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38-827: A camera is positioned to observe a rigid point model worn by the user, the points of which need to be isolated from background light by means of physical and software filtering. Motion is tracked with up to six degrees of freedom (6DOF): yaw, pitch, roll, left/right, up/down and forward/back. Windows-compatible video devices like webcams are supported, as well as special Nintendo Wii Remote camera, iPhone Truedepth camera with Eyeware Beam, and NaturalPoint cameras ( TrackIR , SmartNav and OptiTrack). FreeTrack can output head-tracking data to programs directly using its own open interface, as well as TrackIR , SimConnect and FSUIPC interfaces. Programs that support these interfaces are regarded as being FreeTrack-compatible . FreeTrack can also emulate mouse , keyboard , and joystick (via PPJoy) if

76-406: A color filter array . FreeTrack uses interpolation with low-frame-rate video devices to improve panning smoothness. However, responsiveness is fundamentally limited to the frame rate; a 30 frame/s webcam has a maximal response delay of 33.3 milliseconds compared with 8.33 milliseconds for a 120 frame/s camera. To put this into perspective, a human’s reaction time to visual stimulus (finger reflex)

114-425: A larger tracking region when in close proximity to the camera. At further distances a wide angle is not desirable, more of the frame is unused and the effective resolution drops more rapidly. More peripheral light can also be seen, which can interfere with tracking. Viewing angle can be reduced by using digital zoom at the cost of resolution. The Nintendo Wii Remote effectively uses no CPU, NaturalPoint cameras use

152-470: A level of customization that is not available with official software. In most cases a resolution of 320×240 is sufficient, this is capable of producing a much higher sub-pixel resolution , enough to allow accurate cursor control on a high-resolution monitor. Resolutions 640×480 and above have diminishing returns and correspond to an exponential increase in CPU usage when not sufficiently compressed before reaching

190-472: A program does not support a direct interface. FreeTrack is coded in Delphi 7 and uses DirectShow and DirectX . Head tracking is achieved using implementations of DeMenthon's four-point iterative pose estimation algorithm (POSIT) and Alter's three point geometric algorithm . FreeTrack uses a camera to collect real-time information on the point model worn by the user. Specifically the image coordinates of

228-495: A response curve that can be modified to change the way the virtual head moves for a given real head movement. This is commonly used to create a central deadzone region so that the user’s head can be more relaxed there. Keyboard, mouse and joystick buttons can be used to toggle tracking settings, including the virtual centre location (like adjusting the seat position in a car) and individually toggle axes and outputs. For NaturalPoint cameras, FreeTrack can provide advanced features and

266-422: A small amount, and general video devices can use a significant amount, depending on the brand and the specific camera settings in use. A PlayStation Eye running at the same resolution and frame rate as a TrackIR 4 would be very demanding on a single-core CPU. However, modern multi-core CPUs are making this less of an issue. Resolution and frame rate can always be reduced to conserve CPU resources. FreeTrack requires

304-414: A term often used in the context of virtual reality , typically refers to tracking of rotational motion only: pitch, yaw, and roll. Serial and parallel manipulator systems are generally designed to position an end-effector with six degrees of freedom , consisting of three in translation and three in orientation. This provides a direct relationship between actuator positions and the configuration of

342-486: A violation of the TrackIR software's EULA , it is possible to use it with FreeTrack. NaturalPoint's TrackIR interface SDK is only available under a signed license agreement and is covered by a NDA , so while FreeTrack is free software , the TrackIR interface component is required to be closed source . Six degrees of freedom Six degrees of freedom ( 6DOF ), or sometimes six degrees of movement , refers to

380-439: Is sent to the user's choice of outputs. This is all done in the background, with tracking status displayed in the system tray . A 3D preview is available that shows the virtual head position and orientation for a given real head pose and can be viewed from multiple perspectives, including first-person. This greatly assists with testing and makes it easier to experiment with different settings. Each degree of freedom (axis) has

418-558: Is a method of decreasing the precise angle of view of a digital photograph or video image . It is accomplished by cropping an image down to an area with the same aspect ratio as the original, and scaling the image up to the dimensions of the original. The camera's optics are not adjusted. It is accomplished electronically, so no optical resolution is gained. Digital zooming may be enhanced by computationally expensive algorithms which sometimes involves artificial intelligence. In cameras that perform lossy compression , digital zoom

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456-447: Is important in mechanical systems , especially biomechanical systems , for analyzing and measuring properties of these types of systems that need to account for all six degrees of freedom. Measurement of the six degrees of freedom is accomplished today through both AC and DC magnetic or electromagnetic fields in sensors that transmit positional and angular data to a processing unit. The data is made relevant through software that integrates

494-426: Is preferred to enlargement in post-processing, as the zooming may be applied before detail is lost to compression. In cameras that save in a lossless format, resizing in post-production yields results equal or superior to digital zoom. Lower-end camera phones use only digital zoom and do not have optical zoom, while many higher-end phones have additional rear cameras , including fixed telephoto lenses that allow for

