binocular disparity

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Binocular Disparity. points nearer than horopter have crossed disparity points farther than horopter have uncrossed disparity. The Horopter. Binocular Disparity. Why don’t we see double vision?. Binocular Disparity. Why don’t we see double vision? - PowerPoint PPT Presentation

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  • Binocular Disparitypoints nearer than horopter have crossed disparity

    points farther than horopter have uncrossed disparityThe Horopter

  • Binocular DisparityWhy dont we see double vision?

  • Binocular DisparityWhy dont we see double vision?

    Images with a small enough disparity are fused into a single image

  • Binocular DisparityWhy dont we see double vision?

    Images with a small enough disparity are fused into a single image

    The region of space that contains images with close enough disparity to be fused is called Panums Area

  • Binocular DisparityPanums Area extends just in front of and just behind the horopter

  • Binocular DisparityPanums Area extends just in front of and just behind the horopter

    Images outside of Panums area are often blurry because accommodation is reflexively set according to vergence

  • StereopsisOur brains interpret crossed and uncrossed disparity as depth

    That process is called stereoscopic depth perception or simply stereopsis

  • StereopsisStereopsis requires that the brain can encode the two retinal images independently

  • StereopsisPrimary Visual cortex normally keeps input from the eyes separate

    If normal input is restricted during development, the cortical representation of the bad eye is reduced

    Amblyopia can result

  • AmblyopiaAmblyopia is a visual deficit in which one eye has poor vision because the brain never developed the ability to use signals from that retina

  • AmblyopiaAmblyopia is a visual deficit in which one eye has poor vision because the brain never developed the ability to use signals from that retinaUsually caused by strabismus - when eyes dont lock onto the same point anisometropia - when one eye has very bad optics and the other is normal

  • AmblyopiaPeople with Amblyopia cant see stereograms

  • Stereogramsseeing depth requires only two different images on the retina

  • Stereogramsseeing depth requires only two different images on the retina

    this could be accomplished by an optical device that projects separate images into the two eyes

  • Presenting Binocular ImagesVarious ways to add depth:1. Stereoscope

  • StereogramsLeft EyeRight EyeDividerRight eye sees face to the right; left eye sees face to the left therefore:uncrossed disparity

    Face appears behind the square

  • StereogramsLeft EyeRight EyeDividerWhat would you see?

  • StereogramsLeft EyeRight EyeDividerRight eye sees face to the left; left eye sees face to the right therefore:crossed disparity

    Face appears in front of square

  • Presenting Binocular ImagesVarious ways to add depth:glasses with different lenses

  • Presenting Binocular ImagesVarious ways to add depth:glasses with different lenses

  • Presenting Binocular ImagesVarious ways to add depth:glasses with different lenses

  • Presenting Binocular ImagesVarious ways to add depth:LCD Shutter Glasses

  • Gregory

  • ScienceScience is like a set of procedures:Identify a questionMake a HypothesisMake a PredictionTest ItPrediction holdsPrediction Fails

  • Example: The horizontal-vertical illusion

  • Example: The horizontal-vertical illusionQuestion:

  • Example: The horizontal-vertical illusionQuestion: Why does the vertical line seem longer?Hypothesis:

  • Example: The horizontal-vertical illusionQuestion: Why does the vertical line seem longer?Hypothesis: Wundt -> vertical and horizontal eye movements scan the image differentlyPrediction:

  • Example: The horizontal-vertical illusionQuestion: Why does the vertical line seem longer?Hypothesis: Wundt -> vertical and horizontal eye movements scan the image differentlyPrediction: Stabilized image should eliminate the illusionTest:

  • Example: The horizontal-vertical illusionQuestion: Why does the vertical line seem longer?Hypothesis: Wundt -> vertical and horizontal eye movements scan the image differentlyPrediction: Stabilized image should eliminate the illusionTest: Illusion is still present in afterimage!