# Face Morphing, a Modern Threat to Border Security: Recent Advances and Open Challenges
## 3 The Posed Threat  
Considering the fact that high-quality morphed images, such as the ones shown in Figure 1 can be realistic enough to fool even the trained eye [10,11], the security threat posed by the morphing attack scenario becomes readily apparent.  
From a technological standpoint, as digital image manipulation techniques become more and more advanced, the resulting morphs are expected to be increasingly more difficult to detect. Fortunately, technological advancements work also in favor of mitigating the problem, with increasingly more sophisticated approaches being developed for the automatic detection of morphing attacks. Many of these techniques are going to be presented in the subsequent sections. However, despite these efforts, the proposed techniques are yet to be deployed or even tested under \"real\" attack scenarios, nor is there a standardized procedure in place for evaluating their performance, as it is going to be explained later in more detail.  
What is more, the decision to accept or reject an ID image in face matching scenarios is usually left to a human operator, since, even in cases where automated techniques are initially employed, human users are often required to make the final selection from an automatically selected list of candidates.  
Unfortunately, despite the belief that humans are \"experts\" at face identification, numerous studies have shown that we are basically familiar-face experts but are prone to errors when dealing with unfamiliar faces [12, 13, 14]. Surprisingly (and worryingly), these studies also point out that trained passport officers perform at similar levels to untrained university students when dealing unfamiliar faces, which is especially problematic when dealing with various types of fraudulent identification [15].  
Concerning the issue of morphing attacks, this is perhaps best emphasized by the recent work in [11] (following similar studies presented in [16,17]), aiming at evaluating the performance of humans (with and without training) for the detection of morphed images, in a series of carefully designed experiments using high-quality morphs. In the first two experiments, the participants were asked to identify morphs, before and after receiving training regarding the detection of morphed images. In the first experiment, the task was to correctly classify entries in ten-image arrays containing both morphs and genuine photographs, while the participants of the second experiment were presented with a single image and had to decide on its authenticity. In their third experiment, the authors tested the participants' performance with respect to live face-matching, i.e., their ability to identify whether the person presenting a photograph is the one depicted in it. The general conclusion in all three experiments was that \"naive participants were poor at detecting high-quality morph images and that providing training or tips aimed at improving performance resulted in little or no benefit\". In fact, with few exceptions, the morphing detection performance was barely above chance levels. Furthermore, the authors concluded that \"morphs were accepted as ID photos often enough that they may be feasible as tools for committing fraud.\"