ToF Sensor Binning Circuit Resolution Enhancement
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Solution Overview
Problem
Time-of-flight image sensors face challenges in achieving increased resolution while maintaining data robustness and a smaller form factor, as larger pixels limit practical resolution and contradicting requirements necessitate compromise.
Innovation Solution
A time-of-flight image sensor system incorporating a pixel array with a binning circuit that generates interpolated pixels by averaging adjacent actual pixel values, increasing resolution and reducing noise through pixel interpolation, and an output circuit that outputs virtual pixel values according to an image structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If larger pixels are used in ToF image sensors, then data robustness and signal-to-noise ratio are improved, but resolution is limited and cannot be increased
Solution Approach 1:
The pixel array is segmented into multiple regions, where some pixels are actual sensing elements and others are virtual interpolated pixels. This segmentation allows the system to maintain large actual pixel sizes for robustness while creating smaller virtual pixels through interpolation to achieve higher resolution.
Solution Approach 2:
A binning circuit is introduced as an intermediary component between the actual pixels and the output. This circuit performs interpolation to generate virtual pixels, mediating between the physical pixel array and the desired high-resolution output without requiring physical pixel size reduction.
2Measurement precision
If resolution is increased by reducing pixel size, then more pixels fit in the sensor area, but data robustness and signal-to-noise ratio deteriorate
Solution Approach 1:
The pixel array is segmented into multiple regions, where some pixels are actual sensing elements and others are virtual interpolated pixels. This segmentation allows the system to maintain large actual pixel sizes for robustness while creating smaller virtual pixels through interpolation to achieve higher resolution.
Solution Approach 2:
Virtual pixels are created as copies or interpolations of actual pixel data. The binning circuit generates additional pixel values by interpolating between adjacent actual pixels, effectively copying and transforming existing data to create a higher resolution image without physical pixel size reduction.
3Measurement precision
If more processing is performed to increase resolution, then measurement precision improves, but device complexity and computational load increase
Solution Approach 1:
The interpolation process is performed in advance within the binning circuit before data leaves the sensor. By pre-computing virtual pixel values during the sensing process rather than requiring extensive post-processing, the system reduces computational load on external processors while achieving high resolution.
Solution Approach 2:
Complex software-based image processing is replaced with hardware-based interpolation in the binning circuit. This substitution moves the resolution enhancement function from the computational domain to the hardware domain, reducing overall system complexity and computational requirements.
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 enhances resolution up to three times, improves signal-to-noise ratio, and reduces computational load, providing improved dynamic range and lower noise, thus addressing the limitations of existing ToF image sensors.
Implementation Method 1
each pixel of the pixel array is configured to receive the modulated light signal reflected from an object as a reflected modulated light signal and to demodulate the reflected modulated light signal to generate an electrical signal
Data Source
AI summary
A time-of-flight (ToF) image sensor system includes a pixel array, where each pixel of the pixel array is configured to receive a reflected modulated light signal and to demodulate the reflected modulated light signal to generate an electrical signal; a plurality of analog-to-digital converters (ADCs), where each ADC is coupled to at least one assigned pixel of the pixel array and is configured to convert a corresponding electrical signal generated by the at least one assigned pixel into an actual pixel value; and a binning circuit coupled to the plurality of ADCs and configured to generate at least one interpolated pixel, where the binning circuit is configured to generate each of the at least one interpolated pixel based on actual pixel values corresponding to a different pair of adjacent pixels of the pixel array, each of the at least one interpolated pixel having a virtual pixel value.