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Hopwood: 3 DM Analyst Open Mine Pit Measuring System ADAM Technology wishes to acknowledge Kundana Gold Mining Company for their assistance in the preparation of this demonstration
3 DM Analyst Software Tools for 3 D Measurement The 3 DM Analyst is a set of specialised software tools designed to extract accurate 3 D spatial measurements of objects by analysing images taken with handheld digital cameras. The 3 dimensional data produced can then be viewed, and edited, with standard stereovision systems (e. g. Stereographics Crystal Eyes or Z Screen, even as a low cost anaglyph). The system performs camera calibration and exterior orientation calculations to enable it to create epipolar images which can then be viewed in 3 D. The epipolar images are then used to generate a 3 D Digital Terrain Model (DTM). This DTM can be modified and 3 D Polylines added. 3 D measurements can then be extracted from the data. Once complete the epipolar images and all of the 3 D data can be stored in the job file. The data can also be exported out for further editing and presentation work in other software packages. The advanced texture mapping capability ensures that the 3 D model is accurately represented. This is especially useful for geological observation. The 3 DM Analyst settings can be adjusted to achieve the accuracy required by the user. Typically surface points are measured within an accuracy of around 1/4000 th of the size of the object measured.
3 DM Analyst Photography Suitable photography involves taking a pair of convergent images of the same scene from separate positions. The camera(s) separation depends on the distance of the closest objects in the scene and the degree of stereo one wishes to achieve. The cameras should be angled inwards, so that the imaginary rays projected into the scene intersect at a depth that is intended to be at the projection plane. Objects that are closer than this intersection plane will appear to be closer to the viewer, points behind this intersection plane will appear to be further from the viewer. To provide the most comfortable viewing: A general rule of thumb is for the camera separation to be around 1/20 th of the distance where the camera rays intersect (intersection plane).
3 DM Analyst Stereopair images are loaded into the 3 DM Analyst.
Left Image loaded Right Image loaded
3 DM Analyst Loading Control and Viewing Relative Orientation Points The exterior orientation of a camera position is defined as the position of the projection centre of the camera in space (X, Y, Z) and 3 rotation angles describing the orientation (direction of the camera axis). Image correlation and centroiding software is used to assist the operator in viewing the surveyed control points. This greatly improves accuracy and observation speed. The surveyed control points along with some relative orientation points are then entered into the system. The camera orientation is created from the bundle adjustment process. The bundle adjustment attempts to best match the image coordinates and the 3 D control locations of the two images.
3 DM Analyst DTM Points Generation After the epipolar resample, which aligns the images for easy stereo viewing, the feature points are calculated. These feature points are then used to generate the points of a Digital Terrain Model (DTM). Knowledge of the camera’s orientation ensures that the 3 D DTM data generated is in the coordinate system that you have specified.
3 DM Analyst Triangular DTM Mesh A triangular mesh is applied to the model using the calculated DTM points. This gives the surface a viewable shape.
3 DM Analyst Automatic Contour Generation from Triangular DTM Mesh Contours of a specified height are automatically calculated and can be displayed over the Triangular DTM Mesh.
3 DM Analyst Triangular Mesh and Contours Displayed The 3 D Triangular mesh and Contour display can be viewed and manipulated in 3 D.
3 DM Analyst 3 D View of Model with Texture Mapping The epipolar image is texture mapped over the 3 D Triangular mesh. It too can be viewed and manipulated in 3 D.
3 DM Analyst 3 D View of Model with Contours of any specified value can be automatically applied to the 3 D Model.
3 DM Analyst 3 D Data Exporting The 3 D data can be exported in. DXF and. MAF formats for use in other software packages.
3 DM Analyst 3 D View of Model with Control Points Displayed Viewing objects in 3 D makes extracting 3 D data easy and accurate. We have implemented support for the Stereographics Crystal Eyes or the Z Screen polarising glasses for stereo viewing. The operator can view the object in 3 D, overlay the DTM points and triangles in 3 D, and even drive a floating mark around in 3 D using the mouse, adding and deleting points at will. The Control Point positions in the following model are displayed as X, Y and Z values in the bottom right of the Stereo Display window. Note: The following images have been presented as an Anaglyph for this presentation. In a working situation the Stereographics stereo viewing system is recommended. To view the model in 3 D you will need to use a pair of Anaglyph glasses (red filter - left eye, blue filter - right eye).
3 DM Analyst 3 D Measurement Software • • Open Pit and Stockpile measurement Active Face Mapping for Survey and Geology Engineering Mapping and Measurement A forerunner to Automated Underground Survey and Mapping Systems For more information on 3 D measurement contact: ADAM Technology Suite 3, 41 Belmont Avenue, Belmont, Western Australia 6104 Post: P. O. Box 283, Cloverdale, Western Australia Ph: + 61 8 9 479 5575 Fax: + 61 8 9 479 5585 Email: [email protected] com. au Web: www. adamtech. com. au End