<?php

function neighbourClean($filename, $thresholds, $return=false) {

	if(is_str($filename)) {
		if(!($img = imagecreatefrompng($filename)) {
			return false;
		}
	} else {
		$img = $filename;
	}

	$map = array();
	$width = imagesx($img);
	$height = imagesy($img);


	for($x=0; $x<$width; $x++) {
		for($y=0; $y<$height; $y++) {
			$rgb = imagecolorat($img,$x,$y);

			$r = ($rgb >> 16) & 0xFF;
			$g = ($rgb >> 8) & 0xFF;
			$b = $rgb & 0xFF;

			$gs = (($r*0.299)+($g*0.587)+($b*0.114));

			if ( $gs > 150 ) {
				$map[$x][$y] = 1;
			} else {
				$map[$x][$y] = 0;
			}
		}
	}

	if(!is_array($threshold)) {
		$thresholds = (array) $thresholds;

	foreach($thresholds as $threshold) {
		$rem = array();
		for($x=0;$x<$width; $x++) {
			for($y=0;$y<$height; $y++) {
				if($map[$x][$y] > 0) {
					$n = 0;
					if($map[$x-1][$y] > 0) $n++;
					if($map[$x-1][$y-1] > 0) $n++;
					if($map[$x-1][$y+1] > 0) $n++;
					if($map[$x+1][$y] > 0) $n++;
					if($map[$x+1][$y-1] > 0) $n++;
					if($map[$x+1][$y+1] > 0) $n++;
					if($map[$x][$y-1] > 0) $n++;
					if($map[$x][$y+1] > 0) $n++;

					if($n < $threshold)
						$rem[$x][$y] = 0;
				}
			}
		}

		for($x=0;$x<=$width; $x++) {
			for($y=0;$y<$height; $y++) {
				if(isset($rem[$x][$y]))
					$map[$x][$y] = 0;
			}
		}
	}

	$img2 = imagecreate($width, $height);
	$b = imagecolorallocate( $img2, 0, 0, 0 );
	$w = imagecolorallocate( $img2, 255, 255, 255 );

	$n=0;
	for($x=0;$x<$width; $x++) {
		for($y=0;$y<$height; $y++) {
			if($map[$x][$y] > 0)
				imagesetpixel($img2,$x,$y,$w);
		}
	}

	if($return) {
		return $img2;
	} else {
		imagepng($img2,'clean-'.$filename);
	}
}

?>