Fish Size Calculation with Tail Beat Compensation
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Solution Overview
Problem
Conventional methods for calculating fish length using stereo cameras often result in errors exceeding 2% due to tail-beat motion and deviation errors, leading to inaccurate measurements.
Innovation Solution
A device that uses a stereo camera system to capture multiple pictures at specific intervals, detects the fish and extracts frames where the fish is not bending by measuring camera-tail distance, and selects a frame with an intermediate camera-tail distance for accurate size calculation, adjusting frame rate based on tail beat frequency to reduce system load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional stereo camera methods are used to measure fish length, then the measurement process is simple, but the measurement precision exceeds 2% error due to tail-beat motion
Solution Approach 1:
The system performs preliminary actions by capturing multiple pictures at different time points before final measurement, specifically capturing images at the extreme positions of tail beat motion to establish reference points for accurate length calculation
Solution Approach 2:
The invention transitions from single-dimension conventional measurement to multi-dimensional analysis by capturing spatial-temporal information across multiple frames, using the vertical dimension of tail motion extremes to compensate for horizontal measurement errors
2Measurement precision
If oversampling is used to capture fish motion, then measurement accuracy improves, but the processing load on the system increases heavily
Solution Approach 1:
The system extracts only the essential information needed for measurement by identifying and using only the extreme position frames of tail beat motion, discarding unnecessary intermediate frames to reduce processing load while maintaining accuracy
Solution Approach 2:
Instead of continuous oversampling, the system applies partial action by capturing pictures at specific critical moments (extreme positions of tail beat), achieving sufficient measurement accuracy with reduced sampling frequency and lower processing requirements
Data Source
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AI summary
The disclosure relates to a fish size calculating device, including a camera system (105), a fish detection module (110), a body part detection module (120), a tracking module (130) and a size calculation module (160). The camera system takes a plurality of pictures in time. The fish detection module detects a fish on the plurality of pictures. The body part detection module detects a body part of the detected fish on the plurality of pictures. The tracking module tracks an identical fish among the detected fish on the plurality of pictures. The size calculation module calculates a size of the tracked identical fish.