Light field camera

Light Field Camera (= Plenoptic Camera)

You may have faced a number of situations where the images you captured get blurred. Or sometimes you may miss to click some valuable moments due to delay in focusing. Imagine a camera that doesn’t need to focus before taking a snap. Just take some clicks at random.

Don’t bother whether it blurred or not.

Founstion -

It helps image refocus base on specific software.

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Multiview perspectives

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3D depth estimation

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Stereoscopy

Characteristic -

It consists of a million of microlens to capture 4D light field information from all the distances, obtaining a live picture of the environment.

It captures information of all the light rays coming from the object. This information is processed later and can be tuned to a picture or, more specific to a point or multiple points. * The 4D light field In fact, the redundant information is exactly one dimension, leaving us with a four-dimensional function (that is, a function of points in a particular four-dimensional manifold), so long as we don't try to include both light rays coming in and hitting the object and light rays emanating from the object on the opposite side. Parry Moon dubbed this function the photic field (1981), while researchers in computer graphics call it the 4D light field (Levoy 1996) or Lumigraph (Gortler 1996). Formally, the 4D light field is defined as radiance along rays in empty space.

Structure

Technology Early research

he first light-field camera was proposed by Gabriel Lippmann in 1908, which used integral photography as the underlying technology. In 1992, Adelson and Wang proposed the design of a plenoptic camera that can be used to significantly reduce the correspondence problem in stereo matching.[1] 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.

Standard plenoptic camera

Potentially, this camera system can be used to refocus an image virtually on a computer after the picture has been taken, as explained by Ng et al.[2] 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.

Focused plenoptic camera (for better resolution)

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 before or behind the focal plane of the main lens. This modification samples the light field in a different way that allows for a higher spatial resolution by having a lower angular resolution at the same time. With this design images can be refocused with a much higher spatial resolution. However, the low angular resolution can introduce some unwanted aliasing artifacts.

Coded aperture camera

A different design using low-cost printed film (mask) instead of microlens array was proposed by researchers at MERL in 2007.[4] This design overcomes several limitations of microlens array in terms of chromatic aberrations, loss of boundary pixels, and allows higher-spatial-resolution photos to be captured. However, a mask-based design reduces light compared to microlens arrays.

Manufature Cameras available for purchase

Raytrix From 2010 on, it has sold several models of plenoptic camera for industrial and scientific applications, with resolutions starting from 1 megapixel.

http://www.raytrix.de/index.php/software.html Lytro It was founded by Stanford University Computer Graphics Laboratory alumnus Ren Ng to commercialize the light-field camera he developed as a graduate student there. Lytro has developed a consumer light-field digital camera capable of capturing images using a plenoptic technique. https://www.lytro.com/

In smartphone

Nokia has invested in Pelican Imaging to produce a plenoptic camera system with 16-lens array camera and predicted will be implemented in smartphones in 2014.

Reference

http://en.wikipedia.org/wiki/Light‐field_camera http://www.google.de/imgres?imgurl=http%3A%2F%2F3.bp.blogspot.com%2F‐mnNERbWwmoE%2FTgJhoqf54II%2FAAAAAAAAD 1M%2F762h2XMO_hw%2Fs1600%2FLight‐Field‐Camera.jpg&imgrefurl=http%3A%2F%2Felectrosome.com%2Flight‐field‐camera %2F&h=448&w=458&tbnid=rh1XMhPMrdNGMM%3A&zoom=1&docid=sGR2ylMEoIM0KM&ei=GTM9VO3lL8j8ywOt7ICgDw&tb m=isch&iact=rc&uact=3&dur=1931&page=1&start=0&ndsp=15&ved=0CCEQrQMwAA