kotlinのBufferedImageからRGB値を抽出

val img = ImageIO.read(File("test.png"))
for (y in 0 until img.height) {
    for (x in 0 until img.width) {
        val color = Color(img.getRGB(x, y))
        val r = color.red
        val g = color.green
        val b = color.blue
        // img.setRGB(x, y, color.rgb)
    }
}