CN102184055B - Multi-touch-point recognition method and device - Google Patents
Multi-touch-point recognition method and device Download PDFInfo
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- CN102184055B CN102184055B CN 201110104566 CN201110104566A CN102184055B CN 102184055 B CN102184055 B CN 102184055B CN 201110104566 CN201110104566 CN 201110104566 CN 201110104566 A CN201110104566 A CN 201110104566A CN 102184055 B CN102184055 B CN 102184055B
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Abstract
The invention discloses a multi-touch-point recognition method and device. The method comprises the following steps of: acquiring a frame of image by two cameras respectively, and calculating the image position information and the transverse size information of touched objects in the two images respectively; calculating angles between the joint lines from the touched objects to two cameras according to the image position information of the touched objects, and calculating the coordinates of intersection points of all joint lines from the touched objects to the two cameras according to the angles between the joint lines from the touched objects to the two cameras; selecting one camera, calculating distances from the intersection points of all the joint lines to the camera, and calculating the ratios among all the distances; calculating the ratios among the transverse sizes of all touched object images acquired by the selected camera to be used as reference values; and comparing the ratios among all the distances with reference values to determine a real touch point. By means of the method and device in the invention, the problems of cost increase and design difficulty increase brought by additionally arranging an auxiliary camera are effectively solved.
Description
Technical field
The present invention relates to computer vision field, particularly a kind of method for identifying multiple touch points and device based on the camera location.
Background technology
In recent years, large-scale LCDs shows to have obtained widely in industry in large-scale man-machine interaction to be used, coordinate dull and stereotyped touching technique that infrared LED Scan orientation and ultrasound wave location are arranged and use two cameras to be installed on screen edges and corners, utilize the mode such as light path cross bearing, wherein with two cameras be installed on the locator meams of screen edges and corners high due to bearing accuracy, can Quick Catch and calculate the touch point coordinate and be widely used gradually.
As shown in Figure 1, take panel display screen as example, camera A and camera B are installed on respectively two corners of panel display screen, generally only intercept a few row images that camera collection arrives when identifying the location, these a few row images must be the images of pressing close to the flat pannel display screen surfaces, comprised and touched the image information that object throws on camera, can calculate the touch point to the angle of camera line by the picture position information of touch point, two cameras can unique position of determining a touch point to the line of touch point.
more than for only there being the situation of a touch point on touch-screen, but when existing two to touch object, as shown in Figure 1, two touch object to two camera and all produce separately two lines, four lines that are not parallel to each other can produce four point of crossing (R1 so, R1 ', R2, R2 '), namely had more two " false touch points " (R1 ', R2 '), should at this time touch-screen system determine which two point of crossing is the position of real touch object? in prior art, generally by increase an auxiliary camera in the middle of touch-screen, and verify that above-mentioned four point of crossing are to should whether existing line to reject false touch point by auxiliary camera.But this mode has not only increased hardware cost, has also increased the difficulty of design.
Summary of the invention
For addressing the above problem, the invention provides a kind of method for identifying multiple touch points and device, can determine real touch point in the situation that do not increase auxiliary camera.
A kind of method for identifying multiple touch points comprises the following steps:
Two cameras gather respectively a two field picture, calculate respectively touch objects volume image positional information and widthwise size information in two width images;
According to the angle on described touch objects volume image positional information calculation touch objects volume image and display screen base, and calculate the point of crossing coordinate of all lines that touch object to two camera according to the angle on described touch objects volume image and display screen base;
Selected camera calculates the point of crossing of all lines to the distance of this camera, and calculates the ratio between each distance;
Ratio between each touch objects volume image widthwise size that the selected camera of calculating collects and conduct are with reference to value;
Ratio and described reference value between described each distance are compared, determine the ratio with immediate those two distances of described reference value, respectively with two point of crossing of these two distance correspondences as real touch point.
