At botspot, we thrive on pushing the limits of photogrammetry, constantly challenging ourselves with what was once thought to be impossible to scan. While photogrammetry has many advantages in the 3D scanning world, there are well-known disadvantages that come with it, including scanning monochrome, featureless, shiny or reflective objects. This was previously discussed in an earlier challenge we set for ourselves: scanning a white ceramic bowl. In this article, we highlight our recent success story, conquering the task of scanning a shiny fresh bell pepper. At first glance, this vegetable seems deceptively simple, however, this particular object generally cannot be scanned without using scanning spray due to its surface properties. Despite these difficulties, we achieved this raw result:
Photogrammetry relies on capturing high-quality images of an object’s surface to reconstruct it in 3D. By identifying unique visual features on the surface, 3D modeling software such as RealityCapture can analyze the images taken and essentially “patch” them together to create a model. However, objects like bell peppers pose two major challenges for this technology:
Monochrome Surface: The bell pepper’s uniform red surface provides very few visual landmarks for the software to detect and match across images. The fewer features there are, the harder it becomes to accurately reconstruct the geometry of the object. This would usually result in “holes” or bumps in the mesh of the object, creating a rough surface where it should be smooth.
Shiny Reflective Surface: The glossy surface of the vegetable poses significant challenges, as light gets reflected unevenly, causing glares. The software struggles to understand these differences in light, resulting in an uneven bumpy surface on the 3D model.
Color Hues: The color of the object also plays a role in how well it can be captured in 3D using photogrammetry. For example, cameras can struggle with red hues due to lover sensor sensitivity to red light. Red surfaces are also prone to oversaturation, resulting in a loss of detail or higher image distortion. Combined with a shiny surface, these factors make a red bell pepper particularly tricky to accurately capture the object without using scanning spray, giving a result that usually looks a bit like this:
Using our Studio Scanner, we successfully scanned a red bell pepper without using traditional scanning spray. Through controlled polarized lighting, our own digital spray and the scanner’s glass turntable, which are all features incorporated into the scanner, the geometry of the pepper was perfectly captured:
The polarized light controls the reflection of the object, reducing glare and hot spots that confuse the software. Our digital spray projects a pattern onto the object, switching the surface from plain and monochrome to variegated, creating unique points that the software can easily recognize and reconstruct. The glass turntable prevents the need for flipping or repositioning the scan object, so there is no risk of the object changing or moving position.
Our successful red bell pepper scan, without the use of scanning spray, demonstrates our Studio Scanner’s ability to overcome tough challenges in photogrammetry. From the monochrome surface to the difficulties of capturing red hues and the shiny texture, this project highlights our team’s expertise and innovative approach. At botspot, we’re committed to delivering precise, high-quality scans, no matter how complex the object.