RU2670649C1 - Method of manufacturing virtual reality gloves (options) - Google Patents

Abstract

FIELD: manufacturing technology.SUBSTANCE: invention relates to manipulators and can be used in the manufacture of virtual gloves, designed to work with interactive devices, computer robotics and computer. In the manufacturing method, virtual reality gloves use sensors that have gloves on the fingers, and the sensors are connected to the motherboard. And as sensors use sensors IMU, which are placed on the fingers of the gloves. On the index, middle, ring fingers and little finger set one sensor in the penultimate phalanx of the finger on the outside of the palm, and on the thumb set two sensors on the first and second phalanx on the outside. On the inside of the palm, on the penultimate phalanx of each finger, vibration motors are placed.EFFECT: technical result of the invention is the ability to receive and transmit data on the position of fingers, hands, elbow and shoulder joints to a computer or other device, and also to carry out tactile feedback by transfer of vibration on fingers and more exact calculation of position of a brush in space.11 cl, 4 dwg

Description

The invention relates to manipulators and can be used in the manufacture of virtual gloves, designed to work with interactive devices, computer robotics and computer.

In the prior art, the solution KR 100221335 is known, which describes a system and method for a glove to transmit a sensor value in a virtual reality system, including a series of sensors measuring movements of the wrist and fingers and outputting an electrical signal; The multiplexer selects the number of sensor signals included in one of the sensor groups. The purpose of the patent is fundamentally different from the stated solution. The analogs describe exactly the high-speed data transfer between the sensors and the virtual reality system. In the claimed solution, the data transfer method is irrelevant.

CN 1480822 describes a data entry device for people with disabilities, which is a glove with many sensors capable of detecting finger movement, much faster than is usually required for pressing keys in a conventional keyboard; The sensor contains a virtual key detector and a key decoder, both of which are individually calibrated. The purpose of the glove and the detection method differ. In the analogue, it is proposed to carry out the interaction by touching certain sensors with gloves for people with limited abilities; the contacts will be transmitted to an external device. Our stated decision determines precisely the movements and positions of fingers and hands for transmission to an external device.

In the application US 20150002401 described alternative gloves on the basis of "key" for mobile devices, including at least one pair of gloves, a variety of sensors located on the first side, at least two screens located on each side of the glove. The task of the glove is to enter some keys for mobile devices. In this case, the glove does not detect the movement and position of the fingers and hand, as does the claimed solution.

In the patent US 6870526 described glove mouse with virtual cursor tracking, designed to control the movement of the cursor and ensure the function of a computer mouse. The presented glove is intended only for controlling the cursor and the mouse.

Our stated solution can not only control the mouse cursor, but also determine the movement of all fingers and hands to create a digital 3D model of the hand in virtual space.

In the patent US 7205979 described the device generating control signals for manipulating virtual objects in a computer system in accordance with the gestures of the operator or other parts of the body; The device includes a glove that includes sensors for detecting hand gestures, as well as hand position sensors connected to the glove and connected to a computer system to determine the position of the hand relative to the system.

Differs the principle of determining hand gestures. In analogue, gestures are determined by means of external sensors installed, for example, on a computer monitor. The solution we declared uses inertial sensors built right into the glove.

In decision EP 2624238, a virtual mock-up with a tactile hand is described, having simulated objects that are manipulated with the aid of hand wearable gloves during the operation of the simulator. The fingers on the fingers are equipped with 3D general motion detection tools integrated with at least one sensor for interaction tasks and one tactile component.

The analog is not specified exactly how motion sensors are used.

In the claimed solution, the use of inertial sensors with an accelerometer and a gyroscope is specified.

In international application WO 98050839, a gesture-based data management system is described for processing real-time computer animation, such as virtual reality, and is controlled on a computer. The system includes a digital glove for data management based on operator hand gestures. The solution is based on the use of materials that change their resistance when bent.

The difference between the declared utility model is the use of inertial sensors. In the international application WO 2007129663 (publ .: 11/15/2007), an input device using sensors mounted on a finger is described. The user wears gloves with fingers, each of which has a motion detection sensor and a tactile sensor for each of the finger tips on both hands. Motion information at each of the fingertips is transmitted to various information devices, such as a personal computer (PC), pocket computer, and cell phone, so that the positions of the corresponding fingertips are displayed on the virtual keyboard on the display of one of the information processing devices.

