We greet you.
We tested a 3D scanner from the world famous company Hewlett Packard – HP 3D Structured Light Scanner Pro S3. This scanner uses SLS structured light technology. The essence of the technology is that various template images are projected onto the scanned object using a conventional LED-DLP projector. A camera installed nearby captures the resulting distorted images. After that, a special program for these distortions evaluates the shape, depth, details of the object and converts all this data into a three-dimensional image.
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By and large, this scanner is not new and is a DAVID SLS-3 3D scanner. Hewlett Packard bought out DAVID with all their developments and now produces this scanner under its own brand. The device itself has undergone almost no changes. The appearance of the software has changed, but all the basic functionality remains the same.
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The scanner consists of several components. The projector is, oddly enough, Acer K132 with a resolution of 1280×800 and a brightness of 500 lumens. Camera – HP 3D HD Camera Pro 2.3MP. The camera and the projector are mounted on a special slide rail. And the camera, in turn, is also fixed to a special swivel mount. The slider has a ruler and holes for fixing the projector in different places. The degrees of rotation are marked on the swivel camera mount. This whole structure is mounted on a Hahnel triad 40 lite tripod.
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The kit also contains all the necessary wires for connection and a USB key-flash drive, it also contains the software. For calibration, two glass panels are used, with markers of different sizes applied to them on both sides. The panels are interconnected by flexible fasteners and installed on special plastic corners. Additionally, for this scanner, you can buy one more camera, there is also a turntable. But this one has one camera and no table.
The manufacturer promises scanning accuracy up to 50 microns (0.05% of the total object size), while the size of the model can be from 6 to 50 centimeters.
Let’s move on to preparing the scanner for work. Out of the box, the camera and lens are already attached to the rail. You just need to mount it all on a tripod using a special mount. The camera is initially installed to the left of the projector. This option is suitable for scanning objects up to 350mm. In case you need to scan an object larger than 350mm, the camera must be installed to the right of the projector. To do this, you need to unscrew the projector mounting wing and rotate it 180 degrees. After that, unscrew the restraining bolt from the edge of the guide, unscrew the camera fastening thumbs, remove the camera from the guide, turn it 180 degrees and fix everything back. The distance from the camera to the projector and the angle of its rotation depends on the size and type of the scanned object, we will adjust them before calibration.
Next, you need to connect the projector to the power supply and to the computer using an HDMI cable. The camera is connected to the computer with a USB 3.0 wire and is powered by it. We turn on the projector, in the operating system you need to configure it as a second monitor. After that, you need to install the software. This can be done from the USB stick that comes with the kit, or downloaded from the HP website. A complete installation will install all required drivers automatically. The projector should show a table with horizontal and vertical lines.
And so, launch the installed HP 3D Scan program. The recommended system requirements for it are not very high: a 2GHz dual-core processor, 8GB of RAM and an Nvidia or AMD graphics card. But, naturally, the more powerful the computer, the faster the processing will take place.
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In the first tab, Settings, you need to select the type of scanner, in our case it is HP 3D Structured Light Scanner Pro S3. Projector – Acer K132. And turn on the camera, we have it HP 3D 2.3MP Cam PRO. On the right there is an exposure setting (or rather shutter speed), as a rule, it should be set to 1/60 so that there is no flicker. And the brightness, it is better to always keep it at maximum.
It is advisable to choose objects for scanning without transparent or reflective surfaces. It is also not desirable for the subject to be very dark or black. The black color absorbs light, making the projected image very difficult to see on the camera. If the object does not meet these conditions, it is necessary to cover it with a special matting spray. On the contrary, the background when scanning, it is better to use black, then there will be no need to remove it. If this is not possible, the program can automatically remove the background, but more on that later.
For the first test, we chose a rather difficult object to scan, such as an elephant. It has a complex relief in some places, protruding elements, and besides, it is rather dark, which makes scanning even more difficult.
