Photometric Sensor Infrared Subtraction for Color Accuracy
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Solution Overview
Problem
Conventional image capturing apparatuses face challenges in specific color detection and exposure amount determination due to sensitivity differences between visible and infrared light ranges, leading to hue shifts and focus shifts under different light sources.
Innovation Solution
An image capturing apparatus with a photometric sensor comprising two pixel groups, one sensitive primarily to visible light and the other to infrared light, allows for infrared light subtraction processing to calculate evaluation values, enabling accurate light source determination and specific color detection by adjusting pixel signals to account for infrared light components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a photometric sensor sensitive to both visible and infrared light is used for light source determination, then infrared light detection capability is improved, but hue accuracy deteriorates due to infrared contamination in visible light color filters
Solution Approach 1:
The photometric sensor is segmented into two distinct pixel groups: first pixel groups with visible light color filters (R, G, B) and second pixel groups without color filters that are sensitive to both visible and infrared light. This segmentation allows independent processing of visible and infrared light components, enabling the system to utilize infrared information for light source determination while maintaining accurate color measurement through the filtered first pixel groups.
Solution Approach 2:
The invention extracts the infrared light component by utilizing the difference in output signals between the first pixel groups (with color filters) and second pixel groups (without color filters). The second pixel groups capture both visible and infrared light, while the first pixel groups capture only visible light. By subtracting the visible light component from the second pixel group output, the pure infrared light component is extracted for light source determination, preventing infrared contamination from affecting color accuracy.
2Adaptability or versatility
If color filters sensitive to both visible and infrared light are used, then infrared light detection is improved, but color detection accuracy deteriorates due to hue shifts under different light sources
Solution Approach 1:
The sensor is divided into specialized regions: first pixel groups equipped with visible light color filters for accurate color detection, and second pixel groups without color filters for infrared light detection. This functional segmentation ensures that color filters are not exposed to infrared light that would cause hue shifts, while still enabling infrared detection through the second pixel groups.
Solution Approach 2:
The infrared light component is extracted from the second pixel group output by subtracting the visible light component. This extracted infrared signal is then used for light source determination, while the first pixel groups provide clean visible light color information without infrared contamination, maintaining color detection accuracy under various lighting conditions.
3Device complexity
If a single pixel group sensitive to both visible and infrared light is used, then device complexity is reduced, but measurement precision deteriorates due to inability to separately detect visible and infrared components
Solution Approach 1:
The photometric sensor is segmented into two types of pixel groups within a single sensor array: first pixel groups with visible light color filters and second pixel groups without color filters. This segmentation enables separate detection of visible and infrared light components using a compact integrated sensor structure, avoiding the need for multiple separate sensors while maintaining detection precision.
Solution Approach 2:
The invention merges the functions of visible light color detection and infrared light detection into a single photometric sensor by incorporating both first and second pixel groups. This integration achieves separate detection precision for visible and infrared components while maintaining device compactness and reducing overall system complexity compared to using multiple independent sensors.
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 effectively suppresses hue shifts and focus shifts by aligning photometric and exposure calculations with the spectral characteristics of the image sensor, enabling precise light source determination and specific color detection across various lighting conditions.
Implementation Method 1
a first pixel group whose sensitivity to visible light is higher than a sensitivity thereof to infrared light, and a second pixel group that has a sensitivity to infrared light and has a lower sensitivity to visible light than that of the first pixel group
Data Source
AI summary
An image capturing apparatus includes a photometric sensor having a plurality of pixels having a sensitivity to an infrared light range and a visible light range, an acquisition unit that divides the photometric sensor into a plurality of pixel groups and acquires image information of the infrared light range and image information of the visible light range in each of the plurality of pixel groups, a subtraction unit that generates a visible light component obtained by subtracting an infrared light component that is based on the image information of the infrared light range from the image information of each of the plurality of pixel groups, and a processing unit that performs at least one of light source determination processing, specific color detection processing, and exposure amount determination processing, using the visible light component generated by the subtraction unit.