PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 1999-03-03 INTERCHANGE_FORMAT = ASCII NOTE = "Description of the CALIB directory contents for the Mars Pathfinder Rover archive." END_OBJECT = TEXT END CALIB Directory Contents The rover team has calibrated the rover cameras using what they call a CAHVOR model. Others may choose to use the raw data to calibrate the cameras themselves, using a method they are accustomed to. Or, they may choose to use the calibration results and work with a CAHVOR model. This directory contains files prepared by Todd Litwin to calibrate the flight rover cameras, as installed on the flight rover, all done in a single coordinate system. This system has an origin located off center of the leading face of the rover (front surface), x is in the rover-forward direction, z is down, and y is to the rover's right. Images were obtained using the front and rear rover cameras viewing a target of white dots on a dark background. The rover was rotated between imaging with front cameras and imaging with the rear camera. See [YAKIMOVSKY&CUNNI1978] for a detailed description of the CAHV camera model. [GENNERY1993] provides details on the two additional radial distortion vectors O and R in the CAHVOR camera model. In a nutshell, here are the parameters a CAHV or CAHVOR camera model contains: C: Camera position, vector of the focal center A: Axis vector pointing normal to the CCD array H, V: Horizontal and vertical 3-D orientation vectors. The magnitude of H projected into the image plane is the focal length of the lens expressed in horizontal pixels. The magnitude of V projected into the image plane is the focal length in vertical pixels. H and V are parallel to horizontal and vertical image lines. O: Axis of symmetry of radial distortion, equal to A if there is no asymmetrical distortion. R: Radial symmetry vector, the first three distortion coefficients "rho zero", "rho one" and "rho two" in Gruin and Huang, 1993. Note that all of the image files in this directory received for this archive were in GIF format. They have been converted to PDS format for the sake of the long-term safety of the data. However, the PDS labels contain NO information beyond the physical parameters of the image data. They are not intended to match the PDS labels used on the Rover Camera EDR data files. ---------------------------------------------------------------------- CAMINFOC.ASC - information about the MFEX color camera CAMINFOC.LBL - PDS label describing CAMINFOC.ASC CAMINFOS.ASC - information about the MFEX stereo cameras CAMINFOS.LBL - PDS label describing CAMINFOS.ASC COLORPIX.ASC - information about the color camera row and column positions of red, green, and blue pixels COLORPIX.LBL - PDS label describing COLORPIX.ASC MESRMNTS.ASC - Theodolite measurements taken of distances and angles in the imaging setup. All of these distances are expressed in units of meters, with respect to the rover coordinate system described at the top of this CALINFO file. This data was used as input by the rover team for coming up with a CAHV camera model for the rover cameras. MESRMNTS.LBL - PDS label describing MESRMNTS.ASC ---------------------------------------------------------------------- The following images comprise the raw calibration data. They are full frame images of a calibration target taken by the flight rover cameras on the flight rover, at room temperature. The coordinate of the upper, left pixel of all images corresponds to (row 1, col 0) of the camera CCD, as reported by the rover's software. FC.* - rear color camera, far calibration fixture NC2.* - rear color camera, near calibration fixture FFL.* - front left camera, far calibration fixture NFL.* - front left camera, near calibration fixture FFR.* - front right camera, far calibration fixture NFR.* - front right camera, near calibration fixture ---------------------------------------------------------------------- The following versions of the images have been processed to reduce the effect of dark current noise buildup in each image segment. (UNST is short for unstripe.) FC_UNST.* - rear color camera, far calibration fixture NC2_UNST.* - rear color camera, near calibration fixture FFL_UNST.* - front left camera, far calibration fixture NFL_UNST.* - front left camera, near calibration fixture FFR_UNST.