Imaging Apparatus Noise Subtraction for Wide Dynamic Range
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Solution Overview
Problem
Existing imaging apparatuses face challenges in expanding dynamic range while maintaining frame rate, as they require reading noise and pixel signals twice with different gains, leading to unstable black levels and decreased frame rate.
Innovation Solution
An imaging apparatus with a pixel unit, read out unit, memory unit, and subtraction unit that amplifies noise and pixel signals by different gains, allowing for sequential subtraction of noise signals to stabilize black levels without reducing frame rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If noise signals and pixel signals are read out twice with different gains to expand dynamic range, then the dynamic range is improved, but the frame rate decreases
Solution Approach 1:
The patent applies preliminary action by reading out noise signals with the second gain before reading out pixel signals with the first gain. This allows the noise signals to be stored in advance in the memory unit, so that when pixel signals are read out with the first gain, the corresponding noise signals are already available for subtraction, eliminating the need to read out noise signals again after pixel signal reading.
2Adaptability or versatility
If noise signals are read out with a predetermined gain and pixel signals are read out twice with different gains, then the dynamic range is expanded, but the black level becomes unstable
Solution Approach 1:
The patent applies parameter changes by using different gain parameters for reading out noise signals and pixel signals. Specifically, noise signals are read out with a second gain while pixel signals are read out with a first gain, allowing each signal type to be processed with the appropriate gain setting. This enables proper noise subtraction while maintaining stable black levels, as the noise signals are amplified to match the pixel signal gain level before subtraction.
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
The solution enables the expansion of dynamic range by adjusting black levels for each gain without decreasing frame rate, ensuring stable image signals and proper noise subtraction.
Implementation Method 1
each pixel can output a noise signal and a pixel signal that is generated by photoconversion
Data Source
AI summary
An imaging apparatus having a wide dynamic range and a stable black level without decreasing frame rate comprises a pixel unit including pixels, a read out unit for reading out the noise signal from each pixel and to amplify the noise signal by a first gain to generate a first noise signal, reads out the pixel signal and amplifies the pixel signal by the first gain and a second gain to generate a first and a second pixel signal, a first memory unit for storing a second noise signal generated by amplifying, by the second gain, the noise signal read out from a pixel of a predetermined row, and a subtraction unit for subtracting the first noise signal from the first pixel signal and to subtract the second noise signal stored in the first memory unit from the second pixel signal, while sequentially reading out signals from each pixel.