Image Sensor Variable Integration Time Control
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Solution Overview
Problem
Conventional CMOS image sensors have limited dynamic range due to fixed integration times, which restrict their ability to differentiate luminance effectively in various applications.
Innovation Solution
Implementing image sensors with variable integration times, where the controller samples each row of pixels after a predetermined duration that is less than or greater than the row time period, allowing for a higher ratio of longest to shortest integration times, thereby enhancing dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional CMOS image sensors use fixed integration times, then the device complexity is reduced and manufacturing is simplified, but the dynamic range is limited and luminance differentiation capability is insufficient
Solution Approach 1:
The patent implements variable integration times by dynamically adjusting the exposure duration for different rows of pixels. The controller samples each row after a predetermined duration that varies from the standard row time period, enabling the system to adapt integration time based on lighting conditions and improve luminance differentiation without requiring fundamentally different sensor architecture.
Solution Approach 2:
The patent changes the temporal parameter of integration time to extend the dynamic range. By sampling pixels at different time points relative to the row time period (either earlier or later), the system creates multiple effective integration times, allowing it to capture both bright and dark scenes with appropriate exposure durations for each region.
2Measurement precision
If the row time period is extended to allow longer integration times, then the dynamic range is improved, but the productivity and frame rate of the image sensor are reduced
Solution Approach 1:
The patent applies partial action by extending integration time only for specific rows that require it, rather than extending the integration time for the entire frame. The controller selectively samples individual rows after predetermined durations that differ from the row time period, allowing some rows to have longer effective integration times while maintaining the overall frame rate and productivity of the sensor.
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 improves the dynamic range of image sensors by allowing for a wider range of integration times, enabling better luminance differentiation and addressing the limitations of conventional CMOS image sensors.
Implementation Method 1
Image sensors convert optical light to an electrical signal. Image sensors are formed from an array of pixels, each of which converts light received from a light source into an electrical signal.
Data Source
AI summary
Methods and devices for improving dynamic range in image sensors are disclosed. An image sensing device comprises an image sensor having a plurality of rows of pixels, and a controller for controlling the exposure of each row of pixels. The controller is programmed to perform a shutter operation for one of the plurality of rows of pixels, and to sample the one of the plurality of rows after a predetermined duration following the performance of the shutter operation. The predetermined duration is different from a multiple of a row time period of the image sensing device.