Archive for the ‘Science’ Category

Perfectly hocus-focus

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The magical science of Lytro’s in-camera technology called light field photography aims to bring your photos alive and interactive by being always in perfect focus at any point you want:

The way we communicate visually is evolving rapidly, and people’s expectations are changing in lockstep. Light field cameras offer astonishing capabilities. They allow both the picture taker and the viewer to focus pictures after they’re snapped, shift their perspective of the scene, and even switch seamlessly between 2D and 3D views. With these amazing capabilities, pictures become immersive, interactive visual stories that were never before possible – they become living pictures.

As exciting as adding one more technological capability to the camera may be, such as removing the pesky element of perfectly directed focus (which can be done with Lytro in post-production), it seems this will not be helpful to all. I see this technology as a new tool to help make great photographers take even greater pictures more quickly and more easily. But sadly, this new technology might not be as helpful to all other photographers.

Focus happens to be only one of those things in the entire art and craft of photography, not the only thing. This technology might help get the perfect focus on any part of the picture, but it will not help sharpen the focus of one’s vision.

Written by dominiquejames

June 23, 2011 at 10:35 AM

The magic of Plenoptic Camera aka “Light Field Camera”

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Let’s collectively brush up on our knowledge of the plenoptic camera, or the so-called “light-field camera.” Here’s an entry from Wikipedia on the very subject matter:

A plenoptic camera, also called a light-field camera, is a camera that uses a microlens array (also known as a lenticular lens array) to capture 4D light field information about a scene. Such light field information can be used to improve the solution of computer graphics related problems. Adelson and Wang proposed the design of a plenoptic camera that can be used to significantly reduce the correspondence problem in stereo matching. To achieve this, an array of microlenses is placed at the focal plane of the camera main lens. The image sensor is positioned slightly behind the microlenses. Using such images the displacement of image parts that are not in focus can be analyzed and depth information can be extracted.

The same camera system can be used to enable the possibility to refocus an image virtually on a computer after the picture has been taken as explained by Ng, et al. The drawback of such a system is the low resolution that the final images have. As one microlens samples the light directions at one spatial point an increase in the number of image pixels can only be done by increasing the number of microlenses by the same amount. To overcome this limitation, Lumsdaine and Georgiev describe a new design of a plenoptic camera, called focused plenoptic camera where the microlens array is positioned in front of or behind the focal plane of the main lens. This modification samples the light field in a different way that allows to have a higher spatial resolution by having a lower angular resolution the same time. With this design images can be refocused with a much higher spatial resolution.

So, does this have anything to do with Ren Ng’s light field photography? A photographer friend thinks so.

What’s funny is if you read the Wikipedia article (above) on plenoptic camera it hints [closely] at the fact that Ren Ng is one of the people in the Stanford team that used a plenoptic camera that used a 90,000 microlens array to take a 16-megapixel image that could be refocused after being taken, and describes Lytro as a “Stanford spinoff.” So, yeah. It does, in fact, sound like Lytro uses the plenoptic camera technique.

More and more information comes to light. And it’s all interesting.

Written by dominiquejames

June 22, 2011 at 7:27 PM

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