In this section, in order of sequence, the steps for optimally setting the 3D scanning parameters are presented.
When selecting operating parameters, it is necessary to take into account the individual performance of the PC; for adjustment, you need to connect a scanner and perform preliminary focusing of the optics and calibration.
Some software settings that are suitable for one PC may not be optimal for another, limiting scanning speed or negatively affecting data quality, so it is recommended to select individual settings for each PC.
It is especially important to save the selected scan settings in case of a quick recovery after an emergency reset of all settings or a change in work profile.
<aside> <img src="https://s3-us-west-2.amazonaws.com/secure.notion-static.com/f2a7fe1f-abdd-4b0c-86eb-bffd2a3fdc8e/Exclamation-mark---cropped.png" alt="https://s3-us-west-2.amazonaws.com/secure.notion-static.com/f2a7fe1f-abdd-4b0c-86eb-bffd2a3fdc8e/Exclamation-mark---cropped.png" width="40px" /> Attention!
To restore previously selected user settings, it is recommended to write out especially important ones before updating the software and after updating, replace the default ones with the ones written out.
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Note: In the future, it is planned to implement saving user settings to a file and loading from a file.
The quality and speed of obtaining scans are significantly affected by the software settings of the projector and cameras located in the “Hardware Settings” and on the “Scanning” widget:
Lines/Stripes brightness settings - allows you to adjust the brightness of the projector backlight depending on the color and degree of illumination of the scanned object.
The setting affects the quality of the scan, because if the lines and stripes are not bright enough, then the scans may lack geometry, noise or small holes.
It is not recommended to reduce the brightness of the lines (default 255) as this reduces the contrast between lines and stripes, which increases the noise of scans.
Example 1. The effect of reducing the brightness of the lines on the left 255 and on the right 150.
If the surface of the scanned object has several different colors, then it is recommended to individually correct the brightness of the stripes to scan the surface of each color or matting the surface in one color.
For black surfaces, it is recommended to increase the brightness of the Stripes to get more data.
Example 2. Influence of the brightness of the stripes on the scanning of a black surface. On the left - Poor stripe brightness settings (brightness 150, exposure 50ms. On the right - Good stripe brightness settings (brightness 255, exposure 50ms.
Delay - the amount of time it takes for the projector lights to change during scanning, measured in milliseconds.
Increasing the delay helps in cases where the speed of the cameras is reduced and they do not have time to capture the frame before changing the light, as a result of which artifacts appear on the surface of the scans in the form of torn borders or vertical holes.
The setting affects the quality and time of obtaining a scan, depends on the speed of the cameras and the available data transfer rate on the PC.
Example 3. Dependence of additional delays 0 - 30 - 70 ms for the appearance of artifacts.
The absence of delay in this example demonstrates the appearance of artifacts.
It is recommended to gradually increase the delay with a minimum shutter speed of 16 ms and make several scans, if artifacts are no longer observed, then the delay is chosen correctly.
Cameras Exposure - an electronic parameter that regulates the brightness of the image from the cameras through the driver.
Increasing the electronic shutter speed increases the scan time!
Increasing the shutter speed is useful for scanning black surfaces or in low light conditions.
If you have no skills or have difficulties with selecting the shutter speed parameter, you can use the automatic shutter speed calculation function by following the interface prompts.
If there are black and white surfaces on the scanned object at the same time, it is recommended to turn on the “Second Exposure” option.
If you scan in the single exposure mode, then it is almost impossible to select one optimal exposure for two contrasting colors.
As a result, there may be an excess of brightness on the surface of one color or a deficiency on the surface of the second, which will reduce the amount of data.
In this case, it is recommended to adjust the first shutter speed on a white surface, the second - on a black one.
When setting the second shutter speed on a dark surface, pay no attention on the overbrightened areas. Light surfaces were captured with the first exposure. Using the “Second Exposure” option saves time!
Example 4. Not optimal scanning of a contrasting object with one exposure.
The result - less data on a dark surface, because exposure = 33 ms is optimal for white.
You can set the shutter speed to a dark surface, but then there will be overbrightened areas on a white surface and its scanning quality will decrease.
A solution to the problem is to turn on the second exposure mode.
Example 5. Optimal scanning of a contrasting object with double exposure.
The result is a lot of data on both surfaces, because exposure= 33 ms is optimal for white, and 267 ms for dark.
The time to complete a scan in double exposure mode is longer than in single exposure mode, but the better data quality, saving PC resources by reducing the number of scans, and not having to scan each surface at a separate exposure compensates for the wait.
