Patent Document

CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit under 35 U.S.C. §119( e ) of co-pending U.S. Provisional application Ser. No. 60/622,352 filed on Oct. 27, 2004, which is incorporated by reference herein. 
     
    
     FIELD OF INVENTION  
       [0002]     The present invention relates to image production, more specifically, to the production of a virtual scene previewing system.  
       BACKGROUND OF THE INVENTION  
       [0003]     Virtual Set technology has been used in broadcasting and graphic design applications for years. Feature films, television shows and video games utilize a virtual world to visually enhance the viewers&#39; experience. For example, one of the most common and well-known applications of virtual set technology is a weather broadcast on a local or national news network. To a viewer at home, the scene portrays a broadcaster standing next to or in front of a screen with an image on it, typically a map or satellite photo. This is a virtual set. In reality the broadcaster is standing in front of what is generally referred to as a “Blue Screen”. The blue screen, usually a retro-reflective material, is blank to anyone looking directly at it in the studio. The image of the weather map or satellite photo is generated and superimposed by a computer onto the imagery that is transmitted across the television airwaves using a process known in the art as traveling matte. The broadcaster uses a television off to the side of the set to reference his movements or gestures against the map. The map is added in a real-time algorithm that alters the image from the live camera into the composite image that is seen on television.  
         [0004]     Virtual set technology has expanded greatly in recent years leading to entire television programs and countless numbers of feature film scenes being filmed with the aid of composite images superimposed into the recorded video. The use of computer generated imagery (“CGI”) has allowed film makers and directors to expand the normal conventions of scenery and background imagery in their productions. Powerful computers with extensive graphics processors generate vivid, high-definition images that cannot be recreated by hand, or duplicated by paint. The use of CGI reduces the number of background sets needed to film a production. Rather than have several painted or constructed background scenes, computer generated images can serve as backdrops reducing the space and cost required to build traditional sets.  
         [0005]     In the arena of video games, movies, and television, virtual set technology is used to create backgrounds, model, and record character movement. The recorded movements are then overlaid with computer graphics to makes the video game representation of the movement more true to life. In the past, to create character movement for a video game, complex mathematical algorithms were created to model the movement of the character. Because the character movement model was never completely accurate, the character&#39;s movement appeared choppy and awkward. With the advent of virtual set technology, a “library” of movements can be recorded live and superimposed onto the characters in post-production processing. Video games with unique characters and unique character movements, such as football or baseball simulation games, benefit from such technology. The technology makes the game appear much more realistic to the player.  
         [0006]     The increased capability of employing virtual set technology, however, does come with the added cost of powerful and complex graphics processors, or engines, as well as specialized equipment and background screens. On a set in which the cameras are moving, the computers must track the location of the camera at all times in relation to the screen to properly create a realistic scene. Many existing systems require the use of a special background with embedded markers that enable the computer to calculate the camera&#39;s position in the virtual scene by using a marker detection method. Other existing systems utilize a second camera, called a tracking camera affixed to the first camera, or scene camera. The tracking camera references the location of tracking markers fixed to the ceiling to calculate the location of the camera in the scene. Because the tracking camera is mounted to the scene camera, both move together through the set and can be located along a coordinate grid. This configuration requires the tracking computer to constantly process large numbers of markers to calculate and reference the scene cameras locations. Such heavy processing slows down the computers and transmission of the composite final image. In a live broadcast, these delays create performance problems and a “seamless” combination of live video and imagery is not always achieved.  
       SUMMARY OF THE INVENTION  
       [0007]     Virtual scene previewing systems expand the capabilities of producing video. Virtual scene systems allow a producer to import three-dimensional texture mapped models and high resolution two-dimensional digital photographs and mix them with live video. Use of modern techniques from the world of visual effects like camera projection mapping and matte painting provide for even more flexibility in the creation of a video production.  
         [0008]     Various embodiments of a virtual scene previewing system are provided. In one embodiment, a scene camera records the image of a subject in front of a background. The scene camera is connected to a computer by a data cable. A tracking camera is positioned above the scene camera and is also connected to a computer, either the same computer or another computer on a network, by a data cable. The scene camera has a marker attached to it that can be seen by the tracking camera. The tracking camera records the location of the tracking marker on the scene camera. If the scene camera moves during recording, the tracking camera will process its location by the tracking marker and the images provided by the computer can be adjusted accordingly. Additional tracking cameras may be added to the configuration to create an overlapping network of tracking cameras and creating a larger set space with which a director or camera operator may operate.  
