# An Algorithm for Obtaining 3D Egg Models from Visual Images
## 2 Related Works  
Eggs have the shape of an irregular ellipse. This can be determined visually, but the assessment in these cases is too subjective [9]. According to [PERSON] et al. [10], the judicious assessment of the shape of the eggs can be used only in cases where the requirements for the accuracy of the assessment are not very high. A more accurate idea of the shape can be obtained by measuring the diameters of the egg and calculating the index of the shape as a percentage between the small and large diameters of the egg [11; 12]. Optimal hen eggs have an index of 73-75%, and this trait varies both depending on the age of the laying hens and depending on the genotype (breed or hybrid affiliation). The lower the value of the shape index, the longer the shape of the egg, and vice versa--high values indicate an oval shape [13]. According to [PERSON] and [PERSON] [14], the quail egg shape index is in the range of 78-79%, while [PERSON] et al. [15] report slightly lower values (75%). According to the authors, the average sizes of quail eggs are 34.9 mm large and 26.2 mm smaller in diameter. [PERSON] [16] found a positive relationship between the shape index and the mass of eggs, and according to the author, the determination of mass is more strongly influenced by the small diameter of the egg. The shape of the egg affects the resistance of the egg to breakage. [PERSON] and [PERSON] [17] found that the shape index explains 15 to 35% of shell breakage cases. According to [PERSON] [18], a more rounded shape is more desirable because it makes the egg more resistant to manipulation without compromising the integrity of the eggshell. Thisconclusion is supported by later studies by [PERSON] and [PERSON] [19]. By analyzing the shape and its main characteristics, it is possible to create patterns of the shape of some elements of the eggs, for which it is possible to create patterns in which there is a certain stylization of the shape. The main indicators of the shape of eggs by which classification is made are asymmetry, elongation, and pointedness [20], large and small axis [21], as for the division of eggs, eggs of different bird species, and to take into account the factors that influence the formation of the egg fossa. Although for the presentation of these shape indices by transformation of the feature space by the Principal Component Analysis (PCA) method [22], egg separation is not sufficiently accurate and a strong overlap is observed between data on different bird species. The disadvantage of the methods used so far is that only the external shape of eggs is taken into account, without taking into account their internal characteristics [23], which depend on factors such as bird habitat, feeding, and age. From the first definition of the problem with [PERSON] [6], at the current level of science and technology, the problem of describing the shape of eggs still remains partially solved. The proposed solutions are both at the technological level, for example [PERSON] et al. [21], as well as with modern software and hardware tools, as indicated in the review article by [PERSON] et al. [12]. According to the descriptions in the introduction and related works sections of this paper, the shape is the main physical indicator for identifying a large part of the elements of the eggs, during their incubation, packaging, sorting, and transportation. Such studies are also important for ornithology, where analyses of the change in egg shape depending on the bird's habitat are performed. It is mentioned in the technological research, but also in the technical papers in the available literature cited. Using techniques of computer graphics and image analysis, dielectric and ultrasonic characteristics, and spectral and hyperspectral analysis, it is possible to determine freshness, irregular shape, mechanical damage, internal and external defects, bird status, ecology, and sorting and grouping of eggs. The issue of the practical application of the developed models and methods for egg analysis remains insufficiently clear.