Avalanche Photodiode Imaging Correction for Crosstalk Counts
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Solution Overview
Problem
Photoelectric conversion apparatuses with avalanche photodiodes face issues due to avalanche luminescence, which causes erroneous counts in adjacent pixels, leading to decreased image quality and accuracy.
Innovation Solution
The apparatus includes a photoelectric conversion element with an avalanche photodiode, an image generating unit, an acquisition unit for characteristic information, a first correction processing unit for linearity correction, and a second correction processing unit for pixel interpolation, using first characteristic information to correct for crosstalk and defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If avalanche photodiode is used for photoelectric conversion, then sensitivity and photon counting capability are improved, but avalanche luminescence causes erroneous counts in adjacent pixels
Solution Approach 1:
The patent measures the avalanche luminescence characteristics (crosstalk information) and uses this previously harmful effect as correction data. By quantifying the erroneous counts caused by avalanche luminescence in each pixel, the system converts the harmful crosstalk into useful correction information that can be subtracted from the final image data, thereby eliminating the error while preserving the high sensitivity of the APD.
2Reliability
If correction processing is performed to suppress erroneous counts, then image quality is improved, but processing complexity increases
Solution Approach 1:
The patent performs correction processing in two stages: first, during manufacturing or calibration, the crosstalk characteristics are measured and stored as correction data; second, during normal operation, this pre-prepared correction data is simply subtracted from the captured image. This preliminary action separates the complex measurement process from the operational phase, making the actual image capture and correction computationally simple and efficient.
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 solution effectively suppresses erroneous counts and improves image quality by correcting for linearity and interpolating defective pixels, enhancing the accuracy and precision of the image generated.
Implementation Method 1
a photoelectric conversion element including an avalanche photodiode that photoelectrically converts an optical image
Implementation Method 2
a phenomenon known as avalanche luminescence occurs... the resulting secondary electrons become incident on the adjacent pixels
Data Source
AI summary
A photoelectric conversion apparatus comprises a photoelectric conversion element including an avalanche photodiode for photoelectrically converting an optical image; an image generating unit configured to generate a first image based on a signal that has been acquired by the photoelectric conversion element; an acquisition unit configured to acquire first characteristic information of the photoelectric conversion element; a first correction processing unit configured to perform first correction processing for correcting linearity of the first image using the first characteristic information; and a second correction processing unit configured to perform second correction processing for performing interpolation based on the first characteristic information and information of the first image.