Spine Drift Illusion - Some Explanations - Page-1
This illusion was first introduced By Kitaoka, A., 2010 [link]
Illusory motion in two-dimensional space:
- The motion direction changes depending on: (A) eye movements; (B) how the eyes detect and locate changes during movements.
- The illustration shows the illusory motion direction for a circle when you scroll down. If you scroll up, the direction becomes reversed.
- The motion directions cancel each other out:
Because of the circle's symmetrical structure, it appears stable and not in illusory motion.
- The circle can be divided into four (4) parts, where two (2) of them induce clockwise motion and the other two (2) induce counterclockwise motion.
- Illustrates the direction of movement of spines by placing them in the circle model.
- Contrast inversion does not change the direction (white spine vs black spine).
Reading pattern - Definition:
- Type of spine with its own elements.
- The pattern that the brain tries to read and define its position.
Element - Definition:
- The various components of a spine.
- The image illustrates a spine with three (3) different parts.
Part one - color interaction
- Part 1 strengthens the illusion.
Motion Trigger points (MTP) - Definition:
- Different directional terminal points that defines the start and the end points for the illusory motions.
- To be marked at the beginning and end of an element.
Unspeciffied Motion Trigger points (uMTP) - Definition:
- Motion trigger point with:(A) non-predefined distance, (B) Unspecified marking place.
- It can be used to segment the spine and can be defined as the start or endpoint of a segment.
- The motion intensity can be observed by: (A) placing the MTP at crucial points on the element and (B) dividing the element into several segments, so that they can be observed separately.
Relative Illusory Motion (IM) intensity:
- The intensity of the different parts can be graded relative to each other and not in comparison to other reading patterns.
- The intensity can change depending on which element the segment is connected to.
- The spine can be placed in a coordinate system with radius 10.
- Every 22.5 degrees can be marked with a uMTP. The x and y values of each point can be obtained from the coordinate system.
- These five trigger points corresponds to four segments of equal length.
Calculating the slope, distance and angle for every segment:
- The distance between the segments is equal (rounded).
- When the angle (θ) is minus (-), the illusory motion direction is clockwise, while when the angle (θ) is plus (+), the illusory motion direction is anti-clockwise.
- when the slope increases the intensity increases.
Relative Illusory Motion (IM) intensity - Part 3:
Imaginary Frames - Part 3
- The Illusion Works like a flip book: When you are scrolling down you scrolling through different frames.
- Every frame have different illusory motion intensity/direction. The intensity is Relative.
- The intensity reverses if you scroll left-/or right-ward. The image illustrates the intensity when scrolling down.