CN104361239A - Boxing sandbag training virtualizing method based on Kinect and boxing sandbag training virtualizing system based on Kinect - Google Patents

Abstract

The present invention relates to a kind of method and system of Kinect-based virtual boxing punching bag training, and its specific method comprises: build virtual scene, load virtual boxing glove and sandbag model; Obtain the bone position data of operator's left and right hands through Kinect camera; Control through position data The virtual boxing glove in the virtual system calculates whether it hits the virtual sandbag; calculates the punching speed of the operator, thereby calculates the swing range of the sandbag, and uses the computer graphics interface to virtualize the punching process of the sandbag. The invention virtualizes the most commonly used sandbag hitting practice in boxing training, and provides a new method for training under the condition that real sandbags cannot be hung due to environmental constraints.

Description

A method and system for Kinect-based virtual punching bag training

technical field

The invention relates to computer application technology, in particular to a Kinect-based virtual punching bag training method and system.

Background technique

In the prior art, the virtual boxing or fighting games on the computer are all realized by using a somatosensory device or a handle with an acceleration sensor and a gyroscope. sent to the computer system for interactive processing. It has the following defects: first, the way of using the handle, the operator only needs to operate and hit through the handle buttons, and the purpose of real boxing training cannot be achieved; For training, the somatosensory sensing device only senses the operator's movement, but cannot reflect the operator's punching posture, and the authenticity is not high.

Application No. 200910189787.X "A Method and System for Realizing Virtual Boxing Based on Computer", the operator wears a special hat, the main handle and the auxiliary handle with tracking features on the hands, and obtains the head and hand tracking through the binocular camera Point position, the computer simulates the punching posture of the operator, which solves the problems of the above method to a certain extent. However, in order to facilitate computer identification, the system and method require the operator to wear a hat with tracking features and a main and auxiliary handle, which greatly affects the user experience.

Contents of the invention

The technical problem to be solved by the present invention is to provide a Kinect-based virtual punching bag training method and system, the purpose of which is to simulate the training process of the punching bag and improve the authenticity of the training.

The technical scheme of the present invention is: a kind of method based on Kinect virtual boxing punching bag training, comprises the following steps: S1, obtain operator's left and right hand spatial position data, described left and right hand spatial position data reflect operator's left and right hand position information;

S2. Convert the space position data of the left and right hands of the operator into the screen coordinate data of the left and right virtual boxing gloves, and use the screen coordinate data of the left and right virtual boxing gloves to control the position movement of the virtual boxing gloves on the screen;

S3. According to the screen coordinate data of the left and right virtual boxing gloves in S2, it is judged whether the virtual boxing gloves hit the virtual sandbag;

S4. After hitting the virtual sandbag, calculate the initial swing speed and initial swing angle of the center point of the virtual sandbag;

S5. According to the initial swing speed, initial swing angle and attenuation method of the center point of the virtual sandbag in S4, render the swing process of the virtual sandbag through the computer graphics interface, and display it on the display device.

Wherein, step S1 includes:

S11. Obtain the operator's skeleton image frame from the Kinect video stream;

S12. From the skeleton image frame data in step S11, acquire the coordinate data of the left and right hands of the operator as spatial position data of the left and right hands.

Step S2 includes:

S21. Obtain the screen resolution (x _s , y _s ), convert the left and right hand coordinates HL(x _l , y _l , z _l ), HR(x _r , y _r , z _r ) in the left and right hand spatial position data into left and right virtual Boxing glove screen coordinates VL(x _ls , y _ls ), VR(x _rs , y _rs );

S22. Draw the virtual boxing glove model on the screen coordinates VL(x _ls , y _ls ) and VR(x _rs , y _rs ) of the left and right virtual boxing gloves, thereby controlling the movement of the virtual boxing glove on the screen.

The conversion method of left and right hand coordinates in step S21 is:

x _ls =α*x _l y _ls =β*y _l

x _rs =α*x _r y _rs =β*y _r where the coordinate conversion coefficients α=x _s /320, β=y _s /240.

