当前申请(专利权)人地址：
Golf Course Lane, Filton, BS34 9AU, United Kingdom
摘要：
Boundary detection for an object manufactured by 3D printing comprises receiving 21 an, IR or near-infrared, first image of a first layer of the object. A computer aided design (CAD) model representing the object is sliced 23 into slices, a slice corresponding to the first layer is selected 24 and output 25 as a second image having a border representing an edge of the object. The second image is correlated 26 with the first image and pixels in the first image corresponding to the border in the second image are identified 27 as representing the periphery. Pixels representing the boundary and outside the boundary may be removed 28 from the first image. A defect detection method in which the brightness of a pixel is compared to the average brightness of an image region may be applied to the first image. The AM method may be a powder bed manufacturing method such as electron beam melting or laser metal deposition. Also disclosed is a method of correcting a defect.
权利要求：
CLAIMS
1. A method of boundary detection for an object manufactured by additive manufacturing, the method comprising:
receiving a first, infrared or near-infrared, image of a first layer of an object manufactured by additive manufacturing, the first image having a plurality of pixels;
slicing a computer-aided design model representing the object into a plurality of slices, at least one slice corresponding to a layer of the object as manufactured by additive manufacturing;
selecting a first slice of the computer-aided design model, the first slice
corresponding to the first layer of the object;
outputting at least the first slice of the computer-aided design model as a second, computer-aided design, image having a border representing a boundary of the object;
correlating the second image with the first image; and
identifying as a pixel that represents at least part of a boundary of the object any pixel of the first image that corresponds to the border of the second image. 2. The method of claim 1, wherein the infrared or near infrared image is an image of a layer of an object manufactured on a heated bed.
3. The method of claim 1 or claim 2, wherein the infrared or near infrared image is an image of a layer of an object manufactured by powder bed additive manufacturing. 4. The method of claim 2 or claim 3, wherein the infrared or near infrared image is an image of a layer of an object manufactured by electron beam melting.
5. The method of any preceding claim, further comprising:
removing from the first image any pixels that are identified as representing at least part of the boundary of the object and any pixels that are outside the border of the second image.
6. A method of defect detection for an object manufactured by additive manufacturing, the
method comprising:
(a) performing the method of any preceding claim;
(b) selecting a region of the first image, or, when claim 6 is dependent on claim 5,
the first image with any pixels that are identified as representing at least part of
the boundary of the object and any pixels that are outside the border of the
second image removed, the region consisting of a plurality of pixels;
(c) determining the brightness of a first pixel in the region;
(d) determining the brightness of each of the other pixels in the region;
(e) calculating the average brightness of each of the other pixels in the region;
(f) calculate the difference between the brightness of the first pixel and the average
brightness;
(g) repeating steps (c) to (f) for each of the pixels in the region; and
(h) identifying any pixel not identified as a pixel that represents at least part of a
boundary of the object and having a difference in brightness from the average
brightness above a threshold value as representing at least part of a defect.
7. The method of claim 6 wherein step (a) is performed before steps (b) to (g).
8. The method of claim 6 or claim 7 wherein steps (b) to (g) are repeated for each pixel in the
first image.
9. The method of any of claims 6 to 8, wherein steps (a) to (g) are repeated for a plurality of
infrared or near-infrared images, each infrared or near-infrared image being an image of a
layer of the object being manufactured by additive manufacturing.
10. The method of any of claims 6 to 9, wherein the method comprises identifying as noise any
group of a predetermined number or fewer adjacent pixels having a difference in brightness
from the average brightness that is at or above a threshold value.
11. The method of any of claims 6 to 10, wherein the region consists of nine pixels.
12. The method of any of claims 6 to 11, wherein the computer-aided design model is a first
computer-aided design model, wherein the method comprises determining coordinates of
each pixel representing at least part of a defect, wherein the method further comprises
converting the coordinates of each pixel representing at least part of a defect into a second
computer-aided design model, and wherein the method further comprises combining the
first and second computer-aided design models to produce a third computer-aided design
model of the object and the identified defects in the object.
13. Acomputer-readable storage medium storing instructions that are arranged, when executed
by a computer, to cause the computer to carry out the method of any of claims 1 to 12.
14. An additive manufacturing system arranged to perform boundary detection in an object
manufactured in the system, the system comprising:
an apparatus arranged to manufacture an object by additive manufacturing by
manufacturing a plurality of layers of the object;
an infrared or near-infrared camera arranged to take a first image of a first layer of
the plurality of layers of the object, the first image having a plurality of pixels;
a storage device arranged to store instructions;
a processor communicatively connected to the camera and to the storage device,
and arranged to receive the first image from the camera and instructions from the storage
device, the processor further arranged to carry out instructions received from the storage
device to:
slice a computer-aided design model representing the object into a plurality of slices,
at least one slice corresponding to a layer of the object as manufactured by additive
manufacturing;
select a first slice of the computer-aided design model, the first slice corresponding
to the first layer of the object;
output at least the first slice of the computer-aided design model as a second,
computer-aided design, image having a border representing a boundary of the object;
correlate the second image with the first image; and
identify as a pixel that represents at least part of a boundary of the object any pixel of the first image that corresponds to the border of the second image.
15. The additive manufacturing system of claim 14, wherein the boundary detection module is additionally arranged to remove from the first image any pixels that are identified as representing at least part of the boundary of the object and any pixels that are identified as being outside the boundary of the object.
16. The additive manufacturing system of claim 14 or 15, wherein the system is additionally arranged to perform defect detection in the object manufactured in the system and the processor is additionally arranged to carry out instructions received from the storage device to:
(i) select aregion of the first image, or, when claim 16 is dependent on claim 15,
the first image with any pixels that are identified as representing at least part of
the boundary of the object and any pixels that are outside the border of the
second image removed, the region consisting of a plurality of pixels;
(ii) determine the brightness of a first pixel in the region;
(iii) determine the brightness of each of the other pixels in the region;
(iv) calculate the average brightness of each of the other pixels in the region; (v)
calculate the difference between the brightness of the first pixel and the average
brightness;
(vi) repeat steps (ii) to (v) for each of the pixels in the region; and
(vii) identify any pixel not identified as a pixel that represents at least part of a
boundary of the object and having a difference in brightness from the average
brightness above a threshold value as representing at least part of a defect.