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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 | import type { Types } from '@cornerstonejs/core';
import isClosed from '../math/polyline/isClosed';
import { getSignedArea } from '../math/polyline';
/**
* Finds closed contours (islands) that are smaller than the specified threshold.
* This function identifies small closed polylines based on their area.
*
* @param polylines - Array of polylines to analyze
* @param threshold - Minimum area threshold for identifying islands in cm2
* @returns Array of polyline indexes that are islands (closed contours smaller than threshold)
*/
export default function findIslands(
polylines: Types.Point2[][],
threshold: number
): number[] {
if (!polylines || polylines.length === 0) {
return [];
}
if (threshold <= 0) {
return [];
}
const islandIndexes: number[] = [];
for (let i = 0; i < polylines.length; i++) {
const polyline = polylines[i];
// Skip empty or invalid polylines
if (!polyline || polyline.length < 3) {
continue;
}
// Check if the polyline is closed
const isClosedPolyline = isClosed(polyline);
if (isClosedPolyline) {
// Calculate area for closed polylines (use absolute value since we only care about size)
// Convert from mm² to cm² by dividing by 100 (1 cm² = 100 mm²)
const area = Math.abs(getSignedArea(polyline)) / 100;
// Identify closed contours that are smaller than the threshold (islands)
if (area < threshold) {
islandIndexes.push(i);
}
}
// Open polylines are not considered islands, so we skip them
}
return islandIndexes;
}
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