532-464: Is typically around 200 ms; 30 ms can be regarded as a competitive ping in online reflex-based games, and an LCD monitor refresh rate is typically 17 ms. Higher responsiveness gives a greater feeling of control, but since virtual head motion is amplified, it can also cause it to move unrealistically fast. For this reason, some programs limit head movement speed, wasting some of the responsiveness of higher-frame-rate cameras. A wider viewing angle allows

570-600: The Descent franchise, the Everspace franchise, Retrovirus , Miner Wars , Space Engineers , Forsaken and Overload (from the same creators of Descent ). The space MMO Vendetta Online also features 6 degrees of freedom. Motion tracking hardware devices such as TrackIR and software-based apps like Eyeware Beam are used for 6DOF head tracking. This device often finds its places in flight simulators and other vehicle simulators that require looking around

608-873: The Space Shuttle operated in low Earth orbit , the craft was described as fully-direct-six because in the vacuum of space, its six degrees could be commanded via reaction wheels and RCS thrusters . However, when the Space Shuttle was descending through the Earth's atmosphere for its return, the fully-direct-six degrees were no longer applicable as it was gliding through the air using its wings and control surfaces . Six degrees of freedom also refers to movement in video game-play. First-person shooter (FPS) games generally provide five degrees of freedom: forwards/backwards, slide left/right, up/down (jump/crouch/lie), yaw (turn left/right), and pitch (look up/down). If

646-670: The FreeTrack community. An active point model uses visible or infrared LEDs (5 mm or larger) to represent the tracking points, powered by battery, transformer (plug pack) or USB . The electric circuit is very basic and can be made by someone with little or no experience with electronics. Common LEDs, like those found in remote controls , have a narrow, highly focused beam which is not suitable for optical motion tracking. They can be easily turned into wide angle LEDs by filing their lens tips down flat. Alternatively, wide angle LEDs can be purchased from specialist electronics retailers, like

684-455: The Six degrees of freedom. These types are Direct , Semi-direct (conditional) and Non-direct, all regardless of the time remaining for the execution of the maneuver, the energy remaining to execute the maneuver and finally, if the motion is commanded via a biological entity (e.g. human), a robotical entity (e.g. computer) or both. Transitional type also exists in some vehicles. For example, when

722-477: The SpaceTec IMC company (first bought by Labtec , which itself was later bought by Logitech ). They now offer the 3Dconnexion range of 6DOF controllers, primarily targeting the professional CAD industry. The controllers sold with HTC VIVE provide 6DOF information by the lighthouse, which adopts Time of Flight (TOF) technology to determine the position of controllers. Digital zoom Digital zoom

760-723: The camera hardware and software, a 2160p image sensor would enable up to 2× lossless digital zoom for 1080p video recording, 3× for 720p video, and 4.5× for 480p video by using image sensor cropping. The terms among camera and image sensor manufacturers are "Smart Zoom" ( Sony ), "Safe Zoom" ( Canon ), "Sensor Crop" ( Cisco ) and "Intelligent Zoom" ( Panasonic and others). There are also cameras with digital zoom functions as high as 7.2× and Smart Zoom with approximately 30× total zoom (optical zoom 20× and digital zoom 1.5×) for 7MP from 16MP total resolution, and also 144× total zoom (optical zoom 20× and digital zoom 7.2×) for VGA 640x480. Photographers can purposefully employ digital zoom for

798-431: The camera switches to digital zoom, though hybrid zoom may mitigate this. Many cameras, including mobile phone cameras , also employ lossless digital zoom for video recording by using the spare resolution of the image sensor for cropping by taking advantage of used video frame resolutions often being significantly below the available resolution of the image sensors. This means that, for example, if implemented correctly by

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836-431: The cockpit to locate enemies or simply avoiding accidents in-game. The acronym 3DOF , meaning movement in the three dimensions but not rotation, is sometimes encountered. The Razer Hydra , a motion controller for PC, tracks position and rotation of two wired nunchucks , providing six degrees of freedom on each hand. The SpaceOrb 360 is a 6DOF computer input device released in 1996 originally manufactured and sold by

874-406: The computer. Higher resolutions become more important at greater distances from the camera. The Wii utilizes a low-resolution 128×96 sensor, which is found by some to produce jittery tracking and may require smoothing to improve stability at the cost of decreased responsiveness. For the same resolution, monochrome sensors can resolve finer details much better than color sensors due to the lack of

912-405: The data based on the needs and programming of the users. The six degrees of freedom of a mobile unit are divided in two motional classes as described below. Translational envelopes: Rotational envelopes: In terms of a headset , such as the kind used for virtual reality , rotational envelopes can also be thought of in the following terms: There are three types of operational envelope in

950-494: The first game affected, DCS: Black Shark , tried to release their own head tracking interface but soon after canceled it at NaturalPoint's request. FreeTrack compatibility is still possible using TrackIRFixer to remove the encryption requirement in games. TIRViews.dll is a dynamic-link library file distributed with TrackIR software that provides tailored support for a small number of mostly older games , using special interfaces or memory hacks to facilitate view control. Though

