Time-of-Flight Sensor Block Exposure Control for Ambient Light Saturation
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Solution Overview
Problem
Intense ambient light, such as sunlight, causes saturation in time-of-flight (ToF) sensors, leading to inaccurate ranging and image deterioration due to the inability to effectively separate ambient light signals from reflected light signals.
Innovation Solution
A light receiving device with a photometry sensor that performs photometry to control exposure of other sensors, dividing their light receiving surfaces into blocks, allowing for individual exposure control based on photometry results to prevent saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the ToF sensor receives intense ambient light such as sunlight, then the light receiving capability is improved, but the pixels become saturated and accurate ranging cannot be performed
Solution Approach 1:
The light receiving surface of the sensor is divided into multiple pixel blocks, allowing independent exposure control for each block. This segmentation enables the system to handle intense ambient light in some blocks while maintaining sensitivity in others, preventing saturation while preserving light receiving capability.
Solution Approach 2:
The exposure time for each pixel block is dynamically adjusted based on ambient light conditions detected by the photometry sensor. This dynamic control allows the system to adapt to varying light intensities, preventing saturation during intense ambient light while maintaining accurate ranging capability.
2Use of energy by moving object
If the exposure time is increased to improve light receiving capability, then more light is captured, but saturation occurs under intense ambient light conditions
Solution Approach 1:
The sensor surface is divided into pixel blocks with independent exposure control. This allows the system to capture sufficient light in low-ambient-light blocks while preventing saturation in high-ambient-light blocks, maintaining signal validity across all regions.
Solution Approach 2:
Different exposure times are applied to different pixel blocks based on their local ambient light conditions. This local quality approach ensures that each block operates at optimal exposure levels, capturing adequate light without saturation while maintaining overall system reliability.
3Device complexity
If uniform exposure control is applied to the entire sensor, then the control system is simple, but saturation occurs in regions with intense ambient light
Solution Approach 1:
The sensor is divided into pixel blocks that can be controlled independently. This segmentation allows the system to maintain relative simplicity while achieving differential exposure control, preventing saturation in high-light regions without requiring complex per-pixel control.
Solution Approach 2:
The exposure time parameter is changed across different pixel blocks based on ambient light conditions. This parameter variation allows the system to maintain accuracy in intense light regions while preserving the simplicity of block-level control rather than requiring complex per-pixel management.
4Reliability
If the exposure time is decreased to prevent saturation, then saturation is avoided, but the light receiving capability deteriorates
Solution Approach 1:
By dividing the sensor into pixel blocks with independent exposure control, the system can prevent saturation in blocks exposed to intense ambient light while maintaining longer exposure times in blocks with lower ambient light, preserving overall light receiving capability.
Solution Approach 2:
Different exposure times are applied to different pixel blocks based on their local lighting conditions. This allows the system to prevent saturation where necessary while maintaining optimal light receiving capability in other regions, achieving both goals simultaneously.
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 solution effectively suppresses sensor saturation, enabling accurate ranging and imaging even in high-intensity ambient light conditions by optimizing exposure for each pixel block.
Implementation Method 1
a photometry sensor configured to perform photometry by receiving light
Implementation Method 2
The ToF sensor emits light to radiate the light to a subject. Further, in the ToF sensor, reflected light reflected and returned from the subject is received with the pixels and a distance to the subject is obtained in accordance with a time taken from the light emission to the reception of the reflected light
Data Source
AI summary
The present technology relates to a light receiving device, a control method, and an electronic apparatus capable of suppressing saturation of a sensor that receives light.A control unit performs exposure control to control, in accordance with a photometry result of a photometry sensor that performs photometry by receiving light, exposure of another sensor of which a light receiving surface that receives light is divided into a plurality of blocks, the exposure control being performed for each block. The present technology can be applied, for example, an electronic apparatus such as a digital camera that receives light.