Power-Efficient SPAD Image Acquisition Through Partial Pixel Sampling

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Solution Overview

Problem

Conventional image sensors, such as CMOS and CCD, suffer from high read noise and motion blur under low light conditions, and SPAD sensors face challenges with high power consumption and dark current, especially in illuminated environments.

Innovation Solution

Implement a sampling mode for SPAD image sensors that selectively activates subsets of pixels based on runtime conditions like light and temperature, capturing partial frames with different subsets and combining them to generate composite images, reducing power consumption and temperature-related noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If SPAD sensors are operated in illuminated environments, then image acquisition capability is improved, but power consumption increases

Engineering Contradiction:

Improveimage acquisition capabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The image sensor is divided into multiple pixel regions, and only a subset of pixels is activated at any given time based on runtime conditions. This segmentation allows the system to maintain image acquisition capability while reducing the number of active pixels, thereby lowering power consumption in illuminated environments.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts the number of active pixels based on runtime conditions such as ambient light levels and temperature. By making the pixel activation state dynamic rather than static, the system can optimize between image quality and power consumption depending on environmental conditions.

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If all image sensing pixels are activated, then image quality is improved, but power consumption and temperature increase

Engineering Contradiction:

Improveimage qualityVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

Instead of activating all pixels, the system uses a partial action approach by activating only a subset of pixels sufficient for maintaining acceptable image quality. This partial activation reduces power consumption and heat generation while still capturing necessary image data.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The system changes operational parameters by adjusting the number of active pixels based on runtime conditions. When ambient light is sufficient or temperature is high, fewer pixels are activated, changing the operational state to balance image quality with power consumption and thermal management.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If high framerate image acquisition is performed, then temporal resolution is improved, but motion blur increases

Engineering Contradiction:

ImproveframerateVSAvoidmotion blur

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The system uses periodic action by capturing multiple partial frames at different time points and combining them. This periodic sampling approach allows for high temporal resolution while reducing motion blur through temporal integration of multiple snapshots.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

Multiple partial frames captured at different time points are merged or combined to generate a composite image frame. This merging process integrates information from multiple temporal samples, achieving high framerate capability while reducing motion blur through temporal averaging.

Inventive Principle:

Principle #5Merging (Combining)

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 approach reduces power consumption, minimizes dark current, and maintains high signal-to-noise ratio, enabling high-framerate image acquisition with reduced motion blur and improved image quality in both low light and illuminated conditions.

Implementation Method 1

single photon avalanche diode (SPAD) pixels that are configured to detect photons

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 2

each pixel is configured to generate electron-hole pairs in response to detected photons

Methodology Applied

Scientific EffectPhoton detection: Photoelectric Effect

Data Source

PatentUS20250224616A1Systems and methods for power efficient image acquisition using single photon avalanche diodes (SPADS)

Publication Date: 2025.07.10 MICROSOFT TECHNOLOGY LICENSING LLC

AI summary

A system for power efficient image acquisition is configurable to capture, using an image sensor, a plurality of partial image frames including at least a first partial image frame and a second partial image frame. The first partial image frame is captured at a first timepoint using a first subset of image sensing pixels of the plurality of image sensing pixels of the image sensor. The second partial image frame is captured at a second timepoint using a second subset of image sensing pixels of the plurality of image sensing pixels of the image sensor. The second subset of image sensing pixels includes different image sensing pixels than the first subset of image sensing pixels, and the second timepoint is temporally subsequent to the first timepoint. The system is configurable to generate a composite image frame based on the plurality of partial image frames.