Extracting feature quantities from an image to perform location estimation
First Claim
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1. A feature extraction method for extracting a feature from an image by computer processing, the method comprising:
- receiving an image and measured acceleration data from a mobile device including image acquiring means and acceleration measuring means;
obtaining a gravity vector in the image in a camera coordinate system on a basis of the measured acceleration data;
obtaining a vanishing point in the image in a vertical direction in a screen coordinate system by using the gravity vector;
obtaining differential vectors along two axes for each of pixels in the screen coordinate system;
obtaining a connection line vector connecting each of the pixels with the vanishing point;
identifying a vertical edge on the basis of determination that an angle formed by the differential vector and the connection line vector is within a certain threshold range;
obtaining the sum of strengths of vertical edges and writing the sum in a predetermined variable array;
extracting a keypoint on the basis of the variable array; and
calculating a feature quantity from the keypoint.
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Abstract
A feature extraction method for extracting a feature from an image includes receiving an image and measured acceleration data from a mobile device; obtaining a gravity vector in the image in a camera coordinate system based on the measured acceleration data; obtaining a vanishing point in the image in a vertical direction in a screen coordinate system using the gravity vector; obtaining differential vectors along two axes for each pixel in the screen coordinate system; obtaining a connection line vector connecting each of the pixels with the vanishing point; identifying a vertical edge based on determining that an angle formed by the differential vector and the connection line vector is within a certain threshold range; obtaining the sum of strengths of vertical edges and writing the sum in a predetermined variable array; extracting a keypoint based on the variable array; and calculating a feature quantity from the keypoint.
10 Citations
14 Claims
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1. A feature extraction method for extracting a feature from an image by computer processing, the method comprising:
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receiving an image and measured acceleration data from a mobile device including image acquiring means and acceleration measuring means; obtaining a gravity vector in the image in a camera coordinate system on a basis of the measured acceleration data; obtaining a vanishing point in the image in a vertical direction in a screen coordinate system by using the gravity vector; obtaining differential vectors along two axes for each of pixels in the screen coordinate system; obtaining a connection line vector connecting each of the pixels with the vanishing point; identifying a vertical edge on the basis of determination that an angle formed by the differential vector and the connection line vector is within a certain threshold range; obtaining the sum of strengths of vertical edges and writing the sum in a predetermined variable array; extracting a keypoint on the basis of the variable array; and calculating a feature quantity from the keypoint. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A computer program product comprising a non-transitory computer readable storage medium having computer readable instructions stored thereon that, when executed by a computer, implement a feature extraction method for extracting a feature from an image by computer processing, the method comprising:
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receiving an image and measured acceleration data from a mobile device including image acquiring means and acceleration measuring means; obtaining a gravity vector in the image in a camera coordinate system on the basis of the measured acceleration data; obtaining a vanishing point in the image in a vertical direction in a screen coordinate system by using the gravity vector; obtaining differential vectors along two axes for each of pixels in the screen coordinate system; obtaining a connection line vector connecting each of the pixels with the vanishing point; identifying a vertical edge on the basis of determination that an angle formed by the differential vector and the connection line vector is within a certain threshold range; obtaining the sum of strengths of vertical edges and writing the sum in a predetermined variable array; extracting a keypoint on the basis of the variable array; and calculating a feature quantity from the keypoint. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification
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Current AssigneeInternational Business Machines Corporation
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Original AssigneeInternational Business Machines Corporation
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InventorsTakahashi, Toshihiro
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Primary Examiner(s)Bhatnagar, Anand
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Application NumberUS13/965,439Publication NumberTime in Patent Office707 DaysField of Search382/100, 382/103, 382/104, 382/106, 382/107, 382/120, 382/121, 382/181, 382/190, 382/195, 382/202, 382/203, 348/135, 348/143, 73/13.7, 73/13.8, 73/17.7, 734/88, 735/033, 735/048, 735/041.8, 701/70US Class Current1/1CPC Class CodesG06T 7/579 from motionG06T 7/73 using feature-based methodsG06V 30/142 using hand-held instruments...
