Detect LED state from image created by Raspberry Pi (raspistill)

test-image.php

<?php

#
# PiCam is placed on Buderus control panel
# /opt/vc/bin/raspistill -ISO 200 -t 3000 -rot 270 -awb shade -o /tmp/test.jpg
#
# Sorry, this may be a poor description
#

$img = imagecreatefromjpeg( "/tmp/test.jpg" );

$size_x = imagesx($img);
$size_y = imagesy($img);
print "Original: $size_x x $size_y\n";

# Ausgabe von einem raspistill-Bild:
# 3280x2464

if ( $size_x != 3280 or $size_y != 2464 ) {
	print( "Fehler: Falsche Abmessungen! Abbruch." );
	exit(1);
}



$percent = 0.25;

$new_width = $size_x * $percent;
$new_height = $size_y * $percent;
print "Verkleinert: $new_width x $new_height\n";
$image_p = imagecreatetruecolor($new_width, $new_height);
imagecopyresampled($image_p, $img, 0, 0, 0, 0, $new_width, $new_height, $size_x, $size_y);

#######

function pixelsAboveThreshold( $spot_x, $spot_y, $image, $threshold ) {

	$pixels_on = 0;
	$range = 10;

	for ( $x = $spot_x-$range; $x < $spot_x+$range; $x++ ) {
		for ( $y = $spot_y-$range; $y < $spot_y+$range; $y++ ) {
			$rgb = imagecolorat( $image, $x, $y );
			$r = ($rgb >> 16) & 0xFF;
			#$g = ($rgb >> 8) & 0xFF;
			#$b = $rgb & 0xFF;
			if ($r>$threshold) {
				$pixels_on++;
			}
		}
	}

	return $pixels_on;

}

# Links oben noch nicht getestet, weil noch kein Sommerbetrieb war
print "Pixel links oben ";
print pixelsAboveThreshold( 152, 153, $image_p, 150 );
print "\n";
# Die anderen drei sind geprueft und passen
print "Pixel rechts oben ";
print pixelsAboveThreshold( 686, 153, $image_p, 150 );
print "\n";
print "Pixel links unten ";
print pixelsAboveThreshold(  85, 455, $image_p, 130 );
print "\n";
print "Pixel rechts unten ";
print pixelsAboveThreshold( 680, 435, $image_p, 150 );
print "\n";

exit(0);

$spot_x = 152;
$spot_y = 477;
$pixels_on = 0;
for ( $x = $spot_x-20; $x < $spot_x+20; $x++ ) {
	for ( $y = $spot_y-20; $y < $spot_y+20; $y++ ) {
		$rgb = imagecolorat( $image_p, $x, $y );
		$r = ($rgb >> 16) & 0xFF;
		#$g = ($rgb >> 8) & 0xFF;
		#$b = $rgb & 0xFF;
		if ($r>200) {
			$pixels_on++;
		}
	}
}

print "Pixel an: $pixels_on\n";

#######

$spot_x = 755;
$spot_y = 187;
$pixels_on = 0;
for ( $x = $spot_x-20; $x < $spot_x+20; $x++ ) {
	for ( $y = $spot_y-20; $y < $spot_y+20; $y++ ) {
		$rgb = imagecolorat( $image_p, $x, $y );
		$r = ($rgb >> 16) & 0xFF;
		#$g = ($rgb >> 8) & 0xFF;
		#$b = $rgb & 0xFF;
		if ($r>100) {
			$pixels_on++;
		}
	}
}

print "Pixel an: $pixels_on\n";

exit(0);

#####

for ( $x = 0; $x < $new_width; $x++ ) {
	for ( $y = 0; $y < $new_height; $y++ ) {
		$rgb = imagecolorat( $image_p, $x, $y );
		$r = ($rgb >> 16) & 0xFF;
		$g = ($rgb >> 8) & 0xFF;
		$b = $rgb & 0xFF;
		if ($r>100 and $r<190) {
			#print("$x:$y  ");
			$line[$y]++;
			if ($y==187) { print("<$x>"); }
		}
		#if ($r>3) { var_dump($r, $g, $b); }
	}
}
var_dump($line);




# Rechte obere Ecke pruefen
#for ( $x = 0; $x < 3280; $x++ ) {
#	for ( $y = 2464-1; $y > 0; $y-- ) {
#		$rgb = imagecolorat( $img, $x, $y );
#		$r = ($rgb >> 16) & 0xFF;
#		$g = ($rgb >> 8) & 0xFF;
#		$b = $rgb & 0xFF;
#		if ($r>220) {
#			#print("$x:$y  ");
#			$line[$y]++;
#		}
#		#if ($r>3) { var_dump($r, $g, $b); }
#	}
#}
#var_dump($line);
#for ( $x = floor(3280*0.8); $x < 3280; $x++ ) {
#	for ( $y = floor(2464*0.8); $y > floor(2464*0.6); $y-- ) {
#		$rgb = imagecolorat( $img, $x, $y );
#		$r = ($rgb >> 16) & 0xFF;
#		$g = ($rgb >> 8) & 0xFF;
#		$b = $rgb & 0xFF;
#		if ($r>3) { var_dump($r, $g, $b); }
#	}
#}