Steerable Illumination for Zoned Time-of-Flight Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Three-dimensional (3D) time-of-flight cameras face challenges with signal-to-noise ratio (SNR) degradation due to high ambient light levels, leading to degraded distance accuracy and range, as the ambient component overwhelms the reflected component, and existing solutions like narrowing the field of view or increasing illumination power have drawbacks.
Innovation Solution
A zoned time-of-flight imaging system with a steerable illumination module that focuses light into a smaller angular extent within the sensor's field of view, allowing for more intense illumination and improved SNR, using a combination of diffusing and steering elements to direct the light beam to specific regions of interest, thereby enhancing depth imaging accuracy and range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If illumination power is increased to improve SNR, then signal-to-noise ratio improves, but power consumption increases and light source cost increases
Solution Approach 1:
The patent applies local quality by directing illumination light to specific zones or regions of interest within the scene rather than uniformly illuminating the entire field of view. This is achieved through optical elements such as diffractive optical elements, refractive elements, or reflective elements that shape and direct the light distribution spatially, concentrating illumination power where needed to improve SNR for specific depth ranges while reducing overall power consumption.
Solution Approach 2:
The patent segments the field of view into multiple zones with different illumination requirements. Each zone can be independently illuminated with appropriate power levels, allowing the system to optimize SNR for specific depth ranges or regions of interest without increasing overall power consumption. The illumination module can selectively activate different zones based on scene requirements.
2Measurement precision
If field of view is narrowed to improve SNR, then signal-to-noise ratio improves, but scanning is required to capture entire scene
Solution Approach 1:
The patent segments the field of view into multiple zones that can be simultaneously illuminated with different power levels. This allows the entire scene to be captured in a single frame without scanning, while maintaining improved SNR in specific zones of interest through targeted illumination. The optical elements create multiple illumination beams or patterns that cover different spatial regions concurrently.
Solution Approach 2:
The patent transitions from temporal scanning (one dimension) to spatial zoned illumination (adding spatial dimension). Instead of sequentially scanning different regions over time, the system uses optical elements to create multiple spatially distinct illumination zones that are active simultaneously, capturing the entire scene in one shot while maintaining high SNR in specific regions.
3Length of stationary object
If illumination is increased to improve depth imaging range, then range improves, but power consumption increases
Solution Approach 1:
The patent applies local quality by directing enhanced illumination power to specific depth zones or distance ranges where imaging is needed. Optical elements such as diffractive or refractive components create illumination patterns that extend the effective imaging range to specific distances without requiring uniform high-power illumination across all ranges, thereby reducing overall power consumption while extending functional range.
Solution Approach 2:
The patent enables dynamic zoned illumination where the illumination pattern can be adjusted based on scene requirements. The system can selectively enhance illumination for specific depth ranges or regions of interest, allowing the depth imaging range to be dynamically optimized for different operating conditions without continuously increasing overall power consumption.
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 improves ambient performance, range, and reduces jitter by selectively illuminating regions of interest, allowing for more efficient use of laser light and longer depth imaging range, while maintaining compact and low-cost optical architectures.
Implementation Method 1
a diffusing element operative to diffuse light emitted from the light source
Implementation Method 2
a steering element operative to steer light emitted from the light source
Implementation Method 3
a steering element operative to steer light emitted from the light source
Data Source
AI summary
A zoned time-of-flight (ToF) arrangement includes a sensor and a steerable light source that produces an illumination beam having a smaller angular extent than the field of view (FoV) of the sensor. The illumination beam is steerable within the sensor's FoV to optionally move through the sensor's FoV or dwell in a particular region of interest. Steering the illumination beam and sequentially generating a depth map of the illuminated region permits advantageous operations over ToF arrangements that simultaneously illuminate the entire sensor's FoV. For example, ambient performance, maximum range, and jitter are improved. Multiple steering alternative configurations are disclosed, including mechanical, electro optical, and electrowetting solutions.