Human Eyeball Visual Perception

1. Human EyeballVisual Perception

3. Stereopsis (Contralateral Shift)

4. Color Range

5. Trichromatic Color • http://lite.bu.edu/vision/applets/Color/Addition/Addition.html

6. Visual Perception

7. 1. Figure/Ground Dynamic • The ability to distinguish different objects from one another • Analyzing separate information allows us to re-act to each individual object accordingly • Camouflage – when figures blend into the background

8. Figure-Ground Dynamic

9. Camouflage

10. Gestalt Rules • Gestalt Psychologists focused on how we normally perceive images as groups, not isolated elements • Several factors influence how we will group objects: • Proximity • Similarity • Continuity • Closure

11. 2. Proximity • When objects are close together we tend to perceive them as together rather than separate

12. Proximity

13. Proximity

14. Proximity

15. Proximity

16. 3. Similarity • Objects that are similar in appearance are more likely to be perceived as belonging in the same group

17. Similarity

18. Proximity and Similarity

19. 4. Closure • The tendency to overlook incompleteness, and complete objects so that they fit into our mental preconceptions of what objects are supposed to look like

20. Closure

23. 5. Continuity • To perceive lines and motion in fluid forms rather than jagged motions

24. Continuation

25. Constancy • Constancy refers to our ability to maintain a constant perception of an object despite its relative changes in angle, lighting, distance, etc. to us There are three types of constancy cues: • Size Constancy • Shape Constancy • Brightness Constancy

26. 6. Size Constancy • Objects closer to us will produce bigger images on our retinas, and as they move away they project a smaller image. The actual size of the object does not change. • IE. When a man is right in front of us, he is 6 ft. tall. As he walk further and further away, his image gets smaller. He hasn’t shrunk; he is still 6 ft. tall.

27. Size Constancy

28. 7. Shape Constancy • Objects viewed from different angles will produce different shapes on our retina. Though we may change our position, the shape doesn’t change. • IE. Looking at the top of a glass one way makes it look round; from another angle it looks elliptical. The actual shape hasn’t changed…it is still round.

30. 8. Brightness Constancy • We perceive objects as having a constant color, despite lighting, shading, etc. • A brick wall is still red, whether bright sunlight is on it, or darkness has made it look gray.

31. Depth Cues • Depth Cues allow us to perceive the world in three dimensions. • Monocular Cues are depth cues that do not depend on having two eyes working in conjunction together • Binocular Cues are depth cues that depend on having two eyes working in conjunction with each other

32. Monocular Cues • Linear Perspective • Relative Size • Interposition • Texture Gradient • Shadowing

33. 9. Linear Perspective • Parallel lines seem to converge the further they get from us. The gradual reduction of image size as distance from the object increases • Vanishing Point – where two parallel lines connect in the distance

37. 10. Relative Size • Objects on top of our horizon are smaller and further away, objects below are closer and larger

38. Elevation

39. 11. Interposition • Near objects partially obscure objects further away

43. 12. Texture Gradient • Patterns of distribution tend to grow more dense with distance – things further away seem more smooth, up close more detailed

47. 13. Shadowing • Lighted objects seem closer, darker further away

50. Binocular Cues • Binocular Disparity/Retinal Disparity • Convergence • Motion Parallax