1. Human Vision
Nov
Wu Pei

2. The eye

3. Optical system

5. Cone and Rod Vision:
In a sense, each of us has two visual systems; the photopic system functions in lighted conditions; the scoptopic system functions in dim light
Cones mediate photopic vision; rods mediate scotopic vision; this is called the duplexity theory of vision

6. Distribution of cone and rod

7. Blind point

8. Spatial resolution
 4.5 million cone cells and 90 million rod cells in the human retina in average.
High resolution in middle and low resolution in edge, highest at fovea, about 1.2'.
Field of view: best resolution horizontal 35°and vertical 20°
In all: 1750*1000 in best resolution zone.  About 5-15 megapixel whole field

9. Qualitative representation of visual detail using a single glance of the eyes.

10. Time resolution
Persistence of vision: an afterimage is thought to persist for approximately one twenty-fifth of a second on retina.
Fps: frames per second
The mechanism of film system.

11. Why game need better fps than movie
Movie: 24fps TV: 25fps
Game: 59/60fps

12. Answer
Real video Game

13. Sensitivity to light
Human eye can is self-adaptive to differed light intensity by adjusting rhodopsin concentration.

14. Light sensitivity

15. Evolutionary perspective
Our vision is optimized for receiving the most abundant spectral radiance our star emits.  

16. Compared with camera

17. Contrast sensitivity

18. Color Depth True color :8*3=24 bits HDR: 32*3=96 bits
HDR use float but not fixed point number for luminance ranges from 10-4 to In practice 10bit to encode luminance and 8bit for hue is enough for eliminating quantization error.

19. Generating HDR Image

20. Color banding

21. Hints for video coding
Human eye is less sensitive to chrominance signal than to luminance signal (U and V can be coarsely coded)
Human eye is less sensitive to the higher spatial frequency components
Human eye is less sensitive to quantizing distortion at high luminance levels

22. Estimating bandwidth of eye
Input:24bit*10Mpixel*24fps=720MB/s
Output: ~100kB/s
Compare: H.264,1080p:1.5MB/s

23. How the visual information encoded
The process of neuron development is a process of “training”.

24. Encoding and illusion
Illusion means visually perceived images that differ from objective reality.
Generally visual encoding is a lossy coding. So look at the illusion will be helpful to know the encoding process.

25. Mach band: Lateral inhibition

26. More example: Hermann grid

27. Thank You