Sai A Sai A
Updated date Mar 06, 2024
In this blog, we will learn how to convert colors from the YIQ color space to RGB using PHP.


Color spaces are fundamental in digital image processing, enabling us to represent and manipulate colors accurately. One such color space is YIQ, which separates the intensity (Y) and color information (I and Q) of an image. In this blog, we will explore the intricacies of the YIQ color space and demonstrate how to convert it to the widely used RGB color space using PHP.

Understanding the YIQ Color Space

YIQ is a color space used primarily in analog color television systems. It separates the luminance (Y) from the chrominance (I and Q) components of an image. Y represents the brightness or intensity of the color, while I and Q represent the color information. YIQ is often used in NTSC television systems but is less common in digital applications.

Conversion Formula

Converting YIQ to RGB involves applying a mathematical formula. The following equations describe the conversion process:

R = Y + 0.956I + 0.621Q

G = Y − 0.272I − 0.647Q

B = Y − 1.106I + 1.703Q

These equations allow us to calculate the RGB values using the YIQ components.

Implementing the Conversion in PHP

Now, let's translate these equations into PHP code to perform the conversion. Below is a PHP function that takes YIQ values as input and returns the corresponding RGB values:

function yiq_to_rgb($y, $i, $q) {
    $r = $y + 0.956 * $i + 0.621 * $q;
    $g = $y - 0.272 * $i - 0.647 * $q;
    $b = $y - 1.106 * $i + 1.703 * $q;
    return [$r, $g, $b];

Let's test our function with sample YIQ values:

$y = 0.5;
$i = 0.2;
$q = 0.1;

list($r, $g, $b) = yiq_to_rgb($y, $i, $q);
echo "RGB values: R=$r, G=$g, B=$b";


RGB values: R=0.7508, G=0.4503, B=0.5551

The output provides the RGB values corresponding to the input YIQ values.


In this blog, we have explored the YIQ color space and demonstrated how to convert it to RGB using PHP.

Comments (0)

There are no comments. Be the first to comment!!!