Depth Perception of Surfaces in Pictures: Looking for Conventions of Depiction in Pandora's Box

Perception ◽  
1983 ◽  
Vol 12 (1) ◽  
pp. 5-20 ◽  
Author(s):  
Kevin Berbaum ◽  
David Tharp ◽  
Kenneth Mroczek
Keyword(s):  
Light Source ◽  
Depth Perception ◽  
Local Features ◽  
Apparent Depth ◽  
Source Position ◽  
Background Space ◽  
Made In

The perception of depth in monocularly viewed pictures has been investigated with the use of a binocular rangefinder developed by Gregory. Two experiments are reported which focus upon stimulus conditions that were identified by Haber as conventions for rendering depth in pictures. Several conclusions, which concern assumptions that must be made in interpreting pictures according to such conventions, are supported by the results. There is a default or assumed layout of background space. The interpretation of a point in a depiction depends upon the interpretation of neighboring points, so that interpretations of local features influence the interpretations of nearby ‘empty’ areas. In photographs, the magnitude of apparent depth depends upon the degree of discrepancy between the position of the illuminating source and the observer's supposed light-source position. Also in photographs, apparent depth increases as the contrast between highlights and attached shadows increases.

scholarly journals A Fundamental Approach to Detecting the Light Source Position in a Cubical Room by Using Light Sensors and a Database

2000 ◽  
Vol 84 (8) ◽  
pp. 486-491
Author(s):  
Yuji Honda ◽  
Yasuyuki Iwata ◽  
Etsushi Iki ◽  
Naoyuki Shimomura ◽  
Masayoshi Nagata
Keyword(s):  
Light Source ◽  
Source Position

Light Source Position Measurement Technique Applicable in SOI Technology

2008 ◽  
Vol 43 (7) ◽  
pp. 1588-1593 ◽  
Author(s):  
Christian Koch ◽  
JÜrgen Oehm ◽  
Jannik Emde ◽  
Wolfram Budde
Keyword(s):  
Light Source ◽  
Measurement Technique ◽  
Source Position ◽  
Position Measurement ◽  
Soi Technology

Suprathreshold Stereo-Depth Matches as a Function of Contrast and Spatial Frequency

Perception ◽  
1986 ◽  
Vol 15 (3) ◽  
pp. 249-258 ◽  
Author(s):  
Clifton M Schor ◽  
Peter A Howarth
Keyword(s):  
Spatial Frequency ◽  
Depth Perception ◽  
Low Frequency ◽  
Stereoscopic Depth ◽  
Apparent Depth ◽  
Black Line ◽  
Low Contrast ◽  
Spatial Frequencies ◽  
Vertical Bars ◽  
Thin Black Line

Thresholds for stereoscopic-depth perception increase with decreasing spatial frequency below 2.5 cycles deg−1. Despite this variation of stereo threshold, suprathreshold stereoscopic-depth perception is independent of spatial frequency down to 0.5 cycle deg-1. Below this frequency the perceived depth of crossed disparities is less than that stimulated by higher spatial frequencies which subtend the same disparities. We have investigated the effects of contrast fading upon this breakdown of stereo-depth invariance at low spatial frequencies. Suprathreshold stereopsis was investigated with spatially filtered vertical bars (difference of Gaussian luminance distribution, or DOG functions) tuned narrowly over a broad range of spatial frequencies (0.15–9.6 cycles deg−1). Disparity subtended by variable width DOGs whose physical contrast ranged from 10–100% was adjusted to match the perceived depth of a standard suprathreshold disparity (5 min visual angle) subtended by a thin black line. Greater amounts of crossed disparity were required to match broad than narrow DOGs to the apparent depth of the standard black line. The matched disparity was greater at low than at high contrast levels. When perceived contrast of all the DOGs was matched to standard contrasts ranging from 5–72%, disparity for depth matches became similar for narrow and broad DOGs. 200 ms pulsed presentations of DOGs with equal perceived contrast further reduced the disparity of low-contrast broad DOGs needed to match the standard depth. A perceived-depth bias in the uncrossed direction at low spatial frequencies was noted in these experiments. This was most pronounced for low-contrast low-spatial-frequency targets, which actually needed crossed disparities to make a depth match to an uncrossed standard. This bias was investigated further by making depth matches to a zero-disparity standard (ie the apparent fronto-parallel plane). Broad DOGs, which are composed of low spatial frequencies, were perceived behind the fixation plane when they actually subtended zero disparity. The magnitude of this low-frequency depth bias increased as contrast was reduced. The distal depth bias was also perceived monocularly, however, it was always greater when viewed binocularly. This investigation indicates that contrast fading of low-spatial-frequency stimuli changes their perceived depth and enhances a depth bias in the uncrossed direction. The depth bias has both a monocular and a binocular component.

scholarly journals Interactive light source position estimation for augmented reality with an RGB-D camera

2015 ◽  
Vol 28 (1) ◽  
pp. e1686 ◽  
Author(s):  
Bastiaan J. Boom ◽  
Sergio Orts-Escolano ◽  
Xin X. Ning ◽  
Steven McDonagh ◽  
Peter Sandilands ◽  
...  
Keyword(s):  
Augmented Reality ◽  
Light Source ◽  
Position Estimation ◽  
Source Position

scholarly journals HDlive for Assessment of Placenta and Umbilical Cord

2014 ◽  
Vol 8 (4) ◽  
pp. 391-399
Author(s):  
Hirokazu Tanaka ◽  
Masato Mashima
Keyword(s):  
Light Source ◽  
Umbilical Cord ◽  
Depth Perception ◽  
Obstet Gynecol ◽  
Three Dimensional ◽  
Novel Technique ◽  
Shadowing Effects ◽  
Umbilical Cords

