The age progression technique to support Missing Children Argentina: A case report

Photo analysis

The first phase involves examining the photographs provided by the family. Lighting conditions and image resolution are evaluated to determine which facial features can be reliably identified. Both overexposure and underexposure can obscure important facial details or make them invisible altogether. ¹⁰

It is also important to assess the orientation of the faces in the photos, as this can affect the visibility of facial traits. Aging parts of the face that are not clearly visible in the original image may result in inaccurate reconstructions.^11,12 Therefore, collecting multiple photographs of the missing person is recommended, as this increases the likelihood of accurately identifying the greatest number of facial features. ¹⁰

Study of facial features

This phase involves analyzing somatic features in the photos of the missing person, including the shape of the face, eyebrows, eyes, nose, and mouth. The same analysis is repeated for the photos of the parents. These facial traits are classified according to standard morphological categories.^13–16

By determining the morphology of the missing person's features and comparing them with those of the parents, it becomes possible to identify shared traits. This comparison helps predict how the missing person's unique features may have changed over time. Parental images can also serve as visual references for the aging process. ¹⁰

Aging process

The technique is carried out using photographic references, which are represented by high-resolution pictures depicting facial traits categorized by shape. The reference images consist of photos of different parts of the face, such as lips, eyes, and nose, which are grouped based on their morphology according to the standard classification. ¹³ Photographic references are selected based on the current age of the missing person, to account for changes occurring as a result of aging phenomena.

Once the needed shapes of facial traits are detected, the age progression is performed through graphical reassembly to obtain an aged portrait of the missing individual.^{5–8,16–28} The process of reassembling the selected facial features is conducted using tools provided by Adobe Photoshop (2022^®). Each image representing a part of the face is merged with the others using the blur tool to prevent the outlines of each inserted image from being visible. Furthermore, tone and brightness adjustments are made using the software's dedicated tools to obtain a homogeneous color tone in the final result. ²⁹

Finally, the result of the age progression technique is added to the poster of the missing person. To create the poster, some information is required, like a photo of the child at the time of disappearance, full name, sex, age, medical conditions or disability, if any, and any unique features, what kind of clothes the child was wearing when he/she disappeared, where he/she was last seen and when, and contact person information in case of sight.

Once the parental consent has been obtained, the poster is shared via social media.

Photo analysis

Different levels of resolution in the available photographic material were observed: the photos portraying the father's (Figure 1(a)) and the mother's face (Figure 1(c)) are of low resolution, which is evident when the image is zoomed in. In contrast, the photo of Camilla has a higher resolution (Figure 1(b)).

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Figure 1.

Photo of Camilla's father (a), Camilla (b) and Camilla's mother (c). Please note that Camilla's eyebrows are wavy (b), similar to her father's (a), while those of the mother are arched (c). The eyefold is absent both in Camilla's and her father's eyes (b, a), while the mother has a lateral eyefold (c). Camilla's upper lip and lower lip are flat (b), similar to those of her parents (a, c). The shape of the nose is similar both in the parent's and in Camilla's face (a–c).

The lighting is homogeneous in the photos of the father and mother (Figure 1(a) and (c)). Camilla's photo shows lighting discontinuities due to more shaded areas and strong illumination on the tip of the nose (Figure 1(b)). Despite this lack of homogeneity, it is still possible to observe the morphology of the facial features.

The facial orientation in all three images is similar, as all subjects face forward in anterior view (Figure 1(a) to (c)). Minor differences are present: the mother's face is oriented slightly upward, Camilla's slightly downward, and the father's is directly frontal (Figure 1(a) to (c)).

Study of facial features

The parents provided only photos depicting them at their current age. The shapes of the facial traits were nonetheless identified, though with lower accuracy.

Camilla's eyebrows are classified as wavy (Figure 1(b)), similar to her father's (Figure 1(a)). Those of the mother are classified as arched (Figure 1(c)). The eyefold is absent both in Camilla's and her father's eyes (Figure 1(a) and (b)), while the mother has a lateral eyefold (Figure 1(c)).

Camilla's upper lip and lower lip are flat (Figure 1(b)), similar to those of her parents (Figure 1(a) and (c)). The shape of the nose is similar both in the parent's and in Camilla's face (Figure 1(a) to (c)), though only partially visible in the parents’ images due to low resolution.

Aging process

The search for the photographic references took into account the physical changes that occur between 15 and 24 years. ³⁰ According to forensic anthropological methodology, skeletal maturity occurs at approximately 21 years of age, making the transition from sub-adult to adult. In the cranial region, bone maturation includes: fusion of spheno-occipital synchondrosis (13–18 years), closure of the jugular growth plate (22–34 years), an increase of approximately 1.5 cm in the opening and nasal height (13–22 years), fusion of the ethmoid and vomer (20–30 years), and fusion of the vomer with the perpendicular plate of the ethmoid (20–30 years). Facial soft tissues do not show visible signs of loss of tone between the ages of 15 and 24. The element that most indicates the progression of facial aging is the migration of facial fat, which moves slightly downwards, following the force of gravity. ¹³

In Camilla's case, all these variations are mainly defined by a lengthening of the nose, a transition from a rounded to a more oval shape of the face, and a slight decrease in fat located in the cheekbone area.

After identifying the photographic references, they were resembled using Adobe Photoshop (2022^®), and tone and brightness were adjusted. The result of the age progression technique was shared with Camilla's relatives, who approved the image. Consequently, a poster was created with the purpose of dissemination (Figure 2).

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Figure 2.

Poster showing biographical info about Camilla's disappearance, her photo at the time of disappearance, her age progression and contact info in case of sight. Please note that the age progression technique predicts morphological changes including lengthening of the nose, a transition from a rounded to a more oval facial shape, and a slight reduction of fat in the cheekbone area.