1. What is the HD mode?
The High Definition mode is a completely new algorithm that greatly enhances the quality of Artec Eva and Artec Leo scans.
2. What are the advantages of using the HD mode?
The HD mode can increase the resolution of the scan data up to 2X**In order to get a visible improvement at 0.2 resolution, the “HD Data Density” setting should be set to higher than default, and the object must be scanned well.
The HD mode reduced noise on surfaces
This advantage allows for better reconstruction of small holes, that would otherwise be too affected with noise on the fusion.
HD processing reduces noise on the surface of the model. Scans look cleaner and sharper, and fusion will have fewer surface artifacts
There still may be noise around the model, however, it could be filtered with the "Small objects filter" and can be reduced via "HD reconstruction sensitivity".
Extra noise can be cleared via "Outlier removal"
Improves edge curvature and sharp/thin edges reconstruction
HD mode reconstructs corners and edges more accurately compared to SD mode.
Enhances the reconstruction of hard-to-reach areas and difficult-to-scan surfaces
HD mode allows for capturing thin wires, sharp edges, and capture deeper surfaces when scanning holes.
- Decreases texture bias (false geometry reconstruction originating from high-contrast texture)
If fine geometry isn't necessary, lower resolution (0.7-1.0) may decrease the visibility of such bias even further.
|When HD mode is better||When SD mode is better|
|High resolution needed||Simples shapes are being scanned|
An object has a lot of noise
|No powerful PC for processing|
|QA/ Reverse engineering application||Limited time for scanning and processing|
|An object is difficult to scan and/or has thin parts|
3. How does the HD mode work (for Artec Eva)?
In order for raw Eva scans to be converted into HD, the "Capture raw HD data" setting needs to be enabled before the scanning process is started.
For this reason, it is NOT possible to enhance the quality of scans that were made prior to AS15.1.
The scanning process itself remains unchanged. HD processing is performed after scanning, generating HD versions of the scans while also keeping the “Standard Definition” (SD) scans.
(!) Please note that it is possible to postpone HD processing or run it on a different computer since Artec Studio 16.
Each HD scan will contain up to 32 times more points in comparison to an SD scan. Due to this, HD scans require at least twice more RAM as their SD counterparts.
4. How does the HD mode work (for Artec Leo)?
On the Leo scanner, the "Record HD data" parameter needs to be enabled in “Settings” before the scanning process is started.
The default setting of 1/8 can be used in most cases: this will result in each 8th recorded frame being an HD frame. The 1/4 setting (as seen in the screenshot below) will result in each 4th recorded frame being an HD frame. It means that Leo will record the raw data at least one frame out of eight, and all keyframes with texture to convert them into HD. E.g. when imported to Artec Studio, an SD scan that had 4000 frames, will have 500 in HD at minimum
With the setting enabled, the scanning window will feature an HD Recording button.
Projects scanned in HD will also have a corresponding indicator on their preview thumbnail.
HD scans made with the Leo scanner are processed during import. The user may choose to import the scans in SD or HD, by toggling the “Use HD reconstruction” checkbox in the import dialog window.
It is recommended to import Raw data (by checking the respective checkbox) during project import. It will allow changing density and frame count of HD scans without the need for Leo to be connected.
Because Leo's HD frames take considerably more memory and Leo's frame is higher than the one of Eva, not converting 100% frames to HD allows saving a lot of RAM and processing time.
Reducing the number of HD frames will decrease the amount of hard disk space taken and allow for faster processing.
Increasing the number of HD frames above 1/8 will reduce the risk of potential registration problems, at the cost of a heavy project with a long processing time.
HD: recommended combination of parameters for Artec Leo
HD scans can be saved to the MicroSD card since Artec Leo 1.6 version. Without special encryption HD data can only be imported via an ethernet or Wi-Fi connection. An ethernet connection will provide considerably faster import speeds, and is the recommended way of transferring Leo projects.
5. Can the Artec Eva Lite scanner be used in HD mode?
No, the Eva Lite does not support HD mode.
6. Do the Artec [Space] Spider, Artec Micro or Artec Ray scanners work in HD mode?
No, the HD mode is not available for Artec [Space] Spider, Artec Micro or Artec Ray scanners.
7. What does the "HD-scan reconstruction" setting do?
The "Frame frequency"setting in Artec Studio is the same as it is in Leo - it allows to convert only certain frames to HD.
The purpose of this setting is to decrease the size of the scans and decrease the time which is necessary for processing.
In the majority of cases, the default "Frame frequency" setting is optimal (1/8 for Leo and 1/4 for Eva).
If Leo scans were made with any frame frequency limitation (1/8 by default), the settings in Artec Studio will be set to 1 by default to avoid decimating the frame number too much.
If the user decides to decrease the frame frequency further, a warning will be shown which can be disabled.
The "Frames frequency" setting does not decimate the scan frames by the exact number of frames that's specified in the setting: the keyframe will always be left intact to avoid major geometry loss and registration problems.
However, non-key grames may sometimes contain unique information too - at the edges, or in the scans of objects with difficult to reach and holes
Increase the "Frame frequency" (1/4 or 1/2) when the object has difficult-to-reach areas or when the scanning trajectory wasn't optimal.
Keep the "Frame frequency" at a default setting when the object is scanned from all sides and there are plenty of frames.
