D400 Series Calibration
note: i'm using the D415
So we've tested 3 different D415 at a 20m range and it gave us good results with the factory calibration. Similarly, we got 3 tablets with the D415 integrated into it and did the same test. The integrated camera modules gave poor distance measurements at that same distance (distances below 2m is okay with some error). I've been trying to push the tablet manufacturers to do an OEM calibration after they install the integrated module. Instead, they have been recommending to do the "On-chip calibration" and the "On-chip tare calibration" on the tablets.
Can someone explain what those two calibration functions inside the "Depth Quality Tool" actually do? Is it the same as what the OEM calibration can does? I also tried to reset each camera's calibration to the gold settings using the Calibration Tool's "Intel.Realsense.CustomRW.exe -g" without much success.
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Doing an OEM calibration is a good idea for manufacturers integrating the camera into their products, as the act of handling the modules can cause the imagers to require recalibration if the module is flexed during installation. It is up to the manufacturer whether they take this step.
If it were an external USB camera, a simple non-OEM calibration of the extrinsics alone with the standard Dynamic Calibrator program would likely be sufficient to correct miscalibration caused by the camera experiencing a physical stress or shock. In the case of an integrated tablet camera, following the manufacturer advice is recommended.
Information about on-chip calibration support is in the link below. Documentation notes (the November 2019 Specification Update) indicate that alpha support for self calibration and tare calibration was added in firmware 5.11.15.0 and requires at least SDK version 2.29.0.
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Thanks for the link.
So reading the documentation notes, it seems that both this on-chip calibration and the dynamic calibration affects only the extrinsic parameters of this stereo camera (how the two cameras are positioned relatively). Can we assume the intrinsic parameters in the module are correct and stays correct when the manufacturer receives the modules and installs them?
The OEM calibration I was referring to is https://store.intelrealsense.com/buy-intel-realsense-d400-cameras-calibration-target.html . Is this the only tool that can do intrinsic calibrations?
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In 99% of cases, intrinsic calibration by the end-user is not necessary as it is calibration of the extrinsics that have the most effect on image quality and there is no particular disadvantage from being unable to perform intrinsic calibration. For detailed advice on intrinsic calibration, the RealSense GitHub will be the best place to ask.
If the OEM calibrator software is unavailable to you, then you could look at Intel's white paper for developing your own custom calibration solution with the custom calibrator API.
If you would prefer the existing OEM calibrator software but do not want to purchase the OEM board in the store in order to get it, the only possible way that I know of to get the software on its own is if you have an NDA agreement with Intel.
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Hi MartyG, is it stil possible to have an NDA agreement with Intel to get the oem calibration software as I need it to calibrate the camera for underwater use in an integrated device ?
Maybe a used oem kit can be sold as it seems out of stock at the moment.
thank you,
Brice
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Hi Brice Miramont You may not need the OEM calibration software for calibrating for underwater, as there is an extensive discussion on the subject at the link below.
https://github.com/IntelRealSense/realsense-ros/issues/1723
A RealSense team member (agrunnet) provided very detailed technical information about underwater calibration at the link below - please read downwards from the point of the discussion that I have linked to.
https://github.com/IntelRealSense/realsense-ros/issues/1723#issuecomment-808406783
Because the above conversation is so long, please look out for a Load More link to un-hide a substantial amount of the discussion, which also contains details of a custom underwater housing for the camera.
Further discussion about underwater calibration can be found here:
https://github.com/IntelRealSense/librealsense/issues/7966
In regard to applying for an NDA, I would recommend confirming whether or not the information in the above links can provide a solution for you before pursuing NDA application. If you decide that you want to proceed with application then I can pass your contact details to the appropriate RealSense team member.
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Thank you Marty, agrunnet did succeed in calibrating the camera underwater with the help of the oem calibration toolkit. So my question is, how can I get one and at what cost ? If the hardware is not available, maybe I can make one with the schematics and in that case I'll need the software part from Intel.
thank you
Brice
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I once asked agrunnet if a home-made version of the large OEM target board could be printed on paper and was told that it would not work, as the target board is made from a special material.
agrunnet did state in the underwater calibration discussion though that Intel were able to test underwater calibration with a smaller board that they made and used in a large fish tank (agrunnet did add to use the OEM board if calibrating in a pool-sized environment).
https://github.com/IntelRealSense/realsense-ros/issues/1723#issuecomment-834677375
This suggests that the ordinary small official calibration print target for a single camera that is printed off and mounted on a surface such as a wall might have been used with the fish tank (the OEM board is large sized to support calibration of multiple cameras).
In regard to obtaining the OEM board, it does typically come back into stock after being out of stock (I observed that it was in stock last week before it went out of stock). You can subscribe in the store listing for the board to be notified when it is back in stock. The official RealSense Store is the only retailer that stocks the board.
In regard to obtaining the OEM calibration software without the board, my understanding is that one can request it from their 'local Intel representative' (which is typically an NDA-level support request).
Since the On-Chip calibration can calibrate both intrinsics and extrinsics (though in separate calibration actions rather than in the same calibration session), it may be worth testing whether an On-Chip calibration can provide the desired results.
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Hi Brice Miramont The $1500 USD OEM calibration target board has just come back into stock in the RealSense Store today.
https://store.intelrealsense.com/buy-intel-realsense-d400-cameras-calibration-target.html
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