The Working Distance is an important factor in 3D scanning as it affects the quality of the scanned data.
In the FreeScan Combo specifications, the Working Distance for each Scan Mode is provided. This refers to the Optimal Distance for scanning. Scanning at the stated distance will convey the most detailed and accurate results.
In this article, we will focus on the Infrared (IR) Scan mode and its option to edit the Working Distance range.
TABLE OF CONTENTS
- The Effective Scanning Volume
- The Working Distance slider
- The IR Scan Mode Optimal and Working distances
- Portrait Mode
- Object Mode
The Effective Scanning Volume
Before discussing the operation of the Working Distance slider, it is important to note that the region in which the scanner projector beam and cameras sight intersect, together with the minimum and maximum Working Distance, is the volume in which data is to be digitized. Such space is called the Effective Scanning Volume.
In IR Mode, the possibility of adjusting the Effective Scanning Volume allows the user to select the best settings to optimize the scanning process for different objects in the different scenarios.
The Working Distance slider
The Effective Scanning Volume can be easily adjusted by the user through the Working Distance slider.
By changing the minimum and maximum Working Distance, the Effective Scanning Volume is modified. Everything inside this volume, if the conditions to scan a surface are met, is to be digitized.
The IR Scan Mode Optimal and Working distances
In IR Mode the Optimal Working Distance is 300 mm. That means that the most detailed results are obtained when scanning at such distance.
Within the IR Mode, there are two more modes offered: the Portrait and the Object mode. For each of them, the Working Distance range spans differently:
|Scan mode||Minimum Scanning Distance||Maximum Scanning Distance||Scanning Distance Range|
|Portrait||160 mm||1400 mm||≥ 200 mm|
|Object||160 mm||600 mm||≥ 200 mm|
Such different range of Working Distances provides the flexibility required to approach the different nature scans. In the following sections, the use of the Working Distance is discussed.
To optimally scan a person, start by selecting a short Working Distance range centered around 300 mm. The range 160 - 400 mm is suggested.
Since this distance is close to the Optimal Distance, the most detailed results are expected. Use it to scan the person's face and part of the chest and shoulders.
The downside is that, since the Effective Scanning Volume is small, the data gathering process is slower and less data is detected to keep the tracking of the scan:
Once the subject's face has been scanned, set a long Working Distance. It is suggested to set it to its full span: from 160 mm to 1400 mm.
When resuming the scan, return to the face, chest and shoulder area to recover the tracking of the scan.
Since the Effective Scanning Volume has been now extended, the detected areas are large, which leads to an easy tracking and fast data gathering.
The downside is that, since the scan occurs not on the Optimal Distance, the scan might not be as detailed.
In Object Mode, scanning in short or longer Working distance ranges, might be helpful by adapting the Effective Scanning Volume to the environment.
For instance, it can be used to avoid scanning undesired or unnecessary surfaces on the background, such as a wall, thus consuming less PC resources and leading to more efficient scan process: