1 / 27

Human Vision

Human Vision. Nov 15.2012 Wu Pei. The eye. Optical system. 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

trella
Download Presentation

Human Vision

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Human Vision Nov 15.2012 Wu Pei

  2. The eye

  3. Optical system

  4. 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

  5. Distribution of cone and rod

  6. Blind point

  7. 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

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

  9. 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.

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

  11. Answer Real video Game

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

  13. Light sensitivity

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

  15. Compared with camera

  16. Contrast sensitivity

  17. 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 108 . In practice 10bit to encode luminance and 8bit for hue is enough for eliminating quantization error.

  18. Generating HDR Image

  19. Color banding

  20. 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

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

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

  23. 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.

  24. Mach band: Lateral inhibition

  25. More example: Hermann grid

  26. Thank You

More Related