Face Recognition

With Uploadcare, you can detect faces in your images for automatic crop or blur those out.


Please note, detect_faces is not divided from file UUID by the /-/ separator. Hence, it can only be used by itself without piping with any other operations.

detect_faces returns coordinates of faces found in an input image. The output is similar to the json operation. The output is a JSON with the additional list faces that holds coordinates of faces that were detected. Data for each of the found faces are put into separate lists that look like this,

[x, y, x_size, y_size]

Further, lists within faces contain:

  • x, y — coordinates of the upper-left corner of an area where a face was found.
  • x_size, y_size — dimensions of that area.

For example, Let’s run a face-check for this image on our CDN,

To do so, we put detect_faces into the image URL separating it with the forward slash / from the UUID,


Then, this faces list will reside in the resulting JSON,

"faces": [
  [45, 142, 207, 207],
  [460, 113, 238, 238],
  [892, 43, 265, 265]

Technically, the operation detects faces using Haar Cascades. That approach deals with machine learning processes which rely on classifiers holding cascades of features specific to faces, eyes, etc.

detect_faces uses an algorithm that tends to better detect fronts of faces, rather than facial profiles. Also, covering important face features with different objects leads to a decline in detection accuracy.

The detect_faces operation is still subject to testing and recalibrating the backend when needed. So, if you ran into any issue with the operation or simply got questions, make a post in our community area.

We’re always happy to help with code, integration, and other stuff. Search our site for more info or post your question in our Community Area.