Reprojection of 3D points of Superquadrics Curvature caught by Kinect IR-depth sensor to CCD of RGB camera Mariolino De Cecco, Nicolo Biasi, Ilya Afanasyev Facoltà di Ingegneria Trento, /11/2011 1/20

Content 2/20 1. Kinect installation. 2. Kinect calibration. 3. Kinect outputs. 4. MATLAB Preprocessing Kinect data. 5. MATLAB Inputs. 6. SQ Curvature Software. 7. Tests. 8. Results. 9. Links. 21/11/2011

Kinect installation 3/20 1. OpenNI backend: 1. Nicolas Burrus software [1]: Kinect RGBDemo v > supports OpenNI/Nite backends [2] and has the experimental infrared support with OpenNI (still buggy) -> I tried to check this work for OpenNI backend under Windows 64bit. 2. Install Sensor Kinect drivers under Windows 32 bit [3] and OpenNI/Nite modules (Win32) [2] according to the instruction [4] and verified that they work properly. 3. Use RGB-D Capture [1] to grab Kinect RGB and IR images with intensity.raw and depth.raw files. -> the software doesn’t grab IR images!! -> only RGB image, intensity.raw, depth.raw and calibration file (calibration.yml without distortion paraeters)!! 4. “calibrate-openni-intrinsics --pattern-size grab1 calibration.yml” -> gives “openni_calibration.yml” with Intrinsic matrix and distortion coefficients for Kinect RGB camera !! 5. “calibrate-openni-depth.exe --pattern-size grab1” gives partly processed figures with a message about errors. 21/11/ st attempt

The comparison of Kinect calibration results for - Libfreenect backend (under OS Linux / Ubuntu bit) - OpenNI backend (under OS Windows 32bit) - 23/11/2011 The same figures of Intrinsic Matrixes for Kinect RGB and Depth Cameras Libfreenect backendOpenNI backend The Depth Camera Calibration for OpenNI backend is NOT available!!!

The comparison of Kinect calibration results for - Libfreenect backend (under OS Linux / Ubuntu bit) - OpenNI backend (under OS Windows 32bit) - 23/11/2011 There is NO extrinsic mapping between Kinect Depth and RGB cameras for OpenNI backend Libfreenect backendOpenNI backend The reprojection of 3D points from Kinect Depth Camera to RGB image for OpenNI is NOT possible!!

Kinect installation 6/20 1. Libfreenect backend (Windows): 1. Nicolas Burrus software [1]: Kinect RGBDemo v > supports Libfreenect backend [2] and has RGB and infrared support -> I tried to check the work under Windows 64bit. 2. Install Xbox NUI Motor drivers under Windows 32 bit [3] and OpenNI/Nite modules (Win32) [2] according to the instruction [4] and verified that they work properly. 3. Use RGB-D Capture [1] to grab Kinect RGB and IR images with intensity.raw and depth.raw files. -> the software doesn’t grab IR images!! -> only RGB image, intensity.raw, depth.raw and calibration file (calibration.yml without distortion paraeters)!! 4. “calibrate-openni-intrinsics --pattern-size grab1 calibration.yml” -> gives “openni_calibration.yml” with Intrinsic matrix and distortion coefficients for Kinect RGB camera !! 5. “calibrate-openni-depth.exe --pattern-size grab1” gives partly processed figures with a message about errors. 21/11/ nd attempt

Kinect installation 7/20 1. OpenNI backend: 1. Nicolas Burrus software [1]: Kinect RGBDemo v > supports OpenNI/Nite backends [2] and has the experimental infrared support with OpenNI (still buggy) -> I tried to check this work for OpenNI backend under Windows 64bit. 2. Install Sensor Kinect drivers under Windows 32 bit [3] and OpenNI/Nite modules (Win32) [2] according to the instruction [4] and verified that they work properly. 3. Use RGB-D Capture [1] to grab Kinect RGB and IR images with intensity.raw and depth.raw files. -> the software doesn’t grab IR images!! -> only RGB image, intensity.raw, depth.raw and calibration file (calibration.yml without distortion paraeters)!! 4. “calibrate-openni-intrinsics --pattern-size grab1 calibration.yml” -> gives “openni_calibration.yml” with Intrinsic matrix and distortion coefficients for Kinect RGB camera !! 5. “calibrate-openni-depth.exe --pattern-size grab1” gives partly processed figures with a message about errors. 21/11/2011 New Idea

5. MATLAB Inputs. 8/20 Cube_Curvatura_ \ main_reproject.m -> color.png (480x640 pixels) -> calibData.mat: - matrixes of intrinsic parameters for IR camera (K_ir) and RGB camera (K_rgb) - extrinsic mapping between ir (depth) and rgb Kinect camera (R,T) - distortion coefficients (kc_ir, kc_rgb) -> Points.mat (N x 6), where N – number of points with (x,y,z,R,G,B) info 21/11/2011

6. MATLAB Software. 6.1 Elimination of the ground. 9/20 RANSAC search of the ground by using the plane equation. 21/11/2011

Transformation from IR (Depth) to RGB camera reference system: P_rgb = R * P_ir + T, where R,T - extrinsic mapping between ir and rgb Kinect cameras; P_rgb, P_ir – points in RGB and IR camera reference systems. Cube Reprojection without considering distortion (up figures). Cube Reprojection with considering distortion (bottom figures). 10/ D Points Reprojection. ??? Bad calibration? The distance from Kinect to the cube z = 0.5 m 21/11/2011

Cube and Cylinder Reprojection without considering distortion (up figures). Cube and Cylinder Reprojection with considering distortion (bottom figures). 11/ D Points Reprojection. ??? Bad calibration? The distance from Kinect to the objects z = 0.6 m 23/11/2011

12/ RANSAC fitting SQ to 3D data points. With using Levenberg-Marquardt algorithm of distance minimization from SQ to 3D points. Red points – outliers. Blue points – inliers. Green points – SQ model. 21/11/2011

13/ Object structure creation and reprojection on image. Reprojection of the lines between the 3D points of cube vertexes to CCD of Kinect RGB camera (figure a) and to the image with reprojected 3D points (figure b). The information about vertex position was obtained in the previous stage of RANSAC cube pose estimation. Red lines – the cube frameworks Figure a Figure b 21/11/2011

9.References 1. Nicolas Burrus. Kinect. RGBDemo, calibrate and visualize Kinect output. // OpenNI Modules. // 3. SensorKinect drivers. // github social coding How-to: Successfully install Kinect on Windows (OpenNI and NITE). // Vangos Pterneas blog: successfully-install-kinect-windows-openni-nite.aspx 5. Install OpenKinect for Windows 7 and XP. // openkinect-windows-7-and-xp 6. Camera Calibration and 3d Reconstruction. // OpenCV (Open Source Computer Vision) v2.1 documentation: ation_and_3d_reconstruction.html 14/20 21/11/2011