What are x and y in map_msgs/OccupancyGridUpdate?

I'm trying to do some things with occupancy grids, and I cannot figure what the x and y attributes refer to. Anyone know?



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2016-02-16 11:11:03 -0500 asked a question Checking if a Pose would be in Collision

Hey ROS Hive-Mind,

I've been trying out a new localization method and I'm trying to validate my poses before accepting them for robot updates. I was going to write a service to do this, but it occurs to me there is probably already one that is used elsewhere since this seems like a pretty useful thing. Closest I've found so far is link:move_base/make_plan, but that's not actually what I want since I'd have to give a starting position and it could return a negative response for reasons other than the end point is in collision.

Ideally this service would also take into account the inflation layer.

Does anyone know of a service that may meet my needs? Or should I just go ahead and write my own.

Thanks, David

2015-11-19 12:18:30 -0500 asked a question Properly Bring Down Active Node?

I'm currently using ros::shutdown() to bring down a node that I need to kill in c++. I'm fairly certain this is bad as the node fails ungracefully and does not seem to release all of its resources. Is there a better method?

2015-11-18 08:21:45 -0500 commented answer Modifying Ros Driver Before Installing

thanks i'll give this a shot

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2015-11-17 17:06:42 -0500 asked a question Modifying Ros Driver Before Installing

Hi all,

I need to make some rather specific changes to a ros driver specifically to the ros-indigo-pointgrey-camera-driver, before installing it. Does anyone know how I can do this?



2015-11-16 13:10:09 -0500 commented answer Point Grey Camera Image Consistency Issue Exactly 50%

Unfortunately i'm still having this issue. I'm attempting to use the drivers on your git and and getting a compilation error on " fatal error: flycapture/FlyCapture2.h: No such file or directory #include "flycapture/FlyCapture2.h" is there a dependency i missed?


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2015-10-23 11:42:04 -0500 asked a question Point Grey Camera Image Consistency Issue Exactly 50%

I'm running Ubuntu 14.04 with Indigo and a point grey blackfly. Every second time I run my launch file, which includes the camera launch exert below, I get an endless stream of camera consistency errors and no images. And by every second time I mean exactly and only every other time. I tried increasing socket buffer size to no benefit. The problem seems to occur regardless of which camera nodelets I run.

<!-- Point Grey Blackfly -->

<arg name="camera_serial" default="0" />
<arg name="calibrated" default="0" />

  <group ns="camera">
    <node pkg="nodelet" type="nodelet" name="camera_nodelet_manager" args="manager" />
    <node pkg="nodelet" type="nodelet" name="camera_nodelet"
      args="load pointgrey_camera_driver/PointGreyCameraNodelet camera_nodelet_manager" >
      <param name="frame_id" value="$(arg sensor_frame_prefix)/camera_link" />
      <param name="serial" value="$(arg camera_serial)" />
      <param name="frame_rate" value="10" />
      <param name="camera_info_url" if="$(arg calibrated)"
        value="file://$(env HOME)/.ros/camera_info/$(arg camera_serial).yaml" />
    <node pkg="nodelet" type="nodelet" name="image_proc_debayer"
      args="load image_proc/debayer camera_nodelet_manager">
    <node pkg="nodelet" type="nodelet" name="rectify_mono"
      args="load image_proc/rectify camera_nodelet_manager">

The error is:

[ERROR] [1445558727.357774357]: PointGreyCamera::grabImage Failed to retrieve buffer | FlyCapture2::ErrorType 41There is an image consistency issue with this image.

Anyone experienced this problem? Anyone have any idea how to resolve this?