The present invention also provides a kind of multiple touch points recognition device in addition, comprising:
The initial calculation module is used for calculating respectively touch objects volume image positional information and widthwise size information in two width images after two cameras gather respectively a two field picture;
The coordinate Calculation module that is connected with described initial calculation module, be used for according to the angle of described touch objects volume image positional information calculation touch objects volume image with the display screen base, and according to the point of crossing coordinate of described touch objects volume image with all lines of angle calculating touch object to two camera on display screen base;
The distance ratio computing module that is connected with described coordinate Calculation module is used for calculating the point of crossing of all lines to the distance of this camera after a selected camera, and calculates the ratio between each distance;
The reference value computing module that is connected with described initial calculation module, the ratio between each touch objects volume image widthwise size that the camera of selecting for calculating collects and conduct reference value;
The comparison module that is connected respectively with described distance ratio computing module, reference value computing module, be used for ratio and described reference value between described each distance are compared, determine the ratio with immediate those two distances of described reference value, two point of crossing that these two distances is corresponding are as real touch point respectively.
Can find out from above scheme, method for identifying multiple touch points of the present invention and device, owing to having utilized the size that touches object imaging in camera and having touched object to the linearly proportional characteristic of the distance of camera, do not increase auxiliary camera and just can find fast and accurately real touch point, effectively avoided the problem that cost increases and design difficulty increases brought owing to increasing auxiliary camera, had a good application prospect.
Description of drawings
Fig. 1 be on panel display screen two touch object to the schematic diagram of camera line;
Fig. 2 is the process flow diagram of method for identifying multiple touch points of the present invention;
Fig. 3 is two and touches the object imaging schematic diagram in two cameras respectively;
Fig. 4 is multiple touch points recognition device structural representation of the present invention.
Embodiment
The invention provides a kind of method for identifying multiple touch points and device, need to increase the problem that cost that auxiliary camera brings and design difficulty increase in the time of can solving in prior art on display screen multiple touch points location, the below describes embodiments of the invention in detail by reference to the accompanying drawings with the situation when having two touch points on panel display screen.
A kind of method for identifying multiple touch points as shown in Figure 2, comprises the following steps:
Step S1, two cameras gather respectively a two field picture, and calculate respectively touch objects volume image positional information and widthwise size information in two width images.
In the present embodiment, two cameras are installed on respectively the lower left corner, the lower right corner of panel display screen, and all adopt 90 ° of optical lens.
Preferably, after described two cameras gather respectively a two field picture, calculate the touch objects volume image positional information and widthwise size information in two width images before, can also comprise the steps S101: judge in two width images whether have the touch objects volume image.When not touching object on display screen two camera collections to image be complete black, exist if not complete black explanation to touch object, as shown in Figure 3, camera A collects two speck figure L1 and L2, camera B collects two speck figure L3 and L4.
Touch objects volume image positional information in above-mentioned calculating two width images and touch object widthwise size information are specially: calculate respectively middle axial coordinate Lx1, Lx2, Lx3, the Lx4 of speck L1, L2, L3, L4, these coordinates can represent the positional information that touches object; The resolution of supposing in addition camera employing horizontal 2048 gathers image, the coordinate that speck is corresponding so is in the scope of 0-2047, what pixels are the widthwise size of speck be namely across, can be by calculating widthwise size value Lw1, Lw2, Lw3, the Lw4 of each speck.
Step S2, touch angle between object to two a camera line according to described touch objects volume image positional information calculation, and touch the point of crossing coordinate of all lines of object to two camera according to the angle calculation between described touch object to two a camera line.
In conjunction with Fig. 1, the process that touches object to two a camera line angle by touch objects volume image positional information calculation is specific as follows: 2048 * 90 ° of speck L1 and display screen base angle a1=90 °-Lx1 ÷, 2048 * 90 ° of the angle a2=90 °-Lx2 ÷ on speck L2 and display screen base, 2048 * 90 ° of the angle b1=Lx3 ÷ on speck L3 and display screen base, 2048 * 90 ° of the angle b2=Lx4 ÷ on speck L4 and display screen base.
