GESTURE IDENTIFICATION WITH NATURAL IMAGES
A method for gesture identification with natural images includes generating a series of variant images by using each two or more successive ones of the natural images, extracting an image feature from each of the variant images, and comparing the varying pattern of the image feature with a gesture definition to identify a gesture. The method is inherently insensitive to indistinctness of images, and supports the motion estimation in axes X, Y, and Z without requiring the detected object to maintain a fixed gesture.
Latest PIXART IMAGING INC. Patents:
The present invention is related generally to a method for gesture identification and, more particularly, to a method for gesture identification with natural images.
BACKGROUND OF THE INVENTIONGesture-control systems provide simple and intuitional convenient operation. However, the systems using touch-controlled human-machine interfaces such as touch panels require users to perform operation by directly contacting the interfaces, thus being inconvenient to some applications. Contrary, the gesture-control systems using non-touch interfaces allows users to perform operation at a relatively distant place therefrom, while being more difficult to implement because such systems determine gestures by capturing and identifying images. Currently, the methods for image-based gesture identification can be classified into two categories, one using natural images without auxiliary illuminant, while the other using unnatural images generated by one or more auxiliary light sources.
Compared to the gesture-control systems using auxiliary illuminant, the gesture-control systems not using auxiliary illuminant are more advantageous because they require lower costs, can be combined with a camera, and save power, while having the innate weakness of more difficulty in gesture identification. The methods for gesture identification employed by a gesture-control system not using auxiliary illuminant are typically established on either motion estimation or shape detection. Since gestures and operational habits are usually different among users, gesture identification using motion estimation is particularly weak in identifying certain gestures, such as click and zoom in/out that include Z-axis motions. On the other hand, gesture identification using shape detection usually requires users to operate with certain gestures that are fixed and recognizable to the system, for example, making a fist or opening a palm.
The method for gesture identification using shape detection includes recognizing the region of skin color in an image, then identifying the shape of the recognized region of skin color, and finally finding out where a hand is in the image. However, skin-color analysis requires complex algorithm and is color temperature dependent, so the error rate is relatively high. Shape recognition also needs complex algorithm. These processes need numerous arithmetic operations, and thus require higher costs for both software and hardware, and slower down the system's response.
SUMMARY OF THE INVENTIONAn objective of the present invention is to provide a method for gesture identification with natural images.
Another objective of the present invention is to provide a method for gesture identification inherently insensitive to indistinctness of images.
Yet another objective of the present invention is to provide a method for gesture identification useful to short distance applications.
Still another objective of the present invention is to provide a method for gesture identification capable of supporting the motion estimation in axes X, Y, and Z without requiring the detected object to maintain a fixed gesture.
Yet still another objective of the present invention is to provide a method for gesture identification without requiring a predetermined gesture shape.
A further objective of the present invention is to provide a method for gesture identification independent of color temperature.
Yet a further objective of the present invention is to provide a method for gesture identification with less calculation.
Still a further objective of the present invention is to provide a lower cost method for gesture identification.
According to the present invention, a method for gesture identification with natural images includes the steps of generating a series of images over time, selecting two or more successive images from the series of images to generate a variant image, extracting an image feature from the variant image, and comparing a varying pattern of the image feature with a gesture definition to identify the gesture.
Since the disclosed method eliminates the use of image recognition and needs not to detect the position of an object in an image, it is free from the shortcomings of the conventional methods.
These and other objectives, features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings, in which:
In the following paragraphs, examples of identifying sliding, rotating, and zooming gestures will be described to illustrate the present invention in further details.
Referring to
Referring to
Referring to
There have been many well-known processes for calculation of an image feature of an image, and any parameters or mathematical formulas capable of expressing the change of images can be used in the method according to the present invention.
In other embodiments, apart from calculating an image feature from a variant image, frequency analysis may be used to process the image feature, for example, applying Fourier transform to convert the movement of images along the vertical and transverse axes from the time domain into the frequency domain, so as to determine the varying pattern. The varying pattern acting as a gesture definition may be set by system designers.
For extracting an image feature from a variant image, a threshold may be added for screening pixels, and only the pixels with a brightness change exceeding the threshold are used in calculating the image feature, so as to improve accuracy.
While the present invention has been described in conjunction with preferred embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and scope thereof as set forth in the appended claims.
Claims
1. A method for gesture identification with natural images, comprising the steps of:
- A.) generating a time-based series of images;
- B.) from the series of the images, each time selecting two or more successive images to generate a variant image;
- C.) extracting an image feature from the variant image; and
- D.) comparing a varying pattern of the image feature with a gesture definition to identify a gesture.
2. The method of claim 1, wherein the step B comprises the step of subtracting between the images being successive in terms of time.
3. The method of claim 1, wherein the step C comprises the step of screening pixels of the variant image by a threshold for calculating the image feature.
4. The method of claim 1, wherein the step C comprises the step of calculating a barycenter, a standard deviation or a variance of the variant image as the image feature.
5. The method of claim 1, wherein the step D comprises the step of processing the image feature by a frequency analysis to determine the varying pattern.
6. A method for gesture identification with natural images, comprising the steps of:
- A.) generating a time-based series of images;
- B.) comparing two or more successive images to generate a differential image from the series of the images; and
- C.) comparing the differential image with a gesture definition to identify a gesture.
7. The method of claim 6, wherein the step B comprises the step of subtracting between the images being successive in terms of time.
8. The method of claim 6, wherein the step C comprises the step of screening pixels of the variant image by a threshold for calculating an image feature.
9. The method of claim 6, wherein the gesture includes a hand left motion, a hand right motion or a hand rotation motion.
10. The method of claim 6, wherein the step C comprises the step of processing the differential image by a frequency analysis to determine a varying pattern.
11. The method of claim 10, wherein the step C comprises the step of comparing the varying pattern of the differential image with the gesture definition to identify the gesture.
Type: Application
Filed: Oct 4, 2013
Publication Date: Apr 17, 2014
Applicant: PIXART IMAGING INC. (Hsin-Chu)
Inventor: Shu-Sian YANG (Hsin-Chu City)
Application Number: 14/046,214
International Classification: G06K 9/00 (20060101);