How or when to get d435 IR 25fps support?

[Mwolk]

As the update to deal with light flickering that was introduced with 5.10.6 does not deal with fluorescent light flickering well, I'd need to use IR sensors at 25fps (European utility line frequency).

However, for some reason 25fps can only be used with Y16, which based on a previous post by an Intel rep here is not supposed to be used, as the images are not aligned. Additionally they're at incredibly noisy.

Based on @idata​  's comment here:

https://forums.intel.com/s/question/0D50P0000490WbBSAU/ir-y16-vs-y8-brightness-and-noise?language=en_US

[MartyG]

24 or 25 FPS support for general use (not just calibration) is a request that has been made by other users, especially for those who wish to use RealSense for applications related to movies,. The RealSense development team are certainly aware of the desire for this feature. They are concerned though with keeping the number of supported modes in check, as adding further modes can mean dong extra testing on SDK releases.

I do not know of any plans to support this feature. In the meantime, the effects of fluorescent lights can be reduced by using an FPS that is close to the operating frequency of the light. For some people it is 30 FPS and for others it is 60 FPS.

[Mwolk]

Hm, I must've replied somewhere else, so here it goes again. The support concern I understand for 24fps, however 25fps is already available. It's just stupidly linked to Y16 only. Also this is not a movie making related request. This product is used in an image recognition context. Your suggestion of using 30 or 60 fps works only in countries with a 60hz line frequency, such as the US. It will NOT work anywhere in Europe or elsewhere with a 50hz line frequency. So to me it seams less of an effort to provide 25fps at Y8 (without the terrible noise of Y16), than to test every flickering lightbulb with some firmware anti flicker solution.

[MartyG]

If you cannot solve fluorescent flicker through FPS speed, another approach is to tackle it by changing shutter speed. The RealSense cameras cannot have their shutter speed physically changed, but it can be affected indirectly by changing the color exposure value. This is because shutter speed is also known as 'exposure time'. To do this, you would have to disable auto-exposure and set your own exposure value.

For European countries that use 50 hz, a shutter speed of 1/50 is recommended. This converts to 20 ms or 0.2 seconds. You can test whether this will work for you in the RealSense Viewer software.

STEP ONE

Expand open the 'RGB Camera' options in the side-panel of the RealSense Viewer and left-click on the blue box beside the 'Enable Auto Exposure' option to turn the blue box black, indicating that auto-exposure is turned off.

STEP TWO

Expand open the 'Controls' option and you will see a set of sliders for manually setting values such as Exposure and Gain.

Hovering the mouse over the '?' information icon on the Exposure option's row tells us "Controls exposure of color camera", indicating that we are at the correct place in the options for altering color exposure time / shutter speed.

By default, the color exposure is set to a value of '156' in the RealSense Viewer software. With auto-exposure disabled, you can find your own ideal exposure value by using the Exposure slider. You can also precisely enter a value manually with the keyboard instead of using the slider by left-clicking on the 'Enter text edit mode' icon at the end of the Exposure option's row.

 If you are using depth or IR streams, you can also disable auto-exposure for those streams too and set your own value.

[Mwolk]

That would work in many short recording cases where you have control over the light situation but I have cameras in various indoor locations recording throughout the year for 10-12 hours a day - which means I need auto exposure.

[MartyG]

Apologies for the delay in responding. The new website does not send me updates when a new comment is made on a post. The reason I came back here was to update you that the RealSense development team does not plan to support a 24 FPS mode.

https://github.com/IntelRealSense/librealsense/issues/1904

I recalled that Intel did some tests with the camera under ambient fluorescent lighting of around 100 to 200 lx, an FPS of 30 and a resolution of 1280x720, and with auto-exposure on. They reported that the best results (visual appeal, clean edges and reduced point cloud spraying) were obtained by using the 'Default' visual preset mode (Visual Presets are a set of different configurations for the cameras that prioritize different areas of performance).

https://github.com/IntelRealSense/librealsense/wiki/D400-Series-Visual-Presets

When using the RealSense Viewer, it typically launches with the 'Custom' preset. You can change the Viewer's preset to Default using a menu at the top of the options side-panel.

You can also define and save your own custom configuration in the Viewer. You have to manually load this config file into the Viewer when you open it rather than have it loaded in automatically, though this may not be too much trouble if you are setting the Viewer up and then leaving the camera to run on its own for 12 hours or more.

[Mwolk]

" The reason I came back here was to update you that the RealSense development team does not plan to support a 24 FPS mode."

That's fine with me, as long as they support 25fps IR (Y8) as 25fps is already there, albeit only with Y16.. The fluorescent lighting tests linked were made with the invalid US centric premise that everyone in the world is using a 60hz line frequency.

It would be nice to hear from an actual Intel representative such as @idata​ , who was discussing at least the matter of y16 before.

[Eliza_D_Intel]

Hello Mwolk, We will report this enhancement request to the RealSense Engineering Team, but unfortunately I cannot promise that it will be developed. I will update the thread when I will have a response from the Engineering Team. Thank you and best regards, Eliza

[Eliza_D_Intel · Accepted solution]

Hello Mwolk, Thank you for submitting this feature request. Unfortunately, this request does not fit into the feature roadmap at this moment. Best regards, Eliza