The front has calculated the angle that touches object to two a camera line on display screen, has known that this angle can calculate the point of crossing coordinate (being two point of crossing coordinates that touch totally four lines of object to two camera) that might exist on display screen.Suppose that the resolution that display screen shows is 1024 * 768, can be in the hope of touch point (point of crossing) coordinate R1 (X1, Y1), the R1 ' that might exist as shown in Figure 1 (X1 ', Y1 '), R2 (X2 by trigonometric function, Y2), R2 ' (X2 ', Y2 ').
Step S3, selected camera arrives the distance of this camera according to the point of crossing of above-mentioned point of crossing all lines of coordinate Calculation, and calculates the ratio between each distance.
For fear of when a plurality of touch point is arranged in the image that camera photographs certain touch point block other touch points (line has overlapped), as an embodiment preferably, can preferentially select to produce that maximum camera of line and carry out follow-up calculating, only need to calculate the many cameras of this line and get final product.As shown in Figure 3, because two cameras in the present embodiment have all photographed two images that touch object, and can produce two to the line of camera, therefore can arbitrarily choose a camera image and calculate, the image of for example choosing camera A calculates.
Because selected the image of camera A to calculate, so according to calculating four point of crossing coordinates of gained in step S2, can calculate four point of crossing and be respectively R1A, R1 ' A, R2A, R2 ' A to the distance of camera A, then calculate above-mentioned ratio between distance in twos.Certainly be in the touch point to the same line of camera A due to R1 and R1 ', therefore need not calculate the ratio between them, in like manner need not calculate the ratio between R2 and R2 '.
In order further to reduce the intensity of calculating, as an embodiment preferably, do not need to calculate the ratio between any two distances, only need calculating and camera A touch object far away to get final product to the ratio between the distance of camera A to the distance of camera A and nearer touch object.Suppose according to image 3 and judge that R1A, R1 ' A are the touch point that may exist nearer apart from camera A, R2A, R2 ' A are the touch point that may exist far away apart from camera A, therefore calculate respectively the ratio value combination of R2 ' A ÷ R1 ' A, R2 ' A ÷ R1A, R2A ÷ R1A, R2A ÷ R1 ' A.
Step S4, the ratio between each touch objects volume image widthwise size that the selected camera of calculating collects, and this ratio is worth as reference.
The image widthwise size of having known L1, L2 that camera A collects from step S1 is respectively Lw1, Lw2, calculates both ratio values.Well-known, because the size that touches object imaging in camera (and is inverse relation with touching object linearly proportional to the distance of camera, be that imaging is larger, distance is less), so this ratio can be referred to as again respectively to touch object to the ratio of the distance of camera.According to inverse relation, and what calculated in integrating step 3 is remote to in-plant ratio, therefore calculate from the touch objects volume image widthwise size of camera A closer distance with from the ratio between the longer-distance touch objects volume image of camera A widthwise size herein, should calculate as can be seen from Figure 3 r=Lw1 ÷ Lw2.
In fact, after a selected camera, step S3 and step S4 also can carry out in no particular order simultaneously.
Step S5, ratio and described reference value between described each distance are compared, determine the ratio with immediate those two distances of described reference value, other false touch point as real touch point, is rejected in two point of crossing that these two distances is corresponding respectively.
For example, after the ratio r contrast that calculates in the ratio value between each distance that calculates in step S3 and step S4, find that the ratio of R2A ÷ R1A is near r, can illustrate that so R2A and R1A are the distance that camera A is arrived in real touch point, therefore choose R2, R1 as real effectively touch point, abandon the touch point of other two falsenesses, and return to the identifying that step S1 begins next round.
As an embodiment preferably, can also comprise step S201 after this step S2 with before step S3: judge the touch object that whether exists on display screen more than.Know by the result of calculation in S2 to have one or a plurality of touch objects on display screen, because according to geometrical principle, only have one when calculating the touch point that might exist, illustrate only to exist to touch an object on display screen; If there are four in the touch point that may exist, explanation has two to touch object ... if only exist one to touch object, the step S3 of back and step S4 can omit.
