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![Source/plate [ Any film sequence or live action shoot ]
Evaluation footage [ camera movement, Tracking Marker, Plate Formats, Placing object or
Character. ]
Additional Information [ Camera reports, Survey Data, set Measurements]
Define the Camera [ Techniques and Match moving Software]
3D [ 3D set, Proxy object for test]
Testing [ Basic test for alignment/Checker Test]](https://image.slidesharecdn.com/fundamentalsofmatchmoving-190120172033/75/Fundamentals-of-matchmoving-6-2048.jpg)
Uploaded byDipjoy Routh
Fundamentals of matchmoving
The document discusses various aspects of camera tracking and motion in video production, highlighting the importance of both 2D and 3D tracking techniques for aligning CGI with live-action footage. It outlines the functions of different software tools used for auto and manual tracking, as well as the significance of focal length and lens distortion in achieving accurate camera models. Additionally, the document emphasizes the necessity of survey data for accurate scene scaling in 3D animation, particularly in high-budget film production.
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Fundamentals of matchmoving
- 2. Prior todigital tracking, in both electronic and optical effects, for most effects shots the camera was locked off. It was just impossible with out motion control of the capturing cameras to align to shots in post-production. While hand tracking has been attempted, the eye is so well adjusted to noticing movement and float - that often times sub pixel accuracy is required to sell a shot and fool an audience.
- 3. Based ondifferences in color and brightness the computer tries to track certain points in the video footage by comparing each frame with its previous frame to determine the new position oft the selected point. As you can see in this example (below) the tracking marker sticks to this little piece of paper on the street, although the camera is moving. That means that the computer needs an accumulation of pixels that remain mostly the same over the whole video. If this group of pixels is altered too much by a sudden bright light source for instance, the computer can not track that anymore.
- 4. 2D TRACKING CompostingPrograms like After Effects, Nuke, Black magic fusion, Shake have TWO DIMENTIONAL motion tracking Capabilities. This feature translates images in two dimensional space and can add effects such as motion blur in an attempt to eliminate relative motion between two features and two moving images. This technique is sufficient to create believability when the two images do not include major changes in camera perspective.
- 5. 3D TRACKING ThreeDimensional tracking /match moving tools make it possible to fetch three dimensional information from two dimensional photography. There are many Applications capable of 3D match moving like Autodesk Match mover, PF-Track, Boujou, SynthEyes, 3D Equalizer , Nuke Camera Tracker, Voodoo Etc. These Applications allow user to extract camera movement and other relative motion from arbitrary footage. The tracking information can be transferred to other 3D software like Maya, 3Ds Max, Modo, Cinema 4d to animate virtual cameras and CGI objects.
- 6. Source/plate [ Anyfilm sequence or live action shoot ] Evaluation footage [ camera movement, Tracking Marker, Plate Formats, Placing object or Character. ] Additional Information [ Camera reports, Survey Data, set Measurements] Define the Camera [ Techniques and Match moving Software] 3D [ 3D set, Proxy object for test] Testing [ Basic test for alignment/Checker Test]
- 7. Auto Tracking Where softwareCalculates the footage and create as best as possible tracking for us, its also called soft tracks. Manual Tracking Where we manually create the tracking points, consider as a best tracking points. Its also called Hard tracks. Tracking color Red means Poor tracks Tracking color Green means GOOD tracks Tracking color Red means Failed tracks
- 8. First software Autotrack for us of we manually Track points Second we solve the camera means where convert 2D point into 3D points and create a 3D word . Thirdly we orient our scene, means define our 3d world, which one is ground, which one is top, Defining coordinate system x y z axis. Forth placing test object for checking the quality of track Fifth export the scene to 3D software where we set fitting the shot or put proxy geo for testing, where we put checker as texture render out and do the ultimate test on composting software by putting checker layer overlay mode on master plate.