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You need to set up your projector and camera. We expose the projector in such a way that the image falls on the entire object and is slightly larger than it. Keep in mind that during scanning, the object will need to be rotated, and it is desirable that it be highlighted in any position. Now you need to focus the projector, this is done using the adjustment lever on the top of the projector. The intersection of the center lines of the projected image must be clearly in focus on the scanned object.
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Let’s move on to the camera. The angle of rotation is 20 to 30 degrees. Typically, the optimal angle is 22 degrees. When scanning large objects or objects with deep holes, it may be necessary to decrease the angle, but distortion and noise may appear at an angle less than 20 degrees. For flat objects it is better to use an angle greater than 22 degrees, up to 30. In our case, the standard 22 degrees is fine. Now you need to align the camera with respect to the projector. We loosen the thumbscrew of its fastening and move it along the guide so that the projected image and the scanned object get into the lens.
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There are two adjustment rings on the camera lens. Closer to the edge – the focusing ring, behind it – the diaphragms. Both rings have locking bolts. The aperture should be set so that the scanned object is not overexposed, but not too dark. So that the projected image can be seen on it.
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Focus should be such that the intersection of the center lines is clear. For convenience, you can zoom in on the image in the program using the mouse wheel. The fixing bolts must be tightened so that the settings do not get lost.
You can now calibrate the scanner. The calibration panels have 4 blocks of different sized dots, three on one side and one largest on the other. You need to calibrate the scanner against the block that is slightly larger in size than the scanned object. For example, for this bishop the third block, the last but one in size, should be suitable. The second block is already too small for him, and the largest is already too large.
We install the calibration panels so that the required block is folded inward.
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We install the scanner in front of them at a distance corresponding to the distance to the scanned object, the picture from the projector and the image from the camera should be as clear as possible. The frame should contain from 15 to 70 points of the selected block. In the field “scaling calibration” you need to specify the block size, it is indicated near the vertical line, next to each block. For the third block it is 120mm. Click on the calibration button. The projector will display several patterns in turn. And if everything was set correctly, a checkered black and white picture will be shown like a checkerboard.
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After calibration, the entire structure can be moved and tilted, but the camera’s distance from the projector, its rotation angle and focus cannot be changed. The manufacturer claims that the diaphragm cannot be changed either. But empirically it turned out that when scanning dark objects, sometimes it is necessary to do this. Because if the template is visible on the model, it will be overexposed on the calibration panels. Conversely, if everything is visible on the panels, the template will be too dark on the model. So this time, for this elephant, the diaphragm had to be slightly opened during scanning, after the calibration.
You can proceed to scanning. In the item “template parameters” you can select the number of templates that will be projected onto the model in one scan, the more there are, the better the quality of the resulting scan.
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There are 4 options: Quality, Default, Speed, and Custom. There are quite a lot of folds and other small elements on the elephant, so let’s choose “Quality” for it, these are 62 templates.
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There are also 4 scanning modes. Single scan – it can be useful if you scan an object from one side, for example, to obtain a relief. Manual scan sequence – scanning an object several times from different sides, rotating it yourself. Automatic turntable – speaks for itself. And background scan – to use this function, you need to remove the scanned object, scan only the background. Then, upon further scanning, the program can automatically remove it from all scans. We will rotate the elephant manually on a black background, therefore it is not necessary to scan the background, and we will choose the mode – manual sequence.
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Next, you need to choose how the object moves. Free movement, horizontal turns or manual rotary table. Free movement is fine for this and most situations.
Automatically register texture – with this function the scanner will capture not only the relief, but also the colors of the object with textures. Thus, you will get a full color 3D model. This can be useful not only for beauty, but also help the program in the future, when comparing scans. But scanning and processing time will increase slightly.
