# Outdoor Content Creation for Holographic Stereograms with iPhone
## 4 Discussion  
The results of this study confirm that ultra-realistic outdoor holograms can indeed be created using simple tools such as strings, smartphones, free phone applications, and free software. The method that produced the best results in terms of speed and quality was the interpolation method. Photogrammetry and Gaussian splatting provided acceptable results but fell short in terms of achieving realism. LiDAR, unfortunately, failed to produce a realistic image under the specific conditions of this experiment. Despite its impressive visual realism and accuracy, the interpolation method does have limitations that affect its broad applicability. It requires a controlled environment free from spatial restrictions and obstacles, making it impractical in varied and uncontrolled settings. The necessity of maintaining a proportional distance relative to the size of the object limits scalability, rendering the method less effective in constrained or expansive scenes. Additionally, complex backgrounds can introduce noise and artifacts that impair the visual clarity of the holograms when interpolated and must be suppressed most of the time. Moreover, this method produces holograms with half parallax, and environmental factors such as lighting and weather conditions can impact image quality, introducing variability and affecting reliability. These limitations underscore the importance of careful planning and consideration when deploying holographic projects using interpolation methods. Nevertheless, despite these drawbacks, the interpolation method remains easy to implement and does not require technical skills or professional equipment, making it accessible to a wider audience. It can be performed with any smartphone or camera. This method allows realistic outdoor content holograms to be developed and disseminated to the public on a larger scale and offers potential applications in various fields such as education, art, and entertainment. 3D methods such as photogrammetry, Gaussian splatting, and LiDAR come with inherent limitations, especially when utilized within free 3D modeling applications. These applications often lack the advanced features and robust processing capabilities found in premium software, resulting in potential drawbacks in terms of processing power and model accuracy. They may struggle with large datasets or complex processing tasks required for high-resolution 3D modeling, resulting in longer processing times and potentially lower-quality models. Additionally, these tools often have limited capabilities for post-processing edits such as texture refinement and quality enhancement, which are crucial for improving visual fidelity. Scalability issues may also arise, as these applications may not efficiently handle extensive image datasets or integrate them seamlessly with other tools or systems. Moreover, while photogrammetry and other 3D modeling methods offer advantages, they cannot match the realistic quality achieved by interpolation methods that use actual images. This advantage makes interpolation valuable for producing highly realistic holograms despite its limitations. However, it is worth noting that 3D methods can achieve full-parallax holograms, providing a more immersive viewing experience, albeit typically requiring specialized hardware like an iPhone. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Method** & **Technology** & **Processing Time** & **No. of Images** & **Visual Quality** \\ \hline Interpolation & Neural Network & 10 min & 11 & High \\ \hline Photogrammetry & Metascan & 42 min & 75 & Good \\ \hline Gaussian Splatting & Scaniverse & 72 min & 2880 & Medium \\ \hline LiDAR & Metascan & 36 min & 1440 & Bad \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparison of the four methods.