1 / 19

Chapter 6: Metacontrast and Motion Perception (pp. 219-233 ) Thomas Otto

EDNE 016: Dynamic Vision. 23.01.2007. Chapter 6: Metacontrast and Motion Perception (pp. 219-233 ) Thomas Otto. Visual persistence. A percept persists for some time after the termination of the stimulus. Visual persistence is about 120 ms under daylight. Motion smear. Burr (1980).

hagen
Download Presentation

Chapter 6: Metacontrast and Motion Perception (pp. 219-233 ) Thomas Otto

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. EDNE 016: Dynamic Vision 23.01.2007 Chapter 6:Metacontrastand Motion Perception (pp. 219-233 )Thomas Otto

  2. Visual persistence A percept persists for some time after the termination of the stimulus Visual persistence is about 120 ms under daylight

  3. Motion smear Burr (1980) Moving objects should be perceived like in a photograph with a 125 ms shutter speed

  4. Suppression of persistence “The amount of motion smear is far less than may be expected from visual persistence” Burr (1980)

  5. Suppression of persistence & metacontrast A “moving stimulus” fulfills the definitionof a metacontrast mask Suppression of persistence & metacontrast are similar from the perspective of PHENOMENOLOGY

  6. Phenomenology Suppression of persistence & metacontrast are similar in: - Dependence on luminance- Spatial and temporal separation- Eccentricity

  7. Motion de-blurring models Models of motion de-blurring can be viewed as models of metacontrast There are mainly two classesbased on: - motion compensation and “fusion”- lateral inhibition

  8. Motion compensation Spatio-temporally oriented receptive fields Burr, Ross & Morrone (1986)

  9. Lateral inhibition The RECOD model Purushothaman, Ogmen, Chen & Bedell (1998)

  10. The RECOD model & an isolated target The RECOD model predicts extensive smearfor isolated targets Purushothaman, Ogmen, Chen & Bedell (1998)

  11. The RECOD model & multiple targets The motion smear is basically removed by the transient activity of nearby stimuli Purushothaman, Ogmen, Chen & Bedell (1998)

  12. Isolated target An isolated target appears to be extensively smeared Chen, Bedell & Ogmen (1995)

  13. Confusing summary paragraph “These findings provide evidence against models where motion plays a causal role in metacontrast” Breitmeyer & Ogmen (2006)

  14. Isolated target A velocity of 10 deg/scorresponds to a SOA of about 5 ms given a target-mask separation of 200”

  15. Confusing summary paragraph “Metacontrast can improve the clarity of form perception by suppressing the smear of moving objects” “A careful parametric analysis shows thatmetacontrast and motion involve different mechanisms” Breitmeyer & Ogmen (2006)

  16. Summary Suppression of persistence and metacontrast are similar from the perspective of STIMULI and PHENOMENOLOGY There might be ONE mechanism responsible for both phenomena!

  17. The end Thanks for your attention!

  18. Transient and sustained activity

  19. Experimental data vs. model prediction

More Related