PHP | Imagick compareImageChannels() Function

The Imagick::compareImageChannels() function is an inbuilt function in PHP which is used to return the difference between one or more than one images. Syntax:

array Imagick::compareImageChannels( Imagick $image, int $channelType, int $metricType )

Parameters: This function accepts three parameters as mentioned above and described below:

• $image: This parameter holds the Imagick object which contains the image to compare.
• $channelType: This parameter holds the Imagick channel constants which provides any channel constant that is valid for your channel mode. Use bitwise operator to combine one or more channel constants. Click here to get the list of channel constants.
• $metricType: It is an Metric type constants. Click here to get the list of metric type constants.

Return Value: It returns an array of new_wand and distortion. Errors/Exceptions: It throws ImagickException while error occurred. Below program illustrates the Imagick::compareImageChannels() function in PHP: Program:

php

<?php

// Store the image path into variables
$imagePath1 =
"https://cdncontribute.geeksforgeeks.org/wp-content/uploads/geeksforgeeks-9.png";

$imagePath2 =
"https://www.geeksforgeeks.org/wp-content/uploads/gfg_200X200.png";

$imagePath3 =
"https://cdncontribute.geeksforgeeks.org/wp-content/uploads/negateImage.png";

// Create new Imagick object
$imagick1 = new \Imagick($imagePath1);
$imagick2 = new \Imagick($imagePath2);
$imagick3 = new \Imagick($imagePath3);

// Use compareImageChannels() function to find
// the difference between images
$diff12 = $imagick1->compareImageChannels($imagick2,
        Imagick::CHANNEL_ALL, Imagick::METRIC_MEANABSOLUTEERROR);

$diff13 = $imagick1->compareImageChannels($imagick3,
        Imagick::CHANNEL_ALL, Imagick::METRIC_MEANABSOLUTEERROR);

// Print the difference in array
print_r($diff12);
print_r($diff13);

?>

Output:

Array ( [0] => Imagick Object ( ) [1] => 0.084920034052215 ) 
Array ( [0] => Imagick Object ( ) [1] => 0.63074787218949 ) 

Reference: https://www.php.net/manual/en/imagick.compareimagechannels.php