Monday, May 18, 2015

Link to PASCAL VOC 2007 Dataset


Link where PASCAL VOC 2007 Dataset available:
http://vision.cs.utexas.edu/voc/
(Thanks to Dr  Jasper Uijlings)

How to download vis Linux terminal:
$ wget -m -np http://vision.cs.utexas.edu/voc/
(Ref: http://stackoverflow.com/questions/8386894/download-an-svn-repository )

Found the official mirror to PASCAL VOC datasets (Thanks to Dr  Jasper Uijlings again):

http://host.robots.ox.ac.uk/pascal/VOC/

Wednesday, May 13, 2015

MATLAB parfor tips from various resources

Mount cellphone (Nokia Lumia 520) on Ubuntu 12.04

http://askubuntu.com/questions/367927/how-to-connect-nokia-lumia-520-to-ubuntu-12-04

Save RGB image using RGBD sensor and ROS

1.
$roscore
2.
$roslaunch openni_launch openni.launch
or
$roslaunch openni2_launch openni2.launch (Depending on the driver that your sensor uses.)
3.
$rosrun image_view image_view image:=/camera/rgb/image_rect_color

A tiny window pops up showing the scene in view. Right click on it to save the image.

Friday, October 24, 2014

Linking Error: undefined reference to symbol 'vtkCellArray::New()' when using pclVisualizer

While compiling the Correspondence_grouping code from pcl (http://www.pointclouds.org/documentation/tutorials/correspondence_grouping.php ) in my ROS Hydro workspace, I got following linking error:

Linking error:
 Linking CXX executable /home/swagatika/catkin_ws/devel/lib/my_pcl_tutorial/correspondence_grouping
/usr/bin/ld: CMakeFiles/correspondence_grouping.dir/src/correspondence_grouping.cpp.o: undefined reference to symbol 'vtkCellArray::New()'
/usr/bin/ld: note: 'vtkCellArray::New()' is defined in DSO /usr/lib/libvtkFiltering.so.5.8 so try adding it to the linker command line
/usr/lib/libvtkFiltering.so.5.8: could not read symbols: Invalid operation
collect2: ld returned 1 exit status
make[2]: *** [/home/swagatika/catkin_ws/devel/lib/my_pcl_tutorial/correspondence_grouping] Error 1
make[1]: *** [my_pcl_tutorial/CMakeFiles/correspondence_grouping.dir/all] Error 2
make: *** [all] Error 2
Invoking "make" failed

Solution:

In  ~/catkin_was/src/my_pcl_tutorial/CMakeLists.txt :

add_executable(correspondence_grouping src/correspondence_grouping.cpp)
target_link_libraries(correspondence_grouping ${catkin_LIBRARIES} ${PCL_LIBRARIES} libvtkCommon.so libvtkFiltering.so )


Ref:

http://www.pointclouds.org/documentation/tutorials/correspondence_grouping.php
http://answers.ros.org/question/37096/error-when-using-pclvisualizer/

Wednesday, October 22, 2014

Openni2 error: No matching device found.... waiting for devices.

I use openni2 with ROS with the ASUS Xtion Pro live (new model with rectangular less instead of the oval one) for capturing data.

However, suddenly openni2_launch stopped working.

$roslaunch openni2_launch openni2.launch

kept giving the following error:

Warning: USB events thread - failed to set priority. This might cause loss of data...
[ INFO] [1414001657.842030853]: No matching device found.... waiting for devices. Reason: openni2_wrapper::OpenNI2Device::OpenNI2Device(const string&) @ /tmp/buildd/ros-hydro-openni2-camera-0.1.3-0precise-20140921-1219/src/openni2_device.cpp @ 74 : Initialize failed
    Could not open "1d27/0601@3/3": USB transfer timeout!

I found solutions for openni for the same problem, but not for openni2.

Although I could not figure out the exact reason for this sudden change in behaviour, trying to re-install the ros-hydro-openni drivers helped to resolve this issue (Thanks to Andreas :) ).

So if you get the same problem, try doing this:

$ sudo apt-get remove ros-hydro-openni2-*

$sudo apt-get install ros-hydro-openni2-camera

$sudo apt-get install ros-hydro-openni2-launch