         [0009]     In one embodiment of the inventive method, a scene camera records an image. The image or images are then transmitted to a computer. A second camera, the tracking camera, captures an image of a marker. The marker is affixed to the scene camera in this embodiment. The images of the tracking marker are also sent to a computer. The computer, using a three-dimensional graphics engine, will superimpose a computer-generated image or images into the live recording image from the camera. The graphics engine processes the location of the tracking marker in combination with the data of the computer generated image to adjust for factors such as proper depth, field of view, position, resolution, and orientation. The adjusted virtual images or background are combined with the live recording to form a composite layered scene of live action and computer generated graphics.  
         [0010]     In yet another embodiment, a retro-reflective background is added to the scene. The background is located opposite the scene camera with the object to be viewed placed in between the background and camera. The first camera views a scene and transmits the imagery to the computer. The tracking camera remains stationary and can track the scene camera, with the affixed marker, so long as the scene camera remains in the field of view of the tracking camera. Multiple tracking cameras can be implemented to create an overlapping field of view. The computer resolves the location of the scene camera in the overlapped areas through common image processing methods. The computer generates a real-time virtual scene image combining the imagery of the scene camera with a stored background image to create a virtual set. The location data from the tracking camera(s) is used to adjust the virtual real-time scene to create a seamless virtual environment. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     The foregoing and other features and advantages of the present invention will be more fully understood from the following detailed description of illustrative embodiments, taken in conjunction with the accompanying drawings in which:  
         [0012]      FIG. 1  depicts a perspective view of a studio with a scene camera positioned to photograph a subject in front of a background in accordance with an embodiment of the present invention;  
         [0013]      FIG. 2  depicts a perspective view of a studio with a scene camera and more than one tracking camera in accordance with an embodiment of the present invention;  
         [0014]      FIG. 3  depicts a block diagram of an embodiment of the present invention describing the data flow between parts of the system;  
         [0015]      FIG. 4A  depicts a subject layer of a composite image seen from a scene camera in one embodiment of the present invention;  
         [0016]      FIG. 4B  depicts a background layer of a composite image stored on the computer as virtual objects in accordance with an embodiment of the present invention; and  
         [0017]      FIG. 4C  depicts a composite proxy image, combining the subject and background layers in accordance with one embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION  
       [0018]     The present invention provides a cost effective, reliable system for producing a virtual scene combining live video enhanced by computer generated imagery. The present invention provides a seamless environment expanding the capabilities of virtual video production. Applications ranging from video games to feature films can implement the system for a fraction of the cost of traditional virtual sets. The system greatly reduces the costly and complex computer processing time required in existing systems. The present invention also eliminates the need for specialized materials used in the backgrounds of virtual sets.  
         [0019]     An embodiment of the present invention is illustrated in  FIG. 1 . A scene camera  30  is positioned to capture an image of a subject  50  in front of a background  60 . The scene camera  30  is mounted on a camera support  40 . This camera support  40  may be in the form of a tripod, dolly, handheld, stabilized, or any other form of camera support in common use. There may be more than one scene camera in order to capture different views of the subject&#39;s performance. The scene camera  30  is connected to a computer  70  by a scene camera data cable  32 . A tracking camera  10  is positioned over the scene camera  30  and oriented so that a tracking marker  20  is within its field of view  15 . The computer  70  may be positioned near the scene camera  30  so that the camera operator can see the system output.  
         [0020]     The tracking marker  20  in one embodiment is a flat panel with a printed pattern on its top. The tracking marker  20 , of this embodiment is advantageous as it requires no power cables, thus the scene camera  30  can easily be adapted for any type of use including handheld, stabilized or other forms of camera shots where extra cables would hamper the scene camera&#39;s  30  motion. The tracking camera  10  is connected to the computer  70  by a tracking camera data cable  12 . The tracking camera  10  and scene camera  30  may also be connected to separate computers  70  that communicate with each other through a network.  
         [0021]     Although the present embodiment depicted describes a data cable as the means of connecting the cameras to the processors, one skilled in the art should recognize that any form of data transmission can be implemented without deviating from the scope of the invention.  
