Hello Bill, I have two cameras, laptop default and uvc: webcam Logitech pro 9000 (Auto focus is off) I enabled uvc and calibrated camera using 8x6 --square 0.108 mm chessboard. It automatically sets the resolution 1600 X 1200 pxl. I did not find a way to change it. In usb_cam_nose.cpp It is mentioned as, node_.param("image_width", image_width_, 640); node_.param("image_height", image_height_, 480); then it asked for the file with the autogenerated name as v046Dp0990d0008dcEFdsc02dp01ic0Eisc01ip00_01604D55_640x480.yaml I created the same name file with below calib parameters: image_width: 1600 image_height: 1200 camera_name: camera camera_matrix: rows: 3 cols: 3 data: [1386.75, 0, 851.704, 0, 1386.18, 572.83, 0, 0, 1] distortion_coefficients: rows: 1 cols: 5 data: [0.072094, -0.133644, -0.001888, 0.006912, 0] rectification_matrix: rows: 3 cols: 3 data: [1, 0, 0, 0, 1, 0, 0, 0, 1] projection_matrix: rows: 3 cols: 4 data: [1386.75, 0, 851.704, 0, 0, 1386.18, 572.83, 0, 0, 0, 1, 0] It works well with image_proc or simple image show. but, /camera topic is published and not display anything in rviz even after camera_info is being generated which i checked using rostopic echo. No CameraInfo received on [/usb_cam/camera_info]. Topic may not exist. > Image: No image received. > Transform [Sender=/usb_cam] = For frame [camera]: Frame [camera] does not > exist I tried to change the parameter of usb_cam_node.cpp from 640 X 480 to 1600 X 1200 and created new file named v046Dp0990d0008dcEFdsc02dp01ic0Eisc01ip00_01604D55_1600x1200.yaml with the same above parameters. When i run ar_pose with below launch file, i get same output in rviz as above along with error messages from one of the codes: "outbuf size mismatch. pic_size: %d bufsize: %d\n",pic_size Am i going wrong somewhere? Is this a right approach to configure ar_pose and usb_cam? Thanks, - Prasad -- View this message in context: http://ros-users.122217.n3.nabble.com/ar-pose-basic-questions-tp2025177p2130075.html Sent from the ROS-Users mailing list archive at Nabble.com.