I want to create polarized 3D image using Matlab or C#?.

Is any way to create 3D image from an开发者_开发知识库y 2D image using Matlab or C#?

Polarized 3D is an effect created in the physical world with physical projectors shining onto the same spot of a physical screen. It's not a digital effect that you can create in an image on a computer screen. You cannot write code to render an image onto a normal computer screen then see 3D with the polarized glasses.

Stereoscopic images for use with polarised glasses are created by projecting the left and right eye images so that they overlap through separate projectors which have a polarising filter fitted.

The same is true for the red and green tinted glasses (which are not the same as the old style anaglyph images).

If you only have one 2D image you cannot create a 3D image from it without getting involved in manual image processing.

Build your own Polarized Stereoscopic Projection System

Principles of Polarization Optics

Polarized Light

Since the late 19th century we know, that light can be described in terms of electromagnetic waves. The theory behind it are the well understood Maxwell Equations. Since this is not an article about electrodynamics just the essentials:

Light is electromagnetic radiation with wavelenghts between 800nm (red) to 400nm (violet).
Electromagnetic radiation has an electric and a magnetic field component.
The electric and magnetic field are transversal, which means perpendicular to the propagation of the wave.
The electric and magnetic field are perpendicular to each other.

http://en.wikipedia.org/wiki/Electromagnetic_radiation

The electric field vector (one could also use the magnetic field, but convention is to use the electric filed) determines the polaization. There are two kinds of polarization:

Linear polarization: The electric component remains in one single plane, the polarization plane
Circular polarization: With each cycle the electric component "swings" into different direction If you look along the propagation the field vector may cycle through:
- ↑→↓← -- this is called right turning polarization
- ↑←↓→ -- this is called left turning polarization
  The effect of circular polarization is created by retarding one component of linear polarized light by a quarter of a wavelength.

See also this Wikipedia article http://en.wikipedia.org/wiki/Polarization_(waves)

Creating Polarized Light

Wikipedia has an excellent article on the details http://en.wikipedia.org/wiki/Polarizer

Here's the essentials.

Linear Polarization

Linear polarized light can be obtained in various ways:

By filtering out all unwanted polarization components from light with a broad polarization distribution. All light emitted in a statistical manner (thermic radiation, high pressure gas discharge, lighting arcs) has this property. One can filter the desired polarization plane using a filter. The following filters are known:
- Brewster Beam Spliters use brewster reflection to split a beam of light into two polarization components, polarized perpendicular to each other.
- Birefringence employs the phenomenon that some crystals have different indices of refraction for different polarization planes. Again the light ways are split.
- Absorption in strechted polymers. Stretching a polymer gives it an anisotropic structure. Some anisotropic polymers will absorb only incoming light polarized parallel (or perpendicular, it depends on the material) to the strechting direction.
The light emited from a laser is linear polarzied. Depending on how the laser is built, the polarization plane will gradually change over time.

http://en.wikipedia.org/wiki/Linear_polarization

Circular Polarization

In optics, circular polarization is created by passing linear polarized light through some anisotropic material, that will retard one of the components (electric or magnetic) by a quarter of the wavelength. This is called a λ/4 retarder.

The angle between linear polarization and the anisotropic material's major axis determines ratio between left and right turning polarized light resulting:

Incoming linear polarized light tilted by +45° will be fully left turning.
Incoming linear polarized light tilted by -45° will be fully right turning.
Incoming linear polarized light tilted by 0° will consist of 50% left and 50% right turning.

It should be noted, that due to the reversibility of the light's way the passing of circular polarized light through a λ/4 retarder will turn it into linear polarized light of the corresponding certain polarization plane. This linear polarized light can the be filtered again by linear polarizers. This is, how circular polarization 3D glasses work.

http://en.wikipedia.org/wiki/Circular_polarization

Polarized Light and Interaction with the Screen

Scattering and Diffraction

The typical projection screen uses very small particles, usually they're TiO2, to scatter and diffract the light into all directions. In the scattering process the light bounces multiple times between the particles. While each bounce leaves a light wave solition polarized in the grand statistical scheme any notable polarization is lost.

Thus a normal white projection screen is unsuitable for polarized stereoscopic projection.

Metallic Reflection

The key for building a polarizing stereoscopic projection system is the use of a screen material that retains the polaization of the incoming light. This is achieved by employing metallic reflection on particles much larger than the light's wavelengths.