         [0022]     The tracking camera  10  is used to collect images of the tracking marker  10 . The image quality required for tracking the tracking marker  10  is lower than the image quality generally required for the scene camera  30 , enabling the use of a lower cost tracking camera  10 . In one embodiment, the tracking camera  10  is a simple electronic camera with a fixed field of view  75 . Since the tracking camera  10  is not focused upon the scene, the tracking performance is independent of the exact contents and lighting of the subjects  50  in the scene. This independence extends to the background  60 . As mentioned before, existing systems require the use of a special background to enable the scene camera&#39;s position to be derived from the images it produces. The present implementation of a separate tracking camera  10 , as shown in the present embodiment, eliminates the need for special background materials and complex set preparation.  
         [0023]     In some existing systems, the tracking camera is mounted on the scene camera and moves with it, while several tracking markers are mounted on the ceiling. This requires the tracking computer to process large numbers of markers, which can cause delays in the performance of the tracking algorithms. Mounting the tracking marker  20  to the scene camera  30  and keeping the tracking camera  10  stationary greatly simplifies processing. The present embodiment requires the computer  70  to search only for one type of tracking marker  20 , thus increasing tracking speed. The computer  70  is not overwhelmed with myriad tracking markers that add to the cost and complexity of the processing method.  
         [0024]     In the embodiment depicted in  FIG. 2 , multiple overlapping tracking cameras  10  are utilized. A scene camera  30  is positioned to capture an image of a subject  50  in front of a background  60 . The scene camera is mounted on a camera support  40 . This camera support  40  may be in the form of a tripod, dolly, handheld, stabilized, or any other form of camera support in common use. There may be more than one scene camera in order to capture different views of the subject&#39;s performance. The scene camera  30  is connected to a computer  70  by a scene camera data cable  32 . The tracking cameras  10  are positioned over the scene camera  30 . Each tracking camera  10  is connected to a separate computer  70 , in this embodiment, to perform tracking calculations. The computers  70  may be connected via a network  85 . When a tracking marker  20  can be seen by two tracking cameras  10  in multiple fields of view  15  simultaneously, the multiple sets of coordinates of the tracking marker  20  must be resolved due to calibration differences between the tracking cameras  10 . This can be achieved by several methods, including but not limited to, averaging, preferential ranking of one tracking camera&#39;s  10  coordinates over another&#39;s, or Kalman type filtering. With simple averaging, the resulting position can be expressed as:  
               ⁢     rPos   =     Resulting   ⁢           ⁢   Position           
         cPos     1   ,   n       =       Camera     1   ,   n       ⁢           ⁢   Position         
       rPos   =       (       ∑   1   n     ⁢     cPos   n       )     n         
 
         [0025]     A preferential weighted average can be computed over several readings (represented below as numStoredValues) with a weighting factor filterWeight, (0&lt;filterWeight&lt;1), as:  
                                                   float currentWeight = 1.0f;           float filterWeight = 0.7f;           float average = 0;           float averageTotal = 0;           int numStoredValues = 5;           float storedValues[5];           for (int i = 0; i &lt; numStoredValues; i++)           {             average += storedValues[i] * currentWeight;             averageTotal += 1.0f * currentWeight;             currentWeight *= filterWeight;           }           rPos = average / averageTotal;                      
 
         [0026]     This filter causes more recent values (placed in storedValues[0]) to be given more weight, and provides a smoothing effect on the data to prevent the camera position from jumping, disturbing the illusion of a seamless image. Before each run, the values in the storedValues array are shifted one over, discarding the oldest value and placing the newest value in storedValues[0]. With two or more cameras supplying coordinates, the coordinates from the various cameras would simply be averaged together before being added to the most recent storedValues[0].  
         [0027]     The tracking marker  20  in this embodiment is a flat panel with a printed pattern on its top. The tracking marker  20  of this embodiment is advantageous as it requires no power cables, thus the scene camera  30  can easily be adapted for any type of use including handheld, stabilized or other forms of camera shots where extra cables would hamper the scene camera&#39;s  30  motion. The tracking camera  10  is connected to the computer  70  by a tracking camera data cable  12 . The tracking camera  10  and scene camera  30  may also be connected to a single computer  70  that is capable of processing both tracking cameras  10  images.  
         [0028]     In addition to studio use, the present invention can be used at a physical set or location; this is advantageous if the background  60  were to be composed of a combination of physical objects and computer generated objects.  
