3D Image Acquisition Exposure Setting Optimization
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Solution Overview
Problem
Current 3D imaging technologies face challenges in achieving high dynamic range (HDR) images due to the difficulty in determining appropriate exposure settings, which affects the signal-to-noise ratio (SNR) and accuracy of three-dimensional coordinates in 3D HDR images.
Innovation Solution
A method for determining optimal groups of exposure settings in a 3D image acquisition process by identifying candidate groups, evaluating signal levels, and selecting settings that maximize the number of well-exposed pixels while minimizing exposure costs, thereby enhancing the SNR in both bright and dark regions of the image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If illumination intensity and sensor exposure time are maximized to ensure sufficient light from darker regions, then signal strength in dark regions is improved, but sensor saturation occurs in brighter regions
Solution Approach 1:
The patent divides the imaging task into multiple separate image captures, each with different exposure settings optimized for specific brightness ranges. Instead of attempting to capture the entire dynamic range in a single image, the system segments the exposure parameters into multiple discrete settings (e.g., short, medium, long exposure times) and captures images at each setting. This allows dark regions to be captured with sufficient signal while bright regions are captured at lower exposure to avoid saturation.
Solution Approach 2:
The patent dynamically adjusts exposure settings based on the brightness characteristics of different regions in the scene. The system evaluates the dynamic range requirements and automatically selects appropriate exposure settings for each region or image capture. This dynamic adaptation allows the system to optimize signal strength for dark regions while preventing saturation in bright regions by changing exposure parameters in real-time or between captures.
2Illumination intensity
If multiple images with different exposure times are captured for HDR imaging, then dynamic range is improved, but image acquisition time increases
Solution Approach 1:
The patent performs preliminary evaluation of the scene's dynamic range characteristics before initiating the full HDR imaging sequence. By assessing the brightness distribution and dynamic range requirements in advance, the system can pre-determine the optimal set of exposure settings and acquisition parameters. This preliminary action allows the system to minimize the number of required captures while still achieving the desired dynamic range, thereby reducing total acquisition time.
Solution Approach 2:
The patent systematically varies exposure parameters (exposure time, aperture, ISO) across multiple image captures to optimize dynamic range. The system changes these parameters in a controlled manner, selecting specific discrete values from a predefined set that balances dynamic range coverage with acquisition speed. By optimizing parameter selection rather than using continuous adjustment, the system achieves HDR imaging with minimal time penalty.
3Object-affected harmful factors
If exposure settings are optimized for bright regions, then saturation is avoided, but signal strength in dark regions becomes insufficient
Solution Approach 1:
The patent segments the imaging process into multiple exposure sessions, each optimized for specific brightness ranges. One set of images is captured with short exposure times optimized for bright regions to avoid saturation, while another set uses long exposure times optimized for dark regions to maximize signal strength. This segmentation allows both requirements to be satisfied simultaneously without compromise.
Solution Approach 2:
The patent applies different exposure quality characteristics to different regions of the scene. Bright regions are captured with short exposure settings that prevent saturation, while dark regions are captured with long exposure settings that provide sufficient signal. The system then combines these region-specific captures into a unified HDR image, allowing each region to have its optimal quality characteristics preserved.
4Loss of time
If a single exposure setting is used, then acquisition time is minimized, but dynamic range is insufficient for scenes with large brightness variations
Solution Approach 1:
The patent segments the exposure parameter space into multiple discrete settings and captures images at each setting. This segmentation enables the system to cover a broader dynamic range than a single exposure setting could provide, while maintaining relatively fast acquisition by using optimized exposure time values. The segmented approach allows parallel or sequential capture of multiple exposure images without requiring excessive time.
Solution Approach 2:
The patent implements dynamic exposure adjustment based on scene characteristics and real-time or pre-computed brightness information. The system adapts exposure settings dynamically to match the dynamic range requirements of the scene, selecting from a predefined set of optimized exposure values. This dynamic adaptation enables HDR imaging with minimal time penalty by avoiding unnecessary exposure settings for regions that don't require them.
Data Source
AI summary
A method for determining one or more groups of exposure settings to use in a 3D image acquisition process carried out with an imaging system, the 3D image acquisition process comprising capturing one or more sets of image data on the image sensor using the respective groups of exposure settings, wherein the one or more sets of image data are such as to allow the generation of one or more 3D point clouds defining the three-dimensional coordinates of points on the surface(s) of one or more objects being imaged, each group of exposure settings specifying a value for one or more parameters of the imaging system, wherein the method comprises identifying one or more candidate groups of exposure settings and selecting from the candidate groups of exposure settings, one or more groups of exposure settings that satisfy one or more optimization criteria.