In fact adopt touch-screen method for identifying multiple touch points of the present invention, not only can effectively identify the situation of one and two touch point, to also identifying more than the situation of two touch points (as three touch points), just algorithm can relative complex some, but principle is consistent, and it will not go into details herein.
Corresponding with above-mentioned a kind of method for identifying multiple touch points, the present invention also provides a kind of multiple touch points recognition device, as shown in Figure 4, comprising:
The initial calculation module is used for calculating respectively touch objects volume image positional information and widthwise size information in two width images after two cameras gather respectively a two field picture;
The coordinate Calculation module that is connected with described initial calculation module, be used for according to the angle between described touch objects volume image positional information calculation touch object to two a camera line, and touch the point of crossing coordinate of all lines of object to two camera according to the angle calculation between described touch object to two a camera line;
The distance ratio computing module that is connected with described coordinate Calculation module is used for calculating the point of crossing of all lines to the distance of this camera after a selected camera, and calculates the ratio between each distance;
The reference value computing module that is connected with described initial calculation module, the ratio between each touch objects volume image widthwise size that the camera of selecting for calculating collects and conduct reference value;
With the comparison module that described distance ratio computing module, reference value computing module are connected respectively, be used for ratio and described reference value between described each distance are compared, determine real touch point.
Preferably, can comprise the first judge module in described initial calculation module, this first judge module is used for after described two cameras gather respectively a two field picture, calculate the touch objects volume image positional information and widthwise size information of two width images before, judge in two width images whether have the touch objects volume image.
In addition, can comprise the second judge module in described coordinate Calculation module, described the second judge module is used for after the point of crossing coordinate that calculates all lines, before a selected camera, judge according to the point of crossing coordinate of described all lines the touch object that whether exists on display screen more than.
In order to reduce the calculating strength of algorithm of the present invention, can comprise relatively calculating sub module of distance in described distance ratio computing module, this module is used for calculating with selected camera touch object far away and arrives ratio between the distance of this camera to the distance of this camera and nearer touch object; And for corresponding with the inverse relation described in method of the present invention, described reference value computing module comprises the reference value calculating sub module, this module be used for to calculate with the nearer touch objects volume image widthwise size of the camera of selecting and touch objects volume image widthwise size far away between ratio.
The other technologies feature of multiple touch points recognition device of the present invention is identical with the description in method of the present invention, and it will not go into details herein.
Method for identifying multiple touch points of the present invention and device are being obtained the touch point that might exist after the distance of selected camera, obtain the ratio between each distance; Then utilize the size that touches object imaging in camera and touch object to the linearly proportional characteristic of the distance of camera, obtain ratio between the image widthwise size that respectively touches object as with reference to value, at last both are compared checking, determine real touch point, realized not increasing auxiliary camera and just can correctly find out the purpose of real touch point.Because adopting the pure software algorithm on the basis of existing technology, the present invention realizes, therefore not only effectively avoided the problem that cost increases and design difficulty increases brought owing to increasing auxiliary camera, and have performance fast and accurately when rejecting false touch point, have a good application prospect.
Above-described embodiment of the present invention does not consist of the restriction to protection domain of the present invention.Any modification of doing within the spirit and principles in the present invention, be equal to and replace and improvement etc., within all should being included in claim protection domain of the present invention.
Claims (9)
1. a method for identifying multiple touch points, is characterized in that, comprises the following steps:
Two cameras gather respectively a two field picture, calculate respectively touch objects volume image positional information and widthwise size information in two width images;
According to the angle on described touch objects volume image positional information calculation touch objects volume image and display screen base, and calculate the point of crossing coordinate of all lines that touch object to two camera according to the angle on described touch objects volume image and display screen base;
Selected camera arrives the distance of this camera according to the point of crossing of described point of crossing all lines of coordinate Calculation, and calculates the ratio between each distance;
Ratio between each touch objects volume image widthwise size that the selected camera of calculating collects and conduct are with reference to value;
Ratio and described reference value between described each distance are compared, determine the ratio with immediate those two distances of described reference value, respectively with two point of crossing of these two distance correspondences as real touch point.
