Photogrammetry at WENDELSTEIN 7-X Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer1Meeting with NCSX, Greifswald, Application of Photogrammetry during Construction of W7-X T. Bräuer Content:How Photogrammetry works? Photogrammetry Equipment at IPP Greifswald Examples of Photogrammmetry Summary, Conclusion

Photogrammetry at WENDELSTEIN 7-X Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer2Meeting with NCSX, Greifswald, How Photogrammetry works? Part 1: Principle 1.Taking a picture from a first camera position 2.Calculation of first camera position from points known (4 pieces; green lines) in the initial co-ordinate system (blue) 3.Calculation of line of sight to New-Points (red lines) 4.Taking pictures from additional camera positions 5.Repetition of step 2 & 3 for the additional camera positions 6.Calculation of the cross section of the line of sights to a New-Point and calculation of the 3- D co-ordinate 7.Finally: Bundle Block Adjustment Position 1 Position 2 Position 3

Photogrammetry at WENDELSTEIN 7-X Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer3Meeting with NCSX, Greifswald, How Photogrammetry works? Part 2: Marking of Points Signalization is made by retro reflex targets Surface points: retro reflective foils (sticky foil) Ø=10mm Primitive geometries: Adapter for Fitted holes edges corners … Adapter for fitted holes Ø=8mmH7 with retro reflex target Surface point: Retro reflex foil Ø=10mm Photogrammtry camera with ring flash Example picture of retro reflective targets with its very high contrast

Photogrammetry at WENDELSTEIN 7-X Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer4Meeting with NCSX, Greifswald, How Photogrammetry works? Part 3: Identify target points with numbers Each object point has to has the same number in all pictures! Coded points are recognized by software image processing Starting from a minimum of 6 coded points per picture it is possible to name all New-Points of a picture unique

Photogrammetry at WENDELSTEIN 7-X Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer5Meeting with NCSX, Greifswald, Photogrammetry-Equipment at IPP Greifswald Measurement system: 2 x Camera Nikon DX1 with ring flash 24mm lense 20mm lense 1 x initial cross 2 x scale bars 1390mm 512 x coded targets Software: AICON 3D-Studio with Image analysis and co- ordinate calculation Deformation analysis Targets: Sticky foil Ø=10mm for surface Targets for Ø=8H7 holes  HUBBs-targets  Crossing point  with Offset (usually 25mm)  vector-targets  ball-targets  3-point-targets  feature-targets  1.5”-CCR-equivalent

Photogrammetry at WENDELSTEIN 7-X Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer6Meeting with NCSX, Greifswald, Examples of Photogrammetry Part 1: Incoming inspection of a coil Planarstütze 1 Standfuß 2 Standfuß 1 Montagestütze 1 u. 2 Druckstütze 2 Zentralstütze 1 u. 2 Messpunkte Ca. 3.5m Coil and its Ref.-points Survey of coil with Photogrammetry and Laser.Tracker Ca. 150 New-Points per coil Comparison Photogrammetrie and Laser-Tracker: 12 reference points RMS = mm Installation of Photogrammetry targets

Photogrammetry at WENDELSTEIN 7-X Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer7Meeting with NCSX, Greifswald, Examples of Photogrammetry Part 2: Survey of coils in assembly stand ≈ 480 pictures necessary 83% resp. 95% of points of a coil are visible Transformation into assembly stand resp. coils co-ordinate system RMS = 0.13 mm Maximum position deviation < 1.2 mm proof, that measurement accuracy required can be reached proof, that adjustment accuracy required can be reached

Photogrammetry at WENDELSTEIN 7-X Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer8Meeting with NCSX, Greifswald, Summery / conclusion Repetition measurement uncertainty of Photogrammetry is better than 0.1…0.15mm in a volume of 5x5x5m³ Photogrammetry is appropriated for complex components with a high number of target points A high number of target points on a component means a high probability to get enough lines of sight Photogrammmetry do not need rigid stand points for the measurement system For 4 or more coils assembled in assembly stand Photogrammetry needs less on-line time for a survey than other survey technique (for instant Laser-Tracker) Photogrammmetry needs off-line post processing time Adjustment off components using Photogrammetry needs a lot of affords or is impossible