The Effect of Contour Closure on Shape Recognition

Patrick Garrigan

doi:10.1068/p7145

The Effect of Contour Closure on Shape Recognition

Perception ◽

10.1068/p7145 ◽

2012 ◽

Vol 41 (2) ◽

pp. 221-235 ◽

Cited By ~ 8

Author(s):

Patrick Garrigan

Keyword(s):

Shape Memory ◽

Shape Recognition ◽

Closed Contour ◽

Gestalt Principle

Recent research on the Gestalt principle of closure has focused on how the presence of closure affects the ability to detect contours hidden in cluttered visual arrays. Some of the earliest research on closure, however, dealt with encoding and recognizing closed and open shapes, rather than detection. This research re-addresses the relation between closure and shape memory, focusing on how contour closure affects the ability to learn to recognize novel contour shapes. Of particular interest is whether closed contour shapes are easier to learn to recognize and, if so, whether this benefit is due to better encoding of closed contour shapes or easier comparison of closed contour shapes to already learned shapes. The results show that closed contours are indeed easier to recognize and, further, that this advantage appears to be related to better encoding.

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Figure – Ground Effects on Shape Memory for Objects versus Holes

Perception ◽

10.1068/p5838 ◽

2008 ◽

Vol 37 (10) ◽

pp. 1569-1586 ◽

Cited By ~ 14

Author(s):

Stephen Palmer ◽

Janet Davis ◽

Rolf Nelson ◽

Irvin Rock

Keyword(s):

Shape Memory ◽

Recognition Test ◽

Central Region ◽

Shape Recognition ◽

Solid Object ◽

Minus Sign ◽

Solid Objects ◽

Ground Effects ◽

Better Than

The circumstances under which the shapes of figure-versus-ground regions are perceived and remembered were investigated in three experiments that replicate, extend, and clarify Rubin's [1921 Visuell wahrgenommene Figuren (Copenhagen: Gyldendals)] classic study on this topic. In experiment 1, observers reported which of two regions they perceived as figure within ambiguous, bipartite, 2-D displays. In a later shape-recognition test, the shapes of regions previously seen as figures were remembered well, but the shapes of regions previously seen as grounds were remembered no better than novel distractor regions. In experiment 2 we examined the same question about memory for the shape of figure-versus-ground regions in nested displays in which the central region could be perceived either as a closer figure surrounded by a farther ground (ie as a solid object) or as a farther ground surrounded by a closer figure (ie as an empty hole). Unlike experiment 1, the shapes of regions initially perceived as grounds (holes) were remembered as well as those of regions initially perceived as figures (solid objects), and much better than those of novel distractor regions. In experiment 3 we further demonstrated that this outcome did not depend on the figure – ground instructions employed in experiment 2, because the same result was obtained with unambiguous 3-D cardboard displays of objects versus holes with no figure – ground instructions at all. The present findings support an account of hole perception in which the shape of an intrinsic hole is encoded as a shaped, immaterial (or virtual) surface where the absence of matter is coded by a functional ‘missing’ symbol (analogous to a minus sign in mathematics) to represent its non-material status.

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Tensile Failure of 55-Nitinol Wire

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100113858 ◽

1975 ◽

Vol 33 ◽

pp. 46-47

Author(s):

F. I. Grace

Keyword(s):

Shape Memory ◽

Shape Memory Effect ◽

Memory Effect ◽

Stoichiometric Composition ◽

Tensile Failure ◽

Initial State ◽

Initial Shape ◽

Nitinol Wire ◽

Cscl Type ◽

Shear Transformation

An interest in NiTi alloys with near stoichiometric composition (55 NiTi) has intensified since they were found to exhibit a unique mechanical shape memory effect at the Naval Ordnance Laboratory some twelve years ago (thus refered to as NITINOL alloys). Since then, the microstructural mechanisms associated with the shape memory effect have been investigated and several interesting engineering applications have appeared.The shape memory effect implies that the alloy deformed from an initial shape will spontaneously return to that initial state upon heating. This behavior is reported to be related to a diffusionless shear transformation which takes place between similar but slightly different CsCl type structures.

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TEM study of order, structure and defects of β and martensite in Cu-Al-Mn shape memory alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100174072 ◽

1990 ◽

Vol 48 (4) ◽

pp. 188-189

Author(s):

J.M. Guilemany ◽

F. Peregrin

Keyword(s):

Shape Memory ◽

Orthophosphoric Acid ◽

Isopropyl Alcohol ◽

Metastable Phase ◽

Characteristic Temperature ◽

Ethanol Solution ◽

Order Structure ◽

Thin Foils ◽

Polycrystalline Alloys ◽

Diamond Saw

The shape memory effect (SME) shown by Cu-Al-Mn alloys stems from the thermoelastic martensitic transformation occuring between a β (L2,) metastable phase and a martensitic phase. The TEM study of both phases in single and polycrystalline Cu-Al-Mn alloys give us greater knowledge of the structure, order and defects.The alloys were obtained by vacuum melting of Cu, Al and Mn and single crystals were obtained from polycrystalline alloys using a modified Bridgman method. Four different alloys were used with (e/a) ranging from 1.41 to 1.46 . Two different heat treatments were used and the alloys also underwent thermal cycling throughout their characteristic temperature range -Ms, Mf, As, Af-. The specimens were cut using a low speed diamond saw and discs were mechanically thinned to 100 μm and then ion milled to perforation at 4 kV. Some thin foils were also prepared by twin-jet electropolishing, using a (1:10:50:50) urea: isopropyl alcohol: orthophosphoric acid: ethanol solution at 20°C. The foils were examinated on a TEM operated at 200 kV.

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