Object Spin State Estimation Across Variable Video Frame Rates
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Solution Overview
Problem
Existing methods for estimating the spin state of an object, such as a flying ball, fail when the frame rate of the input video is low or high, as they rely on a fixed time interval that may not capture the necessary image components for spin estimation, leading to inaccurate results or reduced recordable time.
Innovation Solution
The method estimates the spin state by using a target estimation image generated by spinning the object image based on a hypothesis of spin state and selecting the hypothesis and time interval that maximizes the likelihood of the target estimation image, regardless of the frame rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the frame rate of the input video is increased to enable spin state estimation at high spin speeds, then the spin state estimation accuracy is improved, but the recordable time is shortened
Solution Approach 1:
The patent makes the time interval parameter w dynamic rather than fixed. The system selects different integer values of w based on the spin speed characteristics of the object, allowing the estimation method to adapt to different frame rates and spin conditions. This dynamic parameter selection enables accurate spin state estimation without requiring a fixed high frame rate, thereby extending recordable time while maintaining estimation accuracy.
2Device complexity
If a fixed time interval tc is used for spin state estimation, then the processing is simplified, but the estimation fails when the spin amount per unit time is large and the frame rate is low
Solution Approach 1:
The patent transforms the fixed time interval tc into a dynamic parameter w that can be selected from multiple integer values. The system evaluates spin state hypotheses with different w values and selects the one that produces the highest likelihood, enabling reliable estimation across varying spin speeds and frame rates without excessive processing complexity.
Solution Approach 2:
The patent changes the parameter w from a fixed value to a selectable integer that represents different time intervals. By testing multiple w values and selecting the optimal one based on likelihood evaluation, the system maintains reliability across different operating conditions while keeping the processing method relatively simple through systematic parameter variation.
3Duration of action of moving object
If the frame rate is kept low to extend recordable time, then the recordable time is increased, but the spin state cannot be estimated when the spin amount per unit time is large
Solution Approach 1:
The patent enables the system to dynamically select appropriate time interval values of w based on the actual spin characteristics. When spin speed is high, the system can choose smaller w values to capture sufficient rotational information even at low frame rates. This dynamic adaptation allows accurate spin state estimation to be achieved without requiring high frame rates, thereby maintaining extended recordable time while ensuring estimation accuracy.
Data Source
AI summary
A target estimation image which is an image of a target at a time point t+w·u obtained by spinning the object in an object image which is an image of the object at a time point t obtained from an input video in time-series by w unit time on the basis of a hypothesis of spin state and an object image at the time point t+w·u obtained from the input video are used, to estimate a spin state of the object by selecting a hypothesis of spin state and w in which likelihood of the target estimation image becomes high from among a plurality of hypotheses of spin states and a plurality of w, wherein an absolute value of W is an integer of 1 or more and u is a unit time.