Dynamic Exposure Control for Biological Sample Imaging
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Solution Overview
Problem
Current imaging techniques for biological samples, such as bacterial colonies on agar growth plates, face challenges in detecting subtle contrast changes and distinguishing between colonies, media, and background, leading to difficulties in identifying microbial growth.
Innovation Solution
A system and method that iteratively adjusts exposure time to optimize the signal-to-noise ratio (SNR) for each pixel, using calibration data to determine initial exposure times and iteratively refine them to prevent saturation, allowing for improved contrast and detection of early microbial growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If HDR imaging technique is used to capture greater dynamic range, then both dark and light spots are preserved without compromising quality, but the intensity of the image is distorted
Solution Approach 1:
The patent changes the parameter of exposure time dynamically for different regions of the image. By supervising the image acquisition process and adjusting exposure time based on local luminosity measurements, the system captures adequate detail in both dark and light areas without applying the intensity distortion characteristic of HDR techniques.
2Measurement precision
If iterative image acquisition with multiple exposure times is performed to optimize SNR, then detection precision of subtle changes is improved, but acquisition time increases
Solution Approach 1:
The patent performs preliminary actions by measuring luminosity in different regions before final image acquisition. This preliminary luminosity measurement allows the system to pre-determine optimal exposure times for different regions, enabling subsequent rapid acquisition of images with appropriate exposure settings without iterative adjustments during the actual imaging process.
Solution Approach 2:
The patent segments the image into multiple regions with different luminosity characteristics and applies different exposure times to each segment. This segmentation allows the system to optimize SNR for each region independently while maintaining overall acquisition efficiency, rather than using a single exposure time for the entire image.
3Productivity
If fixed exposure time is used for image acquisition, then acquisition speed is maintained, but subtle contrast changes and early microbial growth are not detected
Solution Approach 1:
The patent transitions from fixed exposure time to dynamic exposure time adjustment. By supervising the image acquisition process and adapting exposure times based on measured luminosity in different regions, the system maintains high acquisition speed while improving contrast detection capability. The dynamic adjustment occurs through pre-measurement and planning rather than slow iterative adjustments during imaging.
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 enhances image quality by improving SNR, enabling the detection of small colonies and subtle changes, providing high-confidence images with optimal exposure times that enhance the visibility of microbial growth.
Implementation Method 1
The bacterial colonies reflect the light differently from the agar
Implementation Method 2
the number of photons reaching the scene per unit time and unit area
Data Source
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AI summary
An image capture system and method for imaging biological samples disposed in culture media supported by a plate (610). The system has a calibration module (110), an image acquisition module (120) and an image presentation module (130). When the system receives a culture plate for imaging, default values for the culture plate and media are used to begin image acquisition at a given time. The captured image is then used to create a pixel by pixel map of the image. The system inspects the pixel-by-pixel map for saturated pixels and for signal to noise ratio and acquires a new image if the number of saturated pixels is at or above a predetermined threshold or the signal to noise ratio for the pixel is below a predetermined threshold. From this inspection a new value of photon flux and/or exposure time is determined and a new image is captured using the new value and the steps are repeated. Upon a determination that a predetermined threshold signal to noise ratio has been obtained for the non-saturated pixels, or when the predetermined upper threshold for the time interval for image acquisition is elapsed the system provides a final image for the given time.