Infrared PDAF Sensor Depth Sensing with Narrowband Filters
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Solution Overview
Problem
Existing depth sensing systems face limitations in outdoor operations due to noise in bright conditions and require large device dimensions for calibration, with passive systems failing in low light and untextured regions, and active systems suffering from signal-to-noise ratio degradation.
Innovation Solution
An infrared phase detection autofocus (PDAF) sensor with focus pixels and narrowband filters is used to generate combined depth data by integrating active and passive depth data, reducing calibration requirements and device dimensions, and enabling capture of IR, NIR, and visible light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If active depth systems transmit infrared or near-infrared light, then depth sensing works well in low visible light conditions, but signal-to-noise ratio decreases in bright outdoor conditions due to ambient light
Solution Approach 1:
The patent uses narrowband filters with specific bandwidths (e.g., 10nm, 20nm, 30nm) to selectively transmit infrared wavelengths while blocking visible light. By adjusting the filter bandwidth and central wavelength parameters, the system optimizes performance for different lighting conditions - narrower bandwidths reduce ambient light noise in bright conditions while maintaining sufficient signal transmission.
Solution Approach 2:
The patent introduces narrowband infrared filters as intermediary components between the infrared light source and the depth sensing camera sensor. These filters act as mediators that selectively pass the transmitted infrared wavelengths while blocking ambient visible light and other unwanted wavelengths, thereby improving signal-to-noise ratio in bright outdoor conditions.
2Illumination intensity
If passive depth systems use stereo or multiple camera systems, then depth sensing works well in daylight, but device dimensions increase due to wide baseline requirements
Solution Approach 1:
The patent merges active infrared illumination with passive depth sensing capabilities into a single integrated system. By combining the infrared projector, narrowband filters, and depth sensing camera into one unit, the system eliminates the need for separate stereo camera systems with wide baselines, thereby reducing device dimensions while maintaining daylight performance.
Solution Approach 2:
The patent creates a multi-functional depth sensing system that can operate in both active (infrared illumination) and passive (ambient light) modes using the same sensor and optical path. This universal system eliminates the need for separate stereo camera systems, reducing device size while maintaining capability across different lighting conditions.
3Measurement precision
If active depth systems use structured light or time-of-flight, then depth data can be generated, but calibration requirements increase device complexity
Solution Approach 1:
The patent implements self-calibration capabilities where the system uses its own infrared projector and sensor to automatically determine intrinsic parameters and extrinsic transformations. The narrowband filters ensure that only the transmitted infrared wavelengths are measured, eliminating the need for external calibration targets or complex calibration procedures, thereby reducing device complexity while maintaining depth data accuracy.
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 depth data accuracy and reduces device size by using focus pixels for calibration and narrowband filters to enhance signal quality in various lighting conditions, providing robust depth sensing across different environments.
Implementation Method 1
The one or more filters may include one or more of a narrowband filter
Implementation Method 2
infrared phase detection autofocus (PDAF) sensor configured to receive reflections of the source light off of objects within the scene
Implementation Method 3
receive reflections of the source light off of objects within the scene
Data Source
AI summary
Various embodiments are directed to a device including an infrared phase detection autofocus (PDAF) sensor. The device may include a projector configured to transmit a source light onto a scene. The device may include the infrared PDAF sensor configured to receive reflections of the source light off of objects within the scene. The infrared PDAF sensor may include a first set of pixels including focus pixels. The device may include a processor coupled to the infrared PDAF sensor and a memory. The processor may be configured to generate first depth data based on the received reflections of the source light. The processor may be configured to generate second depth data based on signals generated from corresponding pairs of the focus pixels. The processor may be configured to generate combined depth data based on the first depth data and the second depth data.