Imaging Device Exposure Adjustment for Spectral Image Accuracy
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Solution Overview
Problem
Conventional exposure adjusting methods for imaging devices are inadequate for generating spectral images, as they adjust exposure time for the entire sensor plane rather than specific areas, leading to reduced detection accuracy and low signal-to-noise ratio in spectral images, especially when dealing with saturated pixels and low luminance values.
Innovation Solution
An imaging device comprising a filter with multiple filter areas of different spectral transmission characteristics, a microlens array, and an exposure adjuster that adjusts the exposure time based on luminance values of spectral images generated from these areas, ensuring appropriate exposure for accurate color detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional exposure adjusting method is applied to adjust exposure for the entire sensor plane, then the exposure is appropriately performed on the entire sensor area, but the exposure time cannot be appropriately adjusted for spectral image areas, leading to reduced detection accuracy and low signal-to-noise ratio
Solution Approach 1:
The sensor plane is divided into multiple spectral image areas corresponding to different filter areas. Each spectral image area is processed independently for exposure adjustment based on its specific luminance characteristics, rather than applying a single exposure setting to the entire sensor plane. This segmentation enables appropriate exposure time adjustment for each spectral image area, improving color detection accuracy.
Solution Approach 2:
Different exposure times are applied to different spectral image areas based on their local luminance characteristics. The exposure adjuster determines appropriate exposure times for each spectral image area individually, allowing each area to have optimized exposure parameters suited to its specific imaging conditions, thereby improving overall detection accuracy.
2Reliability
If exposure time is adjusted for the entire sensor plane, then the overall exposure is balanced, but the signal-to-noise ratio of pixels with low luminance values remains low
Solution Approach 1:
The exposure time is dynamically adjusted for each spectral image area based on its specific luminance characteristics. Rather than using a fixed exposure time for the entire sensor, the system determines appropriate exposure times individually for each spectral image area, enabling optimal signal-to-noise ratio for pixels with low luminance values while maintaining imaging efficiency.
Solution Approach 2:
The exposure adjuster uses luminance information from spectral images as feedback to determine appropriate exposure times. By measuring the actual luminance characteristics of each spectral image area and using this information to adjust exposure settings, the system optimizes the signal-to-noise ratio for low luminance pixels while maintaining overall imaging productivity.
3Measurement precision
If exposure time is extended to improve signal-to-noise ratio for low luminance pixels, then the signal-to-noise ratio improves, but pixels in saturated state increase, reducing detection accuracy
Solution Approach 1:
The sensor plane is divided into multiple spectral image areas, each processed independently for exposure adjustment. This segmentation allows the system to apply different exposure times to different areas based on their specific luminance characteristics, preventing pixel saturation in bright areas while ensuring adequate exposure in dim areas, thereby maintaining color detection accuracy across the entire image.
Solution Approach 2:
Different exposure times are applied to different spectral image areas based on local luminance characteristics. This local optimization prevents overexposure and pixel saturation in bright regions while ensuring sufficient exposure in dim regions, eliminating the need to compromise between these opposing requirements and maintaining high detection accuracy throughout.
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 allows for precise adjustment of exposure time, improving the signal-to-noise ratio and detection accuracy of spectral images, enabling stable color detection by optimizing exposure for each spectral image area.
Implementation Method 1
a filter including a plurality of filter areas having different spectral transmission characteristics
Implementation Method 2
a microlens array including a plurality of microlenses arranged approximately parallel to a light receiving surface of the imaging element
Data Source
AI summary
An imaging device includes a filter, an imaging element, a lens, a spectral image generator, and an exposure adjuster. The filter includes a plurality of filter areas having different spectral transmission characteristics. The imaging element receives light transmitted through the filter and outputs image information. The lens array includes a plurality of lenses arranged approximately parallel to a light receiving surface of the imaging element and is arranged between the filter and the imaging element. The spectral image generator generates a plurality of spectral images respectively corresponding to the plurality of filter areas on the basis of the image information output by the imaging element. The exposure adjuster adjusts an exposure time of the imaging element on the basis of luminance values of the spectral images.