Variable Rate Pixel Data Transfer for Buffer Size Reduction
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Solution Overview
Problem
Conventional imaging systems require large buffers to manage variable memory usage due to fixed input and output rates of pixel data, leading to increased die space and resource inefficiency, especially when the input rate exceeds the discard rate or during processing operations that require spatial transformations.
Innovation Solution
Implementing a variable rate pixel data transfer system that adjusts the output rate of the image sensor, using a combined shutter and readout control module with lookup tables or algorithmic units to dynamically control integration and readout intervals, allowing for flexible correlation of time slots with row integration and readout, thereby reducing memory usage and buffer size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed input and output rates are used for pixel data transfer, then the system is simple to implement, but large buffers are required leading to increased die space and resource inefficiency
Solution Approach 1:
The patent implements variable rate pixel data transfer where the output rate of the image sensor is dynamically adjusted based on processing requirements. The system transitions from fixed rate operation to variable rate operation, allowing the buffer to be optimized in size by controlling the rate at which pixel data is read out from the sensor and written to the buffer, thereby reducing the required buffer size while maintaining system functionality.
Solution Approach 2:
The patent changes the rate parameter of pixel data transfer from fixed to variable. By controlling the readout rate of pixel data from the sensor array and adjusting the write rate to the buffer, the system optimizes memory usage. This parameter change allows the same buffer to handle varying data rates without requiring excessive buffer size, thus reducing die space occupation.
2Device complexity
If fixed rate pixel data transfer is used, then the control system is simple, but memory usage increases when input rate exceeds discard rate
Solution Approach 1:
The patent implements feedback control by monitoring the discard rate of pixel data and adjusting the readout rate accordingly. The system uses feedback from the processing pipeline to dynamically control the sensor output rate, ensuring that pixel data is read out at an optimized rate that matches actual processing needs, thereby reducing memory usage when the input rate exceeds the discard rate.
Solution Approach 2:
The system dynamically adjusts the pixel data transfer rate based on real-time processing conditions. When the input rate exceeds the discard rate, the variable rate mechanism optimizes the readout speed to match actual consumption patterns, preventing memory overflow while avoiding unnecessary memory allocation during low-demand periods.
3Reliability
If larger buffers are allocated to handle peak memory usage, then processing reliability is improved, but die space is increased
Solution Approach 1:
The patent uses dynamic rate adjustment to ensure processing reliability without allocating excessive buffer space. By controlling the readout rate to match actual processing consumption patterns, the system maintains sufficient buffer capacity for peak demands while avoiding over-provisioning. This dynamic approach ensures reliability is maintained with minimized die space allocation.
Solution Approach 2:
The system changes the rate parameter dynamically to optimize the balance between reliability and die space. By adjusting the pixel data transfer rate based on actual processing needs, the system ensures that buffer capacity is sufficient for reliable operation during peak periods while minimizing the overall buffer size required, thus reducing die space occupation.
4Quantity of substance
If variable rate pixel data transfer is implemented, then memory usage is reduced, but the control system becomes more complex
Solution Approach 1:
The patent implements a combined shutter and readout control module that performs multiple functions: controlling the sensor exposure, managing the readout process, and regulating the data transfer rate. This multi-functional approach reduces the need for separate complex control circuits, thereby managing memory usage optimization while keeping the control system complexity at acceptable levels through functional integration.
Solution Approach 2:
The system merges the shutter control and readout control functions into a single integrated module. This consolidation simplifies the control architecture by combining multiple control tasks into one unified system, reducing the overall complexity that would otherwise arise from separate control circuits for each function while still achieving variable rate memory optimization.
Data Source
AI summary
A variable rate image sensor outputs pixel data at a variable rate using lookup tables to selectively read out particular rows at particular times. The readout rate is not constant, allowing for a smaller image buffer in the overall system.