Image Sensor Readout Scrambling to Eliminate Ghost Images
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Solution Overview
Problem
Image sensors with multiple outputs experience ghost images due to residual signals from preceding pixels, causing blurring effects that are not fully compensable by existing methods.
Innovation Solution
The image sensor varies the order in which pixels are switched to output amplifiers, either spatially or temporally, within column groups or between readout cycles, to scramble the pixel spacing and prevent ghost images from being perceptible.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple output amplifiers are used to increase readout speed, then productivity is improved, but ghost images appear due to residual signals from preceding pixels
Solution Approach 1:
The patent applies dynamics by making the assignment of column groups to output amplifiers variable rather than fixed. The control device dynamically changes the assignment sequence between different readout cycles, so that the same column group is assigned to different output amplifiers in different cycles. This dynamic reassignment scrambles the spatial pattern of residual signals, preventing ghost images from forming while maintaining high readout speed through parallel processing
Solution Approach 2:
The patent changes the parameter of assignment sequence between readout cycles. Specifically, it varies which column groups are assigned to which output amplifiers in different cycles, thereby changing the spatial distribution pattern of residual signals. This parameter change effectively scrambles ghost images while preserving the parallel readout capability that provides high productivity
2Device complexity
If signals are read out in strict sequential order, then device complexity is reduced, but ghost images become perceptible due to regular pixel spacing
Solution Approach 1:
The patent introduces dynamics into the readout process by implementing variable assignment sequences that change between readout cycles. The control device dynamically reassigns column groups to different output amplifiers in different cycles, creating an irregular, scrambled pattern of signal routing. This dynamic approach prevents regular ghost image formation while maintaining relatively simple device architecture
Solution Approach 2:
The patent employs periodic action by repeating the readout process in multiple cycles with different assignment sequences. Each readout cycle processes all pixels, but the assignment of column groups to output amplifiers varies periodically between cycles. This periodic variation with changing patterns effectively scrambles ghost images while maintaining systematic and manageable device complexity
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 scrambles ghost images, making them unnoticeable by varying the assignment sequences of columns to output amplifiers and using redundant signal buses for robust readout.
Implementation Method 1
light-sensitive elements or pixels arranged in rows and columns, which convert light falling through a lens of the camera into electrical signals
Data Source
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AI summary
The image sensor has multiple photo-sensitive pixels (P) arranged in lines (Zm-1,Zm) and slots (S1-1,S1-2,S1-3,S1-4,S2-1,S2-2,S2-3,S2-4) and a multiple output amplifiers (V1,V2,V3,V4) with a switching device (11,13,15) is provided, to selectively switch the pixels of the lines in the output amplifiers. A controller (17) is provided for controlling the switching device. The image sensor is formed in such a manner that the sequence is varied against the sequence, in which the pixels are switched in the output amplifiers and are arranged along a line of the image sensor. An independent claim is also included for a method for the selection of an image sensor, particularly a complementary metal oxide semiconductor image sensor, for electronic cameras.