A DIY Stereoscopic Projection System

Making a DIY Silver Screen

You'll need:

aluminum powder pigment
clear acrylic base
deep black textile dye
canvas

This is how you do it:

Dye the canvas deep black. This will absorb any light not reflected, instead of scattering it. Let it dry thorougly. You may repeat step 1 multiple times.
Paint one layer of clear acrylic base on the now deep black dyed canvas. Doing it one side suffices. All futher steps are now done on this clear acrylic base.
Make a very thick aluminum acrylic paint. Here are a few hints:
- Mix the aluminum powder with the acrylic base in very small batches. Don't make a aluminum power paste by mixing it with water!
- After putting each small batch of aluminum powder into the acrylic stir thoroughly so that it is a homogenous mass.
- You should end up with a 1 part aluminum powder to 1 part acrylic base paint
- Once you've got that thick paint, thin it with 1 part of water.
Apply layers of aluminum acrylic paint on the prepared canvas. Let each layer dry. Repeat step 4 until you've got an even aluminum metallic painted surface with no black parts shining through.

Video Projection

Single Projector Setup

Most cinemas are using a single projector and the RealD Z-filter system to alternating show left and right images at a swap rate of 144Hz, where the Z-filter is dynamically modulating the polarization.

Technically the Z-filter is just some large Liquid Crystal Panel. LCs have the property, to rotate the passing light's polarization plane, depending on a voltage applied on the LC. The Z-filter thus rotates the light by +/-45°, controlled by an AC voltage in sync with the left-right-image swap. Before the Z-filter is a linear polarizer, behind it a λ/4 retarder, in parallel to the linear polarizer. The Z-filter will rotate the polarization plane to that either only left or right turning polarized light is leaving the system, if there's stereoscopic material shown.

If the Z-filter is turned off, the light will be turned into 50% left and 50% right turning polarization.

It is perfectly possible to recreate this system DIY. This however shall be described in a separate article still to be written.

Dual Projector Setup

Using two projectors is the most easy way to project the distinct polarized images. The idea is simple: Each projector is equiped with a polarizing filter matching the filter in the viewer's glasses eye filters, so that light projected from the "left" projector will reach only the left eyes, and the "right" projector's light reaches only the viewer's right eyes.

Selecting the Projectors

It boils down to the following: You need two identical projectors which emit either unpolarized light - that are DLP projectors using classical arc lamps - or evenly linear polarized light for all base colours. The later case is more appealing since you'll not "throw away" light. But the safer is, choosing some DLP type. Note that those new nifty LED projectors usually exhibit some uneven polarization, which makes them tricky to next impossible to use for polarized stereoscopy.

Making the Filter Slides

The projector's filter slides can be made from the very same kind of 3D glasses which are worn by the viewers. The 3D glasses of RealD are meant for single use. Although cinemas setup boxes for recycling, there's no harm to the venues if you put those glasses you got in the cinema to your own use. In fact most cinemas will have no problem with giving you some of the glasses returned to the recycling boxes.

You may be tempted to just put those filters right behind the projectors lens. This is however crude and will quickly destroy those filters. Remember that 50% of the lights power may end up in the filters, heating them up.

So you want to distribute the light's power over a significant large area.

You'll need:

a number of used RealD glasses
4 panes of identically sized picture frame glass (something like 50mm × 50mm)
sharp and exact scissors or a paper guillotine
a fine tip water solvent marker pen (or similar) - whiteboard markers do fine!
some adhesive tape. Duct tape works very well (what, did you expect something else?)

This is how it goes:

In all the 3D glasses mark the back side (i.e. the side towards the eyes) with a small letter 'L' or 'R' (left eye or right eye), right in the middle.
By applying some twist/torque on the glasses frames you can separate RealD glasses releasing the filters.
Sort the filters into left and right filters.
Cut the filters into equally sized rectangular pieces sort them into left and right. Don't make them quadratic. It's important that you still know the orientation within the glasses' frame.
Clear the marking, making sure you still know what's front and what's back.
Arrange the filter pieces on the glass panes so that they nearly fill it. Of course all facing the same (i.e. all front or all back). Keep the gaps as small as possible.
Apply the second glass pane, apply the duck tape along the borders.

You've now left and right polarizing filter slides. Put on 3D glasses of the same making and determine the orientation in which each pane blocks the light most efficiently by looking through the filter slide. Important: The filter plane that blocks the light on a eye looking through it directly will be the slide for projection that particular eye later. The reason for that is, that reflection changes chirality, i.e. left and right turning are swapped by reflection.

Setting up the Projection

Align the projectors so that their images match. Vertical alignment must be perfect. Horizontal alignment may be slightly shifted, but it should be done as good as possible, to.
Place the filters in the light's way. The whole filter area should be used.

Show the stereoscopic material, so that each projector display's its eyes picture.