Augmented Reality book
A specific didactic material based on the MagicBook format was developed. The MagicBook brand is one of the most popular examples of educational books that use an AR interface to mix reality with virtual images 
To make such a book with augmented reality, a 3D reconstruction of anatomical structures from medical images obtained by CAT was performed.
The images were processed by the software OsiriX®, which is a software distributed under a GNU license that incorporates a DICOM viewer, a PACS system and a third 3D reconstruction module.
Later, the LabHuman company together with Virtual Medical Vision 3D® used the *.stl files to perform the definitive reconstruction of all the structures and the subsequent codification of the augmented reality to be able to implement it in the book along with the necessary markers. To visualize the 3D aspects of the book, a computer with a dedicated graphic card, the capacity for 3D graphics supported by DirectX 9.0c or higher and a webcam that supports a minimum resolution of 640x480 at 30 fps is necessary.
This study consists of level 1 augmented reality because the book has the ability to be viewed on the computer. At this level of AR, the activators are markers, i.e., figures that when we scan them normally, provide a 3D model that overlaps with the real image. In addition to having interaction ability, the didactic material shows the surgery step-by-step as the user successively presses the "enter" key of the computer. In this way, the student can take the necessary time to assimilate each surgical step.
Thus, a textbook with print markers of AR is the object of the main interface. Students can turn the book pages, look at the photos and read the text without the need for any additional technology. However, if users look at the pages on a computer screen and use a webcam, they can see virtual 3D models appear on the pages (Figure 1), thereby introducing an interesting path for the development of new didactic materials.
Ethical approval was obtained from the Research Ethics Committee of Valencia Catholic University (ref. no. UCV2017-2018-114).
Within the classes taught in the university’s master program is that of Surgical Techniques II, which includes the topic of traditional 5th metatarsal surgery using PowerPoint and video presentations; for the use of augmented reality, the topic of middle-stage hallux valgus surgery was chosen. The sessions lasted approximately 2 hours for each topic.
Augmented reality use allows greater flexibility and adaptation to the students´ interests. The book enriched with augmented reality provided the possibility of connecting with what was said in other sessions, of emphasizing and influencing key elements, of integrating different perspectives and of building better mental images to accompany the interactive narrative of the teacher for the student groups. The use of small groups helped to highlight the issues that emerged and, unlike video presentations, where the sequence of images is predetermined, augmented reality allowed real-time interaction regarding both the surgical sequence and the foot view.
Second, the students had the same material used by the teacher in class available for deeper understanding and self-study. This self-study work is essential to create the necessary mental images that allow podiatrists to generate virtual mental images during minimal incision surgeries where the intervention should take into account the presence of structures that are not going to be directly visible.
To evaluate the didactic materials, a questionnaire  validated both by the Delphi method before and by statistical analyses afterwards (Cronbach’s alpha, ANOVA with the Friedman and Tukey’s tests and factorial analysis) provided relevant information on how the use of augmented reality material contributed to the students’ learning.
The Cronbach’s alpha calculation was performed for the internal validation of the questionnaire, which obtained a value of 0.875; in addition, the questionnaire was grouped into 4 components, which explained 65% of the variability.
The experiment was carried out during the last 4 courses in the 2013-2017 academic years, with a total of 80 students, of which 48 were men and 32 were women. The average age was 32.37 years old.
The results were analysed using the statistical software package SPSS version 21 (SPSS, Inc., an IBM Company, Chicago, IL), and p ≤ .05 was considered significant.
A t-test was performed for related samples by comparison of the means of two variables of a single group.