Microscope Illumination Intensity Control for High Dynamic Range Imaging

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Solution Overview

Problem

Existing methods for achieving high dynamic range images, such as varying exposure time or aperture, result in limitations like frame rate drops or chip noise, and laser-based systems are complex and sensitive to surface finishes, making them unsuitable for color imaging.

Innovation Solution

A microscope using an incoherent light source to illuminate an object at different light intensity levels, capturing low dynamic range images with a constant recording parameter, and combining these images to generate a high dynamic range synthesized image without adjusting exposure time, aperture, or sensitivity, thus maintaining a consistent frame rate and avoiding complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If exposure time is increased to obtain HDR image, then dynamic range is improved, but frame rate drops

Engineering Contradiction:
Improvedynamic rangeVSAvoidframe rate
Core Design Contradiction:
Illumination intensityVSProductivity

Solution Approach 1:

The patent applies dynamics by making the illumination intensity variable rather than fixed. The system dynamically adjusts the light source intensity to capture multiple images at different brightness levels, enabling HDR synthesis without requiring variable exposure times that would reduce frame rate. This is achieved through real-time control of the illumination source to create diverse light conditions for image capture.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the illumination intensity parameter of the light source to capture images at different brightness levels. Instead of changing exposure time (which affects frame rate), the system modifies the illumination parameter directly, allowing multiple images to be captured quickly under varying light conditions and then synthesized into an HDR image.

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If aperture size is reduced to control image brightness, then dynamic range is improved, but image resolution drops

Engineering Contradiction:
Improveimage brightness controlVSAvoidimage resolution
Core Design Contradiction:
Illumination intensityVSMeasurement precision

Solution Approach 1:

The patent changes the illumination intensity parameter instead of the aperture parameter. By adjusting the light source brightness rather than the aperture size, the system achieves different image brightness levels without restricting the aperture, thereby maintaining high image resolution while still capturing diverse brightness information for HDR synthesis.

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If sensitivity (gain) is increased to capture dark images, then dynamic range is improved, but chip noise increases causing brightness fluctuations

Engineering Contradiction:
ImprovesensitivityVSAvoidbrightness stability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent applies preliminary action by capturing a reference image under the same illumination conditions before synthesizing the HDR image. This reference image is used to calculate scaling factors that compensate for brightness fluctuations caused by high sensitivity settings. By preparing this reference data in advance, the system can correct noise-induced variations during the synthesis process, improving brightness stability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses feedback by calculating scaling factors from a reference image and applying them to correct brightness fluctuations in the synthesized HDR image. The system continuously monitors brightness variations and adjusts the synthesis process accordingly, using the reference image as a feedback mechanism to maintain brightness stability even when high sensitivity settings are used.

Inventive Principle:
Principle #23Feedback

4Illumination intensity

If laser illumination is used to increase dynamic range, then dynamic range is improved, but system complexity and sensitivity to surface finish increase

Engineering Contradiction:
Improvedynamic rangeVSAvoidillumination system complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent replaces the expensive and complex laser illumination system with a simpler, more economical light source. Instead of using coherent laser light that requires complex optical systems and is sensitive to surface properties, the patent employs a standard incoherent light source that is easier to implement, less sensitive to surface finish variations, and more suitable for color imaging applications.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent substitutes the mechanical/optical complexity of a laser-based illumination system with a simpler electrical control system. Instead of using laser optics and coherent light properties, the system uses electrically controllable LED or lamp-based illumination that can be adjusted in intensity through simple electrical signals, reducing mechanical and optical complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3204812B1Microscope and method for obtaining a high dynamic range synthesized image of an object
Publication Date: 2023.12.06 LEICA MICROSYSTEMS (SCHWEIZ) AG
  • EP3204812B1 patent drawingFigure 1
  • EP3204812B1 patent drawingFigure 2
  • EP3204812B1 patent drawingFigure 3

AI summary

A microscope (10) for obtaining a high dynamic range synthesized image (21) of an object (12) from a plurality of low dynamic range input images (19) comprises a controller (14), an incoherent light source (16) for illuminating the object (12) at different light intensity levels, and a recording device (18) for recording the plurality of low dynamic range input images (19), wherein each of the low dynamic range input images (19) is recorded at a different light intensity level. The controller (14) is configured to control the recording device (18) such that during recording of the series of the low dynamic range images the recording parameters for obtaining the plurality of low dynamic range input images (19) are kept constant.