Using K-means Clustering algorithm to identify picture main tone _php Tutorial

Because the use of PHP to write the main color recognition function is too much trouble, so I would like to introduce the use of K-means clustering algorithm to identify the image of the main tone method, than PHP 100 times times Oh.

Identify the main color of the picture this, there seem to be several methods on the net, but the most accurate and elegant solution is to use clustering algorithm to do ...

Directly on the code .... However, my test results show that with PHP to do, inefficient, PHP is not suitable for this large-scale operation ~ ~ ~, with Nodejs efficiency can be about 100 times times higher ...

The code is as follows

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$start = Microtime (TRUE); Main (); function Main ($img = ' colors_files/t1ox3exldxxxcqfym._111424.jpg ') { List ($width, $height, $mime _code) = getimagesize ($img); $im = null; $point = Array (); Switch ($mime _code) { # jpg Case 2: $im =imagecreatefromjpeg ($IMG); Break # png Case 3: Default Exit (' Wipe, what image? Can not parse ah '); } $new _width = 100; $new _height = 100; $pixel = Imagecreatetruecolor ($new _width, $new _height); Imagecopyresampled ($pixel, $im, 0, 0, 0, 0, $new _width, $new _height, $width, $height); Run_time (); $i = $new _width; while ($i –) { # Reset Height $k = $new _height; while ($k –) { $rgb = Imagecolorat ($im, $i, $k); Array_push ($point, Array (' r ' = = ($rgb >>) & 0xFF, ' g ' + = ($rgb >> 8) & 0xFF, ' b ' + = $RGB & 0 XFF)); } } Imagedestroy ($im); Imagedestroy ($pixel); Run_time (); $color = Kmeans ($point); Run_time (); foreach ($color as $key = $value) &nb Sp { Echo ' '. Rgbtohex ($value [0]). "; } } function Run_time () { Global $start; Echo ' Consumption: ', Microtime (TRUE) – $start; } function Kmeans ($point =array (), $k =3, $min _diff=1) { Global $ii; $point _len = count ($point); $clusters = Array (); $cache = Array (); for ($i =0; $i < $i + +) { $cache [$i] = $i * $i; } # randomly generated K-values $i = $k; $index = 0; while ($i –) { $index = Mt_rand (1, $point _len-100); Array_push ($clusters, Array ($point [$index], Array ($point [$index])); } Run_time (); $point _list = Array (); $run _num = 0; while (TRUE) { foreach ($point as $value) { $smallest _distance = 10000000; # Find the point with the smallest distance # index is used to hold the nearest K value of point $index = 0; $i = $k; while ($i –) { $distance = 0; foreach ($value as $key = $p 1) { &n Bsp if ($p 1 > $clusters [$i][0][$key]) { $distance + = $cache [$p 1-$clusters [$i][0][$key]]; } Else { $distance + = $cache [$clusters [$i][0][$key]– $p 1]; } } $ii + +; if ($distance < $smallest _distance) { $smallest _distance = $distance; $index = $i; } } $point _list[$index] [] = $value; } $diff = 0; # one 1 Iteration k value $i = $k; while ($i –) { $old = $clusters [$i]; # Move to the center of the queue $center = Calculatecenter ($point _list[$i], 3); # forming a new K-value collection queue $new _cluster = Array ($center, $point _list[$i]); $clusters [$i] = $new _cluster; # calculates the position of the new K value and the point of the queue $diff = Euclidean ($old [0], $center); } # Determine if aggregation is sufficient if ($diff < $min _diff) { Break > } } Echo ' and '. $ii; return $clusters; } # Calculate 2 point distance $ii = 0; function Euclidean ($p 1, $p 2) { $s = 0; foreach ($p 1 as $key = $value) { $temp = ($value – $p 2[$key]); $s + = $temp * $TEMP; } return sqrt ($s); } # move the K value to the center of all points function Calculatecenter ($point _list, $attr _num) { $vals = Array (); $point _num = 0; $keys = Array_keys ($point _list[0]); foreach ($keys as $value) { $vals [$value] = 0; } foreach ($point _list as $arr) { $point _num++; foreach ($arr as $key = $value) { $vals [$key] + = $value; } } foreach ($keys as $index) { $vals [$index] = $vals [$index]/$point _num; } return $vals; } function Rgbtohex ($r, $g = ", $b =") { if (Is_array ($r)) { $b = $r [' B ']; $g = $r [' g ']; $r = $r [' R ']; } $hex = "#"; $hex. = Str_pad (Dechex ($r), 2, ' 0′, str_pad_left); $hex. = Str_pad (Dechex ($g), 2, ' 0′, str_pad_left); $hex. = Str_pad (Dechex ($b), 2, ' 0′, str_pad_left); return $hex; } ?>

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