Autofocusing Method for Spectroscopic Camera Using Wavelength Selection
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Solution Overview
Problem
Spectroscopic cameras using variable filters face time-consuming focus adjustment due to the need to set and measure multiple wavelengths, which is inefficient compared to contrast-based camera apparatuses that can capture R, G, and B photometric data in a single frame.
Innovation Solution
An autofocusing method that involves causing light with multiple wavelengths to sequentially pass through a spectral filter, acquiring image frames, selecting a wavelength with the largest statistical value (average, median, or mode) in a small region, and determining the focusing point in a wider region using the selected wavelength, thereby optimizing focus adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a spectroscopic camera uses a variable filter to perform spectrometric measurement at multiple wavelengths, then spectral measurement capability is improved, but focus adjustment time increases significantly
Solution Approach 1:
The patent divides the image area into two regions: a first region (smaller area) for wavelength selection and a second region (larger area) for focus determination. This segmentation allows the system to perform focus adjustment using only a portion of the captured frames, reducing the overall time required while maintaining spectral measurement capability.
Solution Approach 2:
The patent applies partial action by selecting a single wavelength based on statistical values from the first region, rather than processing all wavelengths across the entire image. This partial processing approach significantly reduces the time required for focus adjustment while still enabling accurate spectral measurements at the selected wavelength.
2Measurement precision
If focus adjustment is performed by maximizing contrast across the entire frame, then focusing accuracy is improved, but processing time increases
Solution Approach 1:
The patent segments the image processing task by first determining wavelength based on statistical values in a small first region, then performing focus determination in a second region. This segmentation reduces the amount of data that needs to be processed for each step, improving processing speed while maintaining accuracy.
Solution Approach 2:
The patent performs preliminary wavelength selection based on statistical values (average, median, or mode) from the first region before proceeding to focus determination. This preliminary action narrows down the processing scope, allowing faster subsequent focus adjustment without sacrificing accuracy.
3Measurement precision
If multiple wavelengths are measured sequentially through a spectral filter, then spectral resolution is improved, but measurement speed decreases
Solution Approach 1:
The patent uses partial action by selecting a single representative wavelength from multiple captured frames based on statistical analysis of a small first region. This approach maintains spectral resolution by capturing multiple wavelengths sequentially, but improves measurement speed by performing focus and wavelength determination on only a portion of the data.
Solution Approach 2:
The patent changes the parameter used for wavelength selection from traditional contrast-based methods to statistical value-based methods (average, median, or mode of pixel values). This parameter change enables faster identification of the optimal wavelength while maintaining spectral measurement quality.
Data Source
AI summary
An autofocusing method includes causing light having n wavelengths different from one another to sequentially pass through a spectral filter and acquiring n image frames corresponding to the n wavelengths, n being an integer greater than or equal to two, selecting a wavelength corresponding to the image frame having the largest statistical value from the n image frames, the statistical value being one of the average, median, and mode of class values of pixels contained in a first region out of entire measurement pixels in each of the image frames, and determining a focusing point in a second region wider than the first region out of the entire measurement pixels while causing the light having the selected wavelength to pass through the spectral filter.