Ambient Light Reflection Detection Using Luminance Histograms
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Solution Overview
Problem
Existing methods for detecting ambient light reflection on eyeglasses face challenges in accuracy, particularly when multiple similar edges are reflected, and in situations where the eyeglasses are worn by a driver moving or when the luminance of the reflection is low, making it difficult to determine the reflection state accurately.
Innovation Solution
A reflection determination apparatus and method that calculates a luminance histogram of the eye area, computes a difference histogram between current and previous luminance histograms, and uses an evaluation value based on weighted luminance fluctuations to determine reflection without relying on edge detection, enabling accurate reflection assessment even in low-luminance conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If edge detection method is used to detect ambient light reflection, then reflection can be detected in high-luminance conditions, but detection accuracy deteriorates when multiple similar edges are reflected or when luminance is low
Solution Approach 1:
The patent changes the detection parameter from edge-based geometric features to luminance histogram-based statistical features. By analyzing the distribution of luminance values and their temporal fluctuations, the system can detect reflections across varying luminance conditions without relying on edge characteristics that become ambiguous in low-luminance or multi-edge scenarios
Solution Approach 2:
The patent replaces the mechanical/geometric edge detection approach with a statistical analysis approach using luminance histograms. This substitution enables the system to detect reflections through luminance distribution patterns rather than relying on spatial edge features, thereby improving performance in conditions where edges are difficult to distinguish
2Measurement precision
If high-luminance area detection method is used, then reflection can be detected in bright conditions, but low-luminance reflection becomes undetectable
Solution Approach 1:
The patent changes from detecting absolute luminance values to detecting temporal fluctuations in luminance histogram distribution. By analyzing how the luminance distribution changes over time rather than relying on absolute brightness levels, the system can detect reflections regardless of the overall luminance intensity, enabling detection in both high and low luminance conditions
3Ease of operation
If edge tracking method is used to detect reflection, then detection can be performed when car is moving forward, but detection accuracy deteriorates when car is circling or driver shakes face
Solution Approach 1:
The patent replaces the motion-based edge tracking method with a temporal luminance fluctuation analysis method. Instead of tracking edge positions and inferring reflection from motion patterns, the system analyzes changes in luminance histogram distribution over time, which provides a more robust indicator of reflection that is less sensitive to complex head or vehicle movements
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
This approach allows for precise determination of ambient light reflection on eyeglasses, improving detection accuracy by considering luminance fluctuations and reducing errors associated with low-luminance reflections, thereby enhancing line-of-sight detection reliability.
Implementation Method 1
reflection of ambient light to lenses of the eyeglasses
Data Source
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AI summary
Disclosed are an ambient light reflection determination apparatus and an ambient light reflection determination method enabling to determine reflection without using an edge and even in a case where luminance of a reflection generating part in eyeglasses is low. In a reflection determination apparatus (100), a luminance histogram calculation section (102) calculates a luminance histogram representing a luminance distribution of an eye area image, a difference calculation section (104) calculates a difference histogram by finding a difference between the two luminance histograms calculated from the two eye area images having different photographing timings, an evaluation value calculation section (105) calculates an evaluation value regarding reflection of ambient light based on the difference histogram and a weight in accordance with luminance, and a reflection determination section (107) determines the reflection of ambient light based on the calculated evaluation value.