- 9. Dolly Camera The dollygets its name from filmmaking where a camera, mounted on a wheel tripod, Is moved towards or away from the scene. PANNING Camera In cinematography, panning refers to the horizontal movement or rotation of a still Or video camera. Panning a camera results in a motion similar to that of someone Shaking their head “no”. Its also called as a nodal pan shot
- 10. Tilting Camera Tilting isa cinematographic technique in which the camera is stationary and rotates In a vertical plane(or tilting plane). Tilting camera motion similar to someone nodding their head “yes” TRACKING Camera Tracking camera in which camera is moved on horizontal and vertical plane only
- 11. Match moving software'sprimary Concern is Camera. After all, it has to take an image sequence and provide 3D cameras that accurately copy the camera that had filmed the sequence. Software must know not only where the camera was positioned and which way it facing but also what focal length and format used.
- 12. The focal lengthis the distance between the center of the primary lens and the film. Focal length depends upon camera’s lens. A shorter focal length gives a more prominent perspective A larger focal length gives more flat look, which means more of the scene is visible in the image.
- 13. Shorter focal lengthgives you wide angle view Where as long focal length gives you narrow angle of view
- 14. Focal length alsodetermine the perspective of an image. But it strictly speaking Perspective only changes with ones location relative to their subject. Wide angle lens Exaggerates or stretches perspective, whereas the telephoto lens compress or flatters Perspective.
- 15. Less of thebackground is visible and background objects appear to be closer.
- 16. In these photographs,we changed the distance between the camera and the subject so that the subject always appears to be the same size. Note the difference in the balance between the portrait subject and the building in the background: the wider the lens, the greater the apparent distance to the building.
- 17. Wide angle lenses(short focal length) capture more because they have a wider picture angle, while telephoto lenses (long focal length) have a narrower picture angle. Below are some typical focal lengths:
- 19. In geometric andcathode ray tube(CRT)displays, distortion is a deviation from Rectilinear projection. Rectilinear projection in which straight lines in scene remain Straight in an image lens distortion is a form of optical aberration. The radial distortion Can usually be classified as one of two types. When straight lines are curved inwards in a shape of a barrel, this type of aberration is called “barrel distortion”. Commonly seen on wide angle lenses, fish eye lens barrel distortion happens because the field of view of the lens is much wider than the size of the image sensor and hence it needs to be “squeezed” to fit. As a result, straight lines are visibly curved inwards, especially towards the extreme edges of the frame. Here is an example of strong barrel distortion Barrel Distortion
- 20. Pincushion distortion isthe exact opposite of barrel distortion – straight lines are curved outwards from the canter. This type of distortion is commonly seen on telephoto lenses, and it occurs due to image magnification increasing towards the edges of the frame from the optical axis. This time, the field of view is smaller than the size of the image sensor and it thus needs to be “stretched” to fit. As a result, straight lines appear to be pulled upwards in the corners, as seen below:
- 21. Lens Distortion canhave a serious effect on the Quality of Tracking and if left uncorrected can make it impossible to get a useable camera track from your footage. Distortion makes the object to appear to change shape depending on where they are in the frame. A cube in the future of the frame will look different to a cube edge of the frame because the distortion increases as you move further from the center. This can make thing very difficult for 3D tracking because it can not work out the 3D structure of non rigid objects. 3D tracking software has such tools that allow you estimate how much distortion there is in your shot and correct for it. These tools unwrapping the image until features that you know should be straight line up with calibration line that is always straight. This task is made much easier if you shoot lens grid below with your camera at the tile of your shoot
- 22. Survey data basicallyproperties of a scene or measurement of set. It will help us to set the over all scale of the scene it mean real world world size of scale value. After taking survey data from set we can use it on 3D tracking software and later export it to 3D software like max and Maya. When you use the survey data in your 3D animation package , the set is already fit on place. There is no need of creating camera rigs or adjusting camera position. But make sure your survey data is accurate. In big budget movies survey data are captured by professional surveyor who used sophisticated survey equipment to accurately plot various points on the set in 3D space.
- 23. Hope you leansomething from this. Wish you all the best. REGARDS DIPJOY ROUTH