Unlocking the Secrets of Photogrammetry

Unlocking the Secrets of Photogrammetry

In the age of digital innovation, the realm of 3D scanning has become increasingly accessible, allowing enthusiasts and professionals alike to capture the beauty of our world in stunning detail. During my recent travels to Turkey and Greece, I embarked on a journey to explore the art of photogrammetry, uncovering the wonders hidden within underground caverns, ancient relics, and timeless sculptures.

Leveraging the power of both photogrammetry and Gaussian splatting techniques, I meticulously scanned the intricate details of these places and objects, capturing their essence in digital form. Through a combination of precise image capture and advanced processing algorithms that Polycam offers, I transformed ordinary scenes and artifacts into immersive 3D models, preserving their beauty and historical significance for future generations to explore and admire

An Underground Cavern in Turkey (Camera view is origin and track route)

Underground Cave Model:

My journey began with the exploration of an underground cavern deep within the rugged landscapes of Turkey. Armed with my trusty iPhone 14 Pro Max, I ventured into the depths of the cavern, eager to capture its hidden treasures through the lens of photogrammetry.

Navigating through the labyrinthine passages, I used the LiDAR mode of the app which captures a video recording inside the cavern’s majestic human legacy representation. Utilizing the advanced capabilities of Polycam and the iPhone’s LiDAR sensor, I processed the images, transforming them into a mesmerizing 3D model that captured the essence of the cavern in stunning detail.

As I went into the heart of the cavern, I encountered several challenges that required careful consideration and planning to overcome. Here are some recommendations based on my experience:

Plan Your Route: Before commencing your photoshoot, carefully plan the route of how you will take shots to navigate around obstacles and potential obstructions. In my case, it was challenging to capture shots without the presence of other explorers in the cavern, so planning the route strategically helped minimize these interruptions.

Use light effectively: The cavern’s environment presented poor lighting conditions, necessitating the use of the few available light sources to capture the depth of objects. Avoid adding extra sources of light, as they may result in unpredictable changes from shot to shot during processing. Instead, utilize existing light sources effectively to highlight the details of the cavern’s formations.

Capture from Multiple Angles: To ensure comprehensive coverage and capture of all details, capture shots from multiple angles. This approach minimizes the risk of missing crucial details and ensures a more accurate representation of the cavern’s features in the final 3D model.

By incorporating these recommendations into your scanning process, you can overcome challenges and achieve stunning results, capturing the essence of underground caverns with precision and detail.

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Digital Twins for VR experiences

Photogrammetry and LiDAR technology are the foundation for creating digital twins of underground caverns and other archaeological sites, laying the groundwork for immersive VR experiences. By capturing detailed 3D models of these sites, researchers can recreate them virtually, allowing users to explore and interact with the environments in virtual reality. This could be a great way to share educational and engaging experiences.

A Mini Obelisk in Greece (difference of Point of Origin)

Obelisk Model:

Continuing my odyssey through the ancient lands of Greece, I stumbled upon a miniature obelisk nestled in the small town of Mesta, Chios. Intrigued by timeless elegance, I embarked on a mission to immortalize this ancient relic through photogrammetry and Gaussian splatting.

I carefully composed each shot, ensuring I captured the obelisk from every angle imaginable. Embracing the simplicity of my setup – a single ambiance light source from the sun was enough to soft glow against the weathered stone, with the backdrop of the ancient architecture framing the obelisk in its historical context.

As I navigated around the obelisk, capturing its details and weathered surface from every angle, I was mindful of the unique requirements for Gaussian splatting processing. To ensure the success of the process, not only was it necessary to shoot from different angles but also different depths to include the fine-line fence surrounding its base. By varying my angles and depths during the photo shoot, I enabled the Polycam Gaussian splatting processor to handle these details with precision, ensuring a faithful representation of the obelisk in the final 3D model.

