Motion Picture Camera Frame Rate Synchronization
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Solution Overview
Problem
Electronic motion picture cameras experience image flicker and latency issues due to mismatched frame and display rates, leading to jerky image perception and increased latency time, making camera operation challenging.
Innovation Solution
A method to synchronize image capture and display by setting the display rate as a product or quotient of the selected frame rate, ensuring a whole-number relationship between the two rates, allowing for continuous or quasi-continuous adjustment within a permitted range, thereby maintaining constant phasing and minimizing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the display rate is set higher than the frame rate (e.g., 100 fps display with 24 fps capture), then image flicker is reduced, but the latency time between image capture and display increases and phasing becomes unstable
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the display rate parameter based on the frame rate parameter. Specifically, the display rate is set to a whole-number multiple of the frame rate (e.g., 4x for 24 fps frame rate giving 96 fps display rate). This parameter relationship ensures that the phasing between capture and display remains constant, preventing both flicker and excessive latency variations.
Solution Approach 2:
The system implements dynamics by making the display rate adaptive rather than fixed. When the frame rate changes, the display rate automatically adjusts to maintain the whole-number multiple relationship. This dynamic adaptation ensures stable phasing and consistent latency regardless of frame rate variations, resolving the contradiction between reducing flicker and minimizing latency.
2Stability of the object's composition
If the display rate is set to a whole-number multiple of the frame rate, then phasing stability is improved and latency is minimized, but the display rate flexibility is reduced
Solution Approach 1:
The system resolves this contradiction through dynamic adaptation. Rather than fixing the display rate to a single value, the display rate is dynamically adjusted based on the current frame rate. The controller continuously monitors frame rate changes and automatically updates the display rate to maintain the whole-number multiple relationship, thus preserving phasing stability while allowing flexibility in operating conditions.
Solution Approach 2:
The patent uses parameter changes to maintain the mathematical relationship between frame rate and display rate. By expressing the display rate as a function of the frame rate (display rate = n × frame rate, where n is a whole number), the system ensures phasing stability while adapting to different frame rate settings. This functional parameter relationship provides both stability and adaptability.
3Productivity
If different refresh rates are used with different images in the buffer memory, then buffer utilization is improved, but image display smoothness deteriorates due to varying display durations
Solution Approach 1:
The patent applies periodic action by using a consistent refresh cycle based on the whole-number multiple relationship between frame rate and display rate. Each frame is displayed for a fixed number of refresh cycles (e.g., 4 refreshes per frame when using 4x multiplication). This periodic, regular display pattern ensures uniform display duration for all frames, maintaining smoothness while efficiently utilizing the buffer memory.
Data Source
AI summary
A motion picture camera arrangement comprises a motion picture camera and a display device, wherein the motion picture camera has an image sensor for taking images at a variable frame rate and wherein the display device displays the taken images at a settable display rate. A method of operating the motion picture camera arrangement comprises the steps of: selecting a frame rate; determining a setting value for the display rate of the display device, wherein the setting value corresponds, in dependence on the selected frame rate, either to the selected frame rate or to a product or quotient of the selected frame rate and a whole-number multiplier or divisor; operating the image sensor at the selected frame rate; and operating the display device using the determined setting value for the display rate.