         [0029]     Although the present embodiments depicted illustrate the use of one scene camera  30 , one skilled in the art should recognize that any number of scene cameras to accommodate multiple views, and multiple viewpoints can be implemented without deviating from the scope of the invention.  
         [0030]     Further, while the present embodiments depicted show the use of one or two tracking cameras, one skilled in the art should recognize that any number of tracking cameras may be implemented to increase the movement range of the scene camera without deviating from the scope of the invention.  
         [0031]     Turning now to  FIG. 3 , the data flow  310  during operation of the system is shown in accordance with an embodiment of the present invention. The tracking camera  10  is focused on the tracking marker  20  and sends tracking image data  14  to a real-time tracking application  74  running on computer  70 . The tracking image data  14  can be simply represented by a buffer containing red, green, and blue data for each pixel; an industry standard is to create image buffers with 8 bytes of data for each red pixel, followed by eight bytes for green and eight bytes for blue. Each component running on computer  70  may optionally be run on a separate computer to improve computation speed. In one embodiment all of the components run on the same computer  70 . A real-time tracking application  74  processes the tracking image data  14  to generate proxy camera coordinate data  76  for a virtual camera  120  operating within a real-time three-dimensional engine  100 .  
         [0032]     The proxy camera coordinate data consists of camera position and orientation data transmitted as a string of floating point numbers in the form (posX posY posZ rotx rotY rotZ). The scene camera  30  sends record image data  34  of the subject  50 &#39;s performance to a video capture module  80  running on the computer  70 . This video capture module  80  generates proxy image data  82  which is sent to a proxy keying module  90 . The proxy image data  82  is generated in the standard computer graphics format of a RGB buffer, typically containing but not limited to twenty-four bytes for each pixel of red, green, and blue data (typically eight bytes each.) The proxy image data  82  includes not only visual information of the scene&#39;s contents, but also information describing the precise instant the image was captured. This is a standard data form known in the art as timecode. This timecode information is passed forward through the system along with the visual information. The timecode is used later to link the proxy images to full resolution scene images  200 , also generated by the scene camera  30 , as well as final rendered images  290 .  
         [0033]     The proxy keying module  90  generates proxy keyed image data  92  which is then sent to an image plane shader  130  operating within the real-time three-dimensional engine  100 . The real-time three-dimensional engine  100  also contains a virtual scene  110  which contains the information needed to create the background image for the composite scene. The real-time three-dimensional engine  100  is of a type well known in the industry and used to generate two-dimensional representations of three-dimensional scenes at a high rate of speed. This technology is commonly found in video game and content creation software applications. While the term “real-time” is commonly used to describe three-dimensional engines capable of generating two-dimensional representations of complex three-dimensional scenes at least twenty-four frames per second, the term as used herein is not limited to this interpretation.  
         [0034]     The real-time tracking application  74  processes the tracking image data  14  to generate the proxy camera coordinate data  76  using a set of algorithms implemented in the ARToolkit software library, an image processing library commonly used in the scientific community. The software library returns a set of coordinates of the target pattern in a 3×4 transformation matrix called patt 13 trans. The positional and rotational data is extracted from the 3×4 patt_trans matrix with the following statements, which convert the data in the patt_trans matrix into the more useful posX, posY, posZ, rotX, rotY, and rotZ components. An example of source code to perform this conversion is shown in Appendix A.  
         [0035]     The use of standard references, or fiducial markers, as tracking markers  20  has many advantages. Since the markers are of a known size and shape, and as the tracking camera  10  can be a standardized model, the calibration of the tracking camera  10  to the tracking marker  20  can be calculated very accurately and standardized at the factory. This enables the use of the system in the field on a variety of scene cameras  30  and support platforms without needing to recalibrate the system. The two components that do the measuring work only need to be calibrated once before delivery. The fiducial marker calibration data can be calculated using standard routines available in the ARToolkit library. The tracking camera calibration data can likewise be generated using these standard routines, and included in a file with the rest of the system. Since the calibration data is based on the focal length and inherent distortions in the lens, the calibration data does change over time.  
