Shift Register Control for CMOS Sensor Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In imaging elements like CMOS sensors, current fluctuations in sense amplifiers during data transfer can introduce noise into pixel signals, leading to lateral band-like and shading noise in captured images, which deteriorate subjective image quality.
Innovation Solution
A signal processing apparatus and method that involves stopping the driving of a shift register controlling pixel data transfer during A/D conversion to minimize current fluctuations in sense amplifiers, thereby reducing noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data transfer is performed during A/D conversion, then productivity is improved, but noise is generated in captured images due to current fluctuation in sense amplifiers
Solution Approach 1:
The patent divides the operational timeline into distinct segments: A/D conversion periods and data transfer periods. During A/D conversion, the shift register is stopped to prevent noise, while during data transfer, the shift register operates normally. This temporal segmentation allows both high-speed conversion and efficient data transfer without mutual interference.
Solution Approach 2:
The system implements periodic alternation between A/D conversion mode and data transfer mode. The shift register is periodically stopped during A/D conversion and periodically activated during data transfer, creating a rhythmic operational pattern that eliminates noise while maintaining productivity.
2Object-affected harmful factors
If shift register driving is stopped during A/D conversion, then noise is suppressed, but data transfer efficiency is reduced
Solution Approach 1:
The patent segments the operational cycle into distinct A/D conversion phases and data transfer phases. By stopping the shift register only during A/D conversion and resuming it during data transfer, the system achieves noise suppression without permanently sacrificing data transfer efficiency.
Solution Approach 2:
The shift register's operating state is dynamically adjusted based on the current operational phase. It transitions from an active state during data transfer to a stopped state during A/D conversion, and back to active state afterward. This dynamic control optimizes both noise suppression and data transfer efficiency.
3Speed
If sense amplifier is driven continuously, then data transfer speed is maintained, but current fluctuation causes magnetic induction noise
Solution Approach 1:
The sense amplifier operates periodically rather than continuously. It is activated during data transfer periods to maintain speed and deactivated during A/D conversion periods to prevent magnetic induction noise, creating a rhythmic on-off pattern that balances speed and noise suppression.
Solution Approach 2:
The sense amplifier's driving state is dynamically controlled based on operational requirements. It switches between active and inactive states in synchronization with the A/D conversion and data transfer phases, optimizing both data transfer speed and noise reduction.
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 effectively suppresses the generation of noise in captured images, thereby improving subjective image quality by preventing current fluctuations during A/D conversion.
Implementation Method 1
Due to magnetic induction caused by the current fluctuation of the sense amplifier, there has been a possibility that noise would be superimposed on a ramp wave or the pixel signal which is an input of the A/D conversion
Implementation Method 2
a pixel array that includes a plurality of pixels each having a configuration for photoelectrically converting incident light
Data Source
AI summary
The present disclosure relates to a signal processing apparatus and method, an imaging element, and an electronic apparatus capable of suppressing deterioration of subjective image quality. Driving of a shift register controlling transfer of pixel data of digital data obtained by A/D conversion is stopped in a part or the entirety of a period in which the A/D conversion is performed on a pixel output of an analog signal. The present disclosure can be applied to, for example, a signal processing apparatus, an imaging element, an imaging device, an image processing apparatus, an electronic apparatus, a signal processing method, a program, or the like.