PhoXi 3D scanner technology overview

PhoXi 3D scanner – technology overview

The technology behind our PhoXi Scan family of Scanners is based on an Advanced Structured Light Technique.

How conventional light technique works

conventional structured light technique is derived from a stereo vision. In the stereo vision (inspired by a nature of a human vision), one uses a pair of cameras to capture an object from two different perspectives.

For every image point A captured on the first image, an algorithm tries to estimate a corresponding image point B on the second image (using epipolar restrictions). Having the correspondence (the position of the same object point on both images), the algorithm computes 3D position of the captured object point using the triangulation principle.

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Disadvantages of conventional light techniques

While the idea is very simple, the search for image correspondences is an ill-posed problem.

  • The technique is computationally complex
  • It requires a well textured object.
  • Due to the real-world restrictions, the technique is not suitable for industrial use.

Advanced structured light technique

On the other hand, in the advanced structured light approach, one of the cameras is interchanged by a pattern projector, which emits a well defined structured illumination. Most often, the source of the structured illumination is a conventional 2D projector (similar technology used for multimedia presentation). The camera and the pattern projector are located on a well known baseline (determined by a system calibration) and are focused towards the scanning area (Object).

How the advanced structured light technique works:

  1. The pattern projector emits a set of coding patterns projected in a succession, one after another. These coding patterns encodes a spatial information.
  2. Camera captures the scanning area once per every projected pattern.
  3. After that, and for every image point A, the algorithm decodes the spatial information encoded in the succession of the intensity values captured by the image point A, under different structured light patterns.
  4. This spatial information encodes the corresponding “image point B” in the view of the projector.
  5. With the correspondence, the algorithm computes an exact 3D position of the object point.

Why to use Advanced structured light technique

  • The technique works independently of the object’s texture. High 3D reconstruction quality
  • Speed of acquisition.

Comparision of PhoXi Scan versus conventional systems

One of the crucial problem of the conventional systems is a complexness of the pattern projectors. The conventional design based on DMD or LCD technology is expensive and optically ineffective. The most of the light created is lost in the system due to the complex optical setup. This light is than converted to heat. Due to the nature of light sources used in these systems, the depth of field is very limited.

Photoneo PhoXi Scan

Unique custom-designed projection unit

In contradiction, the Photoneo PhoXi family uses own projection system based on a coherent laser radiation. The optical system of the PhoXi projector is optimal, delivering all emitted light to the scanning area. This allows PhoXi to use just passive cooling even in tough industrial environment. The PhoXi pattern projector uses light of a specified wavelength, in addition to high quality glass bandpass filters used in a camera’s optics, the system delivers outstanding resistance to other light sources even in challenging indoor environments with multiple lights.

Other advantage of the PhoXi projection system is high depth of field similar to laser line triangulation systems.

The latest, state-of-the-art sensing “muscles”

  • The PhoXi family uses the latest CMOS sensors from Sony to deliver an excellent performance with a small energy footprint.
  • A collaboration with Ximea ensures an industry leading camera sensing performance.
  • Thanks to the NVIDIA® Jetson™ platform, the system has enough horsepower to power advanced reconstruction algorithms with high resolution and fps.
  • The PhoXi capturing and processing pipeline is capable of delivering 16 million measurements per second, either in 3.2 megapixels at 5 fps, or 0.8 megapixels at 20 fps.

The Software package to support new industrial milestones

All necessary computations are performed by the system’s embedded processing and control unit, which left all client’s processing power for an application. PhoXi is connected with a client’s PC trough GigE using our PhoXi control App. The software API delivers advanced features as adaptive scanning procedures for complicated objects (it can adaptively change the scanning pipeline to compensate the effects of interreflections or high dynamic range), an automatic optimal settings (the system analyse the scanning area and determine the optimal scanning parameters).

The API delivers 3D information alongside 2D texture information.

To support new milestones of Industry 4.0, Photoneo is working on smart SDK packages to make a development of 3D vision applications easy even for non-programmers.

The body build to last, but not to burden your robot

The body of the sensor is build from a high quality carbon fiber. Alongside the beautiful look, the body brings a rigid structure that ensures a long lasting calibration. Our design allows us to cover multiple different applications by changing the baseline of the system (factory setup). Even for the longer baseline, the system remains light and the carbon-fiber ensures a minimal thermal expansion. The mount of the sensor is built from an anodized aluminum, so it is easy to mount to a robotic arm or any other moving system.

Download the product specifications on the PhoXi’s product page.

Not sure if our 3D solution will cover your needs? Request a free skype consultation.