1. Nov. 2017 Visualization with 3D CG
3D Digitization
Masaki Hayashi

2. Photogrammetry (break)
Today’s contents
Laser scanning
Photogrammetry (break)
Filming session

3. Laser scanning

4. Laser scanner
Laser beam +
Scanning

5. Range: Very small object (eg. tooth), Middle (eg.
Laser scanning
Range: Very small object (eg. tooth), Middle (eg.
Statue), Very large (eg. ruin, city landscape)
+ Aerial (Huge area)
Output: 3D point cloud
x, y, z coordinates
+ I(intensity) + r, g, b(color)
Good point: High accuracy of shape measurement, less error
Bad point: No texture or poor texture. Expensive.

6. Long-range ( 100 m ) TOL (Travel Of Light) Measure the TOL Laser
c (m/sec) = 299,792,458
Sensor
Lens
Object
Out
Out In In
TOL
TOL (phase)
Pulse modulation
Phase modulation
(more accurate)

7. Laser scanning Example video http://youtu.be/YpcGmh85Hes
Minolta-Konica Vivid 9i

8. Laser scanning
Some scenes

9. Photogrammetry

10. Photogrammetry method
Taking many pictures

11. Range: Almost same as scanner Small object (eg. vase), Middle (eg.
Photogrammetry
Range: Almost same as scanner Small object (eg. vase), Middle (eg.
Statue), Very large (eg. ruin, city landscape)
+ Aerial (Huge area)
Output: 3D point cloud + Color
x, y, z + r, g, b
Good point: Texture color is more realistic. Cheap.
Bad point: More errors in geometry.

12. Principle of photogrammetry
What the software does first is:
To find feature points
Uses image processing algorythm to get as much feature points on a given images.
Searches the corresponding feature points automatically.
Generally, it produces a lot of errors.

13. Principle of photogrammetry
Camera
Camera
3D position can be calculated if the camera parameters are known
by triangulation
Object
UNKNOWN VALUES:
Camera parameter: x, y, z, rx, ry, rz, AngleOfView
Position on the target object: x, y, z
ESTIMATION PROCESS:
Estimates camera parameter
Estimates xyz position of each feature point

14. Recent tech Better Reality : Thorskan https://youtu.be/S06y8Va68XE

15. Recent tech

16. Recent tech