ABSTRACT We present the latest HDlive images of normal and abnormal placentas and umbilical cords. By means of HDlive, more detailed information on placental and umbilical cord abnormalities can be obtained, because this technique is a new surfacerendering mode that uses an adjustable light source to create lighting and shadowing effects, thereby increasing depth perception. HDlive provides extraordinarily realistic imaging of the placenta and umbilical cord, making it almost impossible to differentiate between fetoscopic findings and ultrasound scans. This novel technique may assist in evaluation of the placental and umbilical cord anatomy, and offer potential advantages over conventional two- and three-dimensional ultrasound. HDlive may be an important modality in future placental and umbilical cord research and in the evaluation of their abnormalities. How to cite this article Hata T, Tanaka H, Mashima M, Kanenishi K, Marumo G. HDlive for Assessment of Placenta and Umbilical Cord. Donald School J Ultrasound Obstet Gynecol 2014;8(4):391-399.

Development of the Endo-Periscope for Improvement of Depth Perception in Laparoscopic Surgery

2001 ◽  
Author(s):  
Paul Breedveld ◽  
Shigeo Hirose
Keyword(s):  
Laparoscopic Surgery ◽  
Light Source ◽  
Depth Perception ◽  
Degrees Of Freedom ◽  
Information Source ◽  
Abdominal Cavity ◽  
Torsional Stiffness ◽  
Depth Information ◽  
Institute Of Technology ◽  
Machine Systems

Abstract Laparoscopic surgery is carried out by using an endoscope with a camera that is inserted through a small incision in the abdominal wall. The camera pictures are presented on a monitor. The light source of the endoscope forms a ring around the camera lens, and the endoscope movements are limited by the incision point. The absence of shadows in the camera picture and the restricted ability to observe organs from aside complicate the surgeon’s depth perception. This paper describes the development of a new steerable endoscope that is the product of a close co-operation between the Man-Machine Systems Group of the Delft University of Technology and the Hirose & Yoneda Laboratory of the Tokyo Institute of Technology. The endoscope, which is called Endo-Periscope, uses a new spatial parallelogram-mechanism to transform the movements of the handgrip into movements of the steerable tip. The handgrip contains an arrow that points always in the direction of the line-of-sight of the tip-camera. This provides intuitive control of the tip and it shows the surgeon how the camera is oriented in the abdominal cavity. The light source is located on the shaft and the tip-camera can be moved in six degrees of freedom. This enables the surgeon to observe organs from different sides and to use shadows as a depth information source. Part of the parallelogram-mechanism is a new kind of spring which combines a very high torsional stiffness with a low, asymmetric bending stiffness. The spring and the working principle of the Endo-Periscope have been applied for two patents.

Analysis of the influence on the light source position deviation to the spot

2015 ◽  
Vol 41 (2) ◽  
pp. 111-114
Author(s):  
张嘉钰 ZHANG Jiayu ◽  
李金超 LI Jinchao ◽  
牛虎利 NIU Huli
Keyword(s):  
Light Source ◽  
Source Position

Point Light Source Position Estimation From RGB-D Images by Learning Surface Attributes

2017 ◽  
Vol 26 (11) ◽  
pp. 5149-5159 ◽  
Author(s):  
Sezer Karaoglu ◽  
Yang Liu ◽  
Theo Gevers ◽  
Arnold W. M. Smeulders
Keyword(s):  
Light Source ◽  
Position Estimation ◽  
Source Position ◽  
Point Light Source ◽  
Point Light

BEHAVIOR AND CYCLIC ACTIVITY ASSOCIATED WITH PUPATION OF PHYTOMYZA LANATI SPENCER (DIPTERA: AGROMYZIDAE)

1966 ◽  
Vol 44 (5) ◽  
pp. 793-798 ◽  
Author(s):  
Maurice J. Tauber ◽  
Catherine A. Tauber
Keyword(s):  
Light Source ◽  
Critical Level ◽  
Adaptive Significance ◽  
Leaf Miner ◽  
Time Interval ◽  
Cyclic Activity ◽  
Mature Larva ◽  
Adaxial Surface ◽  
Heracleum Lanatum ◽  
Made In

Phytomyza lanati Spencer is a leaf-miner on Heracleum lanatum Michx. The pupating larva abandons the host via a cut nearly always made in the lower (adaxial) surface of the leaf. Experiments show that the direction of the cut is not determined by the direction of the light source or the orientation of the leaf, but results from conditions within the leaf itself. The possible adaptive significance of this internal leaf cue is that it serves as a sure guide to a direct exit out of the leaf.The mature larva exits from the leaf and drops to the ground during a narrowly defined period near dawn. The phase of emergence was shifted by reversing the photoperiod. There was a consistent time interval between sunset and emergence under different photoperiods, whereas no such consistent relationship was found between dawn and emergence. The data were recorded by a self-operating collecting device.The time-of-emergence cue may be the result of some change that occurs within the larva, or it may result from a rhythmic process within the leaf which reaches a critical level approximately 8 hours after sunset.

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