Fish Measuring Device Using Split Illumination and Fish Blocking

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Solution Overview

Problem

Inland aquaculture environments, where fish cages are indoors, face challenges with insufficient upper body brightness and excessive lower body brightness due to limited natural light, unclear fish-background contrast, and difficulty in maintaining distance for accurate fish measurement, especially in high fish density scenarios.

Innovation Solution

A fish measuring device that illuminates fish from above and the side using adjustable intensity and ratio of first and second illuminating devices, incorporates a background board for enhanced contrast, and employs a fish blocking device to manage fish density and distance, allowing for high-quality image capture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If illumination intensity is increased to improve brightness of the upper part of the fish body, then the brightness of the lower part becomes excessive, but measurement accuracy deteriorates

Engineering Contradiction:
Improvebrightness of upper part of fish bodyVSAvoidaccuracy of fish characteristic features
Core Design Contradiction:
Illumination intensityVSMeasurement precision

Solution Approach 1:

The illumination system is divided into two separate illuminating devices: a first illuminating device positioned above the fish pass to illuminate the upper part of the fish body, and a second illuminating device positioned at the side to illuminate the lower part. This segmentation allows independent control of illumination intensity for each region, preventing over-illumination of the lower part while ensuring sufficient brightness of the upper part, thereby maintaining measurement accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different illumination intensities and angles are applied to different parts of the fish body according to their specific requirements. The first illuminating device provides targeted illumination for the upper part, while the second illuminating device provides complementary illumination for the lower part. This local quality approach ensures optimal brightness distribution across the entire fish body without causing excessive brightness in any single region, preserving the accuracy of characteristic feature extraction.

Inventive Principle:
Principle #3Local quality

2Productivity

If fish density is increased to improve productivity, then distance between fish and camera is reduced, but measurement accuracy deteriorates

Engineering Contradiction:
Improvefish density in cageVSAvoiddistance for accurate fish measurement
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The fish blocking device extracts and blocks the excess fish from the imaging region, allowing only a limited number of fish to pass through the fish pass at any given time. This creates a controlled imaging environment where sufficient distance between the fish and camera can be maintained, ensuring measurement accuracy even when the overall fish density in the cage is high. The blocking device effectively separates the imaging zone from the rest of the fish population.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If background contrast is enhanced to improve fish visibility, then boundary clarity is improved, but device complexity increases

Engineering Contradiction:
Improveboundary between fish and backgroundVSAvoidstructure of measuring device
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The background board is designed with a specific color or pattern that provides high contrast against the fish body, enhancing the visibility of fish boundaries in the captured images. This color-based approach achieves improved boundary clarity without requiring complex mechanical or electronic systems. The background board can be simply replaced or adjusted to match different fish species, maintaining device simplicity while achieving the desired contrast enhancement.

Inventive Principle:
Principle #32Color changes

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

Enables accurate fish measurement by ensuring proper illumination and separation of fish from the background, reducing fish overlap, and optimizing image quality for precise size calculation.

Implementation Method 1

the fish pass is illuminated from above by the first illuminating device

Methodology Applied
Scientific EffectLight: Light

Implementation Method 2

the fish pass is illuminated from side by the second illuminating device

Methodology Applied
Scientific EffectLight: Light

Data Source

PatentEP4292430B1Fish measuring device and fish measuring method
Publication Date: 2025.08.27 FURUNO ELECTRIC CO LTD
  • EP4292430B1 patent drawingFigure 1
  • EP4292430B1 patent drawingFigure 2
  • EP4292430B1 patent drawingFigure 3

AI summary

A fish measuring device (1) including an imaging device (30), a background board (60), a first illuminating device (40), a second illuminating device (50), a fish blocking device (70), and processing circuitry (101), is described. The imaging device (30) captures an image of a fish swimming in water. The background board (60) is at least partially placed in a field of view of the imaging device (30). The first illuminating device (40) illuminates a fish pass (A1) between the imaging device (30) and the background board (60) from above the fish pass (A1). The second illuminating device (50) illuminates the fish pass (A1) from a side of the imaging device (30). The fish blocking device (70) blocks a part of the fish pass (A1) on the imaging device (30) side. The processing circuitry (101) is configured to process the captured image of the fish swimming in the fish pass (A1).