Auto-referenced sensing device for three-dimensional scanning
An auto-referenced sensing device for scanning an object to provide three-dimensional surface points, including: a Light-Emitting Diode (LED) light source emitting light for illuminating and enabling image acquisition of retro-reflective target positioning features provided at a fixed position on the object; a laser pattern projector, additional to the LED light source, for providing a projected laser pattern on a surface of the object for illuminating and enabling image acquisition of dense points between the retro-reflective target positioning features; at least a pair of cameras for simultaneously acquiring a 2D image of the object, the projected laser pattern and the retro-reflective target positioning features are apparent on the image, wherein the simultaneous images contain both positioning measurements from the retro-reflective target positioning features and dense surface measurements from the points enabled by the projected laser pattern.
1. An auto-referenced sensing device for scanning an object to provide three-dimensional surface points in an object coordinate system, comprising:
a Light-Emitting Diode (LED) light source emitting light for illuminating and enabling image acquisition of at least a portion of a set of retro-reflective target positioning features, wherein each of said retro-reflective target positioning features is provided at a fixed position on said object;
a laser pattern projector, additional to said LED light source, for providing a projected laser pattern on a surface of said object for illuminating and enabling image acquisition of dense points between at least two of said retro-reflective target positioning features in said portion of said set;
at least a pair of cameras each for simultaneously acquiring a 2D image of said object, wherein both said projected laser pattern and said portion of said set of retro-reflective target positioning features are apparent on said simultaneous images, a spatial relationship between said pair of cameras being known, said LED light source being provided in close proximity to said at least said pair of cameras;
wherein said portion of said set of retro-reflective target positioning features reflect at least part of said light emitted by said LED light source towards said cameras;
wherein said simultaneous images acquired by said pair of cameras contain both positioning measurements made available from said portion of said set of retro-reflective target positioning features apparent on said images and dense surface measurements made available from said points enabled by said projected laser pattern apparent on said images.
2. The auto-referenced sensing device as claimed in claim 1 , further comprising a transmitter for transmitting said 2D images of said object.
3. The auto-referenced sensing device as claimed in claim 2 , wherein said transmitter is a wireless transmitter.
4. The auto-referenced sensing device as claimed in claim 1 , further comprising:
an image processor for extracting, from said 2D images, at least one set of 2D surface points from a reflection of said projected pattern on said surface, and at least two sets of 2D positioning features from a reflection of said target positioning features on said surface;
a 3D surface point calculator for calculating a set of 3D surface points in said sensing device coordinate system using said set of 2D surface points;
a 3D positioning feature calculator for calculating a set of calculated 3D positioning features in said sensing device coordinate system using said sets of 2D positioning features;
a positioning features matcher for computing transformation parameters to characterize a current spatial relationship between said sensing device coordinate system and said object coordinate system, by matching corresponding features between said set of calculated 3D positioning features in said sensing device coordinate system and a set of reference 3D positioning features in said object coordinate system, said reference 3D positioning features being cumulated from previous observations;
a 3D positioning feature transformer for transforming said set of calculated 3D positioning features into a set of transformed 3D positioning features in said object coordinate system using said transformation parameters;
a 3D surface point transformer for transforming said set of 3D surface points into a set of transformed 3D surface points in said object coordinate system using said transformation parameters; and
a 3D reference positioning feature model builder for cumulating said set of transformed 3D positioning features to provide and augment said set of reference 3D positioning features.
5. The auto-referenced sensing device as claimed in claim 4 , further comprising an electronic chip for implementing at least one of said image processor, said 3D surface point calculator, said 3D positioning features calculator, said positioning features matcher, said 3D positioning features transformer, said reference 3D positioning feature model builder and said 3D surface point transformer.
6. The auto-referenced sensing device as claimed in claim 5 , further comprising a transmitter for transmitting said transformed 3D surface points of said object.
7. The auto-referenced sensing device as claimed in claim 1 , wherein said laser pattern projector provides a crosshair pattern on a surface of said object.
8. The auto-referenced sensing device as claimed in claim 7 , wherein said projected laser pattern comprises a crosshair pattern having two light planes.
9. The auto-referenced sensing device as claimed in claim 8 , wherein said two light planes define a right angle.
10. The auto-referenced sensing device as claimed in claim 9 , wherein said crosshair pattern is oriented such that each of said light planes is nearly aligned with an epipolar plane defined by one camera of said pair of cameras and said laser pattern projector.
11. The auto-referenced sensing device as claimed in claim 1 , wherein said Light-Emitting Diode (LED) light source is a set of LEDs distributed around one camera of said pair of cameras.
12. The auto-referenced sensing device as claimed in claim 1 , wherein said Light-Emitting Diode (LED) light source is a set of two Light-Emitting Diode (LED) light sources, one for each camera of said pair of cameras.
13. The auto-referenced sensing device as claimed in claim 12 , wherein said two Light-Emitting Diode (LED) light sources are two sets of LEDs, each set of said two sets being distributed around one camera of said pair of cameras.
14. The auto-referenced sensing device as claimed in claim 1 , wherein a wavelength of said laser pattern projector is matched to a wavelength of said Light-Emitting Diode (LED) light source.
15. The auto-referenced sensing device as claimed in claim 1 , wherein said laser pattern projector and said pair of cameras define a triangular structure.
16. The auto-referenced sensing device as claimed in claim 15 , wherein said triangular structure is an isosceles rectangular triangular structure.
17. The auto-referenced sensing device as claimed in claim 1 , wherein said pattern projector and said pair of cameras define a symmetrical configuration.