When shooting photos for Gaussian splatting processing, be sure to capture multiple angles to provide sufficient reference points across the photo sequence. Capturing images from different depths enables the processor to handle fine details and depth variations, especially for features like fences or carvings. Embrace simplicity in your setup to ensure clarity and consistency in the captured images, which allows for a seamless photogrammetry and Gaussian splatting process.

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Architectural Visualization

Architects and designers can leverage NERF and Gaussian splatting to visualize architectural designs and urban landscapes with high fidelity. By reconstructing real-world scenes or conceptual models, professionals can explore spatial configurations, lighting scenarios, and material textures in a virtual environment, facilitating the design and planning process.

It’s worth taking a look at the state of the art of these technologies in this paper: 3D Gaussian Splatting for Real-Time Radiance Field Rendering

A Bust Figurine from Turkey

Figurine Model:

Back home, my new endeavor was to scan a 3D model of a small bust figurine of Hermes, “the messenger of the gods,” which I acquired from the Pumakalle Museum shop in Turkey. Mesmerized by its details and timeless beauty, I captured its essence through photogrammetry.

With the bust figurine as my muse, I initially attempted to scan the model. I set up a green screen backdrop and multiple direct lights, intending to simulate a professional product photoshoot. However, to my dismay, this approach proved to be disastrous for the photogrammetry process. I quickly realized that using multiple elements and varying light sources would yield different results. In the realm of 3D scanning using photogrammetry, consistency is key, and the presence of a green screen only adds unnecessary complexity to the process.

Undeterred by the setback, I started again, opting for simplicity and consistency in my setup. I pared down my setup to essentials: one direct light source to illuminate the bust figurine and one ambient light source to provide overall illumination. Additionally, I placed the figurine on a simple white base to ensure a clean and uniform background for the scanning process.

This minimalist approach proved to be the breakthrough I needed. With a streamlined setup and consistent lighting conditions, I embarked on a new series of scans, capturing the delicate features of the bust figurine with precision and clarity. Each shot was meticulously composed, ensuring comprehensive coverage of the figurine from every angle.

As I processed the images and transformed them into a stunning 3D model, I marveled at the level of detail and fidelity captured in the scan. In hindsight, my journey with the bust figurine of Hermes taught me valuable lessons about the importance of simplicity and consistency in the photogrammetry process. 

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3D printing ready objects

Photogrammetry is a powerful technique that enables the creation of detailed and accurate 3D models from a series of overlapping photographs. By leveraging photogrammetry, businesses, and individuals can generate 3D models ready for printing using additive manufacturing technologies such as 3D printing. Just imagine, we could scan an object and replicate it the same day, we could create spare pieces to repair machines or create new accessories for decoration!

Challenges in Photogrammetry: Overcoming Reflection, Brightness, and Repetitive Patterns

I tried to scan other objects with no success, such as metallic or plastic surfaced figurines, but I understood Photogrammetry is the best approach for these kinds of items. In photogrammetry, capturing objects with reflective surfaces, varying brightness levels, or repetitive patterns can pose significant challenges. Reflections from shiny surfaces can distort the captured images, leading to inaccuracies in the final 3D model. Similarly, objects with extreme brightness levels can result in overexposure or underexposure, affecting the overall quality of the scan. Additionally, repetitive patterns, such as intricate carvings or detailed textures, may be challenging to capture accurately, especially if the patterns are not distinct or if there is insufficient contrast between the elements. These factors can complicate photogrammetry, requiring careful consideration and adjustments to ensure optimal results.

Something you need to try

Throughout this journey, I’ve encountered challenges and setbacks, but each obstacle has only served to deepen my understanding of the complexities inherent in the photogrammetry process. From overcoming reflections and brightness variations to navigating the intricacies of repetitive patterns, I’ve learned valuable lessons about the importance of consistency, simplicity, and meticulous planning in achieving optimal results.

As technology continues to evolve and innovations emerge, the possibilities within the realm of photogrammetry and Gaussian splatting are endless. With each scan, we uncover new insights, preserve our cultural heritage, and push the boundaries of what’s possible in the world of digital imaging. 

Posted by on April 10, 2024