Step S3 includes:

S31, equating the virtual sandbag to a rectangular area, and dynamically calculating the four vertex coordinates of the rectangular area;

S32. Determine whether the screen coordinates of the left and right virtual boxing gloves are on the rectangular area shown in step S31. If so, it indicates that the sandbag is hit; otherwise, it indicates that the sandbag is not hit.

The calculation method of the coordinates of the four vertices of the rectangular area of step S31 is: assuming that the height and width of the rectangular area of the virtual sandbag are h and w respectively, the distance between the center point of the virtual sandbag and the suspension point is l, and when the center point of the virtual sandbag is stationary, the screen The coordinates are (x ₀ , y ₀ ), when the offset angle relative to the central axis is θ, the coordinates of the vertex A in the upper left corner of the rectangular area are: The coordinates of vertex B in the upper right corner are: The coordinates of the bottom right vertex C are: The coordinates of the vertex D in the lower left corner are:

Step S4 includes:

S41. Calculate the initial swing velocity V ₀ of the center point of the virtual sandbag;

S42. Calculate the initial swing angle φ of the center point of the virtual sandbag.

Wherein, in the step S41, the calculation method of the initial swing velocity _V of the center point of the virtual sandbag is:

S411. Calculate the punching speed V ₁ of the operator's left or right hand;

S412. Calculate the initial swing velocity V ₀ of the center point of the virtual sandbag according to the punching velocity V ₁ obtained in step S411.

In step S411, the operator's left hand or right hand punching velocity V is calculated as _follows : take the Kinect camera as the origin of the three-dimensional coordinate system, the plane where the front panel of the Kinect camera is located is the XOY plane, wherein the X axis points to the right side of the operator, and the Y axis Point to the top of the operator, and the Z axis points to the front of the operator. Assume that the bone coordinates obtained from the bone image frame hitting the virtual sandbag are P(X ₁ , Y ₁ , Z ₁ ), and take the bone coordinates of the previous frame Q(X ₂ , Y ₂ , Z ₂ ), then the punching vector It is (X ₁ -X ₂ , Y ₁ -Y ₂ , Z ₁ -Z ₂ ), from which we can get punch speed V ₁ :

$V_1=\left|\stackrel{\&Right\; Arrow;}{\mathrm{PQ}}\right|*25=25\sqrt{{(x_1-x_2)}^2+{(Y_1-Y_2)}^2+{(Z_1-Z_2)}^2}$ The unit of _V1 is: m/s.

In step S412, after the operator hits the virtual sandbag with a punching speed of _V1 , the calculation formula for the initial swing speed _V0 of the center point of the virtual sandbag is:

V ₀ =0.025V ₁ .

The calculation method of the initial swing angle φ of the center point of the virtual sandbag in step S42 is:

φ＝argcos(1-V ₀ ² /2lg)

Among them: V ₀ is the initial swing velocity of the center point of the virtual sandbag, l is the distance between the center point of the virtual sandbag and the suspension point, g is the acceleration of gravity, which is 9.8 m/s ² .

In step S5, when rendering the swing process of the virtual sandbag through the graphical interface, the swing angle of the virtual sandbag is reduced by 25% of the initial swing angle φ every time it passes the center line, that is, it is attenuated according to this amplitude, and the virtual sandbag swings two times after hitting from rest. The cycle stops at the centerline, waiting for the next stroke.

