Image Pickup Apparatus Frame Rate Adaptation
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Solution Overview
Problem
Image pickup systems using line sequence image sensors experience increased distortion of moving subjects when changing frame rates without altering the base clock frequency, particularly at lower frame rates like 24 frames per second.
Innovation Solution
The method involves setting a vertical synchronization cycle according to the desired frame rate and maintaining a constant horizontal synchronization cycle, while correcting the time axis and deleting invalid regions from the image pickup signal to prevent distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the base clock frequency is changed to accommodate different frame rates, then the frame rate conversion is simplified, but complex control is required for single pixel units
Solution Approach 1:
The patent changes the synchronization signal parameters (vertical sync cycle) rather than the base clock frequency to adapt to different frame rates. This allows the system to maintain a fixed base clock while adjusting timing parameters to support multiple frame rates (60fps, 50fps, 24fps) without changing the fundamental clocking architecture.
Solution Approach 2:
The patent segments the image pickup region into valid and invalid regions, and processes different portions of the image signal separately. By dividing the image pickup area and handling different frame rates through selective processing of specific regions, the system achieves frame rate conversion without requiring complex per-pixel control.
2Adaptability or versatility
If the horizontal synchronization cycle is changed to adjust frame rate, then frame rate conversion is achieved, but image distortion increases for moving subjects
Solution Approach 1:
The patent applies different processing to different regions of the image signal. The valid image pickup region is processed with time-axis correction to maintain image quality, while the invalid region is discarded. This localized processing ensures that only the relevant portions of the image undergo correction, preventing distortion in the final output while maintaining frame rate conversion capability.
Solution Approach 2:
Instead of changing the horizontal synchronization cycle to adjust frame rate (which causes distortion), the patent inverts the approach by changing the vertical synchronization cycle and adjusting the image pickup region boundaries. This inverted approach maintains a fixed horizontal sync cycle while achieving frame rate conversion, thereby avoiding image distortion.
3Device complexity
If a fixed base clock frequency is used for all frame rates, then control complexity is reduced, but frame rate conversion requires additional processing
Solution Approach 1:
The patent maintains a fixed base clock frequency and achieves frame rate conversion by changing synchronization signal parameters (vertical sync cycle) and adjusting image pickup region boundaries. This approach simplifies the clocking control while introducing timing parameter adjustments that enable multi-frame-rate operation without requiring per-pixel control changes.
4Adaptability or versatility
If the valid image pickup region is expanded to accommodate lower frame rates, then frame rate conversion is enabled, but the time axis correction becomes more complex
Solution Approach 1:
The patent segments the image pickup region into valid and invalid portions and processes them differently. The valid region undergoes time-axis correction while the invalid region is discarded. This segmentation allows the system to handle frame rate conversion by selectively processing only the necessary portions of the image signal, reducing overall processing complexity.
Solution Approach 2:
The patent extracts and discards the invalid region of the image signal that does not contain valid image pickup data. By removing this unnecessary portion before processing, the system reduces the amount of data that requires time-axis correction, thereby simplifying the overall processing complexity while maintaining frame rate conversion capability.
Data Source
AI summary
An image pickup method of picking up images at a frame rate changeably set out of a plurality of frame rates is provided. The method includes the steps of: setting a vertical synchronization cycle in accordance with a set frame rate and adding an image pickup signal that does not include a valid image pickup region in accordance with the set vertical synchronization cycle while keeping a horizontal synchronization cycle of each image pickup signal constant, when obtaining an image pickup signal from an image sensor; and correcting a time axis of an obtained image pickup signal that includes a valid image pickup region, correspondingly to the set frame rate and deleting an obtained image pickup signal that does not include the valid image pickup region.