LYTRO
This word has made buzz with the tech guys quite some time back.Most Guys know it like its a different camera (or) a light field camera that costs a bit more than a medium DSLR(Priced at 41000 in INR).So what's this light field technology(or) a plenoptic camera???This article tries to explore a bit of all this from a common man's point of view
The Normal DSLR camera:
Basically a DSLR(Digital Single-Lens Reflex) Camera consists of an interchangeable lens (or) a lens mount that supports a variety of types of lenses.A pentaprism technology that precisely takes up an image through a 5 sided prism.The transmitting faces of the prism i.e the faces through which the image enters and leaves are coated with a non reflective coating while the reflecting faces are like mirrors and transmits the image without any change in its orientation(technically it does not tamper with the chirality of the image).A simple variation of this pentaprism called as roof pentaprism that utilises a rooflike structure or two prism sides inclined such that angle between them is 90 degrees.and when the light is reflected at such a joint the handedness changes and hence convenient for us to view through the eyepiece of a digital camera.This roof prism technology is used in almost most of the DSLRs.This pentaprism(or sometimes a pentamirror is used) is the main element.It also consists of a mirror that is slotted at an angle of 45 degrees when taking a picture so that the image is exactly reflected through a matte focusing screen, the function of a matte screen is to merge a foreground image into a background and it is photo friendly.Its exactly the photo printing paper kind of thing.Light then passes through a condenser lens and a pentaprism described above.and the transmitted image is seen through the viewer of the camera.The image processing is done by a focal plane shutter and an image sensor at the back of the mirror.When picture has to be taken after focusing the mirror moves completely upwards allowing the entire light and image to fall on a focal-plane shutter that controls the amount of light entering(the entire process is called exposure) and then the image falls on a photo sensor,that converts all the light signals to electrical signals and is saved in a memory card or any other electrical storage medium.
So to sum up a traditional DSLR cam goes on to focus an object as it is with the required quality which changes according to price range,the focused object however cannot be altered to focus a different object on the scene.
So to sum up a traditional DSLR cam goes on to focus an object as it is with the required quality which changes according to price range,the focused object however cannot be altered to focus a different object on the scene.
The LYTRO Camera
The first handheld consumer camera of the plenoptic camera type.A technology envisioned in 1908 by Gabriel Lipman has been made true in the form of a common man's camera by Ren.Ng's dissertation at Stanford University.
The difference in the technology would be the DSLR as explained above captures the individual light rays from the focused object and does not capture the parallel rays from a far away object on the same scene hence refocusing after taking the image is not possible,or atleast if refocused digitally on a computer screen which is popularly known as zooming will result in considerable loss of quality.The light field technology in particular the thesis of Ren Ng tries to address this problem of refocusing and gets success in it by exploiting the light field technology.
To be technical from a lay man's view we can say that a conventional camera records the sum of all light rays that strikes the image plane of the camera or the image sensor part as described above ,Whereas the new Digital light field photographic technology(as referred in RenNg's Dissertation) tries to capture the light field inside the camera which is essentially recording both the light ray and its direction.So let us see how does LYTRO do it
Thus the powerhouse of a LYTRO camera is its microlens array and a powerful photosensor that captures the light from the microlens and reproduces it as it is.This arrangement is named as light field engine.
To simply put in the LYTRO is actually a camera that records not just the amount of light from a picture but the entire light field,the difference being a DSLR just records intensity but the LYTRO goes a step ahead and captures the directional orientation which potrays the spatial orientation of the entire image in a new perspective
The difference in the technology would be the DSLR as explained above captures the individual light rays from the focused object and does not capture the parallel rays from a far away object on the same scene hence refocusing after taking the image is not possible,or atleast if refocused digitally on a computer screen which is popularly known as zooming will result in considerable loss of quality.The light field technology in particular the thesis of Ren Ng tries to address this problem of refocusing and gets success in it by exploiting the light field technology.
To be technical from a lay man's view we can say that a conventional camera records the sum of all light rays that strikes the image plane of the camera or the image sensor part as described above ,Whereas the new Digital light field photographic technology(as referred in RenNg's Dissertation) tries to capture the light field inside the camera which is essentially recording both the light ray and its direction.So let us see how does LYTRO do it
The Marvel named Microlens
The major part of LYTRO camera,that consists of many small lens which are usually size of mm and ranges to as small as micrometer.In LYTRO an array of microlens are used to capture the light field inside the camera.Theses lens cover the photosensor, essentially are placed before the photosensor. Each microlens covers a small area of photosensor array pixels that is, it essentially covers the array of photosensors and separates the light and microlens array and allows small amount of incident lighting proportional to size of the microlens onto the photosensor.
The Microlens array is basically used so that it has a better directional resolution of light rays which is totally absent in DSLRs.Thus the powerhouse of a LYTRO camera is its microlens array and a powerful photosensor that captures the light from the microlens and reproduces it as it is.This arrangement is named as light field engine.
To simply put in the LYTRO is actually a camera that records not just the amount of light from a picture but the entire light field,the difference being a DSLR just records intensity but the LYTRO goes a step ahead and captures the directional orientation which potrays the spatial orientation of the entire image in a new perspective
LYTRO ILLUM
The major reason for writing this article is this new buzz created by the next version of the LYTRO camera named LYTRO ILLUM.Basically it has a bigger sensor than LYTRO of magnitude 40 mega ray,i.e it captures 40 megarays of light at a time,we will update on this on a later blog post.It basically resembles a Modern DSLR camera which is advantageous.