988-528: The first game to support the FreeTrack interface and GP Bikes is the first to have exclusive support. FreeTrack is compatible with the unencrypted version of NaturalPoint's head tracking TrackIR interface that has widespread support in simulation games. NaturalPoint have been supplying game developers with an encrypted version of the interface for more popular titles since late 2008, these can be identified as requiring TrackIR software version 4.1.036 or higher and are incompatible with FreeTrack. The developers of

1026-601: The game allows leaning control, then some consider it a sixth DOF; however, this may not be completely accurate, as a lean is a limited partial rotation. The term 6DOF has sometimes been used to describe games which allow freedom of movement, but do not necessarily meet the full 6DOF criteria. For example, Dead Space 2 , and to a lesser extent, Homeworld and Zone Of The Enders allow freedom of movement. Some examples of true 6DOF games, which allow independent control of all three movement axes and all three rotational axes, include Elite Dangerous , Shattered Horizon ,

1064-439: The infrared Siemens/Osram SFH485P, with a half-angle of 40 degrees. Retroreflective material can be used to represent the tracking points by illumination with an infrared light source. This configuration doesn’t require wires or batteries connected to the user but is more susceptible to interference by background light. In most cases a webcam’s internal infrared blocking filter needs to be removed to increase sensitivity enough that

1102-399: The infrared light reflected by the tracking points can be seen. FreeTrack has a simple interface that can be freely used by third party programs such as Eyeware Beam to access 6DOF tracking data, both real raw measurements and virtual. It is hardware agnostic, so is not dependent on a specific brand or version of hardware and can be used without restriction. Bohemia Interactive's ARMA 2 is

1140-636: The manipulator defined by its forward and inverse kinematics . Robot arms are described by their degrees of freedom . This is a practical metric, in contrast to the abstract definition of degrees of freedom which measures the aggregate positioning capability of a system. In 2007, Dean Kamen , inventor of the Segway , unveiled a prototype robotic arm with 14 degrees of freedom for DARPA . Humanoid robots typically have 30 or more degrees of freedom, with six degrees of freedom per arm, five or six in each leg, and several more in torso and neck . The term

1178-406: The model points, which are either received directly from the camera or extracted from a video stream. These coordinates are used to generate an estimate of the real head pose, which can be transformed by the user in a number of ways to create a virtual pose. One of the most fundamental transformations involves amplifying rotation so that only small head movements are required. Finally, the virtual pose

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1216-564: The optical image to enlarge the image. By reducing the image size, digital zoom occurs without image deterioration of the output image, and some cameras have a "not-deteriorated image" mode or an image deterioration indicator. The table below shows the not-deteriorated zoom limit for some megapixel (MP) image sizes of a particular camera with optical zoom 24x, and digital zoom 4x for its maximum capability: Some camera firmwares store lossily digitally zoomed images with accordingly reduced dimensions (width and height) rather than upscaling it to

1254-436: The original raster resolution. The benefits are reduced file sizes and the ability to calculate the zoom level from the image's dimensions, if not included in its meta data . Cameras may have an intelligent zoom feature that allows an additional magnification of 2.0× on top of its optical zoom. Many cameras have 2 options: 1.4× and 2.0×. The intelligent zoom only uses the centre of the image sensor and does not interpolate

1292-432: The original resolution, so the resulting image quality is good in reduced resolution. Hybrid zoom is a concept used in smartphones that takes advantage of optical zoom, digital zoom, and software to get improved results when zooming in further than the lens' physical capabilities. Smartphones with optical zoom have lenses with 3× or 5× magnification. Trying to zoom in further than this limit may result in loss of quality as

1330-459: The possibility of retroreflective tracking. This is normally a straightforward and reversible procedure for most webcams. Wii Remotes and NaturalPoint cameras are designed for infrared point tracking, so they already have visible-light-blocking filters. Models can be made in a DIY fashion at minimal expense using readily available electronic components. Component kits and fully constructed models are also available for purchase from some members of

1368-417: The simulation of optical zoom. Full-sized cameras generally have an optical zoom lens, but some apply digital zoom automatically once the longest optical focal length possible has been reached. Professional cameras generally do not feature digital zoom. An optical zoom camera can be zoomed to its optical limit, and further zooming is sometimes allowed by digital zoom. Digital zoom uses the centre area of

1406-478: The six mechanical degrees of freedom of movement of a rigid body in three-dimensional space . Specifically, the body is free to change position as forward/backward (surge), up/down (heave), left/right (sway) translation in three perpendicular axes , combined with changes in orientation through rotation about three perpendicular axes, often termed yaw (normal axis), pitch (transverse axis), and roll (longitudinal axis). Three degrees of freedom ( 3DOF ),

1444-532: The tracking points to be isolated from all other light; this is best done using infrared LEDs and a visible-light blocking filter in front of the camera. Photographic film or the magnetic storage medium inside floppy disks can be used as inexpensive visible-light filters. Further filtering can be done in software by adjusting exposure and threshold. All video devices like webcams have a built-in infrared-blocking filter, which can be removed to improve sensitivity to infrared light, allowing better point isolation and

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