The analog is not specified as it is precisely the motion sensors used.

In the claimed solution, the use of inertial sensors with an accelerometer and a gyroscope is specified.

The closest analogue is a virtual glove according to patent US 9060385, publ .: 06/16/2015. The prototype describes a virtual reality glove containing sensors located on the fingers of the gloves, and sensors of the position of the hands located on the phalanges of the fingers of the gloves, with the sensors connected to the microprocessor.

The disadvantage of the prototype and other known solutions is the following.

As is known, a tactile analyzer has a high capacity for spatial localization. Its characteristic feature is the rapid development of adaptation (habituation), i.e. loss of feeling of touch or pressure. The adaptation time depends on the strength of the stimulus, for different parts of the body it varies from 2 to 20 seconds. Thanks to the adaptation, we do not feel the touch of clothes to the body. See [Ekzertseva Ekaterina Vadimovna, Topic 1.1. General issues of life safety, Russian State Technological University. K.E. Tsiolkovsky (MATI), Lectures, http://www.studfiles.ru/preview/854779/page:6/]

Similar problems with working with virtual gloves are also caused by well-known counterparts, which reduces the effect of perception on the user over a certain period of work in them.

The disadvantage of using IMU-sensors without additional external tracking is the problem of “drift” - accumulation of gyro / inertial sensor errors, a significant deviation of the obtained data from the real ones and, as a result, the impossibility of exact absolute positioning.

To solve this problem, it is necessary to impose restrictions on the data obtained, thereby limiting the mobility of the "virtual hand" - the hand is fixed in the elbow joint. Thus, all movements are interpreted within the framework of a hemisphere, which the hand can describe when the elbow joint is fixed - hand movements in the horizontal plane are completely ignored, which causes inconvenience in practice.

The objective of the invention is to eliminate these problems.

The technical result of the invention is the ability to receive and transmit data on the position of fingers, hands, elbow and shoulder joints to the computer or other device, as well as to carry out tactile feedback by transmitting vibration to the fingers.

Also, the technical result is a more accurate calculation of the position of the brush in space and giving an additional degree of freedom to the hand.

Also, the technical result is the ability to fix a virtual model of the hand not in the elbow joint, but in the shoulder and with high accuracy to recognize and transfer to the computer or other device all possible hand movements, including in the horizontal plane.

Another advantage over other known devices based only on external tracking is the ability to use outside stationary equipped rooms, which is convenient when using the solution with mobile devices (smartphones) or portable solutions of virtual and augmented reality.

This technical result in the first embodiment is achieved due to the fact that a method of manufacturing a virtual reality glove is declared, using sensors that have gloves on the fingers, and the sensors are connected to the system board, characterized in that sensors of IMU are used as sensors gloves, with the index finger, middle finger, ring finger and little finger set on one sensor in the penultimate phalanx of the finger, on the outside of the palm; two sensors are placed on the thumb - on the first and second phalanx, from the outside; in addition IMU-sensors are installed on the hand; IMU-sensors with a cable connected to the motherboard; additionally, on the inside of the palm, on the penultimate phalanges of each finger, vibration motors are placed, which are fixed in the same way as IMU-sensors, and also connected to the system board with a cable; At least two photodiodes are placed on the motherboard, while the outer case for the control module is made of transparent material that transmits light, either entirely or only in those areas where the photodiodes are located, and in the outer case itself for the control module they build in the motherboard and battery.

Additional photodiode set next to the IMU-sensor on the wrist.

Preferably, the additional photodiode is arranged together with the IMU sensor in the shoulder module.

Photodiodes register light signals sent by a pair of special external light emitters installed stationary, stationary and separate from the described controller (system board and a set of sensors in the form of gloves or other form), on either side of it.

Emitters perform in such a way that they generate light pulses of a certain length, shape and direction, at certain intervals of time. The light from the emitters emit both in the visible and in the infrared or ultraviolet.

Through a single emitter, a set of short pulses of light is generated, and then a narrow band is generated by a laser mounted on a rotating mechanism rotating in a horizontal plane, and through another emitter in parallel, but at different time intervals, generate the same pulses, but in a vertical plane.

Data on time intervals, sequences of light pulses, the shape and nature of the pulses, which are known from the parametric data of the emitters, are compared with those received through the external device driver: the registration time of the photodiodes of various light pulses, whereby their coordinates are calculated relative to the emitters in space, then these data are used to correct the absolute position of the hand in space, calculated using IMU-sensors, and eliminate the accumulated error.

