Image Sensor Readout Timing for Motion-Adaptive Power Saving
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Solution Overview
Problem
Existing image sensing devices face challenges in implementing a power saving mode while maintaining high performance in applications such as digital cameras, smartphones, and medical micro cameras.
Innovation Solution
The image sensing system incorporates a pixel array with a first and second subpixel array, utilizing different column lines for reading out pixels in alternating orders and adjusting integration times based on motion vector metadata to optimize power usage and image processing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the image sensor operates in a power saving mode by reducing readout frequency, then power consumption is reduced, but image processing performance and responsiveness deteriorate
Solution Approach 1:
The patent implements dynamic readout timing adjustment where the readout circuit adapts its operation frequency based on motion vector metadata. When object motion is detected to be small, the readout frequency is reduced to save power. When motion increases, the frequency is increased to maintain image quality. This dynamic adaptation resolves the contradiction between power saving and performance maintenance.
Solution Approach 2:
The system changes the readout timing parameter dynamically based on motion vector analysis. The readout circuit modifies its operational parameters (readout frequency, integration time) according to the magnitude of object motion, allowing the system to operate efficiently in low-motion scenarios while maintaining high performance when needed.
2Device complexity
If the readout circuit reads out all pixels sequentially in fixed order, then circuit design is simplified, but power consumption increases and processing efficiency decreases
Solution Approach 1:
The patent segments the pixel array into different regions (first and second subpixel arrays) that can be read out independently or selectively. This segmentation allows the readout circuit to activate only necessary pixel groups based on motion vector information, reducing overall power consumption while maintaining a relatively simple circuit architecture.
Solution Approach 2:
The readout circuit performs partial readout operations by selectively reading out only the necessary pixel groups based on motion detection. When motion is minimal, fewer pixels are read out, reducing power consumption. This partial action approach maintains simplicity while improving energy efficiency.
3Device complexity
If the integration time for all pixels is synchronized, then timing control is simplified, but image quality deteriorates when object motion is present
Solution Approach 1:
The patent implements dynamic integration time adjustment where different pixel groups have different integration time periods based on motion vector metadata. When object motion is detected, the integration timing is adjusted to compensate for motion, improving image quality. This dynamic approach balances timing control simplicity with image quality requirements.
4Manufacturing precision
If the system processes image data at high frequency to maintain image quality, then image quality is preserved, but power consumption increases
Solution Approach 1:
The system dynamically changes processing frequency parameters based on motion vector analysis. When object motion is small, processing frequency is reduced to save power. When motion increases, frequency is increased to maintain image quality. This parameter adaptation resolves the contradiction between quality and power consumption.
Solution Approach 2:
The patent uses motion vector metadata as feedback to control the readout and processing frequency. The system continuously monitors motion magnitude and adjusts processing parameters accordingly, creating a feedback loop that optimizes power consumption while maintaining image quality based on actual scene conditions.
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 enables power-saving operations without compromising image quality, allowing for efficient image processing and metadata generation, particularly in devices requiring high performance like digital cameras and medical micro cameras.
Implementation Method 1
Each of the plurality of pixels may include, for example, a photodiode (PD). The photodiode may serve to convert incident light into an electrical signal.
Data Source
AI summary
An image sensing system includes a first subpixel array including a first pixel and a second pixel, connected to a first column line, and a second subpixel array including a third pixel and a fourth pixels, connected to a second column line, a readout circuit connected to the first and second column lines, read out in an order of the first pixel and the second pixel, and read out in an order of the third pixel and the fourth pixel, and output image data based on output signals from the first to fourth pixels, and an image signal processor configured to generate metadata related to a motion vector of an object based on the image data. A start time point of an integration time is the same for the first pixel and the third pixel, and the same for the second pixel and the fourth pixel.