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Below in the field “scan result” you can adjust the anti-aliasing parameters, validation of fixed points, filtering and removal of parts that are smaller than the largest integral part. The manufacturer recommends not changing these parameters unnecessarily. And then you can turn on the checkbox – Background removal. If the background was previously scanned, it will automatically install.
Let’s proceed directly to scanning. You can manually press the scan button (or the F5 hotkey), rotate the object, and press the button again. Alternatively, you can check the “Automatic next scan” checkbox then the program will count down a few seconds before automatically making the next scan. Moreover, if you move the object at this moment, the counter will be automatically reset. Thus, the next scan will be done only when the object is stationary.
For this elephant, we will not scan the textures and set an automatic next scan so that we do not have to press the button every time. We direct the projector at the object so that the template completely illuminates it. And press the scan button. After each scan, we rotate the model a little so that the scans have enough common elements for subsequent comparison. And so a full circle. The manufacturer recommends taking 6-8 shots, but the more shots there are, the easier it will be for the program to match the scans and the more details it will be able to capture.
After one full circle, you can raise the scanner on a tripod, tilt it from top to bottom and scan the object at a different angle to fix horizontal planes that were not in the frame.
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The same can be done from below. If it is not possible to raise the scanner high or low enough, the object can be turned over by itself.
When scans have been made in all possible positions, you can click on the “end sequence” button. The program will automatically try to match all scans with each other. In most cases, scans will match well, provided they have enough general shapes. If any unnecessary fixed elements get into the camera lens, they can interfere with the comparison. Then, before clicking the “complete sequence” button, you need to go to the “form merge” tab. In the purification block, you can select the selection method.
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Select unnecessary objects and delete them by pressing the button with a cross in the same block, or by pressing the DEL hotkey. And after that, return to the scanning tab and complete the sequence.
If the automatic matching did not work as expected, you can manually match the scans in pairs. To do this, select “arbitrary” in the “form merge” tab in the “alignment” block.
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Select two scans with common shapes, they will be automatically matched. In order for the screen to display not all scans at once, you can click on the eye icon in the list of scans at the top. And click on the same icon next to the required scans to display them.
If such a comparison did not work, you can check the “contact pair selection” checkbox.
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This will make it possible to manually mark on each scan the same elements by which the program will navigate. You can enable “use texture” if scanning was done with textures. As well as “use surface features”, this will also improve matching, but also increase processing time. Already aligned scans can be combined into groups, then, when combined with the next scan, the program will use the group as one whole scan.
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After this manual alignment, you select the “global high precision alignment” alignment. The program will neatly and accurately fit the previously aligned scans. Before high-precision alignment, it is advisable to split the scans combined into groups back.
If some areas of the scanned object are not visible on the scans, you can always make a few more scans from the desired sides.
As a result, about 30 scans were made for this elephant from different sides, top and bottom. But it must be borne in mind that this object is rather complex and dark. The camera could not always see and fix surfaces evenly. But as a result, it turned out to collect a whole elephant from the scans. The scan took about 20 minutes.
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At this stage, it is a point cloud. Now you can assemble it into a full-fledged 3D model – mesh. To do this, we will use the “merge” block. There are 3 parameters, resolution, sharpness and close holes. Resolution marks the quality of the final model, increasing this parameter greatly affects the processing time and the use of computer resources. Sharpness, responsible for smoothing. Decreasing this parameter will make the model blurry and hide flaws. On the contrary, magnification will make the model clear, but the flaws will become more noticeable. The hole closure speaks for itself.
In most situations, the standard parameters are sufficient. This elephant ended up with the default settings.
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You can export a model in several formats – STL, OBJ, PLY and 3MF
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For the second test, we tried scanning a smaller object. Here is a dental cast printed on an SLA printer.
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The dimensions are only 7.5x5x3 centimeters, that is, almost the minimum for this scanner.
Of course, there is no special sense in scanning what has already been printed, but for an example it will do. The result was a pleasant surprise, the quality was very good. Detailing at height. The scanner was able to see even the slightest transitions between layers, and printing flaws. Despite the fact that they are quite difficult to see even with your eyes.
