Image Sensor Column Line Switching for Brightness Deviation
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Solution Overview
Problem
Image sensors with multiple data outputs often suffer from block-shaped brightness deviations due to differences in output amplifiers and analog/digital converters, leading to noticeable image field blocks with varying brightness, which affects the subjective image quality.
Innovation Solution
The image sensor employs a switch network that allows column lines to be switched to multiple data outputs, distributing brightness deviations as a dot pattern rather than a block-shaped pattern, reducing perceptibility and requiring no horizontal bus lines across the entire sensor width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If column lines are strictly divided into column line groups with each group assigned to a single data output, then horizontal bus lines are eliminated and space/energy consumption are reduced, but block-shaped brightness deviations become noticeable and image quality deteriorates
Solution Approach 1:
The patent applies dynamic switching to assign column lines to data outputs. Instead of a fixed assignment where each column line group is permanently bound to one data output, the system dynamically reconfigures the assignment through a switch network. This allows the same physical infrastructure (reducing space requirements) to serve multiple functional purposes, while preventing persistent block-shaped artifacts by varying which column lines are routed to which data outputs during different time periods.
Solution Approach 2:
The patent changes the assignment parameter between column lines and data outputs over time. By varying the routing configuration through the switch network, the system transforms the static parameter assignment into a dynamic one. This parameter change ensures that no single data output consistently processes signals from the same column line group, thereby distributing quantization artifacts across the entire image rather than confining them to specific blocks.
2Reliability
If multiple data outputs are used to increase dynamic range, then signal amplification flexibility is improved, but the number of data outputs increases space consumption and cost
Solution Approach 1:
The patent makes data outputs universal by enabling each data output to serve multiple column line groups at different times through the switch network. Instead of dedicating specific data outputs to specific column line groups, the system allows any data output to handle signals from any column line group sequentially. This multi-functionality maintains the dynamic range benefits of multiple data outputs while reducing the total number of data outputs needed, thereby decreasing space consumption.
Solution Approach 2:
The dynamic reconfiguration capability allows the system to flexibly allocate data output resources. By dynamically assigning different column line groups to different data outputs based on current readout requirements, the system optimizes the utilization of available data outputs. This dynamic resource allocation reduces the need for excessive data outputs, thereby reducing space consumption while maintaining the ability to handle high dynamic range signals.
3Ease of manufacture
If column lines are assigned to different data outputs through switching, then block-shaped brightness deviations are reduced and image quality improves, but device complexity increases due to switch network requirements
Solution Approach 1:
The patent segments the column lines into multiple column line groups that can be independently switched and assigned to different data outputs. This segmentation allows the switch network to manage assignments in a structured manner, processing one group at a time rather than requiring complex simultaneous management of all column lines. The segmented approach reduces the complexity of the switching logic while still achieving the goal of distributing artifacts across the image.
Solution Approach 2:
The system employs periodic action by cycling through different assignment configurations in a systematic sequence. The switch network follows a predetermined periodic pattern to assign column line groups to data outputs, which simplifies control logic compared to arbitrary assignments. This periodic switching ensures that all column lines are eventually assigned to all data outputs in a regular pattern, reducing artifacts while maintaining manageable device complexity through predictable, repeating sequences.
Data Source
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AI summary
The sensor has light sensitive pixels arranged in rows and columns, and column lines associated with respective data outputs (27) by a multiplexer device. The column lines are divided into a set of column line groups (31), and a switch network is provided between the column lines and the data outputs. The switch network is designed to associate the column lines of the respective groups with the different data outputs. A control device controls the switch network, such that the association of the column lines of the respective groups to the data outputs varies from one row to the next row. An independent claim is also included for a method for reading an image sensor.