Imaging Apparatus Noise Removal Timing Control
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Solution Overview
Problem
Existing imaging apparatuses face challenges in reducing horizontal stripe noise, which degrades image quality and focus state detection accuracy, especially when noise sources periodically change the power supply voltage during signal reading, affecting both captured image signals and focus state detection signals.
Innovation Solution
The imaging apparatus incorporates a pixel unit with first and second photoelectric conversion units that divide the exit pupil of the imaging optical system for one micro-lens, and a controller that synchronizes the timing of noise removal operations with the frequency of noise sources to minimize horizontal stripe noise in both captured and focus state detection signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If signal reading of the imaging element is performed to obtain captured image signal and focus state detection signal, then imaging function is achieved, but horizontal stripe noise occurs in both signals due to periodic power supply voltage changes from noise sources
Solution Approach 1:
The patent applies periodic action by controlling the read timing of the imaging element to operate at a frequency different from the noise source frequency. The controller adjusts the reading frequency of the imaging element such that it does not coincide with the periodic frequency of the noise source, thereby preventing synchronization that would cause horizontal stripe noise in both captured image signals and focus state detection signals.
Solution Approach 2:
The patent changes the timing parameters of the read operation. Specifically, the controller modifies the read timing frequency of the imaging element to be different from the noise source frequency. This parameter change ensures that the periodic power supply voltage changes from noise sources do not align with the signal reading process, thus eliminating horizontal stripe noise while maintaining reliable imaging function.
2Measurement precision
If two photodiodes are provided in one pixel to obtain A image signal and A+B image signal for focus detection, then focus state detection capability is improved, but horizontal stripe noise also occurs in the focus state detection signal
Solution Approach 1:
The patent applies periodic action by controlling the read timing of the imaging element to operate at a frequency different from the noise source frequency. The controller adjusts the reading frequency of the imaging element such that it does not coincide with the periodic frequency of the noise source, thereby preventing synchronization that would cause horizontal stripe noise in both captured image signals and focus state detection signals.
Solution Approach 2:
The patent changes the timing parameters of the read operation. Specifically, the controller modifies the read timing frequency of the imaging element to be different from the noise source frequency. This parameter change ensures that the periodic power supply voltage changes from noise sources do not align with the signal reading process, thus eliminating horizontal stripe noise while maintaining reliable imaging function.
3Object-affected harmful factors
If noise removal operation is performed on image signals, then horizontal stripe noise is reduced, but the timing coordination between multiple read operations becomes complex
Solution Approach 1:
The patent applies periodic action by controlling the read timing of the imaging element to operate at a frequency different from the noise source frequency. The controller adjusts the reading frequency of the imaging element such that it does not coincide with the periodic frequency of the noise source, thereby preventing synchronization that would cause horizontal stripe noise in both captured image signals and focus state detection signals.
Solution Approach 2:
The patent changes the timing parameters of the read operation. Specifically, the controller modifies the read timing frequency of the imaging element to be different from the noise source frequency. This parameter change ensures that the periodic power supply voltage changes from noise sources do not align with the signal reading process, thus eliminating horizontal stripe noise while maintaining reliable imaging function.
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 effectively reduces horizontal stripe noise in both captured and focus state detection signals, enhancing image quality and focus detection accuracy by controlling the timing of noise removal operations relative to the noise source frequency.
Implementation Method 1
a pixel unit having first and second photoelectric conversion units configured to generate image signals by photoelectrically converting optical fluxes passing through different regions into which an exit pupil of an imaging optical system is divided for one micro-lens
Data Source
AI summary
Provided is an imaging apparatus including an imaging element including a pixel unit having first and second photoelectric conversion units configured to generate image signals by photoelectrically converting optical fluxes passing through different regions into which an exit pupil of an imaging optical system is divided for one micro-lens. The imaging apparatus controls each of the timing of a first removal operation of removing a noise component from a first image signal read from the first photoelectric conversion unit and the timing of a second removal operation of removing a noise component from a second image signal read from the first and second photoelectric conversion units to have a predetermined relationship with a frequency of a noise source occurring during an operation of reading the image signals.