I need to calculate the human face's rotation angle of face images like the following examples. For example, the first image has rotated 10 degrees to the right or the second image has rotated 90 degrees to the left.
please some on tell me how can I do it.
Dear Zahra Pezhman ,
At the first, you have to determine that you need to detect the
rotation angle among some limited degrees, only 10 and 90 degrees for example, or you want to estimate the exact angle in every moment of time. It is clear that the first goal is easier to achieve only by some traditional features and a efficient classifier like SVM.
Dear Mrs. Zahra Pezhman
The general approach for your purpose is "Rigid registration". It is implemented in two steps:
(1) extract some useful features that describe main foreground of an image. the features should be extracted for both images(the initial image and the rotated image)
(2) estimate the geometric transformation of the matched features in two images.
a sample openCV code can be found in:
https://docs.opencv.org/3.4/dd/d52/tutorial_js_geometric_transformations.html
and a Matlab function can be found:
https://www.mathworks.com/help/vision/ref/estimategeometrictransform.html
,and the following reference described the details:
[1] Hartley, R., and A. Zisserman, "Multiple View Geometry in Computer Vision," Cambridge University Press, 2003.
I hope it can be useful.
Regards
Aslan Modir Thank you for your answer. In my application, the faces have 0 to 90 degrees rotation to the left or right, and I want to get roughly the amount of rotation for each input image.
Ali Kermani Thank you for your answer.
I have only one image in the input that I want to get the amount of the rotation angle. Note that I do not have the original image
Dear Mrs. pezhman
if you don't have original image, you can follow two different approaches:
(1) find specific features or specific organ in face and use a suitable classifiers(such as knn, SVM,...). In this regard, you need a labeled image dataset.
(2) estimate the position of the main organ of a face: "eyes/eye-pair". And then, find roll angle of the eye-pair. the details can be found in the following reference:
" Karaaba, M. F., Surinta, O., Schomaker, L. R. B., & Wiering, M. A. (2015). In-plane Rotational Alignment of Faces by Eye and Eye-pair Detection. In VISAPP (2) (pp. 392-399). "
Regards
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