With Uploadcare, you can detect faces in your images for automatic crop or blur those out.
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
y— coordinates of the upper-left corner of an area where a face was found.
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,
faces list will reside in the resulting JSON,
[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.
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.