Integrated Image Sensor Distance Determination via Photon Ratio
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Solution Overview
Problem
Existing three-dimensional image sensors face challenges in accurately determining object distances, particularly at macroscopic distances, due to complex alignment requirements, long response times, and incompatibility with portable devices, especially when dealing with moving scenes.
Innovation Solution
An integrated image sensor with a pixel array and microlenses, where each pixel is composed of sub-pixels that calculate the ratio of photon detection between a central and peripheral sub-pixel to determine image diameters, allowing for distance calculation using a main lens and microlens focal distances, and comparing these diameters with reference values to determine object distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If stereo vision techniques are used to determine object distances, then distance information can be obtained, but the system complexity and alignment requirements increase significantly
Solution Approach 1:
The image sensor is divided into multiple pixels, with each pixel further segmented into a central sub-pixel and peripheral sub-pixels. This segmentation allows each pixel to independently perform distance measurements through photon ratio calculations, eliminating the need for complex multi-camera alignment while maintaining accurate depth mapping across the entire scene
Solution Approach 2:
Each pixel in the sensor array serves multiple functions: it captures image information through its photosensitive area and simultaneously performs distance measurement by calculating photon ratios between central and peripheral sub-pixels. This self-service capability eliminates the need for separate active light sources or complex transceiver systems, reducing overall device complexity while maintaining measurement precision
2Measurement precision
If triangulation methods with laser scanning are used, then distance information can be obtained, but the response time becomes too long for moving scenes
Solution Approach 1:
The sensor performs continuous distance measurements for all pixels simultaneously during a single image exposure, rather than scanning sequentially with a laser. By continuously capturing photons across the entire pixel array and calculating ratios in parallel, the system achieves real-time distance mapping that can track moving scenes without the long response times associated with sequential laser scanning
Solution Approach 2:
The sensor uses all pixels in the array to perform distance measurements simultaneously, rather than using a single scanning point. This excessive use of parallel measurement channels dramatically reduces the time required to acquire complete distance information for the entire scene, enabling real-time tracking of moving objects
3Measurement precision
If TOF method is used for distance determination, then distance information can be obtained, but the method is not adapted for short distances and requires high power for instantaneous mapping
Solution Approach 1:
The patent replaces the active light transmission mechanism of TOF with a passive optical measurement approach. Instead of transmitting high-power waves and measuring their return time, the sensor passively captures photons from the scene and determines distance through geometric relationships encoded in the photon distribution across sub-pixels. This substitution dramatically reduces power consumption while enabling accurate short-distance measurements
Solution Approach 2:
The sensor measures distance by detecting changes in the spatial distribution of photons across central and peripheral sub-pixels, rather than measuring time-of-flight. By changing the measurement parameter from time to photon ratio, the system achieves sensitivity to short distances and eliminates the need for high-power transmission, as the photon ratio naturally encodes distance information for objects at any range
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 solution enables fast and accurate distance determination in real-time, even for moving scenes, overcoming the limitations of prior art sensors by providing a compact and efficient method for instantaneous mapping of object distances.
Implementation Method 1
each pixel being formed of an assembly of sub-pixels each comprising a photosensitive area... means for determining the ratios between the amount of photons detected by a central sub-pixel and the amount of photons detected by at least one peripheral sub-pixel
Implementation Method 2
each pixel in the array being associated with a microlens... the microlenses being placed in the focal plane of the main lens
Data Source
AI summary
An integrated image sensor capable of determining the distance to objects contained in a scene, including a pixel array, each pixel in the array being associated with a microlens and being formed of an assembly of sub-pixels, each including a photosensitive area.