Shiny Area Normal Vector Detection for Light Source Direction
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Solution Overview
Problem
Existing methods for estimating light source direction and location are prone to errors, particularly when hair sways over a face, leading to inaccurate determination of light incident direction.
Innovation Solution
An information processing apparatus that calculates a normal vector at the shininess center of a shiny area using a captured image and specifies the light source direction based on the normal vector and positional relationship between the imaging device and the shininess center.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light source direction is estimated from face shade, then light incident direction can be determined, but determination becomes erroneous when hair sways over the face
Solution Approach 1:
The patent extracts the shiny area from the face region and uses it as a separate, reliable indicator for light source direction estimation. By focusing on the shiny area's normal vector rather than the overall face shade, the method isolates the most reliable feature for determination, avoiding interference from moving elements like hair.
Solution Approach 2:
The patent applies local quality by analyzing the normal vector at the specific location of the shiny area center rather than using global face shade information. This localized approach ensures that the light source direction is determined based on the most reflective and stable region, which is less affected by hair movement.
2Manufacturing precision
If visual effects are applied to all frames, then effect quality is maintained, but computational load increases significantly
Solution Approach 1:
The patent implements periodic recalculation of light source parameters based on detected changes in subject movement or device posture. Instead of continuous processing, the system periodically updates the light source direction and shininess center position only when necessary, maintaining effect quality while reducing unnecessary computational load during stable periods.
Solution Approach 2:
The patent uses feedback mechanisms by monitoring subject movement and device posture changes to trigger recalculation. The system continuously monitors these parameters and only reprocesses visual effects when changes exceed thresholds, ensuring quality maintenance while optimizing processing efficiency through conditional execution.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Accurately determines the light source direction and location, enabling precise application of visual effects such as catch light and backlight correction, reducing computational load by selective recalculation based on subject movement and device posture changes.
Implementation Method 1
a shiny area that is an area on a subject and is a bright area reflecting light from a light source
Data Source
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AI summary
An information processing apparatus includes: a normal vector calculation unit that calculates, on the basis of a captured image, a normal vector at a shininess center located at the center of a shiny area that is an area on a subject and is a bright area reflecting light from a light source; and a light source location specifying unit that specifies, on the basis of the normal vector, a light source direction that is a direction in which the light source is located.