# Unwind: Interactive Fish Straightening

## TL;DR

Unwind is an interactive tool that automatically straightens and untwists volumetric fish scans, facilitating biological analysis by providing canonical pose datasets with minimal user effort.

## Contribution

It introduces a novel interactive visualization system that extracts and unbends fish from volumetric scans using a harmonic function-based skeleton, enabling efficient dataset creation.

## Key findings

- Successfully deployed in marine biology labs for dataset construction.
- Enables rapid and minimal-interaction unbending of fish volumes.
- Supports biomechanical analysis and scientific publication figures.

## Abstract

The ScanAllFish project is a large-scale effort to scan all the world's 33,100 known species of fishes. It has already generated thousands of volumetric CT scans of fish species which are available on open access platforms such as the Open Science Framework. To achieve a scanning rate required for a project of this magnitude, many specimens are grouped together into a single tube and scanned all at once. The resulting data contain many fish which are often bent and twisted to fit into the scanner. Our system, Unwind, is a novel interactive visualization and processing tool which extracts, unbends, and untwists volumetric images of fish with minimal user interaction. Our approach enables scientists to interactively unwarp these volumes to remove the undesired torque and bending using a piecewise-linear skeleton extracted by averaging isosurfaces of a harmonic function connecting the head and tail of each fish. The result is a volumetric dataset of a individual, straight fish in a canonical pose defined by the marine biologist expert user. We have developed Unwind in collaboration with a team of marine biologists: Our system has been deployed in their labs, and is presently being used for dataset construction, biomechanical analysis, and the generation of figures for scientific publication.