Masked Pixel Array for Dark Current Noise Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image sensors face challenges in accurately calculating and subtracting dark current fixed pattern noise due to temperature variations, which can lead to noise in image data, especially when cooling systems are not practical.
Innovation Solution
The implementation of a mask configured to darken specific pixels in an image sensor array, allowing for real-time determination of dark current fixed pattern noise by interpolating from darkened pixels to correct 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 implemented to reduce dark current fixed pattern noise, then the dark current noise is reduced, but the device complexity and cost increase
Solution Approach 1:
The pixel array is divided into two functional types: darkened pixels (shielded from light) that measure dark current, and active pixels that capture images. This segmentation allows dark current measurement without cooling the entire sensor array, reducing system complexity while maintaining noise reduction capability
Solution Approach 2:
Darkened pixels serve as intermediary elements that indirectly measure the dark current affecting active pixels. By measuring dark current at darkened pixel locations and interpolating to active pixel locations, the system reduces dark current noise without requiring direct thermal control of the entire sensor
2Ease of operation
If previously recorded dark current fixed pattern noise is used for subtraction, then the processing is simple, but the accuracy decreases due to temperature variations
Solution Approach 1:
The system continuously measures dark current at darkened pixels during operation and uses this real-time feedback to update the dark current fixed pattern for active pixels. This feedback mechanism maintains accuracy despite temperature variations while keeping processing relatively simple through automated interpolation and subtraction
Solution Approach 2:
The dark current fixed pattern is made dynamic by continuously updating it based on real-time measurements from darkened pixels. Instead of using a static previously recorded value, the system adapts to temperature changes by measuring and interpolating dark current values during actual operation
3Measurement precision
If masked pixels are distributed throughout the active pixel region, then dark current measurement is improved, but the active imaging area is reduced
Solution Approach 1:
Different regions of the pixel array are assigned different functions: darkened pixels are optimized for dark current measurement while active pixels are optimized for image capture. This local differentiation allows each pixel type to perform its specialized function effectively without compromising the other
Solution Approach 2:
A small percentage of pixels (e.g., 1-10%) are allocated as darkened pixels, which is sufficient for accurate dark current measurement and interpolation. This partial allocation provides adequate dark current data without excessively reducing the active imaging area, representing an optimized compromise
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 method provides a more accurate calculation and subtraction of dark current fixed pattern noise, resulting in improved image quality and reduced noise levels, particularly beneficial for chemiluminescent measurements and maintaining reliability across varying temperatures.
Implementation Method 1
a mask coupled with the image sensor, the mask configured to darken at least one pixel in the array of pixels
Data Source
Figure 1
Figure 2
Figure 3
AI summary
One embodiment of the invention is directed to an imaging device comprising an image sensor comprising an array of pixels, and a mask coupled with the image sensor, the mask configured to darken at least one pixel in the array of pixels.