Introducing the RealSense D435f stereo depth camera
Hi everyone,
A new RealSense D435f camera has been added to the RealSense 400 Series range of stereo depth camera products and is now available for purchase from the official online RealSense Store.
https://store.intelrealsense.com/buy-intel-realsense-depth-camera-d435f.html
The D435f adds an IR pass filter to the pair of depth sensors. Full details of this new camera model are available in the data sheet document for the 400 Series.
https://dev.intelrealsense.com/docs/intel-realsense-d400-series-product-family-datasheet
The data sheet provides the following information about the new filter:
D435f = D435 with 750nm near-infrared filter (CLAREX® NIR-75N) applied to cover glass, with holes over projector and RGB sensor openings. Filter transmits near-infrared light and absorbs visible light. Filter’s thickness = 0.5 mm.
Pages 64 and 65 of the data sheet provides a feature comparison between the D435f and the rest of the 400 Series range, a comparison of D435 and D435f, and a chart of the filter's optical properties.
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Hi Alex, a discussion about use of external IR illuminator lamps with RealSense 400 Series cameras at the link below may be a helpful reference for you.
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Hi Sunardi Yes, you can apply physical optical filter products over the front glass of the camera. Past examples of mounting the filters include using a 3D printed housing (see an infrared filter mounting blueprint for the D435 model at the link below) or simply wrapping rubber bands around the outside of the camera to hold it in place.
https://www.thingiverse.com/thing:5140445
A RealSense team member once recommended a company called Astra Products as a purchasing source for optical filters to use with RealSense cameras.
https://github.com/IntelRealSense/librealsense/issues/2875#issuecomment-446793681
Astra Products have information about the CLAREX NIR-75N filter at the following page:
https://astraproducts.com/info-acrylic-nir-filters.asp
A request for a price quote can be submitted.
https://astraproducts.com/gen-quote.asp
You can also research other retailers who stock this filter by googling for the term 'purchase clarex nir-75n'
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hi MartyG thank you for the all the info shared above. I have one doubt regarding the application of filter in D435F. In the product brief, it shows that the filter in placed in front of the glass cover. So how is the filter being held there. Is there any adhesive layer between the glass cover and the filter.
We are working with Intel D430 and we are accommodating our own custom glass cover, but we are having issue with assembling the filter, glass cover and the adhesive.
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Hi Deepak There is not information available about how the filter and glass cover material are held in place in RealSense cameras, unfortunately. A couple of examples of mounting methods applied by RealSense users (a 3D-printed clip or simple rubber bands) are mentioned earlier in this discussion.
https://support.intelrealsense.com/hc/en-us/community/posts/6657795804947/comments/7031677325459
If you would prefer an adhesive solution then the choice of adhesive is not likely to matter so long as the adhesive is applied to the cover / filter in areas where it does not obscure the sensors' view through the material (i.e spread the adhesive around the edges of the material). It may also be worth using heat resistant adhesive so that it does not unbond if the camera becomes hot.
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Thanks MartyG for the reply. Can you provide any information on the type of material of the cover window ? Is it PMMA sheet or B270 glass or Gorilla Glass. None of these materials have more than 92% transmissivity which is the recommended value in the intel datasheet.
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There is also not specific information about the cover material, though a set of recommendations for choosing a cover material are provided in the data sheet document (shown below).
Gorilla Glass should be a valid choice so long as the guidelines recommended at the link below are followed.
https://github.com/IntelRealSense/librealsense/issues/2566#issuecomment-431852571
The data sheet provides the following additional advice about the cover material:
* Uncoated clear acrylic (plexiglass) plastic cover is an example for a cover material
* Anti-reflective coatings can help increase the transmission of the cover material
* If a different cover material is used in front of the cameras and the IR projector to maximize transmission based on component wavelengths, cover design considerations should ensure that the FOV of the cameras and FOP of the IR projector are not impacted.
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Thanks again MartyG for the info.
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Hi MartyG, I have one more doubt w.r.t filter used in D435F. I want to use the same filter infront of D430. Now, I understand the point of cutout used in the filter of D435F in front of the RGB camera. However, I do not understand the cutout in the filter for the IR projector which is also emitting in the same NIR spectrum. What are the effects the filter will have if we do not have a cutout in front of the IR projector.
If there is no bad effect, I can just use the filter in front of the D430 without any cutout, since it doesn't have RGB camera and not use any cover material.
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Okay. Just wanted to clarify if the only issue possible is the reflection from the underside of the filter. Other than that, there is no issue like NIR75 filter cutting off IR projector light ? I mean blocking Visible spectrum in front of the IR projector will have no effect on the IR projector performance.
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