public function colourCalibrate($colours, $expand = 25, $SD = 2)
{
// $colours lists x-coordinate, y-coordinate, and L, a* and b* values for each colour on the checker chart
// $expand = number of pixels plus or minus the reference x and y-corrdinates
// $SD = exclude pixels more than $sd standard deviations from the mean for that area
if (!imageistruecolor($this->_image)) {
return false;
}
$w = $this->getWidth();
$h = $this->getHeight();
$rgb255 = array();
foreach ($colours as $cname => $c) {
// get color from x and y coordinates
$imgcolor = array();
for ($x = $c[0] - $expand; $x <= $c[0] + $expand; $x++) {
for ($y = $c[1] - $expand; $y <= $c[1] + $expand; $y++) {
$rgb = imagecolorat($this->_image, $x, $y);
$imgcolor['r'][] = $rgb >> 16 & 0xff;
$imgcolor['g'][] = $rgb >> 8 & 0xff;
$imgcolor['b'][] = $rgb & 0xff;
}
}
foreach ($imgcolor as $rgb => $valuearray) {
$mode = mode($valuearray, 0.25);
$stdev = stdev($valuearray);
foreach ($valuearray as $i => $v) {
if ($v > $mode + $SD * $stdev || $v < $mode - $SD * $stdev) {
// remove from list
unset($valuearray[$i]);
}
}
$averages[$rgb] = round(mean($valuearray), 12);
$stdevs[$rgb] = round(stdev($valuearray), 4);
$counts[$rgb] = count($valuearray);
}
$rgb255[] = $averages;
$lab = rgb2lab($averages['r'], $averages['g'], $averages['b']);
$deltaE = deltaE($lab, array($c[2], $c[3], $c[4]));
$check[$cname] = sprintf("Lab(%.1f, %.1f, %.1f)\n", round($lab['L'], 1), round($lab['a'], 1), round($lab['b'], 1));
/*
$check .= "--myLab: (" . implode(',', $lab['lab']) . ")\n";
$check .= "--chartLab: ($c[2], $c[3], $c[4])\n";
$check .= "--deltaE = $deltaE\n";
$check .= "--RGB: (" . implode(',', $averages) . ")\n";
$check .= "--SD: (" . implode(',', $stdevs) . ")\n";
$check .= "--N: (" . implode(',', $counts) . ")\n";
*/
if (!is_nan($deltaE)) {
$deltaEs[] = $deltaE;
}
}
$meanDeltaE = round(mean($deltaEs), 4);
$maxDeltaE = round(max($deltaEs), 4);
$patch = $expand * 2 + 1;
$this->setDescription(array("colour calibrate" => array("path dimension" => "{$patch} x {$patch}", "SD" => $SD, "deltaE" => array("M" => $meanDeltaE, "max" => $maxDelta), "check" => $check)));
/* MATLAB code ************************************
% Calculate camera Characterisation - Least Squares fit of rgb to Lab patches:
rgb = Rgb_vals/255;
for i = 1:length(rgb)
train(i,:) = rgb2rgbpoly(rgb(i,:),11);
end
R=train\spectrod65;
% Calculate predicted lab values from characterisation
lab_calc = train*R;
squaredDifference = (lab_calc-spectrod65).^2;
meanDeltaE = mean(sqrt(sum(squaredDifference')))
maxDeltaE = max(sqrt(sum(squaredDifference')))
**************************************************/
include_once "Math/Matrix.php";
foreach ($colours as $v) {
$spectrod65[] = array($v[2], $v[3], $v[4]);
}
foreach ($rgb255 as $i => $v) {
foreach ($v as $j => $c) {
$rgb1[$i][] = $c / 255;
}
}
foreach ($rgb1 as $v) {
$train[] = rgb2rgbpoly($v, 11);
}
$rgbM = new Math_Matrix($rgb1);
$trainM = new Math_matrix($train);
return $this;
}
function image_lab($image)
{
$width = imagesx($image);
// echo "width: " . $width . "-";
$height = imagesy($image);
// echo "height: " . $height . "<br/>";
$thumb_width = 4;
$thumb_height = 5;
$thumb = imagecreatetruecolor($width, $height);
// echo $thumb . "<br/>";
imagecopyresampled($thumb, $image, 0, 0, 0, 0, $thumb_width, $thumb_height, $width, $height);
$lab = array();
for ($x = 0; $x < $thumb_width; $x++) {
for ($y = 0; $y < $thumb_height; $y++) {
$index = imagecolorat($thumb, $x, $y);
$rgb = imagecolorsforindex($thumb, $index);
$lab[] = rgb2lab(array($rgb['red'], $rgb['green'], $rgb['blue']));
}
}
return $lab;
}
$filecontents = "x,y,L,a,b\n";
if ($_POST['ignore_mask'] == 'true') {
$mask_color = imagecolorat($image, 0, 0);
$return['ignore_mask'] = $mask_color;
} else {
$mask_color = -1;
$return['ignore_mask'] = $mask_color;
}
for ($x = 0; $x < $return['width']; $x++) {
for ($y = 0; $y < $return['height']; $y++) {
$color_index = imagecolorat($image, $x, $y);
if ($color_index != $mask_color) {
$r = $color_index >> 16 & 0xff;
$g = $color_index >> 8 & 0xff;
$b = $color_index & 0xff;
$lab = rgb2lab($r, $g, $b);
$l = round($lab['L'], 4);
$a = round($lab['a'], 4);
$b = round($lab['b'], 4);
$filecontents .= "{$x},{$y},{$l},{$a},{$b}\n";
}
}
}
if (file_exists($filename)) {
unlink($filename);
}
if (!($file = fopen($filename, 'w'))) {
$return['errorText'] = "Could not open the file {$return['newFileName']}";
} else {
if (!fwrite($file, $filecontents)) {
$return['errorText'] = "Could not write to the file {$return['newFileName']}";
