analyzeBlurLevel static method

String analyzeBlurLevel(Uint8List grayBytes, { required int width, required int height, })

Analyzes blur severity of a grayscale image buffer using Laplacian variance.

Returns a severity string: 'sharp', 'mild', 'moderate', or 'heavy'.

Implementation

static String analyzeBlurLevel(Uint8List grayBytes, {required int width, required int height}) {
  if (grayBytes.isEmpty || width <= 2 || height <= 2) return 'heavy';

  double sumSquared = 0;
  double sum = 0;
  int count = 0;

  for (int y = 1; y < height - 1; y++) {
    for (int x = 1; x < width - 1; x++) {
      final idx = y * width + x;
      if (idx + width < grayBytes.length && idx - width >= 0) {
        final lap = 4 * grayBytes[idx] -
            grayBytes[idx - 1] - grayBytes[idx + 1] -
            grayBytes[idx - width] - grayBytes[idx + width];
        sum += lap;
        sumSquared += lap * lap;
        count++;
      }
    }
  }

  if (count == 0) return 'heavy';
  final mean = sum / count;
  final variance = (sumSquared / count) - (mean * mean);

  if (variance.abs() > 500) return 'sharp';
  if (variance.abs() > 200) return 'mild';
  if (variance.abs() > 50) return 'moderate';
  return 'heavy';
}