Could you please provide Dynamic Calibration Print Target for A4 Size Paper?

[ravijo]

Hi,

The current one given at the following URL belongs to US Letter size paper:
https://dev.intelrealsense.com/docs/calibration

While printing it on A4 size paper with "Actual Size", I notice 3-4 mm difference. Therefore could you please provide Dynamic Calibration Print Target for A4 Size Paper?

[MartyG-RealSense]

Hi @ravijo I loaded the US Letter calibration target PDF into Word, changed the page format to A4 and re-saved the PDF. I have attached it to this message. Could you print it on A4 paper and see whether it provides you with better results, please?

print-target-fixed-width-A4.pdf

[ravijo]

Hi @MartyG-RealSense

Thank you very much for the quick response.

I tried many options today. Converting US Letter to A4 via MS Word and Acrobat. But faced a few mm difference.

Is it possible for you to check the attached file once please because I left my workplace already? Can you confirm the dimensions, please?

[MartyG-RealSense]

My PDF reader states that the modified document is 8.27x11.69 inches, which pretty much matches to A4 size.

[ravijo]

Well, I did similar steps and page was shown A4 and used "Actual Size" in printing. But the output wasn't satisfactory. that 3-4 mm difference !!!

[MartyG-RealSense]

The Dynamic Calibration system offers alternatives to a printed paper target. You can install an Android application that displays a calibration target on the Android device's screen to point the camera at, or use target-less calibration (though this can be less accurate than target-based calibration).

[ravijo]

@MartyG-RealSense

I will print PDF given by you above. If it doesn't work, I am gonna use the iPhone app. Though I am concerned about possible reflection on the phone screen.

Anyway, I don't wanna use target-less calibration, because my priority is all about depth accuracy.

[MartyG-RealSense]

You can significantly dampen glare from reflections by purchasing a physical thin-film linear polarization filter product and applying it over the camera lenses on the outside of the camera. You can find out more about affordable linear polarization filters by going to Amazon and searching for linear polarization sheet.

Any thin-film polarizer that is linear should work - circular polarizers used in 3D glasses won't work.

[ravijo]

@MartyG-RealSense

Hi @ravijo I loaded the US Letter calibration target PDF into Word, changed the page format to A4 and re-saved the PDF. I have attached it to this message. Could you print it on A4 paper and see whether it provides you with better results, please?

print-target-fixed-width-A4.pdf

I printed this file on A4 size paper. I found 1 mm difference in width (50 mm) and 2 mm at height (100 mm)

[MartyG-RealSense]

It sounds like an improvement on the 3-4 mm difference that you had at the beginning of this case, @ravijo

[ravijo]

I printed this file on A4 size paper. I found 1 mm difference in width (50 mm) and 2 mm at height (100 mm)

Sorry, this is slightly wrong. The error in height is more than I said before. Please see the attached picture below:

The above picture is a print of print-target-fixed-width-A4.pdf

By the way, are you sure that you get the exact dimensions when printing on a US Letter page? Can you please print one and measure the dimensions? If the original PDF doesn't have correct dimensions, then A4 paper will accommodate those errors too.

[MartyG-RealSense]

I checked the original US Letter calibration PDF in my PDF reader. It stated that the dimensions of the document were correctly 8.5x11"

I tried a different approach. I copied the calibration image from the original US Letter PDF in Word, reformatted the page size in Word to A4 and then pasted in the original US Letter document's image. This should mean that the original image is used within the confines of the changed page margins.

print-target-fixed-width (1).pdf

If that file does not result in improved accuracy then I would recommend moving on to one of the other calibration methods, such as Android screen image or On-Chip.

[ravijo]

@MartyG-RealSense

I was able to print it perfectly. I used an A3 size page to print US Letter paper.

print-target-fixed-width (1).pdf

Please wait for some time, I can check the new file provided by you.

[MartyG-RealSense]

Thanks very much, @ravijo - I look forward to your next report. Good luck!

[MartyG-RealSense]

Hi @ravijo Do you have an update that you can provide about this case, please? Thanks!

[ravijo]

@MartyG-RealSense

Please give me a couple of days as it is new year vacation currently.

[MartyG-RealSense]

Okay, that's no problem at all, @ravijo - thanks!

[ravijo]

@MartyG-RealSense

I tried a different approach. I copied the calibration image from the original US Letter PDF in Word, reformatted the page size in Word to A4 and then pasted in the original US Letter document's image. This should mean that the original image is used within the confines of the changed page margins.

print-target-fixed-width (1).pdf

Thank you for waiting. I printed the above PDF in A4 size paper and unfortunately, it doesn't look good to me. Please see attached picture below.

[MartyG-RealSense]

Instead of trying to adapt the original US Letter PDF to A4, an alternative approach would be to buy a pack of US Letter paper and adjust the border sliders in the printer tray to fit the US Letter size, then print off the US Letter PDF. You could locate retailer sources in your country to purchase such paper by googling for buy us letter paper in <name of country>. For example, buy us letter paper in uk or buy us letter paper in australia

[ravijo]

@MartyG-RealSense

Thank you very much. As I said I could print it.

I was able to print it perfectly. I used an A3 size page to print US Letter paper.

At this point in time, may I request you to create a feature request (internally for the dev team), so that we can have the calibration target in A4 size too? It is not urgent but defiantly will help!

[MartyG-RealSense]

As your request to create an A4 version of the calibration target PDF document is of a documentation nature rather than engineering or SDK programming, I will place a Documentation tag on this case to highlight it to the RealSense team for future attention. This case should now be kept open, but you do not need to take further action in regard to the request. Thanks!