Dual-Sensor HDR Image Acquisition via Beam Splitting
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Solution Overview
Problem
Current image acquisition systems face challenges in achieving a wide dynamic range without saturating in high luminance conditions while maintaining resolution, often degrading the signal-to-noise ratio and requiring complex processing or increased latency.
Innovation Solution
An image acquisition system utilizing two sensors with identical spectral response curves, where the irradiance is split into fractions and integration times are controlled to optimize dynamic range and resolution, allowing for high-quality image merging without saturation and increased contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If successive images are captured with various integration times to achieve high dynamic range, then the dynamic range is improved, but the overall acquisition time is considerably increased
Solution Approach 1:
The incident beam is segmented into two separate beams using separation means (beam splitter), with each beam directed to a different sensor. This allows simultaneous capture of images with different integration times, resolving the time penalty associated with sequential capture while maintaining high dynamic range capability.
Solution Approach 2:
The solution transitions from temporal multiplexing (sequential capture in time) to spatial multiplexing (parallel capture using two sensors). By adding the spatial dimension with a second sensor, the system achieves high dynamic range without the time penalty of sequential acquisition.
2Illumination intensity
If a mixed matrix with small and large pixels is used to capture high dynamic range, then the dynamic range is improved, but the overall resolution of the matrix is reduced
Solution Approach 1:
Instead of mixing pixel sizes within a single sensor matrix, the solution segments the optical path to direct different portions of the incident beam to two separate sensors with identical pixel matrices. This preserves the resolution of both sensors while achieving high dynamic range through differential integration times.
Solution Approach 2:
The system applies local quality by assigning different integration times to different sensors based on their respective roles: one sensor uses long integration time for low luminance regions while the other uses short integration time for high luminance regions, optimizing each sensor's performance for its specific function.
3Illumination intensity
If pixels with three or more transistors using logarithmic function are used, then the dynamic range is improved, but the spatial noise is increased and complex post-processing is required
Solution Approach 1:
The system uses two sensors with identical spectral response curves and homogeneous pixel structures, avoiding the need for complex logarithmic transformations. The high dynamic range is achieved through homogeneous linear response sensors operating at different integration times, simplifying the merging process and reducing post-processing complexity.
4Illumination intensity
If two cameras disposed adjacent to one another with different integration times are used, then the dynamic range is improved, but the resolution is degraded owing to correlation defects and parallax
Solution Approach 1:
The system merges images from two sensors that share a common optical path and focusing optics, ensuring perfect spatial alignment. This eliminates correlation defects and parallax issues that plague dual-camera systems with separate optical paths, while maintaining high resolution through precise image registration.
Solution Approach 2:
A single set of focusing optics acts as an intermediary, directing light to both sensors through separation means. This shared optical path ensures that both sensors receive perfectly correlated images from the same scene, eliminating parallax and correlation defects that occur when two separate cameras are used.
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 system achieves a dynamic range greater than 160 dB with high resolution and reduced latency, preserving intrinsic sensor performance and avoiding parallax issues, enabling real-time image sequence capture with improved reactivity to luminance changes.
Implementation Method 1
separation means separating the irradiance of the beam coming from the focussing optics into first and second predetermined fractions, the separation means furthermore orienting the first fraction of the beam irradiance coming from the focussing optics towards the first sensor and the second fraction of the irradiance of the beam coming from the focussing optics towards the second sensor
Data Source
AI summary
An image acquisition system comprises: a single set of focussing optics focussing an incident beam from a scene to be imaged on a first sensor and a second sensor exhibiting identical spectral response curves; followed by separation means separating the irradiance of the beam coming from the focussing optics into first and second predetermined fractions, the separation means orienting the first fraction towards the first sensor and the second fraction towards the second sensor; control means for controlling a first acquisition time of the scene to be imaged by the first sensor to obtain a first image and/or a second acquisition time of the scene to be imaged by the second sensor to obtain a second image; and merging means that merge the first image coming from the first sensor and the second image coming from the second sensor to generate a final image.