“HD data density” is a key parameter for HD reconstruction. It controls the balance between resolution and reconstruction enhancement of the HD mode, and notably impacts the size of the HD-processed scans.
The multiplier number in the “HD data density” setting reflects the number of points that an HD scan will have in comparison to its SD counterpart (e.g. an HD scan processed with the "4x" HD data density setting will have 4 times more points than the corresponding SD scan). The more points the scans will have, the more RAM they will need, and the more time all the algorithms and tools will require during post-processing.
The “HD data density” setting does not affect the duration of the HD reconstruction process that is executed after scanning. The reconstruction process will be of equal duration regardless of the density setting chosen.
HD scans made with the "1x" setting will be of roughly equal size as normal SD scans. The 1x setting is recommended for users with low-end PC configurations or users who value the HD mode mainly for its noise reduction and more accurate edge and corner reconstruction capabilities. A noticeable resolution increase is not to be expected when using the 1x setting.
The default setting for Artec Eva (x4) is the optimal balance between how big the scans are and how much their quality is enhanced, however, it is possible to increase it even further to get better resolution and/or difficulty to reach areas reconstruction.
Higher settings values (x8, x16, x36) will allow for more surfaces to be reconstructed at the edges and will sharpen the fine details even further.
In order to be able to work with density settings, be sure to have enough RAM, because the required amount of memory will increase dramatically with each next density value.
As long as you have raw data, you can re-run HD reconstruction multiple times with different density settings.
8. What is HD reconstruction sensitivity?
The “HD reconstruction sensitivity” setting allows decreasing the amount of noise on the scans.
This setting is similar to "Outlier Removal", but not as aggressive towards the actual object surface - only pieces that aren't connected to the main surface of the scan will be filtered.
Low - removes as much texture bias as possible. It won't smooth any geometry, but the details won't be at their sharpest.
Ultra settings make fine geometry as sharp as possible at the cost of ignoring texture bias
Low and Medium sensitivity are recommended when fusing scans with a lot of noise, texture bias or registration errors.
High and Ultra sensitivity settings are recommended when scans contain excessive noise.
Increasing HD sensitivity settings do not increase the sharpness of larger edges or the accuracy of the object. It is recommended to keep the settings as Low or Medium unless fine geometry in the highest resolution is needed.
9. HD Mode scanning Tips and Tricks
- Avoid capturing unnecessary frames
If the object is more than 4000 frames, please consider scanning and processing without HD reconstruction first.
Move the scanner faster, especially when scanning flat areas. If you scan slowly, please decrease FPS speed to 10 for Artec Eva and 15 for Artec Leo.
Avoid getting unnecessary background objects in the field of view.
- Safe time on erasing
For Artec Eva scans the Base Removal feature only works if "Launch HD reconstruction after scanning" is checked
To make erasing the unwanted objects later easier, make sure that these objects do not touch the scanned object and use the "Lasso" tool to erase them.
Elevating the object above the ground allows to sue the "Cut-off plane selection"
- Make scans easier to manage
Limiting the number of frames per scan makes HD scans more manageable and easier to process manually. We recommend setting the limit of 500-1000 frames per scan
10. HD Mode processing Tips and Tricks
- Copy Transformation Feature (a special tool that allows instantly copying scans registrations from SD to HD) - use when your PC does not have enough resources for large HD scans registration.
How to use:
- Align and register SD scans
- Right Click of SD scan -> Copy Transformation
- Right Click on HD copy of the exact scan -> Paste Transformation
- Repeat for other scans
After the transformation transfer, the position of every frame will be copied giving the HD scans the Global Registration results that SD scans have.
If transformations are copied to an incorrect scan, frames will be positioned chaotically, so check visually all HD scans prior to starting Fusion.
HD scans have superior reconstruction, thus Global Registration registers them better compared with SD scans. If if the maximum resolution is required - please run Global Registration on HD scans anyway.
If you encounter a registration error due to a lack of frames in the Leo HD scan, the best way to solve it without rescanning - import SD scans and register with HD scans or transfer their transformations.
- Subsampling (Smart Subsampling automatically adjusts the input geometry data as required, to speed up the processing. Designed for scans with HD reconstruction, enabling this option can speed up processing in Geometry and texture mode)
We recommend disabling Smart Subsampling in the following cases:
- if you want to decrease the settings lower than recommended to make registration faster
- if you want to increase the settings higher than recommended to boost the registration quality.Decreasing "Subsampling" might cause less reliable registration by Geometry and should be used on feature-rich objects. Increasing "Subsampling" will use more points for the registration, however, will make it longer. We recommend 0.5-0.8 setting for superior registration.
If you plan to work with both HD and SD scans (to transfer transformation later on), it will save your time to user Eraser on similar SD and HD scans, since they have identical coordinates by default
Apply the Eraser for 1000-1500 HD frames for easy processing.
"3D Selection" and "Points" might slow down the working speed
HD scans from Artec Eva and Artec Leo can be successfully fused with a resolution of 0.3. Models made this way will gain additional details and won’t have artificial surface noise.
With a high “Density” setting (8 and higher), the fusion’s resolution may even be increased to 0.2. Use this only if there is fine geometry on the object.
HD data cleans a lot of noise, but if there is residual noise on HD scans, you can run “Outlier removal” on them. Be sure to set the resolution to 0.3, and the noise level to 4 or higher.