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It should be noted that the scanner perceives color changes on the scanned object as small relief changes. So, for example, there are some light-colored scratches on these teeth. And on the final model, they look like protruding stripes. But all these shortcomings can be easily corrected with further post-processing, for example, in Meshmixer. Unfortunately, no 3D scanner gives a perfect result that does not require post-processing.
Scans for this test took only 10, 8 from one angle, one slightly higher and one slightly lower.
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When scanning, especially such small objects, the scanner is very sensitive to vibration. Roughly speaking, even a printing printer standing a meter away from it can create enough vibrations, due to which waves are obtained on scans. Walking near the scanner at the time of scanning is generally contraindicated. While the tripod seems to be sturdy and reliable, the heavy part with the projector and camera is very sensitive to any vibration. Due to the fact that our specimen does not have a turntable, these teeth had to be turned very carefully during scanning, without making sudden movements and practically not breathing.
In any case, the result of this test is very decent. Considering that very few scans were required, they were matched automatically without problems. Glued into the model quickly. In total, this scan took no more than 10-15 minutes.
And the third test we did was with a bigger part. This is a part of the intake manifold, also printed on an SLA printer, it was not possible to get the real part.
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Its width is 34 centimeters, not the maximum for this scanner, but quite large. The part is difficult to scan, has many thin elements, depressions and holes. It was really difficult to scan it. Despite the fact that a turntable in this situation would not help. The part had to be twisted, turned over at different angles, shown to the scanner from all sides. There was no black background of this size, so I had to scan on white. As we have already mentioned, you can make it so that the background is automatically removed from the scans. To do this, you need to scan it without a model at the very beginning. The background is removed, but not always entirely, leaving small areas at a short distance from the model. They can be removed without any problems, but because of this, the scan time takes much longer. When scanning large objects, the accuracy is slightly reduced, since the projector and the camera have to be placed at a greater distance and it is no longer possible to accurately capture small elements. But it turned out that after scanning the whole model and getting the general shapes. You can always recalibrate the scanner with a smaller scale of the pattern of the calibration panels, scan individual areas closer and align them with the previously obtained scans. I was pleasantly surprised that even with such manipulations, all sizes are transmitted correctly and without distortion. The scans obtained after recalibration were compatible with the original ones without any problems. You can always recalibrate the scanner with a smaller scale of the pattern of the calibration panels, scan individual areas closer and align them with the previously obtained scans. I was pleasantly surprised that even with such manipulations, all sizes are transmitted correctly and without distortion. The scans obtained after recalibration were compatible with the original ones without any problems. You can always recalibrate the scanner with a smaller scale of the pattern of the calibration panels, scan individual areas closer and align them with the previously obtained scans. I was pleasantly surprised that even with such manipulations, all sizes are transmitted correctly and without distortion. The scans obtained after recalibration were compatible with the original ones without any problems.
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The result was, of course, not perfect. But worthy considering the complexity of the part. In some places it was not possible to crawl with a scanner, their program finished drawing as best it could. It took a lot of time for scanning and processing, no matter how lying, a total of 2-2.5 hours.
Finally, we scanned a few more small objects with textures to show you how the scanner can capture colors and patterns. There is not much to tell about them, it was not difficult to scan them. So here are just a few photos.
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What can be said in the end. The scanner can hardly be called easy to use. You need to understand the principles of its operation and the specifics of its use in different situations. Black, transparent and shiny objects should be coated with a matting spray, but this should be done with almost any 3D scanner. The software is powerful and does its job quite well. But, as with the scanner itself, it requires certain skills, an understanding of the capabilities and principles of operation.
We were pleasantly surprised by the quality when scanning small objects and the ability to additionally scan separate detailed areas for larger objects.
With the proper skill, you can get very high-quality 3D models with this scanner.
