DIY Camera Array 1: Computational Photography Primer.


Introduction: DIY Camera Array 1: Computational Photography Primer.

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DIY Camera Array 1: Computational Photography Primer.
DIY Camera Array 2: Computational Refocusing With Just One Camera
DIY Camera Array 3: ... TBA

This first Instructable is a primer on the field of Computational Photography, which is a new field of research that is developing extremely powerful cameras. These cameras allow the Depth of Field, the object in focus, and the position of the camera to be modified after the picture is taken. None of those things are possible with a traditional camera.

We show how to build one kind of computational camera -- a light field array. There are many other designs out there.

Imagine focusing a picture after you take it.

Imagine focusing right through fences, trees, and people.

Step 1: What Is It All About?

Over the last half decade, a new field of research has developed, called Computational Photography. Computational Photography is still in the process of defining itself. As a young field, it incorporates insights from many other fields: mathematics, image processing, optics, art, visual neuroscience, and more. Central to the field is extending the capabilities of the camera. You may be surprised to learn that cameras have hardly deviated from the camera obscura (box-with-a-hole-in-it) design over the last hundred fifty years. Computational photography is, to date, the most radical re-imagining of what a camera is, and what a camera can do. Frédo Durand recently said "Computation is the new Optics" and this is probably the best field-defining phrase we've heard yet. But there is no computation without hardware.

Researchers have created many new camera designs, extending and enhancing almost every functional element of the camera. Many of these new cameras attempt to capture a richer representation of light, which is called the "light field". What is the light field? Surrounding you, now and always, is a reverberating volume of light. Rays of light bounce around you from every possible angle. Some new computational cameras attempt to capture this light field, which has the potential to give the photographer unprecedented creative control... after taking the picture.

Step 2: Wrapping Up the Primer... Be Sure to Read Part 2.

This camera array, with its twelve cameras, captures only a very coarse representation of the light field. It is far from the state of the art. However, many of the most sophisticated light field cameras are confined to the laboratory, or cost from $5-10,000. This camera array (from here on, called the Large Light Field Camera Array or LLFC) can be built for a few hundred dollars with old used cameras, and is happy to go outside and take pictures.

The refocusing technique demonstrated here is called Synthetic Aperture Refocusing. Ted Adelson at MIT wrote an early influential paper on it, and it was also investigated in depth by many people at many labs, including MIT (Frédo Durand, Ramesh Raskar, Ren Ng) and Stanford (Mark Levoy). Todor Georgiev at Adobe has developed and documented some very sophisticated camera systems and written up lots of tutorial material. Synthetic aperture refocusing is now pretty well understood. Our camera array may be the first to exploit cheap, high resolution cameras that don't need a computer connected, and our refocusing software LFtextures may be the first open-source, cross-platform application available. Our goal is to make these technologies accessible and understandable, and to encourage experimentation by people of all stripes.

This tutorial is just the beginning. We (Daniel Reetz and Matti Kariluoma) will present a series of tutorials on how to build an array, how to operate it, and how to make synthetically refocused images from the output of the array. These updates will come about 1 per week for the next six or seven weeks. While this deviates a bit from the normal Instructables format, we felt it would be a better approach than a hundred-step Instructable, as I did with my previous "DIY Book Scanner" project. PS. If you're interested in book scanning, drop by the DIYBookScanner forums.



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    9 Discussions


    8 years ago

    Hello, and welcome to the Instructables community! It's great that you've decided to tell the world about something you've made by publishing an Instructable. We just wanted to let you know that your project still needs a little more work if you want it to be well received on Instructables. Projects that don't include certain basic elements tend not to get the attention that they deserve, and so we'd love for you to check out the list below of what makes a successful Instructable. Successful projects on Instructables include: - clearly written details of a finished project with instruction - as many steps as are necessary to explain your project - clear images that you took of your project for most, if not all of your steps - an intro image - proper spelling and grammar - appropriate cautions or safety considerations I'll give you another opportunity to make any final changes to your project before we publish it. Once you're all set to go, please republish your project and send me a quick comment letting me know that you've made some changes. I'll give it a quick final check to make sure you're on the right path, and then remove this note. Thanks for your submission and we hope to see your project published soon!

    5 replies

    Hi Admin,

    Would you comment on what was actually wrong with the Instructable? Do I need to combine all such instructables into another 79-step monster, like the Book Scanner Instructable?

    Daniel Reetz

    Hello again admin Robot.

    As you can see, the instructable consists mostly of pictures, though the admin bot is telling me to include pictures.

    I'm not sure why this Instructable is causing so much trouble. I'd be happy to delete it, as well as the companion piece,  and move the tutorial material to my own site.

    Daniel Reetz

    To be more specific, just adding more steps to this Instructable is all you need to do.  You can have the three topics broken out as separate projects like you've got if you'd like to avoid having one massive Instructable.

    Of course!

    Sorry, that was just a form comment.

    The project looks awesome, you just need to break it out into separate steps...doesn't have to be 79 different ones mind you.

    If you do that and then republish it, you should be good to go.

    Let noahw know if you have any other questions.


    8 years ago

    Hey, this is a great instructable and is very informative. Just one thing is missing... pictures! It really helps a lot when trying to follow directions so you should consider taking some photographs. Once you do that and leave me a message when you have so that we can publish your work. Thanks! Thanks for the cool instructable and we hope to publish this soon!

    Amazing. looking over the 102 pg pdf dont know when i will comment back on it but its a great idea/concept.  Good luck with your projects