b-sriram's profile - activity

Hi,

I have a px4flow smart camera sensor, and use the px4flow_node to read the sensor output.

The topic /px4flow/optflow has a message type:

Header header

float32 ground_distance  # distance to ground in meters
int16   flow_x           # x-component of optical flow in pixels
int16   flow_y           # y-component of optical flow in pixels
float32 velocity_x       # x-component of scaled optical flow in m/s
float32 velocity_y       # y-component of scaled optical flow in m/s
uint8   quality          # quality of optical flow estimate

But when I see the output I only have values for flow_x and flow_y. I am only using it for a 2D robot so assuming I always know the ground distance, can someone please tell me how to calculate the x and y velocities using the flow_x and flow_y values?

Line Strips and Points in Marker array not being published with correct pose Hi, I'm trying to publish a marker for eve

I did do that. I took the library and wrote my own subscriber. There was no difference. (still lags) I though of the sam

@Stefan seems to be the same issue. I'll follow the post. Thanks!

@Stefan seems to be the same issue. I follow the post. Thanks!

I didn't set any thread limits. So its weird for me too.

April tag 2 ROS pose detection Hi, I am using the Apriltag2_ros package to detect the apriltags in my scene. Everythin

Its using a lot of CPU around 200%

April tag 2 ROS pose detection Hi, I am using the Apriltag2_ros package to detect the apriltags in my scene. Everythin

The resolution is 2048 x 2048.

Intel Xeon Processor with 4 cores and 32gb RAM. "does this mean it only lags when you try and visualize in rviz". Its l

Intel Xeon Processor with 4 cores and 32gb RAM. "does this mean it only lags when you try and visualize in rviz". Its l

That the time taken for the algorithm to process one image is extremely high. This makes the pose detection really slow.

April tag 2 rose pose detection Hi, I am using the Apriltag2_ros package to detect the apriltags in my scene. Everythi

Hi @msy is your Ethernet port configured properly? Are you on the same subnet as the OXTS?

Hi,

I have an OXTS box basically a imu + gps. I have connected it through Ethernet port.

I'm fairly new to ROS and don't know how to create a UDP socket in ros to receive the data i.e the UDP broadcast from the OXTS.

Could someone please suggest where I should start? Thanks

Hi,

In the robot_localisation package, when the use_control param is set to true then the values from the cmd_vel topic are used for the state prediction. But what if its set false. How does the prediction setup work?

I looked at one of the questions posed where it is explained how the prediction step works link.

The transition function for x is x_new = x_old + vx * t + 0.5 * a * t^2

Normally this would mean the vx and aare obtained from the previous state and when the use_control param is true, then these values are obtained from cmd_vel topic.

When I look at the documentation of robot_localisation package, it says

Note: The presence and inclusion of linear acceleration data from an IMU will currently “override” the predicted linear acceleration value.

Which I'm not able to understand as the values from the IMU are used for the correction step and not prediction.

I know I'm assuming something wrong here, but could someone please explain to me how it works?

Thanks Sriram

ueye_cam sick camera Hi, I use the ueye_cam driver to connect to a sick pico camera which uses the IDS software suit to

... I dont get the proper inverse. This is because the coordinate system of the ar tags detected are rotated as compared

How to create a static tf from artags to map frame? Hi, I am using the ar_track_alvar package to detect artags placed i

... I dont get the proper inverse. This is because the coordinate system of the ar tags detected are rotated as compared

... I dont get the proper inverse. This is because the coordinate system of the ar tags detected are rotated as compared

I created two transform objects: 1. Position of Markers in marker frame (inverse of the tf published by ar_track_alvar)

Ros driver for picocam SICK? Hi, I have a SICK picoCam and was searching for a ROS driver to connect with the camera.

I get I have to connect the tags to a world frame but I'm really new to Ros and don't know the code to do it. If you cou

So my tags when sensed would give me the relative position of the camera(robot) with respect to it's position. Now what

I already have an EKF running to localise using my encoder and Imu . This would then publish a transfrom from the Odom f

Ok I do know the transformation between the gazebo frame and map origin. The only problem is I cannot create a static TF