TOF Image Sensor Pixel Switching for Multi-Range Distance Sensing
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Solution Overview
Problem
Existing image sensors struggle to efficiently measure distances to target objects with varying ranges while balancing spatial and temporal resolution and power consumption.
Innovation Solution
An image sensing device with a pixel array comprising both direct and indirect pixels, each using different Time of Flight (TOF) methods, allows for selective activation based on distance to optimize measurement performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pixel array is used for TOF distance sensing, then the device structure is simple, but the spatial resolution and measurement precision deteriorate across varying distance ranges
Solution Approach 1:
The pixel array is divided into multiple types of pixels (first pixels and second pixels) with different TOF measurement characteristics. Each pixel type is optimized for specific distance ranges or measurement requirements, allowing the system to segment the measurement space and achieve high precision across varying distances without requiring an overly complex single-array design
Solution Approach 2:
Different regions or types of pixels within the array are assigned different functional qualities - first pixels optimized for certain distance ranges and second pixels for others. This local differentiation allows each pixel type to excel at its designated measurement range, improving overall spatial resolution and measurement precision while maintaining a manageable device structure
2Measurement precision
If high-resolution pixels are activated for all distance ranges, then the spatial resolution is improved, but the power consumption increases
Solution Approach 1:
The system dynamically selects and activates appropriate pixel types based on the measured distance to the target object. When the target is within a certain distance range, first pixels are activated; when beyond that range, second pixels are activated. This dynamic adaptation ensures high spatial resolution is maintained only when necessary, significantly reducing overall power consumption compared to continuously activating all high-resolution pixels
Solution Approach 2:
The system changes operational parameters by switching between different pixel types with different power consumption characteristics. First pixels may be optimized for lower power consumption at closer ranges, while second pixels provide higher resolution at longer ranges. By changing which pixel type is active based on distance parameters, the system optimizes the balance between spatial resolution and power consumption
3Adaptability or versatility
If multiple pixel arrays with different TOF techniques are included, then the adaptability to different distance ranges is improved, but the device complexity increases
Solution Approach 1:
The pixel array is segmented into multiple types (first pixels and second pixels) that use different TOF measurement techniques. Each segment is designed to handle specific distance ranges or measurement scenarios, allowing the system to achieve broad adaptability across varying distances while keeping each individual pixel type relatively simple and manageable
Solution Approach 2:
The pixel array is designed with multi-functional capability by incorporating different pixel types that can handle various distance ranges and measurement requirements. This universal design allows a single array structure to perform multiple functions (measuring both close and far distances with appropriate precision) without requiring entirely separate systems, thus improving adaptability while controlling overall complexity
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 device achieves efficient distance measurement across varying ranges with improved spatial and temporal resolution and reduced power consumption by selectively activating direct or indirect pixels based on distance.
Implementation Method 1
an image sensing device for sensing a distance to a target object using a Time of Flight (TOF) method
Implementation Method 2
at least one second pixel configured to measure the distance to a target object using a phase of light reflected from the target object
Data Source
AI summary
An image sensing device and a photographing device including the same are disclosed. The image sensing device includes a pixel array configured to have a first pixel and a second pixel that are different from each other in terms of at least one of an effective measurement distance, temporal resolution, spatial resolution, and unit power consumption, and a timing controller configured to determine whether a distance to a target object is equal to or less than a predetermined threshold distance, and selectively activate any one of the first pixel and the second pixel according to the result of determination.