The shoulder module is additionally secured to the shoulder joint with an IMU-sensor, which is connected to the motherboard with a cable via the socket of the combined module or wirelessly.

This technical result according to the second variant is achieved due to the fact that a method of manufacturing a virtual reality glove is declared, using sensors that have gloves on the fingers, and the sensors are connected to a system board, characterized in that sensors of IMU are used as sensors gloves, with the index finger, middle finger, ring finger and little finger set on one sensor in the penultimate phalanx of the finger, on the outside of the palm; two sensors are placed on the thumb - on the first and second phalanx, from the outside; in addition IMU-sensors are installed on the hand; IMU-sensors with a cable connected to the motherboard; additionally, on the inside of the palm, on the penultimate phalanges of each finger, vibration motors are placed, which are fixed in the same way as IMU-sensors, and also connected to the system board with a cable; At least two light or infrared LEDs are placed on the motherboard, while the outer case for the control module is made of transparent material that transmits light, either entirely or only in those areas where the LEDs are located, and in the outer case itself for the control module they embed motherboard and battery.

At least two video cameras are used, from which the image from the cameras is accessed by an external control device; on the images generated from the cameras, they find the position of the LEDs and then, using the relative position of the cameras, the linear distance between the LEDs and the resulting size and distortion (rotation / compression) of the LED images, calculate the absolute position of the LEDs in space, after which these data are used to correct absolute position of the hand in space, calculated using IMU-sensors, and eliminate the accumulated error.

Brief Description of the Drawings

FIG. Figure 1 shows an example of a glove using a wrist and an IMU sensor and without using photodiodes.

FIG. Figure 2 shows an exemplary glove with the use of photodiodes and a combined module on the wrist containing a photodiode and an IMU sensor.

FIG. Figure 3 shows an example of a glove without using photodiodes in the motherboard and located on the wrist of a combined module containing a photodiode and an IMU sensor.

FIG. 4 shows an example of connecting to a glove of the shoulder module.

In the drawings: 1 - glove, 2 - inertial sensor (sensor) IMU, combining accelerometer, gyroscope and magnetometer, 3 - vibrating motor, designed to transmit vibration sensations, 4 - motherboard, 5 - battery, 6 - wires, 7 - the case that combines the motherboard and battery, 8 - photodiode, 9 - combined module, 10 - shoulder module, 11 - connecting wire between the combined module and the shoulder module.

The implementation of the invention

The claimed solution allows receiving and transmitting data on the position of fingers, hands, elbow and shoulder joints to a computer or other device, as well as providing tactile feedback by transmitting vibrations to the fingers.

This is achieved as follows.

Gyroscopic / inertial sensors (IMU-sensors) are mounted on fingers: on the index, middle, ring fingers and little finger one sensor is installed in the penultimate phalanx of the finger, on the outside of the palm; two sensors are installed on the thumb - on the first and second phalanx, from the outside. Additionally, similar sensors are mounted on the hand, from the outside, and on the wrist, from the outside or inside of the palm.

The sensors can be fixed in these positions with a rag glove, sewn into the required positions, or each sensor can be attached independently with a rag (or other material) ring (fastening) worn on the finger / hand / wrist or any other in a way that ensures the immobility of the sensor relative to the finger / hand / wrist, respectively.

As an IMU-sensor can be used, for example:

https://www.digikey.com/product-detail/en/invensense/MPU-6000/1428-1005-1-ND/4038006

Sensors are connected via cable to the control module located on the outside of the palm in a plastic case. The control module contains microcontroller-based control electronics, a wireless radio module, and a battery.

Sensors constantly collect motion data and transmit it to the microcontroller, which transmits this data over the air to a computer or other device.

A software driver is installed on the computer (or other device) that uses data from the sensors (angular velocities and acceleration vectors) and converts them into quaternions of space rotation for the following joints: rotation (fold) of the last phalanx of the finger relative to the palm for the index, middle, unmarked fingers and little finger, in a vertical plane relative to the palm of the hand; rotation of the index, middle, ring fingers and little finger in the horizontal plane (palm plane); twist / fold of the thumb relative to the palm in space; twist / fold of the hand (palm) relative to the elbow joint; rotation of the elbow joint relative to the shoulder joint. Then, from the angles obtained, using the inverse kinematics algorithms (data on the joints of the joints and their linear dimensions), the turns of all the other joints and the relative position of all the joints of the hand are calculated.