A kind of Kinect-based virtual boxing punching bag training system comprises a Kinect camera, a computer and a display device; the Kinect camera is connected with the computer, and the computer and the display device are connected by a video cable;

Wherein, the Kinect camera is used to obtain the spatial position data of the left and right hands of the operator, and the spatial position data of the left and right hands reflects the position information of the left and right hands of the operator;

The computer converts the space position data of the left and right hands of the operator into the screen coordinate data of the left and right virtual boxing gloves, uses the screen coordinate data of the left and right virtual boxing gloves to control the position movement of the virtual boxing gloves on the screen, and then judges the virtual boxing gloves according to the screen coordinate data of the left and right virtual boxing gloves Whether to hit the virtual sandbag; after hitting the virtual sandbag, calculate the initial swing speed and initial swing angle of the virtual sandbag center point, and render the virtual sandbag swing process through the computer graphics interface according to the initial swing speed, initial swing angle and attenuation method of the virtual sandbag center point ;

The display device is used for displaying a boxing training scene, a virtual sandbag, a virtual boxing glove, and a process in which an operator hits the sandbag.

Description of drawings

Fig. 1 is a system structure diagram of the present invention.

Fig. 2 is a flow chart of the method of the present invention.

Fig. 3 is a schematic diagram of sandbag swing of the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

As shown in Figure 1, the system of the Kinect-based virtual punching bag training of the present invention comprises a Kinect camera 1, a computer 2, a display device 3 and connection lines 4,5. The Kinect camera 1 is used to acquire spatial position data of the left and right hands of the operator, and the spatial position data of the left and right hands reflect the position information of the operator's left and right hands. The computer converts the space position data of the left and right hands of the operator into the screen coordinate data of the left and right virtual boxing gloves, uses the screen coordinate data of the left and right virtual boxing gloves to control the position movement of the virtual boxing gloves on the screen, and then judges the virtual boxing gloves according to the screen coordinate data of the left and right virtual boxing gloves Whether to hit the virtual sandbag; after hitting the virtual sandbag, calculate the initial swing speed and initial swing angle of the virtual sandbag center point, and render the virtual sandbag swing process through the computer graphics interface according to the initial swing speed, initial swing angle and attenuation method of the virtual sandbag center point ; The display device is used to display the boxing training scene, the virtual sandbag, the virtual boxing glove and the process of the operator hitting the sandbag.

The Kinect camera uses various Xbox or Windows version devices produced by Microsoft, and is connected to the computer through a dedicated USB cable. The display device can be a computer monitor, a digital TV with an HDMI interface, or a large screen projected through a projector. The computer and the display device pass through Video cable connection. The operator 6 aims at the camera and hits sandbags in the screen within a distance of 1.5 meters to 2.3 meters in front of the Kinect camera. The computer first designs and loads the virtual boxing gloves, virtual sandbag model and the background of the boxing training room. Taking the Max3D and Direct 3D graphics interface as an example, the virtual boxing gloves and virtual sandbag models are established in the Max3D software, saved as .x files, and used in D3D graphics The interface D3DXLoadMeshFromX function loads the .X format file, and then uses the skybox background principle to build a virtual boxing ring background. Afterwards, the bone frame data is extracted from the data sent back by Kinect, and the spatial position coordinates of the left and right hands of the operator are obtained from them, and converted into screen coordinates, the virtual fist is manipulated to hit the sandbag, and the sandbag is hit according to the relevant algorithm.

As shown in Figure 2, the method for the virtual punching bag training based on Kinect specifically includes the following steps:

S1. Obtain coordinates of the left and right hands of the operator. By initializing the Kinect device, the computer obtains the frame image of the operator's skeleton from the interface, and extracts the space coordinates HL(x _l , y _l , z _l ) and HR(x _r , y _r , z _r ) of the operator's left and right hands. The coordinate system refers to Figure 1 shows.

S2. Control the position change of the virtual boxing glove. First obtain the screen resolution (x _s , y _s ) of the display device, and convert the bone coordinates HL(x _l , y _l , z _l ) and HR(x _r , y _r , z _r ) in the spatial position data of the left and right hands into The screen coordinates of the virtual boxing glove are VL(x _ls , y _ls ), VR(x _rs , y _rs ). Wherein the transformation method is, coordinate conversion coefficient α=x _s /320, β=y _s /240, then: x _ls ＝α*x _l , y _ls ＝β*y _l , x _rs ＝α*x _r , y _rs =β*y _r ; then draw the virtual boxing glove model on the screen coordinates VL(x _ls , y _ls ), VR(x _rs , y _rs ) of the virtual boxing glove, thereby controlling the movement of the virtual glove on the screen . Taking the Direct 3D graphics interface as an example, by assigning coordinate values to D3DPosition in real time, the virtual boxing glove moves with the operator's fist.

