Analog Front-End Device for Image Pickup with Continuous Data Generator
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Solution Overview
Problem
Conventional analog front-end devices in digital cameras generate fixed pattern noise due to discontinuous noise components when operating at high speeds, especially under highlight environments, which degrades image quality.
Innovation Solution
The analog front-end device incorporates a continuous data generator that converts discontinuous image data into continuous data by using an output stop position signal, temporarily stopping pixel signal readout during high-speed electronic shutter operations and employing clock delay devices and memory to manage data continuity, thereby suppressing fixed pattern noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-speed electronic shutter operation is implemented with exposure control period less than one horizontal period, then shutter speed is improved, but fixed pattern noise increases due to discontinuous noise components
Solution Approach 1:
The timing generator proactively generates output stop position signals before discontinuous readout operations occur, allowing the continuous data generator to pre-prepare compensation operations. The system predicts when discontinuities will occur and takes preliminary actions to prevent fixed pattern noise before it degrades image quality.
Solution Approach 2:
The continuous data generator acts as an intermediary between the discontinuous pixel readout and the final image output. It receives discontinuous image data containing noise components, processes them through buffering and timing coordination, and outputs continuous data that eliminates fixed pattern noise while preserving the high-speed shutter effect.
2Adaptability or versatility
If control pulses are output at arbitrary positions within the valid data period for high-speed electronic shutter, then exposure control flexibility is improved, but discontinuous noise components are generated
Solution Approach 1:
The timing generator continuously monitors the valid data period and provides real-time output stop position signals to the continuous data generator. This feedback mechanism allows the system to adapt to arbitrary control pulse positions while maintaining continuous data output, eliminating the harmful discontinuous noise components that would otherwise result from flexible exposure control.
Solution Approach 2:
The system dynamically adjusts the readout timing based on the output stop position signals. Rather than using fixed readout intervals, the continuous data generator flexibly coordinates data transfer timing to match the dynamic control pulse positions, ensuring continuous output despite variable exposure timing.
3Productivity
If simultaneous processing of CDS, GCA, and A/D conversion is executed during valid data output period, then processing efficiency is improved, but operation noise is generated within the valid period
Solution Approach 1:
The processing pipeline is segmented into distinct stages with the continuous data generator creating a separate data transfer channel. By separating the timing-critical data output from the noise-generating processing operations, the system maintains high processing efficiency while isolating operation noise to non-valid periods.
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 solution effectively eliminates fixed pattern noise, ensuring high-quality image data is produced by controlling the timing of pulses and data continuity, even during high-speed electronic shutter operations, enhancing image quality without influencing the horizontal drive pulse or sensor analog signal.
Implementation Method 1
a solid-state image pickup sensor that photoelectric-converts an optical image of a subject into an electric signal
Data Source
AI summary
A preprocessor converts an analog image signal, which is outputted from a solid-state image pickup sensor that photoelectric-converts an optical image of a subject, into digital image data. A timing generator periodically generates a drive pulse for driving the solid-state image pickup sensor continuously/discontinuously, and generates an output stop position signal that indicates an output stop position of the solid-state image pickup sensor when the solid-state image pickup sensor is driven discontinuously in sync with the drive pulse. A continuous data generator lets through the image data when the output stop position signal is invalid, and converts the image data inputted in a discontinuous state into continuous image data when the output stop position signal is valid.