Masked Pixel Array for Dark Current Noise Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Dark current fixed pattern noise in image sensors is challenging due to temperature variations, which existing methods struggle to accurately account for, especially in devices without cooling systems.
Innovation Solution
A system that uses a mask to darken specific pixels in an image sensor array, allowing for real-time determination of dark current noise patterns, which are then interpolated to correct for noise in un-darkened pixels, thereby improving the accuracy of noise subtraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a cooling system is added to reduce dark current noise, then dark current fixed pattern noise is reduced, but device complexity increases
Solution Approach 1:
The patent extracts only the essential function of dark current measurement by using a dedicated dark region in the sensor array, rather than requiring a complete cooling system. This allows dark current characterization to be performed independently of temperature control mechanisms.
Solution Approach 2:
The sensor array performs self-characterization by using its own dark regions to measure and track dark current variations over time and temperature, eliminating the need for external cooling systems or separate calibration equipment.
2Ease of operation
If previously recorded dark current fixed pattern noise is used, then processing is simplified, but accuracy deteriorates due to temperature variations
Solution Approach 1:
The patent implements continuous feedback by repeatedly measuring dark current in dedicated dark regions during normal operation, allowing the system to track and compensate for temperature-induced variations in real-time without complex processing.
Solution Approach 2:
The dark current correction values are made dynamic and time-varying, updating continuously based on measurements from dark regions, rather than using static pre-recorded values. This allows the system to adapt to changing temperature conditions automatically.
3Manufacturing precision
If all pixels are used for imaging, then image quality is maximized, but dark current noise correction accuracy deteriorates
Solution Approach 1:
The sensor array is segmented into imaging regions and dedicated dark regions, allowing simultaneous optimization of both functions. The dark regions serve exclusively for dark current measurement while imaging pixels capture the actual scene, enabling accurate noise correction without compromising image quality.
Data Source
AI summary
In one application, an imaging device includes an image sensor having an array of pixels, and a mask coupled with the image sensor. The mask is configured to darken a plurality of isolated pixels or groups of pixels interspersed within the array of pixels. The imaging device also includes a processor coupled with the image sensor and configured to receive image data from the image sensor, and determine a dark current fixed pattern noise based on the image data received from the plurality of darkened pixels or groups of pixels.