Finger movement detection method and apparatus
First Claim
1. A finger movement detection method comprising:
- a fingerprint detection step of detecting a fingerprint in an area smaller than a fingertip to obtain a first sensor image and a second sensor image; and
a pattern matching step of extracting a partial image area of the obtained second sensor image as a small block, searching for an image area having a fingerprint pattern that agrees with a fingerprint pattern in the small block of the second sensor image from the first sensor image, and obtaining a vector indicating a movement of a finger, based on a displacement of the small block in the second sensor image from the image area in the first sensor image corresponding to the small block.
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Abstract
A fingerprint area and a barycentric position of the area are obtained for a current sensor image, and an area near the barycentric position is divided into a plurality of small blocks. An image area that agrees with a fingerprint image is searched for, for each of the small blocks with respect to the fingerprint area in a previous sensor image. A candidate vector is obtained from a deviation between the position of the small block in the current sensor image and the position of the image area in the previous sensor image corresponding to the small block. A candidate vector with the highest matching degree between the fingerprint images in the current and previous sensor images is selected from the candidate vectors to obtain a detected vector, and the detected vector is corrected to exclude an influence of erroneous detection and to control a movement of a pointer.
14 Citations
15 Claims
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1. A finger movement detection method comprising:
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a fingerprint detection step of detecting a fingerprint in an area smaller than a fingertip to obtain a first sensor image and a second sensor image; and
a pattern matching step of extracting a partial image area of the obtained second sensor image as a small block, searching for an image area having a fingerprint pattern that agrees with a fingerprint pattern in the small block of the second sensor image from the first sensor image, and obtaining a vector indicating a movement of a finger, based on a displacement of the small block in the second sensor image from the image area in the first sensor image corresponding to the small block. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A finger movement detection apparatus comprising:
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a fingerprint sensor that detects a fingerprint in an area smaller than a fingertip to obtain a first sensor image and a second sensor image; and
a pattern matching unit that extracts a partial image area of the second sensor image as a small block, searches for an image area having a fingerprint pattern that agrees with a fingerprint pattern of the small block in the second sensor image from the first sensor image, and obtains a vector indicating a movement of a finger, based on a displacement of the small block in the second sensor image from the image area in the first sensor image corresponding to the small block. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A pointing method comprising steps of:
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obtaining a vector indicating a movement of a finger, by using a finger movement detection method including detecting a fingerprint in an area smaller than a fingertip to obtain a first sensor image and a second sensor image, and extracting a partial image area of the obtained second sensor image as a small block, searching for an image area having a fingerprint pattern that agrees with a fingerprint pattern in the small block of the second sensor image from the first sensor image, and obtaining a vector indicating the movement of the finger, based on a displacement of the small block in the second sensor image from the image area in the first sensor image corresponding to the small block; and
controlling a movement of a pointer displayed on a screen, based on the vector.
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15. A pointing apparatus comprising:
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a finger movement detection apparatus including a fingerprint sensor that detects a fingerprint in an area smaller than a fingertip to obtain a first sensor image and a second sensor image, and a pattern matching unit that extracts a partial image area of the second sensor image as a small block, searches for an image area having a fingerprint pattern that agrees with a fingerprint pattern of the small block in the second sensor image from the first sensor image, and obtains a vector indicating a movement of a finger, based on a displacement of the small block in the second sensor image from the image area in the first sensor image corresponding to the small block; and
a control unit that controls a movement of a pointer displayed on a screen, based on the vector indicating the movement of the finger obtained by the detection apparatus.
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Specification