compute method

@override double compute(Image image)

Implementation

@override
double compute(img.Image image) {
  final int width = image.width;
  final int height = image.height;

  // Convert image to grayscale
  List<int> gray = List<int>.filled(width * height, 0);
  for (int y = 0; y < height; y++) {
    for (int x = 0; x < width; x++) {
      int pixelIndex = y * width + x;
      final pixel = image.getPixel(x, y);

      // Assuming the pixel object has r, g, b properties
      final red = pixel.r.toDouble();
      final green = pixel.g.toDouble();
      final blue = pixel.b.toDouble();

      gray[pixelIndex] = (0.299 * red + 0.587 * green + 0.114 * blue).toInt();
    }
  }

  // Apply Laplacian filter
  List<int> laplacian = List<int>.filled(width * height, 0);
  for (int y = 1; y < height - 1; y++) {
    for (int x = 1; x < width - 1; x++) {
      int pixelIndex = y * width + x;
      int value = (-4 * gray[pixelIndex] +
              gray[pixelIndex - width] +
              gray[pixelIndex + width] +
              gray[pixelIndex - 1] +
              gray[pixelIndex + 1])
          .abs();
      laplacian[pixelIndex] = value;
    }
  }

  // Calculate variance
  double mean = laplacian.reduce((a, b) => a + b) / laplacian.length;
  double variance =
      laplacian.map((x) => (x - mean) * (x - mean)).reduce((a, b) => a + b) /
          laplacian.length;

  return variance;
}