* - front right camera, far calibration fixture NFR_UNST.* - front right camera, near calibration fixture ---------------------------------------------------------------------- The following images have been linearized to help straighten out lines. FC_WARP.* - rear color camera, far calibration fixture NC2_WARP.* - rear color camera, near calibration fixture FFL_WARP.* - front left camera, far calibration fixture NFL_WARP.* - front left camera, near calibration fixture FFR_WARP.* - front right camera, far calibration fixture NFR_WARP.* - front right camera, near calibration fixture ---------------------------------------------------------------------- The following text files contain the coordinates of the corners and information about dot size and spacing for the calibration target for the different images. These are measured in meters with respect to the rover coordinate system described at the beginning of this CALINFO.TXT file. Also see the text at the beginning of each of the files. CLRFRFIX.ASC - color camera with target in far position CLRFRFIX.LBL - PDS label describing CLRFRFIX.ASC CLRNRFIX.ASC - color camera with target in near position CLRNRFIX.LBL - PDS label describing CLRNRFIX.ASC STRFRFIX.ASC - stereo cameras with target in far position STRFRFIX.LBL - PDS label describing STRFRFIX.ASC STRNRFIX.ASC - stereo cameras with target in near position STRNRFIX.LBL - PDS label describing STRNRFIX.ASC ---------------------------------------------------------------------- The following files contain output from the calibration process. These are least squares iterations. Ignore the 'model may be no good' message. Output contains values for the 3-D vectors C, A, H, V, O, and R. S is the 18 x 18 covariance matrix from the camera model fitting routine, which indicates the accuracy of the result (only 16 of these are independent because A and O are of unit length). Hs, Hc, Vs, Vc are the scale factors (s) and entrance pupil centers (c) of the horizontal and vertical vectors, and theta is the angle between the two axes. Hs, Hc, Vs, and Vc can be derived from H and V vectors, and are in a convenient form for projecting a point from the 3D coordinate system to the 2D image plane. 'S internal' is the covariance matrix after radial distortion correction. The upper left of the 2-D images is (0,0). However the raw images started with row 1, so we're off by one. To fix this, they generated *S*.cahvor versions (shifted the camera model over by one pixel) to correct for this. CAHVOR_C.ASC - color camera CAHVOR_C.LBL - PDS label describing CAHVOR_C.ASC CAHVOR_L.ASC - left camera CAHVOR_L.LBL - PDS label describing CAHVOR_L.ASC CAHVOR_R.ASC - right camera CAHVOR_R.LBL - PDS label describing CAHVOR_R.ASC CAHVORFC.ASC - fake stereo pair made for the rear color camera by shifting the camera model in order to be able to generate a linearized version of the images from the rear color camera CAHVORFC.LBL - PDS label describing CAHVORFC.ASC CAHVORSC.ASC - color camera; model shifted by one pixel CAHVORSC.LBL - PDS label describing CAHVORSC.ASC CAHVORSL.ASC - left camera; model shifted by one pixel CAHVORSL.LBL - PDS label describing CAHVORSL.ASC CAHVORSR.ASC - right camera; model shifted by one pixel CAHVORSR.LBL - PDS label describing CAHVORSR.ASC ---------------------------------------------------------------------- The following files are the same as the above files, except without the radial distortion parameters. CAHV_C.ASC - color camera CAHV_C.LBL - PDS label describing CAHV_C.ASC CAHV_L.ASC - left camera CAHV_L.LBL - PDS label describing CAHV_L.ASC CAHV_R.ASC - right camera CAHV_R.LBL - PDS label describing CAHV_R.ASC CAHV_WC.ASC - color camera; warped CAHV_WC.LBL - PDS label describing CAHV_WC.ASC CAHV_WL.ASC - left camera; warped CAHV_WL.LBL - PDS label describing CAHV_WL.ASC CAHV_WR.ASC - right camera; warped CAHV_WR.LBL - PDS label describing CAHV_WR.ASC ---------------------------------------------------------------------- The following files contain residuals resulting from the calibration process for CAHV and CAHVOR models. RSDUAL_C.ASC - color camera RSDUAL_C.LBL - PDS label describing RSDUAL_C.ASC RSDUAL_L.ASC - left camera RSDUAL_L.LBL - PDS label describing RSDUAL_L.ASC RSDUAL_R.ASC - right camera RSDUAL_R.LBL - PDS label describing RSDUAL_R.ASC