Spatial vision i revised jan 25 2011
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The document defines contrast and modulation transfer function (MTF). It explains that a square wave can be represented as a sum of sine waves, with the fundamental sine wave having the same frequency as the square wave and harmonics being integer multiples of this frequency. MTF is defined as the ratio of image contrast to object contrast, with a value of 1 for an ideal lens. The document includes an MTF table showing contrast values at different frequencies. It also mentions the contrast sensitivity function and discusses ganglion cell receptive fields and various visual acuity tests like Snellen, HOTV, and Landolt C for measuring resolution and recognition acuity.
Spatial vision i revised jan 25 2011
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- 9. Fourier Analysis Square wave = Sum of sine waves Square wave = Fundamental sine wave + harmonics Fundamental sine wave is a wave with the same frequency as the square wave Third harmonic is a sine wave with 3 times the square wave Fifth harmonic is a sine wave with 5 times the frequency of the square wave
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- 12. Modulation Transfer Function Object Contrast-> Lens -> Image contrast MTF = Image Contrast/ Object Contrast MTF = 1.0 for an ideal lens (or system) MTF is determined by frequency to obtain a graph.
- 13. Modulation Transfer Function (MTF) Frequency Object Contrast Image Contrast MTF 2 10 8 0.80 5 9 7.5 0.83 8 8.7 6.3 0.72 10 7.5 5.2 0.69 15 6.3 3.8 0.60 18 5.2 2.1 0.40 25 4.2 1.5 0.36 30 4 0.9 0.23 40 4 0.7 0.18 50 3.8 0.4 0.11 60 3.6 0.33 0.09
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- 39. Ganglion cell Receptive Field
- 40. Ganglion cell receptive field
- 41. Ganglion cell receptive field
- 42. Ganglion cell response to diffuse illumination
- 43. Ganglion cell response to spatial grating
- 44. Mach bands Dark band Bright band
- 45. Mach bands
- 46. Recognition Acuity Snellen HOTV LEA Patti Pics
- 47. LEA Symbols
- 48. Patti Pics
- 49. HOTV Test
- 50. Resolution Acuity Tumbling E Landolt C Broken Wheel
- 52. Tumbling E
- 53. Landolt C
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- 56. Hyperacuity Vernier Alignment test Tilt test
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