Camera Lighting Control for Specular Reflection Reduction
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Solution Overview
Problem
Shooting systems with integrated lighting face challenges in unpredictable object positions, leading to specular reflections and poor contrast due to uneven illumination, which affect image quality, especially in non-deterministic setups like biometric and document scanning.
Innovation Solution
A controlled lighting system driven by a control unit that estimates a 3D model of the object using structured light or time-of-flight cameras, and implements stereoscopic methods to determine the object's position and simulate lighting conditions, selecting optimal lighting modes to minimize artefacts and enhance contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the object position is not predetermined in non-deterministic setups, then the system is more versatile and adaptable, but specular reflections and artifacts are created that disrupt the imager
Solution Approach 1:
The system performs preliminary actions by estimating the 3D model of the object and simulating lighting conditions before the actual image capture. This allows the control unit to predict artifact locations and pre-adjust lighting parameters to minimize specular reflections and artifacts, resolving the contradiction between adaptability and harmful reflections.
Solution Approach 2:
The system uses feedback by estimating the 3D model from initial images, simulating lighting effects, and using this information to adjust lighting parameters before final capture. This closed-loop approach allows the system to adapt to different object positions while predicting and minimizing harmful reflections through iterative optimization.
2Adaptability or versatility
If the object position is not predetermined, then the system can handle various objects, but areas other than the brightest ones remain in shadow with poor contrast
Solution Approach 1:
The system performs preliminary lighting simulation based on estimated 3D models before actual image capture. This allows the control unit to predict shadow areas and pre-adjust lighting parameters to ensure adequate illumination and contrast across the entire object, not just the brightest areas.
Solution Approach 2:
The system dynamically changes lighting parameters (intensity, direction, position) based on simulated lighting conditions and estimated 3D models. This allows optimization of illumination distribution to maintain good contrast across different object positions and geometries, resolving the contradiction between versatility and image contrast.
3Measurement precision
If dynamic lighting adjustment is implemented, then image quality is improved, but the device complexity increases
Solution Approach 1:
The system uses the imager and processing units already present in the camera system to perform 3D model estimation and lighting simulation. By reusing existing components for multiple functions (image capture, 3D modeling, lighting control), the system achieves high image quality without proportionally increasing device complexity.
Solution Approach 2:
The control unit performs multiple functions: it controls the imager, estimates 3D models from images, simulates lighting conditions, and adjusts lighting parameters. This multi-functionality allows the system to achieve high image quality through dynamic lighting adjustment while minimizing the need for additional dedicated components, thus managing device complexity.
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
The solution effectively reduces artefacts and improves image contrast by dynamically adjusting lighting, ensuring high-quality images even in non-deterministic object positions, thereby enhancing the usability of the imaging system.
Implementation Method 1
said 3D imaging system is a structured light system, or consists of a time-of-flight camera
Implementation Method 2
said step of determining said 3D model implements a stereoscopic method from pairs of views taken by said 3D imaging system
Data Source
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AI summary
The present invention relates to a method for shooting, by means of an imaging device, one or more images of an object or of a portion of an object presented at a distance in front of said imaging device, said object being illuminated by means of a lighting system. According to the invention, said method comprises the following steps: a step of estimating a 3D model of the object as it will appear at a predetermined time of the shooting of the image by said imaging device; a step of simulating, using said 3D model thus estimated, the lighting of the object as it will appear at said time in order to obtain estimated images of said object respectively in a plurality of potential lighting modes of said lighting system; a step of selecting a lighting mode of the lighting system based on the estimated images; a step of controlling the lighting system in order for same to be in the selected lighting mode; and a step of controlling the imaging device, at said time of shooting the image of said object, in order for said shooting to be carried out. The present invention also relates to a camera system for implementing said method.