S3. Sandbag hit determination. As shown in Figure 3, the effective hit area is equivalent to the area where the rectangle ABCD is located, and the calculation method of the coordinates of the rectangle vertices assumes that the height and width of the sandbag rectangular area are h and w respectively, the distance between the center point of the sandbag and the suspension point is l, and the center point of the sandbag The screen coordinates at rest are (x ₀ , y ₀ ), when the offset angle relative to the central axis is θ (positive to the right, negative to the left), the four vertices (upper left, upper right, lower right, lower left ) dynamic coordinates are: $B$ $(x_0+l*\sin \mathrm{\θ}+\frac{w}{2},{\mathrm{the\; y}}_0-l*(1-\cos \mathrm{\θ})+\frac{h}{2}),$ $C(x_0+l*\sin \mathrm{\θ}+\frac{w}{2},{\mathrm{the\; y}}_0-l*(1-\cos \mathrm{\θ})-\frac{h}{2}),$ When the virtual boxing glove screen coordinates VL(x _ls , y _ls ), VR(x _rs , y _rs ) fall into this area, it is considered a valid hit.

S4. Calculate the initial swing velocity V0 and the initial swing angle φ of the center point of the virtual sandbag. First, calculate the operator's left and right punching speed V ₁ , refer to the skeleton frame coordinate system in Figure 1, take the camera as the origin of the three-dimensional coordinate system, the plane where the front panel of the camera is located is the XOY plane, the X axis points to the right side of the operator, and the Y axis points to the operator above the operator, the Z axis points to the front side of the operator, assuming that the bone coordinate P(X ₁ , Y ₁ , Z ₁ ) obtained in the bone frame hitting the sandbag is taken, the bone coordinate Q(X ₂ , Y ₂ , Z ₂ ), then the punching vector is (X ₁ -X ₂ , Y ₁ -Y ₂ , Z ₁ -Z ₂ ). Skeleton frame sampling rate is 25 frames per second, from which the punching speed can be obtained: $V_1=\left|\stackrel{\&Right\; Arrow;}{\mathrm{PQ}}\right|*25=25\sqrt{{(x_1-x_2)}^2+{(Y_1-Y_2)}^2+{(Z_1-Z_2)}^2},$ The unit is: m/s.

As shown in Figure 3, when the operator hits the virtual sandbag at the punching speed V ₁ , the momentum theorem is simplified, assuming that the punching speed is 0m/s after punching, the mass of the fist is 0.5Kg, and the weight of the sandbag is 20Kg, then the initial velocity of the sandbag is The calculation formula is: V ₀ =0.025V ₁ . Then by the law of conservation of energy, the maximum deflection angle φ=argcos(1-V ₀ ² /2lg) of the center of the virtual sandbag can be drawn, wherein: l is the distance from the center point of the sandbag to the suspension point, and g is the acceleration of gravity, which is 9.8 meters/ Second ² , the meaning of each variable is shown in Figure 3.

S5. Render the virtual sandbag swing effect through the image interface. Decrease the swing angle of the virtual sandbag by 25% of the initial swing angle φ every time it crosses the center line, that is, linearly attenuate according to this rule, and the sandbag will stop at the center line after swinging for two cycles after being stationary, waiting for the next hit. Taking the D3D graphics interface as an example, call the D3DXMatrixRotationX(&Rx,θ) interface function to realize the sandbag swing.

The above embodiments are only used to illustrate the technical solutions of the patent of the present invention, and are not intended to limit it; although the patent of the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be used for the foregoing implementations. The technical solutions described in the examples are modified, or some of the technical features are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the patent of the present invention.