The projector's frequency is an electronic parameter measured in Hz that affects the quality of the scan.
If horizontal stripes are observed on the images from the cameras, this means that the update rate of the projector and cameras is critically out of sync.
In the case of work with desynchronization, artifacts in the form of stripes will be observed on the scanning surface.
Example 6. Artifacts caused by cameras and projector out of sync.
To eliminate the desynchronization, it is necessary to select from the list the optimal frequency at which there will be no horizontal lines in the views from the cameras.
In most cases, 60Hz is the optimal projector frequency.
It is recommended to set the program frequency in the system settings for the projector.
Drawing method is the choice of the method of displaying the image on the projector.
Changing the method helps in cases when the proportions of the light are broken or distorted, or the light is changing incorrectly.
Rendering methods differ in the performance and quality of scans, so it is important to choose the best one for your PC.
Example 7. The effect of changing the drawing method on the quality of scans with the same projector delay.
| Cameras / Drawing method | GDI | DX | Dxv2 |
|---|---|---|---|
| Version | NG 2022.1 | NG 2022.1 | NG 2022.1 |
| IDS 3880 | 3.66-3.70 | 3.27-3.36 | 3.30-3.32 |
| Daheng MER 630 | 3.38-3.46 | 2.69-2.72 | 2.69-2.75 |
Laptop Intel (R) Core (TM) i5-6300HQ CPU @ 2.30GHz Scanning zone 2, geometry snap number - default, delay - 55, exposure 50
| Cameras / Drawing method | GDI | DX | Dxv2 |
|---|---|---|---|
| Version | NG 2022.1 | NG 2022.1 | NG 2022.1 |
| IDS 3880 | 3.74-3.81 | 3.03-3.09 | 3.04-3.06 |
| Daheng MER 630 | 3.44-3.45 | 2.71-2.78 | 2.72-2.75 |
NUC Intel (R) Core (TM) i5-10210U CPU @ 2.11GHz Scanning zone 2, geometry snap number - default, delay - 55, exposure 50
Example 8. Effect of changing rendering method on scanning performance.
Geometry snap numbers - setting the number of projector highlights when scanning.
The setting is algorithmic and belongs to the current line scanning algorithm.
Decreasing or increasing the number of frames from the default value affects scan speed, surface quality, and data volume.
It has been proven in practice that increasing the number of frames allows you to get more data on parts made of translucent plastic (for example, polyamide).
Example 9. Influence of geometry snap number on the amount of data.
It is recommended to individually select the setting for each PC according to the type of object surface.
It is necessary to find a compromise solution between speed and data volume.
It is not recommended to use a low number of frames - less than 6, because in most cases
scans will contain many holes.
The normal scanning mode is limited to the selection of the most used parameters, when switching to the testmode mode, rarely used values become available.
Cameras frequency - a software setting that is responsible for the speed of the cameras.
The optimal frequency is calculated automatically by the camera driver and usually does not require correction.
It is not recommended to disable the "Auto-detect frequency" option when the scanning is stable.
Example 10: If the camera frequency does not match during scanning, a warning is issued.
If the cameras work unstable with the automatically selected parameter, periodically turning off or a warning is issued, then you can disable the “Auto-detect frequency” option, reduce the frequency parameter and check the stability of the scan.
<aside> <img src="https://s3-us-west-2.amazonaws.com/secure.notion-static.com/e4cad055-3196-4f6a-a77f-6a2f5e037be1/Exclamation-mark---cropped.png" alt="https://s3-us-west-2.amazonaws.com/secure.notion-static.com/e4cad055-3196-4f6a-a77f-6a2f5e037be1/Exclamation-mark---cropped.png" width="40px" /> Attention! If there is no frequency setting for your scanner, this means that the camera driver only supports one operating frequency.
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Camera resolution - a software setting that allows you to select full or reduced camera resolution.
Decreasing the resolution is useful to speed up the scanning process and reduce the volume of scans on the hard drive by reducing the detail of the scans.
Decreasing camera resolution is irreversible for scans, i.e. meshes obtained with a reduced resolution cannot be recalculated to a higher one.
In one project, you can repeatedly change the resolution of the cameras, but it is not recommended to do this, because when combining scans made with different resolutions, the overall detail of the model will be averaged.
The camera resolution set in the project is remembered and when the project is continued after re-opening, the camera resolution previously set in this project is active.
Example 11. Two scans with different software resolution.
Example 12. Difference in acquisition time for scans with different resolutions.
