Vladimir Goncharov has a tutorial posted to his Medium.com site showing how to integrate machine learning and computer vision into a PHP application using the opencv library. The php-opencv library is a C-level implementation (via an extension) making it easer to use it directly from PHP.

Now, “Machine learning” is developing very fast, it has already written a lot of articles, including the ones on the medium, and almost every developer would like to start using it in their work tasks and home projects, but where to start and what to use is not always understandable. Most articles for beginners offer a bunch of literature, on the reading of which there is not enough life, “inexpensive” courses, etc.

[...] I was considering writing a php-opencv module by myself using SWIG and spent a lot of time on it, but I did not achieve anything. [...] Then I found the library of php-opencv on the github space, it is a module for php7, which makes calls to opencv methods.

He then starts in on the code making use of the library to read in images, perform face detection, facial recognition, and locating facial marks/landmarks. He also includes a section covering the use of neural networks to improve the quality of images, classify them and the use of Tensorflow models to detect certain kinds of objects. The post ends with a look at getting the requirements installed to use the tool and links to other examples.

Maurice Svay has a new blog post that includes a script he's developed to perform facial recognition (detect faces in images) with PHP without the need of the Open-CV library.

OpenCV seems to perform well but you need to be able to install it on your server. In my case, I wanted to have a pure PHP solution, so it can work with most hosts. So I started to think about implementing it myself. [...] I kept searching and finally found a canvas+javascript implementation of face detection at http://blog.kpicturebooth.com/?p=8. The code looked fairly compact and simple. Shouldn't be hard to port to PHP.

The class takes in the filename of an image (just JPG, but could easily be adapted) and a data file to use to run the image through the GD image library and output a JPG similar to this with the face highlighted by a red square.

Robert Eisele has posted on an interesting topic recently - using a PHP interface to the OpenCV library (from Intel) to detect faces in images.

The headline does say facedetection - but what does this mean? Easy said, this article focus on how to find faces on images with PHP. Faces have a certain form and so it is possible to search for it. At the end of the search you will say how many human faces are on the image or better: Where are human faces on my image. This article is not intended to be mathematically.

The OpenCV library is a pattern-detection tool that can, based on the "experience" it has trained on with sample files, do its best to find similar structures in any given image. He's come up with a wrapper that handles most of the details for you. You can define the xml file type (frontalface, lowerbody, upperbody, etc) that you want it to try to match to.

He gives some examples of the output from each on one of the sample images included in the training group as well as a random photo grab from flickr that dynamically tries to apply one of the face filters.