1. An Algorithm of Eye-Based Ray Tracing on MATLAB
Instructor: Prof.Emery
Group Members:
Xingjian Yang Zhengqi Long Haonan Peng

2. 1. Introduction 1. 1 Ray Tracing
Ray tracing is a special rendering algorithm in 3D computer graphics.

3. V.S 1. Introduction 1. 2 Ray Tracing Method Eye-based Ray Tracing
Light-based Ray tracing
All the light computed is significant for the image plane.
Most of the light contribute very less to image plane.
Not very good for diffuse light.
Very good for diffuse light.
Computational efficient.
Relatively inefficient.
V.S

4. How do every element in the environment contribute on the image plane?
1. Introduction
1. 3 Basic Idea
How do every element in the environment contribute on the image plane?

5. 2. Illumination model 2. 1 Basic models 1. Light source
Choose point light as the light source.
Point light: light rays shine out in a spherical manner from a center point.(In real world, like a light bulb or a candle flame)
2. RGB color model
This model is an additive color model that adds red, green and blue light together to produce other colors.
3. Simple illumination model: Phong model

6. Ambient light → sampling rays
2. Illumination model
2. 2 Phong model and modifications
Ambient light: represents the effect that one object has on another one.
Ambient light → sampling rays
Effect of ambient light

7. 2. Illumination model 2. 2 Phong model and modifications
Resulting set of equations:
Diffuse reflection
Non-ideal specular reflection
Parameters set for each surface: Kdr, Kdg, Kdb, Ks and ns.

8. 2. Illumination model 2. 3 The result of parameter change
Change Kd components and we can change the color of a surface:

9. 2. Illumination model 2. 3 The result of parameter change
Increase Ks and we can make the surface look more smooth:

10. 2. Illumination model 2. 3 The result of parameter change
Increase ns and we can make the surface look more shiny:

11. 3. Rendering
3.1 scene setting & sphere definition

12. 3. Rendering
3.1 scene setting & sphere definition

13. 3. Rendering
3.1 scene setting & sphere definition

14. 3. Rendering
3.2 camera and image plane setting

15. 3. Rendering
3.3 First-order rendering

16. 3. Rendering
3.4 second-order rendering

17. 3. Rendering
3.5 refraction rendering

18. 4. Conlusion and Discussion
4. 1 Conclusion
The order 1 algorithm gives basic light response of the image point, works well for rough surface and smooth surface.
The order 2 algorithm gives light response for reflection light and diffuse light for non-transparent surface, and refraction light for transparent surface.
By combining order 1 and order 2 with proper percent, we can deal with partial smooth partial rough surface, as well as partial transparent surface.
The diffuse hemisphere is an efficient way to calculate to estimate the diffuse light effect of the pixel on image plane.
This algorithm is suitable for most of environment compared with other current light rendering technology

19. 4. Conlusion and Discussion
Need to use matrix calculation to replace for loops.
Some parts of the rendering picture need denoising.
Can not deal with multiple specular reflection.

20. Instructor: Prof.Emery Xingjian Yang Zhengqi Long Haonan Peng
An Algorithm of Eye-Based Ray Tracing on MATLAB
ME 535 Project
Thank you !
Instructor: Prof.Emery
Group Members:
Xingjian Yang Zhengqi Long Haonan Peng