Claims (10)

1. a method for Kinect-based virtual punching bag training, is characterized in that, comprises the following steps: S1. Obtain spatial position data of the left and right hands of the operator, the spatial position data of the left and right hands reflect the position information of the operator's left and right hands; Said step S1 comprises: S11. Obtain the operator's skeleton image frame from the Kinect video stream; S12. From the skeleton image frame data in step S11, acquire the coordinate data of the left and right hands of the operator as spatial position data of the left and right hands. S2. Convert the space position data of the left and right hands of the operator into the screen coordinate data of the left and right virtual boxing gloves, and use the screen coordinate data of the left and right virtual boxing gloves to control the position movement of the virtual boxing gloves on the screen; Described step S2 comprises: S21. Obtain the screen resolution (x _s , y _s ), convert the left and right hand coordinates HL(x _l , y _l , z _l ), HR(x _r , y _r , z _r ) in the left and right hand spatial position data into left and right virtual Boxing glove screen coordinates VL(x _ls , y _ls ), VR(x _rs , y _rs ); the conversion method of left and right hand coordinates is: x _ls =α*x _l y _ls =β*y _l x _rs ＝α*x _r y _rs ＝β*y _r Among them, coordinate transformation coefficient α＝x _s /320, β＝y _s /240; S22. Draw the virtual boxing glove model on the screen coordinates VL(x _ls , y _ls ) and VR(x _rs , y _rs ) of the left and right virtual boxing gloves, thereby controlling the movement of the virtual boxing glove on the screen. S3. According to the screen coordinate data of the left and right virtual boxing gloves in S2, it is judged whether the virtual boxing gloves hit the virtual sandbag; S4. After hitting the virtual sandbag, calculate the initial swing speed and initial swing angle of the center point of the virtual sandbag; S5. According to the initial swing speed, initial swing angle and attenuation method of the center point of the virtual sandbag in S4, render the swing process of the virtual sandbag through the computer graphics interface, and display it on the display device. 2. the method for a kind of Kinect-based virtual boxing punching bag training according to claim 1, is characterized in that, described step S3 comprises: S31, equating the virtual sandbag to a rectangular area, and dynamically calculating the four vertex coordinates of the rectangular area; S32. Determine whether the screen coordinates of the left and right virtual boxing gloves are on the rectangular area shown in step S31. If so, it indicates that the sandbag is hit; otherwise, it indicates that the sandbag is not hit. 3. the method for a kind of Kinect-based virtual boxing sandbag training according to claim 2, is characterized in that, the calculation method of the four vertex coordinates of the rectangular area of described step S31 is: assume that the virtual sandbag rectangular area is high and wide are h and w respectively, the distance between the center point of the virtual sandbag and the suspension point is l, the screen coordinates when the center point of the virtual sandbag is stationary is (x ₀ , y ₀ ), when the offset angle relative to the central axis is θ, the rectangle The coordinates of vertex A in the upper left corner of the area are: $(x_0+l*\sin \mathrm{\θ}-\frac{w}{2},{\mathrm{the\; y}}_0-l*(1-\cos \mathrm{\θ})+\frac{h}{2}),$ The coordinates of vertex B in the upper right corner are: $(x_0+l*\sin \mathrm{\θ}+\frac{w}{2},{\mathrm{the\; y}}_0-l*(1-\cos \mathrm{\θ})+\frac{h}{2}),$ The coordinates of the bottom right vertex C are: $(x_0+l*\sin \mathrm{\θ}+\frac{w}{2},{\mathrm{the\; y}}_0-l*(1-\cos \mathrm{\θ})-\frac{h}{2}),$ The coordinates of the vertex D in the lower left corner are: $(x_0+l*\sin \mathrm{\θ}-\frac{w}{2},{\mathrm{the\; y}}_0-l*(1-\cos \mathrm{\θ})-\frac{h}{2}).$ 4. the method for a kind of Kinect-based virtual boxing punching bag training according to claim 1, is characterized in that, described step S4 comprises: S41. Calculate the initial swing velocity V ₀ of the center point of the virtual sandbag; S42. Calculate the initial swing angle φ of the center point of the virtual sandbag. 