Smartphone Color Calibration with Arbitrary Cases
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Solution Overview
Problem
Current color matching technologies require extensive calibration data sets and are impractical for use with phone cases, as they alter the distance between the camera and color targets, leading to inconsistent color measurements.
Innovation Solution
A two-step calibration method for smartphones with phone cases using one to three calibration colors, adjusting exposure time and applying linear or higher-order fitting to match measurements with and without a case, reducing the need for full color calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If full color calibration using hundreds to thousands of calibration colors is performed, then measurement precision is improved, but device complexity and time consumption increase significantly
Solution Approach 1:
The calibration process is segmented into two distinct steps: (1) exposure time adjustment using white calibration targets, and (2) raw count correction using linear or higher order fitting with one to three calibration color patches. This segmentation allows each step to be optimized independently, reducing overall complexity while maintaining precision.
Solution Approach 2:
Instead of requiring full color calibration with hundreds to thousands of calibration colors, the invention uses a partial approach with only one to three calibration color patches. This partial action is sufficient to achieve the desired measurement precision when combined with the exposure time adjustment step.
2Measurement precision
If calibration is performed without phone cases, then measurement consistency is improved, but adaptability to real-world usage decreases
Solution Approach 1:
The calibration process performs preliminary actions by first adjusting exposure time using white calibration targets measured both with and without the phone case, then using these adjusted parameters to correct raw counts for all subsequent measurements. This preliminary calibration establishes a baseline that accounts for the phone case's impact.
Solution Approach 2:
The invention changes the exposure time parameter based on measurements taken with and without the phone case. By calculating an optimized exposure time that compensates for the phone case's effect on light transmission, the system maintains measurement consistency across different usage conditions.
3Measurement precision
If exposure time is adjusted for each calibration, then measurement accuracy is improved, but calibration time increases
Solution Approach 1:
The system performs preliminary exposure time adjustment using white calibration targets, then stores the optimized exposure time parameters for use in subsequent measurements. This preliminary action eliminates the need for repeated exposure time adjustments during normal operation, reducing overall time loss.
Solution Approach 2:
The calibration process uses feedback from measurements taken with and without the phone case to calculate an optimized exposure time. This feedback mechanism allows the system to automatically adjust exposure parameters and store them for future use, reducing the time needed for repeated calibrations.
Data Source
AI summary
In one or more implementations, the apparatus, systems and methods disclosed herein are directed to calibrating a smart phone with an arbitrary phone case for color lookup applications, wherein the calibration process includes obtaining, with the smartphone without the case equipped, a first measurement data set that includes at least one measurement of each of a black, white and grey calibration target; obtaining, with the smartphone with the case equipped, at least three exposure measurements of a white calibration target at least three different exposure times; calculating an optimized exposure time using at least the at least three exposure measurements; obtaining, with the smartphone with the case equipped, a second measurement data set that includes at least one measurement of each of a black, white and grey calibration target at the optimized exposure time; generating fitting parameters from the first and second measurement datasets; and storing the generated fitting parameters and optimized exposure time in at least one of a local or remote data storage device.