The obtained data is then provided for access in the form of an application programming interface (API) and can be used by third-party software manufacturers for any purpose.

Additionally, on the inside of the palm, on the penultimate phalanx of each finger, a vibration motor is placed, which is mounted in the same way as IMU-sensors, and is also connected via cable to the motherboard and microcontroller.

The application programming interface (API) allows the vibration motor to be launched independently on each of the fingers, setting the required parameters for pulse-width modulation (vibration frequency / intensity).

The command from the software interface is processed by the device driver and, via the radio channel, is transmitted to the microcontroller, which directly controls the vibration motor.

Thus, the vibration can be controlled by third-party software manufacturers using the application programming interface (API).

As a vibration motor can be used, for example:

https://ru.aliexpress.com/item/50pcs-DC3V-0820-8-2-0mm-Mobile-phone-micro-flat-vibration-motor-Coin-motor-Mini-vibrator/32783671636.html

The disadvantage of using IMU sensors without additional external tracking (tracking - locating moving objects over time using the camera) is the problem of "drift" - the accumulation of gyro / inertial sensor errors, a significant deviation of the received data from real and, as a result, the inability to accurately absolute positioning.

To solve this problem, it is necessary to impose restrictions on the data obtained, thereby limiting the mobility of the "virtual hand" - the hand is fixed in the elbow joint. Thus, all movements are interpreted within the framework of a hemisphere, which the hand can describe when the elbow joint is fixed - hand movements in the horizontal plane are completely ignored, which causes inconvenience in practice.

For this reason, another gyroscopic / inertial sensor (IMU sensor) can be additionally attached to the shoulder joint, for example, inside the shoulder module (10) (Fig. 4) and connected to the system board (4) with the help of a cable (11) through socket module (9).

The data from the sensor is transmitted to the microcontroller, and then through the radio channel to the driver software, where they are used to calculate the rotation of the elbow joint relative to the shoulder joint, as well as the rotation of the elbow joint in a plane perpendicular to it. This allows you to more accurately calculate the position of the brush in space and give additional degrees of freedom to the hand.

Thanks to this approach, it is possible to fix the virtual model of the hand not in the elbow joint, but in the shoulder and with high accuracy to recognize and transfer to the computer (or other device) all possible hand movements, including in the horizontal plane.

To fully solve the problem of accumulated error in the calculated absolute position of the sensors, it is permissible to add support for external "tracking".

To do this (in the first embodiment), two or more photodiodes reacting to flashes of light are placed on the control module. In this case, the housing for the control module is made of a transparent material that transmits light, either entirely or only in those areas where the photodiodes are located. Another photodiode is located next to the IMU-sensor on the wrist. Optionally, another photodiode is also located along with the IMU-sensor on the shoulder joint.

Photodiodes register light signals sent by a pair of special external light emitters installed stationary, stationary and separate from the described controller (system board and a set of sensors in the form of gloves or other form) on either side of it.

Emitters are programmed in a special way and generate light pulses of a certain length, shape and direction, at certain time intervals. Light can be emitted both in the visible and in the invisible (infrared, ultraviolet) ranges.

For example, the emitter can generate a set of short pulses of light, and then generate a narrow strip with a laser mounted on a rotating mechanism, rotating in a horizontal plane. Another emitter can do the same in parallel (but at different time intervals), but in the vertical plane. The time intervals, the sequence of light pulses, the shape and nature of the pulses (for example, the laser light beam shape and the speed of the turning mechanism) are known in advance, these data are compared by the software driver with the photodiode registration time of various light pulses, thereby calculating their position relative to the emitters, and so image - the absolute position of the photodiodes in space. These data are then used to correct the absolute position of the arm in space, calculated using IMU sensors, and to eliminate the accumulated error.

As a photodiode can be used, for example: https://www.digikey.com/product-detail/en/osram-opto-semiconductors-inc/BPW-34-S-Z/475-2659-1-ND/1893861

As an external radiator can be used, for example:

https://www.microsoftstore.com/store/msusa/en_US/pdp/HTC-Vive-Base-Station/productID.5073718900

An alternative method (the second implementation option) is to arrange light or infrared LEDs in the same positions instead of photodiodes and replace light emitters with two or more video cameras. In this case, the software must have access to the image received from the cameras.