         [0036]     The real-time three-dimensional engine  100  uses the proxy camera coordinates  76  to position the virtual camera  120  and the image shader  130  within the virtual scene  110 . The image shader  130 , containing the proxy keyed image data  92 , is applied to planar geometry  132 . The planar geometry  132  is contained within the real-time three-dimensional engine  100  along with the virtual scene  110 . The planar geometry  132  is typically located directly in front of the virtual camera  120  and perpendicular to the orientation of the virtual camera&#39;s  120  lens axis. This is done so that the virtual scene  110  and the proxy keyed image data  92  line up properly, and give an accurate representation of the completed scene. The code sample, provided in Appendix A provides the proper conversions to generate the position and orientation format needed by the engine: centimeters for X, Y, and Z positions, and degrees for X, Y, and Z rotations. When the scene camera  30  is moved, the virtual camera  120  inside the real-time three dimensional engine  100  sees both the virtual scene  120  and the proxy keyed image data  92  in matched position and orientations, and produces composited proxy images  220 .  
         [0037]     The image combination, according to one embodiment is shown in  FIGS. 4A, 4B , and  4 C. The planar geometry  132  may be located at an adjustable distance from the virtual camera  120 ; this distance may be manually or automatically adjustable. This allows the proxy keyed image data  92  to appear in front of or behind objects in the virtual scene  110  for increased image composition flexibility. As the planar geometry  132  moves closer to the virtual camera  120 , its size must be decreased to prevent the proxy keyed image data  92  from being displayed at an inaccurate size. This size adjustment may be manual or automatic. In the present embodiment this adjustment is automatically calculated based upon the field of view of the virtual camera  120  and the distance from the planar geometry  132  to the virtual camera  120 .  
         [0038]     The design of the real-time three-dimensional engines  100  is well established within the art and has been long used for video games and other systems requiring a high degree of interactivity. In one embodiment, the real-time three-dimensional engine is used to generate the composited proxy images  220 . As an additional embodiment, the real-time three-dimensional engine  100  may also produce the final rendered images  290  given the proper graphics processing and computer speed to narrow or eliminate the quality difference between real-time processing and non real-time processing.  
         [0039]     The proxy image sequence may also be displayed as it is created to enable the director and the director of photography to make artistic decisions of the scene camera  30  and the subject  50 &#39;s placement within the scene. In one embodiment, the proxy image sequence is displayed near the scene camera  30 , allowing the camera operator to see how the scene will appear as the scene camera  30  is moved.  
         [0040]     In addition to composited proxy image sequence  220 , the real-time three-dimensional engine  100  also produces a camera data file  230  and a proxy keyed image data file  210 . These files collect the information from the proxy camera coordinate data  76  and the proxy keyed image data  92  for a single take of the subject&#39;s  50  performance. These may be saved for later use. In an embodiment of the present invention, a second virtual camera can be created within the virtual scene  110  that moves independently from the original virtual camera  120 . The original virtual camera  120  moves according to the proxy camera coordinate data  76 , and the planar geometry  132  containing the proxy keyed image data  92  moves with the original virtual camera  120 . In this manner, a second virtual camera move, slightly different from the original virtual camera  120  move, can be generated. If the second camera moves very far away from the axis of the original virtual camera  120 , the proxy keyed image data  92  will appear distorted as it will be viewed from an angle instead of perpendicular to the plane it is displayed on. A second virtual camera, however, can be used to create a number of dramatic camera motions. The final versions of the camera data and scene image data can also be used to create this effect.  
         [0041]     To create a final composite set image, the precise scene camera  30  location and orientation data must be known. A camera data file  230 , as it is the collected data set of the proxy camera coordinate data  76 , will generally not be sufficiently accurate for final versions of the composite image. It can be used, however, as a starting point for the scene tracking software  250 . The scene image tracking software  250  uses the full resolution scene images  200  to calculate the precise scene camera  30  location and orientation for each take of the subject&#39;s  50  performance, using inter-frame variation in the images. This type of software is well known and commercially available in the visual effects industry; examples include Boujou by 2d3, Ltd., of Lake Forest, Calif. and MatchMover by Realviz, S.A, of San Francisco, Calif. The level of accuracy of this type of software is very high, but requires significant computer processing time per frame and as such is not useful for the real-time calculation of the proxy camera coordinate data  76 . The scene image tracking software  250  is used to generate final camera coordinate data  252  which is then imported into a final three-dimensional rendering system  270 . This three-dimensional rendering system  270  generates the final high quality versions of the background scene. The background information is very similar to that found in virtual scene  110  but with increased levels of detail necessary to achieve higher degrees of realism.  
