Image Sensor Color Filter Calibration via Baseline Comparison
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Solution Overview
Problem
Solid-state image capture devices in consumer electronics often exhibit color balance variations due to manufacturing differences, leading to inconsistent color representation across devices of the same make and model, particularly in red and infrared content.
Innovation Solution
An apparatus and method for calibrating image capture devices by comparing the response of their color filters to a baseline filter, adjusting the pixel and/or pixel processing path to specific wavelengths like IR, allowing for calibration without disassembly, using a system with a calibration pattern, memory, and central processing unit to store and apply correction values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If solid-state image capture devices are manufactured using semiconductor fabrication principles, then cost effectiveness is improved, but color balance consistency deteriorates due to manufacturing variations
Solution Approach 1:
The patent applies preliminary action by pre-storing the color response characteristics of baseline filters in the memory device before actual image capture. This allows the system to pre-compute and have ready the correction factors needed for calibration, eliminating the need for real-time complex calculations and enabling consistent color correction across devices manufactured with varying tolerances
Solution Approach 2:
The patent implements parameter changes by adjusting the color response parameters of individual pixels based on comparison with baseline filter responses. The system modifies the stored color response data for each pixel, transforming the raw manufacturing-varied data into calibrated data that matches the baseline color balance characteristics, thereby compensating for manufacturing variations
2Ease of operation
If color calibration is performed after manufacturing, then device assembly simplicity is improved, but calibration precision may deteriorate without disassembly access to internal components
Solution Approach 1:
The patent applies universality by designing a calibration system that works through the existing device interface without requiring disassembly. The same image capture device that captures images also performs its own calibration by comparing its output against stored baseline responses, making the calibration function universal and accessible without modifying the device structure
Solution Approach 2:
The system implements self-service calibration where the image capture device calibrates itself by comparing its pixel responses against pre-stored baseline filter responses. The device uses its own resources (memory, processor, and existing optical path) to perform calibration without external intervention or disassembly, maintaining both ease of operation and adequate precision
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
Ensures consistent color response across image capture devices, reducing color variations and improving image quality by aligning the device's color filter response with an ideal standard, even after manufacturing, without requiring device disassembly.
Implementation Method 1
at least one color filter optically coupled to at least one array of pixels
Data Source
AI summary
An apparatus and method are disclosed for calibrating image capture devices, such as the type used in electronic devices. In some embodiments, the electronic device may include at least one array of pixels and a memory coupled to the at least one array of pixels. The electronic device may further include a central processing unit (CPU) coupled to the memory and at least one color filter optically coupled to the at least one array of pixels. The memory may further include one or more storage locations that include a response of the at least one color filter to one or more predetermined wavelengths from a target test source, as well as, one or more storage locations that include a response of one or more baseline color filters.