The software finds the position of the LEDs in the image and then, using the data on the relative position of the cameras, the linear distance between the LEDs and the resulting size and distortion (rotation / compression) of the LED image, calculates the absolute position of the LEDs in space.

These data are then used to correct the absolute position of the arm in space, calculated using IMU sensors, and to eliminate the accumulated error.

The claimed solution can be used to animate 3D models of a human (or other) hand in computer programs, as a way of interacting with interfaces in virtual (VR - virtual reality) or augmented (AR - augmented reality) realities, as well as video games, simulators of various activities and in any other tasks where obtaining, processing, storing or transmitting precise hand movements in space is required.

For example, the claimed solution can also be used in medicine, for patients with impaired motility of the hands to track the movements of the hands and fingers and stimulate their activity.

Feedback using vibration motors can be used to simulate the sensations of touching objects in virtual reality, when data on the position of the hand and fingers are used to identify collisions with virtual objects and, if they are detected, feed vibration fingers to the corresponding point of contact. The degree of vibration may depend on the shape of the contact - the size of the intersection area, or on the characteristics of the virtual object. Another possible scenario of using vibration is to confirm an event with interactions with virtual interfaces — for example, pressing a virtual button.

The claimed solution offers a new way of placing IMU-sensors and, as a result, high accuracy of the results: the relative position of the sensors allows you to get the necessary angles between the fingers, hand, elbow and shoulder joints; secondly, such an arrangement of sensors and vibration motors makes it possible to free the last phalanx of fingers, which is convenient in practical application - the user can use touch screens, perform actions requiring fine finger motor skills, etc.

The advantage of using a combined approach (using IMU sensors and external tracking in the same technology) is the high accuracy of measuring spatial displacement, even higher than any alternative methods such as strain gauges (bend sensors) or solutions based only on IMU sensors. In addition, unlike the methods based on external optical or other external tracking, this approach completely lacks "blind spots", even if there is no direct view between the LED (photodiode) and the camera (light emitter), the stated solution will still allow quite accurately calculate the position of the arm in space.

Another advantage over other known devices based only on external tracking is the ability to use outside stationary equipped rooms, which is convenient when using the solution with mobile devices (smartphones) or portable solutions of virtual and augmented reality.

The method can be implemented on the example of performing gloves in the following design.

The glove (Fig. 1) (1) is made of fabric inside which there are: IMU sensors (2), each of which contains an accelerometer, gyroscope and magnetometer, with four IMU sensors (2) located on the penultimate phalanges of the little finger, nameless , middle and index fingers, two IMU sensors (2) are located on the first and second phalanges of the thumb, one IMU sensor (2) is located on the system board.

The fingers of the gloves (1) also have vibration motors (3) fixed, one on each finger, and on all fingers except the big one, the vibration motors (3) are fixed on the penultimate phalanges of the fingers, and on the thumb a vibration motor (3) is fixed on the last phalanx.

The motherboard (4) is fixed on the glove (1), where the computing module is located. At the same time, the Bluetooth wireless communication module, for communication with a computer or other device via radio, is installed on the motherboard (4).

The motherboard (4) is mounted on top of the battery (5), which is mounted on the glove (1).

IMU sensors (2), vibration motors (3), battery (5) are connected to the system board (4) by means of wires (6).

If necessary, the motherboard (4) and the battery (5) can be made in a single package (7) of translucent plastic.

Photodiodes (8) are also installed on the system board (4), which are connected to a combined module (9) containing a photodiode and an IMU sensor.

Preferably, the photodiodes (8) can be mounted on the system board (4) at its edges equidistant. There may be four.

A module (9) with an IMU sensor and a light sensor is placed on the wrist of the glove (1). An additional advantage of the virtual glove (1) is the use of an additional shoulder module (10), which is placed on the shoulder (biceps), and connected to the system board using a wire (11) through the module (9), which is performed containing a connector connector (in the drawings shown).

An IMU sensor can be installed inside the shoulder module (10).

This mutual arrangement of IMU sensors using a sensor fixed in the shoulder module (10) makes it possible to effectively deal with the problem of “drift” of data on the position of fingers and hand in space and more effectively track the movements of the shoulder joint. Unlike systems with external tracking (based on photodiodes or LEDs and external cameras), this solution can be used without any external devices, which is convenient for working with mobile devices (smartphones).

