Image analysis – Applications – Target tracking or detecting
Reexamination Certificate
1998-09-25
2001-04-10
Bella, Matthew C. (Department: 2721)
Image analysis
Applications
Target tracking or detecting
C382S100000, C382S288000
Reexamination Certificate
active
06215890
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to hand gesture recognizing devices, and more particularly to a hand gesture recognizing device which can automatically recognize hand gestures.
2. Description of the Background Art
Conventionally, some methods are known for recognizing hand gestures, for sign language, for example. A first method is to measure movement of the body by sensing movement of a sensor attached to the body. (For example, refer to “Hand Gesture Recognizing Method and Applications,” Yuichi Takahashi et al., The Institute of Electronics Information and Communication Engineers, Papers D-2 Vol.J73-D-2 No.121990, n.pag., and Japanese Patent Laying-Open No.8-115408.) According to a second method, the hands are sensed by a camera with multi-colored gloves put on the hands so as to measure movements of the fingers by extracting information about the outline of the hands through color information. (For example, refer to “Hand Structure Recognition Using Color Information,” Kazuyoshi Yoshino et al., The Institute of Electronics Information and Communication Engineers, Technical Research Paper PRU94-52, pp.39-43) Further, in a third method, variation in the quantity of light emitted from an optical fiber attached to the body is sensed to measure variation of the finger shape (refer to Japanese Patent Laying-Open No.8-115408).
However, the first to third methods described above require that users be equipped with a sensor, gloves, or an optical fiber, which gives an uncomfortable feeling to the users and limits movements of the users. Further, the conventional methods which recognize movements by using absolute coordinate values of body parts obtained in advance from a particular person are susceptible to recognition errors due to differences in body size among actual users, movement of the body during performance, and the like. It may be suggested that coordinate values of the body parts be recorded for a plurality of users. However, this method will encounter the problem that an enormous amount of data must be recorded in proportion to the number of users. Moreover, in the conventional methods, measured hand movements are compared with hand movements corresponding to hand gesture words recorded in a dictionary, word by word, for recognition. This raises the problem that the time required for recognition exponentially increases as the number of words to be recognized increases.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a hand gesture recognizing device which can recognize and translate hand gestures without requiring that users be equipped with some tools.
Another object of the present invention is to provide a hand gesture recognizing device which can correctly recognize and translate hand gestures without error, regardless of differences in body size among users, movements of the body during performance, and the like.
Still another object of the present invention is to provide a hand gesture recognizing device which can achieve recognizing and translating processing in a short time even with an increased number of words to be recognized.
A first aspect is directed to a hand gesture recognizing device for recognizing hand gestures performed by a user comprises:
photographing means having at least two cameras for stereoscopically taking pictures of the user;
image storage means for storing stereoscopic image data of the user outputted from the photographing means at arbitrary sampling interval;
feature image extracting means for taking out the stereoscopic image data in order from the image storage means, extracting feature image showing body features of the user from each stereoscopic image data, and disassembling and outputting the feature image in a plurality of channels;
spatial position calculating means for detecting three-dimensional spatial positions of body parts of the user on the basis of parallax of the feature image outputted from the feature image extracting means;
region dividing means for dividing a space surrounding the user into a plurality of regions related to the body of the user on the basis of the parallax of the feature image outputted from the feature image extracting means;
hand gesture detecting means for detecting how three-dimensional spatial positions corresponding to the hands of the user, in the three-dimensional spatial positions of the body parts calculated by the spatial position calculating means, move with respect to the regions divided by the region dividing means;
hand gesture word determining means for determining a corresponding hand gesture word on the basis of the movement of the hands detected by the hand gesture detecting means; and
output means for outputting the result determined by the hand gesture word determining means in a form which can be recognized by an operator.
As stated above, according to the first aspect, the device extracts features of body parts from stereoscopic image data obtained by taking pictures of a user and detects three-dimensional movement of a hand gesture by utilizing parallax of the stereoscopic image data, and recognizes the hand gesture word on the basis of the detected result. This allows the hand gesture to be recognized without requiring the user to be equipped with any tools, and without contact. The device further divides the space surrounding the user into a plurality of regions corresponding to the body of the user and detects how the three-dimensional spatial positions of the user's hands move with respect to the divided regions. Accordingly it can always make proper recognition in accordance with the user's body, independent of body size of the user and movement of the body of the user, which remarkably improves the recognizing accuracy.
According to a second aspect, in the first aspect,
the feature image extracting means outputs the feature image in the corresponding channels on the basis of color information of individual picture elements forming the stereoscopic image data.
According to a third aspect, in the second aspect,
the feature image extracting means sets a color transformation table for each channel on the basis of a color to be extracted and a color not to be outputted which are specified by the operator,
transforms the color information of the individual picture elements forming the stereoscopic image data according to the color transformation table, and
discriminates values transformed according to the color transformation table with a predetermined threshold to output the feature image in the corresponding channels.
According to a fourth aspect, in the first aspect,
the region dividing means estimates a position of a body part which does not appear in the feature image on the basis of the three-dimensional spatial positions of the body parts calculated by the spatial position calculating means and divides the space surrounding the user into still smaller regions on the basis of the estimated position.
As stated above, according to the fourth aspect, a position of a body part which does not appear in the feature image is estimated and the space surrounding the user is divided into still smaller regions on the basis of the estimated position, which enables more accurate recognition.
According to a fifth aspect, in the first aspect,
the region dividing means calculates a difference value between the feature images adjacent in time and performs the process of dividing regions only when that difference value is equal to or larger than a predetermined threshold.
As stated above, according to the fifth aspect, the device divides regions only when a difference value between feature images adjacent in time reaches or exceeds a predetermined threshold, which reduces the calculating load for the region dividing.
According to a sixth aspect, in the first aspect,
the region dividing means divides a space extending in front and rear of the body of the user into a plurality of layers and further divides each of the layers into a plurality of regions.
According to a seventh aspect, in the
Igi Seiji
Imagawa Kazuyuki
Lu Shan
Matsuo Hideaki
Takata Yuji
Bella Matthew C.
Choobin M. B.
Matsushita Electric - Industrial Co., Ltd.
Wenderoth Lind & Ponack LLP
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