Autofocus

Automatic image focal point detection.

Overview

Autofocus is an image analysis library which attempts to determine where the focal point of an image is.

Installation

composer require freshleafmedia/autofocus

Usage

use FreshleafMedia\Autofocus\FocalPointDetector;

$focalPointDetector = new FocalPointDetector();

$point = $focalPointDetector->getPoint(new Imagick('/path/to/image'));

$point->x; // 283
$point->y; // 157

How it works

The algorithm works by picking the busiest area of the image:

1. Detect edges
2. Apply a vignette. This pushes the focus towards the centre
3. Split the image into segments
4. Calculate the average brightness within each segment
5. Pick the segment with the highest brightness

Options

The FocalPointDetector constructor takes a number of options:

new FocalPointDetector(
    segmentSize: 20, // The size of the Segments in pixels
);

Debugging

You can get access to the processed image to see how the focus was determined:

use FreshleafMedia\Autofocus\FocalPointDetector;

$focalPointDetector = new FocalPointDetector();

$focalPointDetector
    ->debug(new Imagick('/path/to/image'))
    ->drawHeatMap()
    ->drawGrid()
    ->getRawImage()
    ->writeImage(__DIR__ . '/debug.jpg');

Tests

Unit tests can be run via composer test

Credits

This library is essentially a PHP port of https://github.com/sylvainjule/kirby-autofocus.

License

See LICENSE