The shoulder module (10) can also be implemented in the wireless version, and connect to the computing module via radio (Bluetooth or Wifi). In this case, a battery and a radio module (not shown in the drawings) and a wire (11) are not used in a single module with a sensor (10).

Also, the shoulder module (10) can be optionally implemented not with an IMU sensor, but with the help of one or several strain gauges (fold sensors). In this case, a microcontroller is installed in the shoulder module (10) to which the resistance strain gages are connected, and through them aggregates the information and transfers it to the main computing module of the motherboard (4).

Claims (11)

1. A method of making a virtual reality glove that uses sensors that have gloves on fingers, and sensors are connected to a motherboard, characterized in that sensors of IMU are used as sensors, which are mounted on fingers of gloves, and on index, middle, ring fingers and the little finger is installed on one sensor in the area of the penultimate phalanx of the finger on the outside of the palm; two sensors are placed on the thumb - on the first and second phalanx from the outside; in addition IMU-sensors are installed on the hand; IMU-sensors with a cable connected to the motherboard; additionally, on the inside of the palm, on the penultimate phalanx of each finger, vibration motors are placed, which are fixed in the same IMU-sensor method, and also connected to the system board with a cable; At least two photodiodes are placed on the motherboard, while the outer case for the control module is made of transparent material that transmits light, either entirely or only in those areas where the photodiodes are located, and in the outer case itself for the control module they build in the motherboard and battery. 2. The method according to p. 1, characterized in that the additional photodiode is installed near the IMU-sensor on the wrist. 3. The method according to p. 2, characterized in that the additional photodiode is placed together with the IMU-sensor in the shoulder module. 4. The method according to p. 1, characterized in that by means of photodiodes register light signals sent by a pair of special external light emitters installed stationary, stationary and separate from the described controller, on opposite sides of it. 5. The method according to p. 4, characterized in that the emitters are performed in such a way that they generate light pulses of a certain length, shape and direction at certain intervals of time. 6. The method according to p. 4, characterized in that the light from the emitters emit both in the visible and in the infrared or ultraviolet. 7. The method according to p. 4, characterized in that by means of a single emitter, a set of short light pulses is generated, and then a narrow band is generated by a laser mounted on a turning mechanism rotating in a horizontal plane, and by means of another emitter in parallel, but at different time intervals, generate the same pulses, but in a vertical plane. 8. The method according to p. 7, characterized in that the data on the time intervals, the sequence of light pulses, the shape and nature of the pulses, which are known from the parametric data of the emitters, are compared with those obtained through the external device driver: the registration time of the photodiodes of various light pulses calculate their coordinates relative to the emitters in space, then these data are used to adjust the absolute position of the hand in space, calculated using IMU sensors, and eliminate the accumulation hydrochloric error. 9. The method according to p. 1, characterized in that the shoulder joint additionally secure the shoulder module with an IMU-sensor, which is connected to the system board with a cable through the connector of the combined module or wirelessly. 10. A method of making virtual reality gloves using sensors that have gloves on fingers, and sensors are connected to a motherboard, characterized in that sensors of IMU are used as sensors, which are mounted on fingers of gloves, and on index, middle, ring fingers and the little finger is installed on one sensor in the area of the penultimate phalanx of the finger on the outside of the palm; two sensors are placed on the thumb - on the first and second phalanx from the outside; in addition IMU-sensors are installed on the hand; IMU-sensors with a cable connected to the motherboard; additionally, on the inside of the palm, on the penultimate phalanx of each finger, vibration motors are placed, which are fixed in the same IMU-sensor method, and also connected to the system board with a cable; At least two light or infrared LEDs are placed on the motherboard, while the outer case for the control module is made of transparent material that transmits light, either entirely or only in those areas where the LEDs are located, and in the outer case itself for the control module they embed motherboard and battery. 11. The method according to p. 10, characterized in that use at least two video cameras, from which the external control device accesses the image from the cameras; on the images generated from the cameras, they find the position of the LEDs and then, using the relative position of the cameras, the linear distance between the LEDs and the resulting size and distortion (rotation / compression) of the LED images, calculate the absolute position of the LEDs in space, after which these data are used to correct absolute position of the hand in space, calculated using IMU-sensors, and eliminate the accumulated error.