Reflectance Determination Using Flash Illumination and Image Interpolation
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Solution Overview
Problem
Existing methods for determining object reflectance, such as using diffraction spectrometers, are expensive and difficult for unskilled operators to use, necessitating a more reliable and easy-to-implement approach.
Innovation Solution
A method and device that utilize a series of flashes of light with known illumination, captured by an electronic color image sensor, to form equations that account for object reflectance and external illuminant, employing approximations to solve for reflectance even with variable external illumination, and interpolating to achieve precise results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If specialized high-precision devices such as diffraction spectrometers are used to determine reflectance, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses a color image sensor to capture reflected light and creates a mathematical model that copies the function of expensive spectrometers. Instead of using complex optical instruments, the system captures images under controlled illumination and processes them through algorithms to determine reflectance, achieving spectrometric measurements through imaging rather than specialized spectroscopic hardware
Solution Approach 2:
The patent replaces complex mechanical/optical measurement systems with an electronic imaging system. Instead of using diffraction gratings, prisms, or other optical components found in spectrometers, the invention uses a standard color image sensor combined with computational methods to achieve reflectance measurement, substituting physical complexity with electronic and algorithmic processing
2Measurement precision
If specialized high-precision devices are used to determine reflectance, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The patent makes specialized measurement capabilities accessible through standard imaging equipment. By using a color image sensor that can be found in ordinary cameras or smartphones, the system copies the functionality of expert-level spectrometers and makes it available to non-specialized operators through simple image capture and automated processing
Solution Approach 2:
The system performs automated processing of captured images to determine reflectance without requiring operator expertise. The mathematical model and algorithms automatically analyze the images, calculate reflectance values, and provide results, eliminating the need for specialized knowledge in operation while maintaining high measurement precision
3Reliability
If multiple flashes of light with known illuminance are used to solve for reflectance under variable external illuminant, then reliability is improved, but calculation complexity increases
Solution Approach 1:
The patent illuminates the object with multiple flashes of light having known illuminance values before measuring under the external illuminant. This preliminary illumination creates a system of equations with known parameters that can be solved to separate the object's reflectance from the unknown external illuminant, providing reliable results even when the external lighting conditions vary
Solution Approach 2:
The system uses the captured images and the mathematical model to iteratively solve for reflectance and external illuminant characteristics. By incorporating feedback from multiple measurements under different known illuminations, the system refines its calculation to accurately determine reflectance despite varying external conditions, balancing computational complexity with measurement reliability
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 reliable modeling of object reflectance with reduced calculation time and improved precision, making it accessible and efficient for determining uniform diffuse reflectance across various materials and applications.
Implementation Method 1
emission of at least one flash of light illuminating the object, each flash of light being emitted by a source and having a known illuminance in a range of wavelengths
Implementation Method 2
collection of the wave reflected by the object to form at least one image on a sensor
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The invention concerns a method for determining the reflectance of an object (4), the method comprising a step of solving an equation having several unknowns, the equation being obtained from formed images, the reflectance of the object (4) and the illumination of the external light source (6) being two unknowns of the equation. The step of solving the equation comprises: calculating solution points of the equation, interpolating the calculated points by means of an interpolation function, and using at least one of the following approximations to solve the equation: a first approximation according to which each image is derived from the emission of a separate light flash, a second approximation according to which the interpolation function determines the stability points of the equation.