Single-Camera Depth Imaging via Temporal Light Pulse Segmentation
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Solution Overview
Problem
Existing methods for producing images with associated depth information typically require multiple cameras, which can be cumbersome and less effective in conditions like fog, whereas a single-camera solution is desired for applications such as stereogram creation and obstacle detection.
Innovation Solution
A method using a pulsed light source and an image sensor with pixels that accumulate charge, emitting N successive trains of light pulses with controlled temporal offsets to determine depth levels, allowing each pulse train to observe points at specific distances, thereby generating images with embedded depth information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple cameras are used to obtain depth information, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the depth measurement process by dividing the time domain into multiple discrete integration windows, each corresponding to a specific distance range. Instead of using multiple cameras simultaneously, a single camera captures depth information at different time intervals, with each time slot dedicated to measuring reflections from objects at specific distances. This temporal segmentation allows one camera to perform the function that would otherwise require multiple cameras.
Solution Approach 2:
The patent employs periodic pulsed light emission with regular time intervals between pulses. Each pulse triggers a measurement cycle, and the camera performs repeated measurements at periodic time slots. This periodic action enables the single camera to accumulate depth information for multiple distance ranges over successive cycles, effectively replacing the need for multiple simultaneous cameras while maintaining measurement precision.
2Device complexity
If a single camera is used to reduce device complexity, then measurement precision deteriorates
Solution Approach 1:
The patent transitions from spatial dimension to temporal dimension by introducing time as an additional measurement parameter. Instead of using multiple cameras positioned at different spatial locations, the system uses a single camera that measures at different time points. Each time slot corresponds to a specific distance range, creating a time-distance mapping that preserves measurement precision while reducing device complexity.
Solution Approach 2:
The patent changes the measurement parameter from spatial configuration (multiple cameras at different positions) to temporal configuration (single camera at multiple time points). By varying the integration time slots and their offsets relative to light pulse emissions, the system extracts depth information for multiple distance ranges using the same camera, thereby maintaining measurement accuracy while simplifying the device structure.
3Measurement precision
If light pulse duration is shortened to improve depth resolution, then productivity decreases
Solution Approach 1:
The patent implements dynamic adjustment of integration time slot durations and offsets based on the desired depth resolution and measurement range. The system adaptively configures the timing parameters for each measurement cycle, allowing optimization between depth resolution and acquisition speed. This dynamic parameter adjustment enables the system to maintain high depth resolution with short effective integration windows while preserving overall productivity through efficient time management.
Solution Approach 2:
The patent performs preliminary configuration of multiple integration time slots with predetermined offsets before actual depth measurement begins. The timing parameters are pre-calculated and set based on the expected distance ranges and required resolution, allowing the system to execute measurements without real-time parameter adjustments. This preliminary setup enables fast, high-resolution depth acquisition by eliminating computational delays during the measurement process.
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
Enables precise determination of depth information using a single camera, enhancing applications like stereogram creation and obstacle detection, especially in foggy conditions, by accurately associating distance with each pixel in the image.
Implementation Method 1
each pixel comprising a photodiode
Data Source
AI summary
The invention relates to the production of images associating with each point of the image a depth, i.e. a distance between the observed point and the camera that produced the image.A light source emits N trains of light pulses. For each train of rank I=1 to N, charge is integrated in a short time slot of length Tint that starts with a temporal offset ti relative to the pulse, this temporal offset representing a journey time of the light pulse between the light source and the sensor after reflection from a point placed a distance di from the sensor. The temporal offset ti is the same for all the light pulses of the ith pulse train but the temporal offsets ti of the N trains are different from one another in order to correspond to various distances relative to the sensor. The charge photogenerated by the pulses of a given train is accumulated; then the accumulated charge is read in order to produce an image of rank i representing the pixels located at the distance di. The observation of a scene comprises producing N different images by virtue of which it is possible to associate a distance with each pixel.