Running PiCamera on Ubuntu in C++ - c++

Question

I'm trying to get my PiCamera Module v2.1 running on my RaspberryPi4. Unfortunately I must install the Ubuntu 19.10 64bit distribution. So far so good.
I've installed Opencv4. There was some big trouble because it seems like Ubuntu does not come with VideoCore, raspi-config etc. So I downloaded and updated my firmware with sudo rpi-update and installed userland.
First I tried to open the camera with Videocapture cap(0), but this throws a bunch of errors (see here Ubuntu 19.10: Enabling and using Raspberry Pi Camera Module v2.1) and I've read that this is only for usb cameras (actually i can't believe this, because under Raspbian, I can use the module like this)
So I googled and found this repo https://github.com/cedricve/raspicam. I've installed it, but even with this I cannot get it running.
Again here is what I've down:
install opencv4
update firmware
install userland
writing start_x=1 and "gpu_mem=128" to /boot/firmware/config.txt
doing modprobe bcm2835-v4l2
sudo vcgencmd get_camera results in supported and detected = 1
When I use sudo raspistill -o test.jpg a window opens and the image is saved. But there are some errors:
mmal: mmal_vc_shm_init: could not initialize vc shared memory service
mmal: mmal_vc_component_create: failed to initialise shm for 'vc.camera_info' (7:EIO)
mmal: mmal_component_create_core: could not create component 'vc.camera_info' (7)
mmal: Failed to create camera_info component
Also I need to start it with sudo, although I've run sudo usermod -a -G video ubuntu several times (also rebooted). Strange, isn't?
My example script for accessing the camera is:
#include <iostream>
#include <raspicam/raspicam_cv.h>
using namespace std;
int main ( int argc,char **argv ) {
time_t timer_begin,timer_end;
raspicam::RaspiCam_Cv Camera;
cv::Mat image;
int nCount=100;
//set camera params
Camera.set( cv::CAP_PROP_FORMAT, CV_8UC1 );
//Open camera
cout<<"Opening Camera..."<<endl;
if (!Camera.open()) {cerr<<"Error opening the camera"<<endl;return -1;}
//Start capture
cout<<"Capturing "<<nCount<<" frames ...."<<endl;
time ( &timer_begin );
for ( int i=0; i<nCount; i++ ) {
Camera.grab();
Camera.retrieve ( image);
if ( i%5==0 ) cout<<"\r captured "<<i<<" images"<<std::flush;
}
cout<<"Stop camera..."<<endl;
Camera.release();
}
Compilation is successful:
sudo g++ stream.cpp -I/usr/local/include/opencv4 -I/usr/local/include -L/usr/local/lib -L/opt/vc/lib -lraspicam_cv -lopencv_core -lraspicam -lmmal -lmmal_core -lmmal_util -lopencv_highgui -lmmal_vc_client -lvcos -lbcm_host -o stream
Executing stream (even with sudo) results in:
Opening Camera...
mmal: mmal_component_create_core: could not find component 'vc.ril.camera'
Failed to create camera componentopen Failed to create camera component/home/raspicam/src/private/private_impl.cpp 103
Error opening the camera
Does anyone have an idea what I can try?
Thanks !

Answer 1

I had this error while compiling a ROS node for the raspicam.
I fixed it by adding the following to my CMakeLists.txt:
set (CMAKE_SHARED_LINKER_FLAGS "-Wl,--no-as-needed")
The issue was that the reference to the library containing the 'vc.ril.camera' was optimized out by the linker and count not be found at run time.
Hopefully it will work for you.