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| computational_photography_talk [2010-10-27 17:00] – davegriffiths | computational_photography_talk [2010-11-12 23:38] (current) – davegriffiths | ||
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| - | ==odd things that people do with cameras== | + | 11 November presentation at Aalto University on computer |
| - | or | + | |
| - | ==machine vision== | + | |
| - | or | + | |
| - | ==understanding images with a computer== | + | |
| - | as a computational photographer, | + | Link to presentation: |
| - | * everything you do with digital photography derives from this field, eg | + | Videos: |
| - | - digital filtering (from ccd de-bayer algorithms upwards) | + | |
| - | - auto focus/ | + | |
| - | - face finding/ | + | |
| - | * a lot of the future will come from this field | + | * particle filter: [[http:// |
| - | - object | + | * eigenface animation: [[http:// |
| - | | + | * expression |
| - | | + | * 3d morphable face model: [[http:// |
| - | (will talk of some of this later) | + | * slam augmented reality: [[http:// |
| - | | + | Code: |
| - | - lots going on | + | |
| - | - much to be discovered | + | |
| - | - lots of _hard_ problems to be solved | + | |
| - | but not hard to get fun things happening yourself | + | Links: |
| - | * as an artist you can cherry pick the easy/fun bits or use good quality prewritten libraries | + | * opencv: [[http:// |
| + | * artoolkit: [[http:// | ||
| + | * nasa vision workbench: [[http:// | ||
| - | what computer vision is not: | ||
| - | * anything to do with neuroscience (a lot of people think it is) | ||
| - | * it's all statistics! | ||
| - | |||
| - | ==example 1 : separate moving and still things in a sequence of images== | ||
| - | |||
| - | * frame differencing | ||
| - | * finding overall direction of movement | ||
| - | |||
| - | * this actually works, is robust to lighting changes, camera wobble etc | ||
| - | * results in useable data | ||
| - | * (all eyetoy games use this technique) | ||
| - | |||
| - | why it works - temporal memory is short and well defined | ||
| - | |||
| - | ==example 2 : seperate background from person in scene== | ||
| - | |||
| - | * subtract current image from reference image without persion | ||
| - | * works! (for a few minutes) | ||
| - | |||
| - | lighting changes, camera auto settings, passing cars... all conspire against us. | ||
| - | |||
| - | doesn' | ||
| - | |||
| - | _very hard problem_ seen much time and money sunk into solving this without result | ||
| - | |||
| - | ==example 3 : faces== | ||
| - | |||
| - | faces are great for computational photographers because: | ||
| - | * most images have a few in them | ||
| - | * we all have one | ||
| - | * we are particually attuned to understanding them | ||
| - | * a lot of research has been done on this, a lot we can build on as artists | ||
| - | |||
| - | actually several problems | ||
| - | |||
| - | - recognising what is a face in an image (face finding) | ||
| - | - recognising who is who in an image (face recognition) | ||
| - | |||
| - | * face finding: haar cascades, wavelets, example images | ||
| - | * face recognition: | ||
| - | |||
| - | ==eigenfaces== | ||
| - | |||
| - | * extracting information on age, gender, ethnicity, expression from a face image | ||
| - | * modifying this information - changing a faces age, gender .... | ||
| - | |||
| - | scary examples | ||
| - | |||
| - | ==augmented reality== | ||
| - | |||
| - | * marker pose estimation | ||
| - | * rendering 3D objects in the real world | ||
| - | * yeah yeah but you need a marker... | ||
| - | |||
| - | ==SLAM: simultaneous location and mapping== | ||
| - | |||
| - | * gradually building a model of the scene from a camera in realtime | ||
| - | * example video | ||
| - | * no markers needed | ||
| - | * lots of cool things will come from this in future | ||
| - | |||
| - | ==3D cameras== | ||
| - | |||
| - | * RGB + depth per pixel | ||
| - | * microsoft project natal | ||
| - | |||
| - | solves a lot of problems, creates some interesting new ones | ||
| - | |||
| - | how? | ||
| - | * stereo cameras | ||
| - | * structured light | ||
| - | * wavefront analysis | ||
| - | |||
| - | ==where do I get some of this stuff?== | ||
| - | |||
| - | * opencv | ||
| - | * artoolkit | ||
| - | * nasa image processing library | ||
| - | * lots of research code is out there and waiting for artistic (mis)use! | ||
| - | * they may actually help you in between publishing papers | ||
| - | |||
| - | tips | ||
| - | |||
| - | * think like a photographer - how can I set the scene to suit what I am trying to do, lights, camera position etc etc are as important as finding the right algorithm. | ||