Image processing methods and apparatus
First Claim
1. A computer-implemented of determining data characterising a set of images of an object, the method being implemented in a computer comprising processor and a memory in communication with the processor, the method comprising:
- inputting, to the processor, data from a first set of images of said object captured from a plurality of different positions;
determining, by the processor, frontier point data from said data for said first set of images and data defining said image capture positions, said frontier point data defining a plurality of frontier points on said object, and for each said frontier point, a direction of a normal to the surface of the object at the frontier point;
inputting, to the processor, data from a second set of captured images of said object, said second set of images having substantially the same viewpoint and different illumination conditions; and
determining, by the processor, data characterising said second set of images using said data for said second set of images and said frontier point data, said image set characterising data comprising object reflectance parameter data (β
) and, for each image of said second set, illumination data (L) comprising data defining an illumination direction and illumination intensity for the image;
wherein said determining of frontier point data uses pair of images of said first set of images, the two images of said pair being captured by first and second respective cameras; and
wherein each frontier point is a point in three-dimensions on the surface of the object wherein the plane defined by the frontier point and centres of said first and second cameras viewing the frontier point is tangent to the object.
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Abstract
We describe methods of characterizing a set of images to determine their respective illumination, for example for recovering the 3D shape of an illuminated object. The method comprises: inputting a first set of images of the object captured from different positions; determining frontier point data from the images, this defining a plurality of frontier points on the object and for each said frontier point a direction of a normal to the surface of the object at the frontier point, and determining data defining the image capture positions; inputting a second set of images of said object, having substantially the same viewpoint and different illumination conditions; and characterizing the second set of images said frontier point data to determine data comprising object reflectance parameter data (β) and, for each image of said second set, illumination data (L) comprising data defining an illumination direction and illumination intensity for the image.
21 Citations
16 Claims
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1. A computer-implemented of determining data characterising a set of images of an object, the method being implemented in a computer comprising processor and a memory in communication with the processor, the method comprising:
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inputting, to the processor, data from a first set of images of said object captured from a plurality of different positions; determining, by the processor, frontier point data from said data for said first set of images and data defining said image capture positions, said frontier point data defining a plurality of frontier points on said object, and for each said frontier point, a direction of a normal to the surface of the object at the frontier point; inputting, to the processor, data from a second set of captured images of said object, said second set of images having substantially the same viewpoint and different illumination conditions; and determining, by the processor, data characterising said second set of images using said data for said second set of images and said frontier point data, said image set characterising data comprising object reflectance parameter data (β
) and, for each image of said second set, illumination data (L) comprising data defining an illumination direction and illumination intensity for the image;wherein said determining of frontier point data uses pair of images of said first set of images, the two images of said pair being captured by first and second respective cameras; and wherein each frontier point is a point in three-dimensions on the surface of the object wherein the plane defined by the frontier point and centres of said first and second cameras viewing the frontier point is tangent to the object. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 10, 11)
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9. A method of determining data characterising a set of images of an object, the method comprising:
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inputting, by the processor, data from a first set of images of said object captured from a plurality of different positions; determining , by the processor, frontier point data from said data for said first set of images and data defining said image capture positions, said frontier point data defining a plurality of frontier points on said object, and for each said frontier point, a direction of a normal to the surface of the object at the frontier point; inputting, to the processor, data from a second set of captured images of said object, said second set of images having different viewpoints and illumination conditions; and determining, by the processor, data characterising said second set of images using said data for said second set of images and said frontier point data, said image set characterising data comprising object reflectance parameter data (β
) and illumination data comprising data defining a common angular illumination intensity distribution for all the images of said second set of images;wherein said determining of frontier point data uses pair of images of said first set of images, the two images of a said pair being captured by first and second respective cameras; and wherein each frontier point is a point in three-dimensions on the surface of the object where the plane defined by the frontier point and centres of said first and second cameras viewing the frontier point is tangent to the object.
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12. A system for determining data characterising a set of images of an object, the system comprising:
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an input to input data from a first set of images of said object captured from a plurality of different positions, and data from second set of captured images of said object, said second set of images having substantially the same viewpoint and different illumination conditions; data memory for storing data to be processed; program memory storing processor control code; and a processor coupled to said input, data memory and program memory to load and implement said stored code, said code comprising code for controlling the processor to; determine frontier point data from said data for said first set of images and data defining said image capture positions, said frontier point data defining a plurality of frontier points on said object and for each said frontier point, a direction of a normal to the surface of the object at the frontier point; and determine data characterising said second set of images using said data for said second set of images and said frontier point data, said image set characterising data comprising object reflectance parameter data (β
) and, for each image of said second set, illumination data (L) comprising data defining an illumination direction and illumination intensity for the image;wherein said determining of frontier point data uses pairs of images of said first set of images, the two images of a said pair being captured by first and second respective cameras; and wherein each frontier point is a point in three-dimensions on the surface of the object where the plane defined by the frontier point and centres of said first and second cameras viewing the frontier is tangent to the object. - View Dependent Claims (13, 14, 15)
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16. A computer-implemented method of determining data characterising a set of images of an object, the method being implemented in a computer comprising processor and a memory in communication with the processor, the method comprising:
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inputting, to the processor, data from a first set of images of said object captured from a plurality of different positions by at least a first camera and a second camera; determining, by the processor, frontier point data from said data for said first set of images and data defining said image capture position, said frontier point data defining a plurality of frontier points on said object, and for each said frontier point, a direction of a normal to the surface of the object at the frontier point, wherein each frontier point is a point in three-dimensions on the surface of the object where the plane defined by the frontier point and centres of said first and second cameras viewing the frontier point is tangent to the object; inputting, to the processor, data from a second set of captured images of said object, said second set of images having substantially the same viewpoint and different illumination conditions; and determining, by the processor, data characterising said second set of images using said data for said second set of images and said frontier point data, said image set characterising data comprising object reflectance parameter data (β
) and, for each image of said second set, illumination data (L) comprising data defining an illumination direction and illumination intensity for the image.
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Specification