Structured Light Lecture 1 Matt Waibel COMP 290-075 4-17-2000.
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Transcript of Structured Light Lecture 1 Matt Waibel COMP 290-075 4-17-2000.
![Page 1: Structured Light Lecture 1 Matt Waibel COMP 290-075 4-17-2000.](https://reader035.fdocuments.in/reader035/viewer/2022062300/56649d415503460f94a1c215/html5/thumbnails/1.jpg)
Structured LightLecture 1
Matt Waibel
COMP 290-075
4-17-2000
![Page 2: Structured Light Lecture 1 Matt Waibel COMP 290-075 4-17-2000.](https://reader035.fdocuments.in/reader035/viewer/2022062300/56649d415503460f94a1c215/html5/thumbnails/2.jpg)
Overview
• Background
• General Setup
• Light Point Projection 2D and 3D
• Light Stripe Projection
• Static Light Pattern Projection– Binary Encoded Light Stripes
– Segmenting Stripes
• 3D Photography on Your Desk
![Page 3: Structured Light Lecture 1 Matt Waibel COMP 290-075 4-17-2000.](https://reader035.fdocuments.in/reader035/viewer/2022062300/56649d415503460f94a1c215/html5/thumbnails/3.jpg)
Background
• Intersecting the projection ray with an additional ray or plane will lead to a unique reconstruction of the object point
• Structured Light: projection of light patterns into a scene (active method)
![Page 4: Structured Light Lecture 1 Matt Waibel COMP 290-075 4-17-2000.](https://reader035.fdocuments.in/reader035/viewer/2022062300/56649d415503460f94a1c215/html5/thumbnails/4.jpg)
General Setup
• one camera• one light source
– types• slide projector
• laser
– projection• spot
• stripe
• pattern
![Page 5: Structured Light Lecture 1 Matt Waibel COMP 290-075 4-17-2000.](https://reader035.fdocuments.in/reader035/viewer/2022062300/56649d415503460f94a1c215/html5/thumbnails/5.jpg)
Light Spot Projection 2D
imageplane
![Page 6: Structured Light Lecture 1 Matt Waibel COMP 290-075 4-17-2000.](https://reader035.fdocuments.in/reader035/viewer/2022062300/56649d415503460f94a1c215/html5/thumbnails/6.jpg)
Light Spot Projection 2D
• Coordinates found by triangulation– can be found by projection geometry – d = b*sin()/sin( + )
– X0 = d*cos()
– Z0 = h = d*sin()
![Page 7: Structured Light Lecture 1 Matt Waibel COMP 290-075 4-17-2000.](https://reader035.fdocuments.in/reader035/viewer/2022062300/56649d415503460f94a1c215/html5/thumbnails/7.jpg)
Light Spot Projection 3DZ
![Page 8: Structured Light Lecture 1 Matt Waibel COMP 290-075 4-17-2000.](https://reader035.fdocuments.in/reader035/viewer/2022062300/56649d415503460f94a1c215/html5/thumbnails/8.jpg)
Light Spot Projection 3D
– X0 = (tan()*b*x)/(f + x*tan())
– Y0 = (tan()*b*y)/(f+x*tan())
– Z0 = (tan()*b*f)/(f+x*tan())
![Page 9: Structured Light Lecture 1 Matt Waibel COMP 290-075 4-17-2000.](https://reader035.fdocuments.in/reader035/viewer/2022062300/56649d415503460f94a1c215/html5/thumbnails/9.jpg)
Light Stripe Projection
P
![Page 10: Structured Light Lecture 1 Matt Waibel COMP 290-075 4-17-2000.](https://reader035.fdocuments.in/reader035/viewer/2022062300/56649d415503460f94a1c215/html5/thumbnails/10.jpg)
Static Light Pattern Projection
![Page 11: Structured Light Lecture 1 Matt Waibel COMP 290-075 4-17-2000.](https://reader035.fdocuments.in/reader035/viewer/2022062300/56649d415503460f94a1c215/html5/thumbnails/11.jpg)
Static Light Pattern Projection
• Project a pattern of stripes into the scene to reduce the total number of images required to reconstruct the scene
• Problem: how to uniquely identify light stripes in the camera image when several are simultaneously projected into the scene
![Page 12: Structured Light Lecture 1 Matt Waibel COMP 290-075 4-17-2000.](https://reader035.fdocuments.in/reader035/viewer/2022062300/56649d415503460f94a1c215/html5/thumbnails/12.jpg)
Binary Encoded Light Stripes
• Set of light planes are projected into the scene
• Individual light planes are indexed by an encoding scheme for the light patterns– Obtained images form a bit-plane stack
– Bit-plane stack is used to uniquely address the light plane corresponding to every image point
![Page 13: Structured Light Lecture 1 Matt Waibel COMP 290-075 4-17-2000.](https://reader035.fdocuments.in/reader035/viewer/2022062300/56649d415503460f94a1c215/html5/thumbnails/13.jpg)
Binary Encoded Light Stripes
![Page 14: Structured Light Lecture 1 Matt Waibel COMP 290-075 4-17-2000.](https://reader035.fdocuments.in/reader035/viewer/2022062300/56649d415503460f94a1c215/html5/thumbnails/14.jpg)
Binary Encoded Light Stripes
![Page 15: Structured Light Lecture 1 Matt Waibel COMP 290-075 4-17-2000.](https://reader035.fdocuments.in/reader035/viewer/2022062300/56649d415503460f94a1c215/html5/thumbnails/15.jpg)
• Another Problem: How can we find the stripes in the images?
• Thresholding is dependent on the contrast
Segmenting Stripes
![Page 16: Structured Light Lecture 1 Matt Waibel COMP 290-075 4-17-2000.](https://reader035.fdocuments.in/reader035/viewer/2022062300/56649d415503460f94a1c215/html5/thumbnails/16.jpg)
Segmenting Stripes
• Better Method:– Use the inverse image (opposite stripes) and
determine where the intensities intersect with the original image
![Page 17: Structured Light Lecture 1 Matt Waibel COMP 290-075 4-17-2000.](https://reader035.fdocuments.in/reader035/viewer/2022062300/56649d415503460f94a1c215/html5/thumbnails/17.jpg)
3D Photography on Your Desk
• Method that uses very common tools to do 3D photography
• Requirements: PC, camera, stick, lamp, and a checker board
• Uses “weak structured light” approach
![Page 18: Structured Light Lecture 1 Matt Waibel COMP 290-075 4-17-2000.](https://reader035.fdocuments.in/reader035/viewer/2022062300/56649d415503460f94a1c215/html5/thumbnails/18.jpg)
3D Photography on Your Desk