Examination of Light Source Direction Estimation System using Photodiodes

2017 ◽  
Vol 2017 (0) ◽  
pp. 2P2-A10
Author(s):  
Yasuharu KUNII ◽  
Hiroki KIDA ◽  
Takao MAEDA ◽  
Masataka USHIJIMA
Keyword(s):  
Light Source ◽  
Direction Estimation ◽  
Estimation System ◽  
Light Source Direction

Revisiting Pentland’s estimator of light source direction

1994 ◽  
Vol 11 (1) ◽  
pp. 118 ◽  
Author(s):  
Wojciech Chojnacki ◽  
Danny Gibbins ◽  
Michael J. Brooks
Keyword(s):  
Light Source ◽  
Light Source Direction

scholarly journals On the feasibility of determining light-source direction from an image

1998 ◽  
Vol 56 (2) ◽  
pp. 289-307
Author(s):  
Wojciech Chojnacki ◽  
Michael J. Brooks ◽  
Daniel Gibbins
Keyword(s):  
Light Source ◽  
Light Source Direction

A New Algorithm to Exposing Image Forgeries by Detecting Ambient Illumination Consistency

2012 ◽  
Vol 433-440 ◽  
pp. 5463-5468
Author(s):  
Wei Dong Zhong ◽  
Jun Jie Zhu ◽  
Li Xian Wei ◽  
Xiao Yuan Yang
Keyword(s):  
Light Source ◽  
Binary Tree ◽  
Error Function ◽  
New Method ◽  
General Situation ◽  
Ambient Illumination ◽  
Light Source Direction

Illumination consistency makes one of important roles in image authenticity, especially in splicing and copy-move rendering. This paper proposes a new method to estimate illuminant direction based on idea of binary sort tree. The algorithm calculates the least error function to structure the binary tree of illuminant direction. And it doesn’t need to expand much time to solve pathosis equation and access accuracy is improved. The experiment shows that, the algorithm can effectively calculate the light source direction of different objects and backgrounds in an image especially in infinite light source, and the detection correct rate reaches 85.4% in general situation , what’s more, 88.1% in infinite light source. Anyway, the algorithm in this paper is a great advancement of blind forensics based on consistency in lighting direction.

scholarly journals The hollow-face illusion monocularly observed in a box

2014 ◽  
Vol 31 (3) ◽  
pp. 359-366
Author(s):  
Maria Amélia Cesari Quaglia ◽  
Lívia da Silva Bachetti ◽  
Arthur Alves
Keyword(s):  
Light Source ◽  
Face Perception ◽  
Higher Order ◽  
Predominant Role ◽  
Tape Measure ◽  
Light Source Direction ◽  
Low Order

Under monocular conditions, 40 students observed the reverse of polychrome and monochrome masks and judged them to be concave, convex or flat. The mask was presented upright and illuminated from above, below, right and left and in the upside down position illuminated from below. The magnitude of the perceived depth or relief was estimated using a retractable tape measure. Regardless of color, lighting and orientation, the majority of responses indicated that the hollow masks were perceived to be convex. No significant differences were observed between the depth or convexity of the metric magnitudes and scalar magnitudes of the concave masks in relation to variations in the light source direction, color, and position. The illusory depth, seeing the concave mask as convex, is a robust phenomenon that suggests the predominant role of higher-order processes over the low-order processes in visual face perception.

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