5. the method for a kind of Kinect-based virtual boxing sandbag training according to claim 4, is characterized in that, in described step S41, the computing method of virtual sandbag central point initial swing velocity V ₀ is: S411. Calculate the punching speed V ₁ of the operator's left or right hand; S412. Calculate the initial swing velocity V ₀ of the center point of the virtual sandbag according to the punching velocity V ₁ obtained in step S411. 6. the method for a kind of Kinect-based virtual boxing punching bag training according to claim 5, is characterized in that, in described step S411, the calculation method of operator's left hand or right hand punching speed V ₁ is: take Kinect camera as three-dimensional The origin of the coordinate system, the plane where the front panel of the Kinect camera is located is the XOY plane, where the X-axis points to the right side of the operator, the Y-axis points to the top of the operator, and the Z-axis points to the front side of the operator. The bone coordinate obtained in the image frame is P(X ₁ , Y ₁ , Z ₁ ), and the previous frame bone coordinate Q(X ₂ , Y ₂ , Z ₂ ), then the punching vector It is (X ₁ -X ₂ , Y ₁ -Y ₂ , Z ₁ -Z ₂ ), from which we can get punch speed V ₁ : $V_1=\left|\stackrel{\&Right\; Arrow;}{\mathrm{PQ}}\right|*25=25\sqrt{{(x_1-x_2)}^2+{(Y_1-Y_2)}^2+{(Z_1-Z_2)}^2}$ The unit of _V1 is: m/s. 7. the method for a kind of virtual boxing punching bag training based on Kinect according to claim 5, is characterized in that, after the operator hits the virtual punching bag with the punching speed of V ₁ in the step S412, the center point of the virtual punching bag The formula for calculating the initial swing velocity V ₀ is: V ₀ =0.025V ₁ . 8. a kind of method based on the virtual boxing sandbag training of Kinect according to claim 4, is characterized in that, in the described step S42, the calculation method of virtual sandbag central point initial swing angle φ is: φ＝argcos(1-V ₀ ² /2lg) Among them: V ₀ is the initial swing velocity of the center point of the virtual sandbag, l is the distance between the center point of the virtual sandbag and the suspension point, g is the acceleration of gravity, which is 9.8 m/s ² . 9. the method for a kind of Kinect-based virtual boxing sandbag training according to claim 1, is characterized in that, when rendering virtual sandbag swing process by graphical interface in the described step S5, the virtual sandbag swing angle crosses the center line every time Decrease 25% of the initial swing angle φ, that is, attenuate according to this amplitude, and the virtual sandbag will stop at the center line after swinging for two cycles after being stationary, waiting for the next strike. 10. A system based on the Kinect-based virtual boxing sandbag training, characterized in that the system includes a Kinect camera, a computer and a display device; the Kinect camera is connected with a computer, and the computer and the display device are connected by a video cable; Wherein, the Kinect camera is used to obtain the spatial position data of the left and right hands of the operator, and the spatial position data of the left and right hands reflects the position information of the left and right hands of the operator; The computer converts the space position data of the left and right hands of the operator into the screen coordinate data of the left and right virtual boxing gloves, uses the screen coordinate data of the left and right virtual boxing gloves to control the position movement of the virtual boxing gloves on the screen, and then judges the virtual boxing gloves according to the screen coordinate data of the left and right virtual boxing gloves Whether to hit the virtual sandbag; after hitting the virtual sandbag, calculate the initial swing speed and initial swing angle of the virtual sandbag center point, and render the virtual sandbag swing process through the computer graphics interface according to the initial swing speed, initial swing angle and attenuation method of the virtual sandbag center point ; The display device is used for displaying a boxing training scene, a virtual sandbag, a virtual boxing glove, and a process in which an operator hits the sandbag.