Reflection refuting laser scanner
Some embodiments described herein relate to optical systems and methods for determining the shape and/or size of objects that include projecting a pattern of light onto the object. The pattern of light can be configured such that first-order reflections can be distinguished from second- and/or higher-order reflections, which can be rejected. Thus, even in instances in which the pattern of light is reflected onto the object multiple times, the original, or first-order, reflection can be detected, distinguished, and/or used for laser triangulation. In some embodiments, a pattern of light that does not have reflection and/or rotational symmetry is projected onto the object, such that second-order and/or higher-order reflections can be distinguished from the first-order reflection.
1. An apparatus, comprising:
a light source configured to project a pattern onto a part, the pattern having a predetermined geometry such that a first-order reflection of the pattern has a geometry that is distinguishable from a geometry of second-order reflections of the pattern;
a detector configured to capture an image the part; and
a compute device communicatively coupled to the detector, the compute device configured to process the image to identify a first-order reflection of the pattern based on the geometry of the first-order reflection and to filter second-order reflections of the pattern based on the geometry of the second-order reflections.
2. The apparatus of claim 1 , wherein the compute device is further configured to identify a shape of a portion of the part onto which the pattern is projected based on the first-order reflection of the pattern.
3. The apparatus of claim 1 , wherein:
the light source is configured to scan the pattern over the part;
the image is from a plurality of images;
the detector is configured to capture the plurality of images, a different portion of the part producing a first-order reflection of the pattern in each image from the plurality of images; and
the compute device is configured to process the plurality of images to identify the first-order reflection of the pattern in each image from the plurality of images and filter second-order reflections of the pattern from each image from the plurality of images.
4. The apparatus of claim 3 , wherein the compute device is further configured to identify a shape of a surface of the part based on the first-order reflection of the pattern in each image from the plurality of images.
5. The apparatus of claim 3 , wherein the compute device is further configured to generate a three-dimensional model of a surface of the part based on the first-order reflection of the pattern in each image from the plurality of images.
6. The apparatus of claim 1 , wherein the predetermined geometry does not have reflection symmetry.
7. The apparatus of claim 1 , wherein the predetermined geometry does not have rotational symmetry.
8. The apparatus of claim 1 , wherein the light source is configured to project a first portion of the pattern in a first color and a second portion of the pattern in a second color.
9. A method, comprising:
projecting a predefined non-symmetric pattern from a light source onto a part such that the light source produces a first-order reflection of the predefined non-symmetric pattern at a first portion of the part where the predefined non-symmetric pattern first illuminates the part and such that the first portion of the part reflects the predefined non-symmetric pattern to a second portion of the part thereby producing a second-order reflection of the predefined non-symmetric pattern;
capturing an image of the part including the first-order reflection of the predefined non-symmetric pattern and the second-order reflection of the non-symmetric pattern;
processing the image of the part to remove the second-order reflection of the predefined non-symmetric pattern; and
identifying a shape of the first portion of the part based on deviations of the predefined non-symmetric pattern in the image of the first-order reflection.
10. The method of claim 9 , further comprising:
scanning the predefined non-symmetric pattern over the part;
capturing a plurality of images of the part including the image;
processing each image from the plurality of images to remove second-order reflections of the predefined non-symmetric pattern; and
generating a three-dimensional model of a surface of the part based on deviations of the predefined non-symmetric pattern in first-order reflections depicted in the plurality of images.
11. The method of claim 9 , wherein the predefined non-symmetric pattern includes a linear portion and a non-symmetric portion.
12. The method of claim 11 , wherein identifying the shape of the first portion of the part includes identifying nonlinear portions of the first-order reflection of the linear portion of the predefined non-symmetric pattern.
13. The method of claim 9 , wherein the predefined non-symmetric pattern includes a plurality of non-isosceles right triangles.
14. The method of claim 9 , wherein at least a portion of the predefined non-symmetric pattern is projected from a laser line projector.
15. The method of claim 9 , wherein the light source is a first light source and the non-symmetric pattern is a first predetermined non-symmetric pattern, the method further comprising:
projecting a second predetermined non-symmetric pattern from a second light source onto the part;
processing the image of the part to remove greater-than-first-order reflections of the second predetermined non-symmetric pattern; and
identifying a shape of a third portion of the part based on nonlinear portions of a first-order reflection of a linear portion of the second predetermined non-symmetric pattern.
16. A non-transitory processor readable medium storing code configured to be executed by a processor, the code comprising code to cause the processor to:
receive a plurality of images of a part illuminated by a pattern having a predetermined geometry, each image from the plurality of images including a first-order reflection of the pattern, and at least one image from the plurality of images including a second-order reflection of the pattern;
filter the second-order reflection of the pattern from the at least one image by comparing a geometry of the second-order reflection to the predetermined geometry; and
generate a three-dimensional model of at least a portion of the part based on triangulating a linear portion of the pattern in first-order reflections captured in the plurality of images.
17. The non-transitory processor readable medium of claim 16 , wherein the predetermined geometry does not have rotational or reflection symmetry.
18. The non-transitory processor readable medium of claim 16 , wherein:
the predetermined geometry does not have rotational or reflection symmetry such that each second-order reflection of the pattern has a geometry different from the predetermined geometry; and
the code to cause the processor to filter the second-order reflection of the pattern further includes code to cause the processor filter all reflections of the pattern that have a geometry other than the predetermined geometry.
19. The non-transitory processor medium of claim 16 , wherein:
the linear portion of the pattern has a first color; and
a second portion of the pattern that lacks rotational and reflection symmetry has a second color.
20. The non-transitory processor medium of claim 16 , wherein the three-dimensional model of at least a portion of the part is generated based, at least in part, on a stored location of an imaging device that captured the plurality of images and a stored location of a light source that projected the pattern onto the part.