2. method for identifying multiple touch points according to claim 1, it is characterized in that, after described two cameras gather respectively a two field picture, calculate the touch objects volume image positional information and widthwise size information in two width images before, also comprise step: judge in two width images whether have the touch objects volume image.
3. method for identifying multiple touch points according to claim 2, it is characterized in that, after calculating the point of crossing coordinate of all lines, before a selected camera, also comprise step: judge according to the point of crossing coordinate of described all lines the touch object that whether exists on display screen more than.
4. according to claim 1 and 2 or 3 described method for identifying multiple touch points, is characterized in that, the process of a selected camera is specially: select to produce that maximum camera of line.
5. method for identifying multiple touch points according to claim 1, it is characterized in that, the process of ratio between each distance of described calculating is specially: calculate with selected camera touch object far away and arrive ratio between the distance of this camera to the distance of this camera and nearer touch object;
And
The process of the ratio between each touch objects volume image widthwise size that the selected camera of described calculating collects is specially: the ratio between the touch objects volume image widthwise size that the camera that calculates and select is nearer and touch objects volume image widthwise size far away.
6. a multiple touch points recognition device, is characterized in that, comprising:
The initial calculation module is used for calculating respectively touch objects volume image positional information and widthwise size information in two width images after two cameras gather respectively a two field picture;
The coordinate Calculation module that is connected with described initial calculation module, be used for according to the angle of described touch objects volume image positional information calculation touch objects volume image with the display screen base, and according to the point of crossing coordinate of described touch objects volume image with all lines of angle calculating touch object to two camera on display screen base;
The distance ratio computing module that is connected with described coordinate Calculation module is used for calculating the point of crossing of all lines to the distance of this camera after a selected camera, and calculates the ratio between each distance;
The reference value computing module that is connected with described initial calculation module, the ratio between each touch objects volume image widthwise size that the camera of selecting for calculating collects and conduct reference value;
The comparison module that is connected respectively with described distance ratio computing module, reference value computing module, be used for ratio and described reference value between described each distance are compared, determine the ratio with immediate those two distances of described reference value, two point of crossing that these two distances is corresponding are as real touch point respectively.
7. multiple touch points recognition device according to claim 6, it is characterized in that, described initial calculation module comprises the first judge module, before being used for after described two cameras gather respectively a two field picture, calculating the touch objects volume image positional information and widthwise size information of two width images, judge in two width images whether have the touch objects volume image.
8. according to claim 6 or 7 described multiple touch points recognition devices, it is characterized in that, described coordinate Calculation module comprises the second judge module, be used for after the point of crossing coordinate that calculates all lines, before a selected camera, judge according to the point of crossing coordinate of described all lines the touch object that whether exists on display screen more than.
9. according to claim 6 or 7 described multiple touch points recognition devices, it is characterized in that, described distance ratio computing module comprises relatively calculating sub module of distance, is used for calculating with selected camera touch object far away arriving ratio between the distance of this camera to the distance of this camera and nearer touch object;
And
Described reference value computing module comprises the reference value calculating sub module, be used for to calculate with the nearer touch objects volume image widthwise size of the camera of selecting and touch objects volume image widthwise size far away between ratio.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6504532B1 (en) * | 1999-07-15 | 2003-01-07 | Ricoh Company, Ltd. | Coordinates detection apparatus |
| CN101639747A (en) * | 2009-08-31 | 2010-02-03 | 广东威创视讯科技股份有限公司 | Spatial three-dimensional positioning method |
| CN101794184A (en) * | 2010-04-07 | 2010-08-04 | 广东威创视讯科技股份有限公司 | Coordinate detection device and locating method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6504532B1 (en) * | 1999-07-15 | 2003-01-07 | Ricoh Company, Ltd. | Coordinates detection apparatus |
| CN101639747A (en) * | 2009-08-31 | 2010-02-03 | 广东威创视讯科技股份有限公司 | Spatial three-dimensional positioning method |
| CN101794184A (en) * | 2010-04-07 | 2010-08-04 | 广东威创视讯科技股份有限公司 | Coordinate detection device and locating method thereof |
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