• Fig. 3 and Table II shows the actual decrement in the identification
performance of face recognition algorithms due to plastic
surgery. For example, PCA yields 59.3% rank-1 identification
accuracy and when using the non-surgery database (face images
with neutral expression, proper illumination and no occlusion).
On the other hand, the accuracy decreases by ˜30% when
evaluated with pre and post surgery face images. Similarly, the
performance of other face recognition algorithms decreases by
26-30%. This comparison accentuates that plastic surgery is a
very challenging problem and hence it is required to develop
algorithms to confound these effects.
• As shown in Table III, face recognition algorithms cannot handle
global facial plastic surgery such as skin resurfacing and full
face lift. With 10 times cross validation, the performance of
recognition algorithms varies in the range of 18-54% which
is not acceptable in real world applications. In most of the
test cases, for global surgery, differences between pre and post
surgery images of the same individual is very large. In other
words, facial features and texture are drastically altered after
surgery and hence the algorithms do not yield good performance.
For some test cases of skin resurfacing that have relatively
closer resemblance in pre and post surgery images, most of the
recognition algorithms are able to perform correct classification.
However, with major skin resurfacing such as surgeries to look
younger, none of the algorithms are able to correctly classify the
faces. Dermabrasion is another important and common surgical
procedure that affects the face recognition performance.
• Among different types of plastic surgery, Otoplasty, i.e. ear
surgery has lowest effect on the performance of face recognition.
On the other hand, local facial regions such as nose, chin,
eyelids, cheek, lips and forehead play an important role in face
recognition. Any change in one of the regions, in general, affects
the identification accuracy. For example, in LFA, nose and eyes
play an important role and most of the local features are found