Single-Lens Camera Reflection Detection via Optical Flow Analysis
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Solution Overview
Problem
Existing reflection determining apparatuses for in-vehicle cameras require a twin-lens setup, making them unsuitable for single-lens cameras and limiting their application.
Innovation Solution
A reflection determining apparatus for single-lens cameras that includes a camera hood to prevent reflections and uses optical flow calculations to detect reflections by determining areas with low optical flow values persisting over a predetermined time, distinguishing between moving objects and reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a twin-lens camera setup is used to determine reflections, then reflection detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent replaces the mechanical/optical twin-lens system with a computational approach using optical flow analysis on single-lens video sequences. Instead of using multiple physical cameras to detect reflections through spatial comparison, the invention uses temporal analysis of pixel movement patterns in video frames to identify reflection areas, thereby eliminating the need for complex multi-lens hardware while maintaining reflection detection capability
Solution Approach 2:
The patent creates a virtual reference image by warping the current frame using optical flow information, effectively copying and transforming the current frame to compare with a previous frame. This virtual copying approach simulates the function of multiple cameras without requiring additional physical sensors, allowing reflection detection through comparison of the original frame with its warped version
2Area of stationary object
If optical flow calculation is performed on the entire image, then reflection detection coverage is improved, but calculation time increases
Solution Approach 1:
The patent divides the image processing task into two stages: first performing optical flow calculation on a down-sampled or partial region to identify potential reflection areas, then applying refined analysis only to those specific regions. This segmentation approach reduces the overall computational burden while maintaining comprehensive reflection detection coverage by focusing resources on areas most likely to contain reflections
Solution Approach 2:
The patent performs optical flow calculation at reduced resolution or on selected regions rather than full-resolution entire-image processing. By applying partial action (processing only necessary portions at full detail), the system achieves acceptable reflection detection performance with significantly reduced computation time, avoiding the excessive time cost of processing every pixel at maximum detail
3Object-generated harmful factors
If a reflection preventer is added to the camera, then reflection prevention capability is improved, but device complexity increases
Solution Approach 1:
The patent converts the harmful reflection effect into a useful detection signal. Instead of trying to physically prevent or eliminate reflections through optical elements, the invention utilizes the reflected light patterns themselves as the basis for detection. By analyzing optical flow patterns in regions where reflections occur, the system identifies and flags reflection areas, transforming the harmful optical phenomenon into a detectable signature that enables reflection determination
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 reflections in the camera's field of view without the need for a twin-lens setup, preventing erroneous reflections and enhancing the camera's imaging capabilities.
Implementation Method 1
a camera hood configured to prevent reflection on the glass in a partial area of a photographed image of the camera
Implementation Method 2
a calculator configured to calculate an optical flow of an area in which the reflection is not prevented by the reflection preventer
Data Source
AI summary
A reflection determining apparatus is configured to determine reflection for a camera, wherein the camera is configured to photograph an external environment of a vehicle through a glass from an inside of the vehicle and the camera includes a reflection preventer configured to prevent reflection on the glass. The reflection determining apparatus is provided with: a calculator configured to calculate an optical flow of an area in which the reflection is not prevented in a photographed image of the camera; and a determinator configured to determine that there is the reflection in the photographed image of the camera if a duration in which a particular area is detected is greater than or equal to a predetermined time, wherein the particular area is defined by points with a value of the optical flow that is smaller than a predetermined threshold value.