以编程方式确定图像的人类可读的颜色（例如红色，绿色等） [英] Programmatically determine human readable color (e.g. Red, Green, etc..) of an image

问题描述

我试图想出一个脚本，将以编程方式运行图像，并告诉我它的基本颜色。

I'm trying to come up with a script that will programmatically run through an image and tell me it's primary color(s).

当前脚本获取每个像素的RGB值。将它们与预定义的规则进行比较，并尝试对每种颜色的像素数进行计数。

Currently the script gets the RGB value of each pixel. Compares them against predefined rules and attempts to count up the number of pixels of each colour.

我的问题是脚本有点击中。有没有人知道这样做的更好的方法（也许使用不同的颜色编码系统，更容易翻译成英语）或一组现有规则通过RGB定义颜色？

My problem is the script is a little hit and miss. Does anyone know of a better way of doing this (maybe using a different colour coding system that's easier to translate to english) or an existing set of rules defining colours via their RGB?

<?php
$file = "8629.jpg";

$colors = array("Red" => array("rel" => true, "r" => 0.65, "g" => 0.09, "b" => 0.25, "var" => 0.3),
                "Blue" => array("rel" => true, "r" => 0.21, "g" => 0.32, "b" => 0.46, "var" => 0.3),
                "Green" => array("rel" => true, "r" => 0, "g" => 0.67,"b" =>  0.33, "var" => 0.3),
                "Black" => array("rel" => false, "r" => 0, "g" => 0,"b" =>  0, "var" => 30),
                "White" => array("rel" => false, "r" => 255, "g" => 255,"b" =>  255, "var" => 30));                 

$total = 0;

$im = imagecreatefromjpeg($file);
$size = getimagesize($file);

if (!$im) {
    exit("No image found.");
}

for ($x = 1; $x <= $size[0]; $x++) {
    for($y = 1; $y <= $size[1]; $y++) {
        $rgb = imagecolorat($im, $x, $y);
        $r = ($rgb >> 16) & 0xFF;
        $g = ($rgb >> 8) & 0xFF;
        $b = $rgb & 0xFF;

        $colorTotal = $r + $g + $b;

        $rRatio = $r > 0 ? $r / $colorTotal : 0;
        $gRatio = $g > 0 ? $g / $colorTotal : 0;
        $bRatio = $b > 0 ? $b / $colorTotal : 0;

        foreach($colors as $key => $color) {
            if ($color["rel"]) {
                if ((($color["r"] - $color["var"]) <= $rRatio && $rRatio <= ($color["r"] + $color["var"])) &&
                    (($color["g"] - $color["var"]) <= $gRatio && $gRatio <= ($color["g"] + $color["var"])) &&
                    (($color["b"] - $color["var"]) <= $bRatio && $bRatio <= ($color["b"] + $color["var"]))) {

                    $colourCount[$key]++;
                    $total++;
                }
            } else {
                if ((($color["r"] - $color["var"]) <= $r && $r <= ($color["r"] + $color["var"])) &&
                    (($color["g"] - $color["var"]) <= $g && $g <= ($color["g"] + $color["var"])) &&
                    (($color["b"] - $color["var"]) <= $b && $b <= ($color["b"] + $color["var"]))) {

                    $colourCount[$key]++;
                    $total++;
                }
            }
        }
    }
}

var_dump($colourCount);

foreach($colourCount as $key => $color) {
    $colourPrecent[$key] = $color / $total;
}

arsort($colourPrecent);
var_dump($colourPrecent);

foreach($colourPrecent as $key => $color) {
    if ($prevVal) {
        if ($color < ($prevVal - 0.1)) {
            break;
        }
    }

    $primary[] = $key;
    $prevVal = $color;
}

echo("The primary colours in this image are " . implode(" and ", $primary));

?>

推荐答案

解决方案是将RGB转换为HSL赫伯特。转换为人类的功能仍然需要一些调整/完成，但在这里是：

Solution was to convert the RGB to HSL as suggested by Herbert. Function for converting to human still needs a little tweaking / finishing off but here it is:

function hslToHuman($h, $s, $l) {

$colors = array();

// Gray
if ($s <= 10 && (9 <= $l && $l <= 90)) {
    $colors[] = "gray";
}

$l_var = $s / 16;

// White
$white_limit = 93;
if (($white_limit + $l_var) <= $l && $l <= 100) {
    $colors[] = "white";
}

// Black
$black_limit = 9;
if (0 <= $l && $l <= ($black_limit - $l_var)) {
    $colors[] = "black";
}

// If we have colorless colors stop here
if (sizeof($colors) > 0) {
    return $colors;
}

// Red
if (($h <= 8 || $h >= 346)) {
    $colors[] = "red";
}

// Orange && Brown
// TODO

// Yellow
if (40 <= $h && $h <= 65) {
    $colors[] = "yellow";
}

// Green
if (65 <= $h && $h <= 170) {
    $colors[] = "green";
}

// Blue
if (165 <= $h && $h <= 260) {
    $colors[] = "blue";
}

// Pink && Purple
// TODO

return $colors;
}

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