I am new in Android programming, but I want to develop an Android Application for my final project. From the brain and skull CT Scans I have stored the Grey Values in a 3D matrix. I have 175 matrixes, each having 256 x 256 lines & columns. Can anyone please help me to represent them using OpenGL ES ? I have already done this in Java, but I have 2D representation for every axis xy, zy, yz and it can be seen every layer inside the brain using a slider. It isn't enough to represent each point with Vertex, I have to use triangle strips to batch vertex points , but I have no idea how to do this.
The technique you are searching for is called "raycasting".
The basic idea is to render a cube with a special vertex shader that interpolates ray-coordinates for a fragment shader which then casts one ray per pixel into the volume texture, thereby adding up the intensity values of the volume.
There are hundrets of implementations of this technique. I would look for a WebGL implementation because they are more or less automatically OpenGL ES (2) compatible. For example take a look here.
For the JOGL setup code you may have a look at my implementation (although I'm not sure if its ES compatible).
Another completely different approach is to simply use a stack of planes/rects where each is assigned a texture from the volume set and then use additive blending to create the illusion of a volume rendering. It has some flaws but is very easy to implement. For JOGL implementation also see my blog post here (guess it can be easily ported to ES).