         [0042]     In one embodiment of the present system, the final camera coordinate data  252  drives a motion control camera taking pictures of a physical set or a miniature model; this photography generates the final background image which is then composited together with final keyed scene data  262 .  
         [0043]     The full resolution scene images  200  are also generated from the scene camera  30  using a video capture module  80 . This can be the same module used to generate the proxy scene image data  82  or a separate module optimized for high quality image capture. This can also take the form of videotape, film, or digitally based storage of the original scene images. The present embodiment uses the same video capture module  80 .  
         [0044]     The full resolution scene images  200  are then used by both the scene image tracker software  250  and the high quality keying system  260 . The scene image tracker software  250 , as previously mentioned, generates the final camera coordinate data  252  by implementing the image processing applications, mentioned above, on the scene image. The high quality keying system  260  creates the final keyed scene images  262  through a variety of methods known in the industry, including various forms of keying or rotoscoping. These final keyed scene images can then be used by the final three dimensional rendering system  270  to generate final rendered images  290 . Alternatively, the final keyed scene images can be combined with the final rendered images  290  using a variety of compositing tools and methods well known within the industry. Common industry tools include Apple Shake, Discreet Combustion, and Adobe After Effects; any of these tools contain the required image compositing mathematics. The most common mathematical transform for combining two images is the OVER transform; this is represented by the following equation, where Color a  is the foreground value of the R, G, and B channels, and Color b  is the background value of the same. Alpha a  is the value of the alpha channel of the foreground image; this is used to control the blending between the two images. 
 
 Color   output   =Color   a   +Color   b  ×(1 −Alpha   a ) 
 
         [0045]     The composite proxy images  220  may then brought into an editing station  240  for use by editors, who select which performance or take of the subject  50  they wish to use for the final product. The set of decisions of which take to be used, and the location and number of images within that take needed for the final product, are then saved in a data form known in the industry as an edit decision list  280 . The composited proxy image  220  is linked to the matching full resolution scene image  200  using the previously mentioned timecode, which adds data to each image describing the exact moment that it was captured. The edit decision list  280  is initially used by the final three-dimensional rendering system  270  to select which background frames to be rendered, as this is an extremely computationally expensive process and needs to be minimized whenever possible. The edit decision list  280 , however, will change throughout the course of the project, so industry practice is to render several frames both before and after the actual frames requested in a take by the edit decision list. The final rendered images  290  can then be assembled into a final output sequence  300  using the updated edit decision list  280  without having to recreate the final rendered images  290 .  
         [0046]     In addition to the description of specific, non-limited examples of embodiments of the invention provided herein, it should be appreciated that the invention can be implemented in numerous other applications involving the different configurations of video-processing equipment. Although the invention is described hereinbefore with respect to illustrative embodiments thereof, it will be appreciated that the foregoing and various other changes, omissions and additions in the form and detail thereof may be made without departing from the spirit and scope of the invention.  
                       APPENDIX A                                       double sinPitch, cosPitch, sinRoll, cosRoll, sinYaw, cosYaw;           double EPSILON = .00000000001;           float PI = 3.14159;           sinPitch = −patt_trans[2][0];           cosPitch = sqrt(1 − sinPitch*sinPitch);           if ( abs(cosPitch) &gt; EPSILON )           {             sinRoll = patt_trans[2][1] / cosPitch;             cosRoll = patt_trans[2][2] / cosPitch;             sinYaw = patt_trans[1][0] / cosPitch;             cosYaw = patt_trans[0][0] / cosPitch;           }           else           {             sinRoll = −patt_trans[1][2];             cosRoll = patt_trans[1][1];             sinYaw = 0;             cosYaw = 1;           }           // Rotation data           float tempRot = atan2(sinYaw, cosYaw) * 180/PI;           camRaw.rotY = −(180 − abs(tempRot))* tempRot/abs(tempRot));           tempRot = atan2(sinRoll, cosRoll) * 180 / PI;           camRaw.rotX = (180 − abs(tempRot))* (tempRot/abs(tempRot));           camRaw.rotZ = atan2(sinPitch, cosPitch) * 180 / PI;           // Position data           camRaw.posX = patt_trans[1][3];           camRaw.posY = −patt_trans[2][3];           camRaw.posZ = patt_trans[0][3];

Technology Category: 3