D415 x D435 short range face/landmarks tracking

[RRibe8]

Hi,

I'm planing to buy the intel new realsense camera D4xx series.

I have a doubt to choose between D415 and D425 cameras

My objective is to use it in a car to track the driver face and gaze.

The distance will be from 20 mm to 150 mm

It will also need to work well in outdoor scenario

So, I'd like to know which one of the new cameras will fit better in those cases

and which one I'll have more accuracy and details to track the driver's face.

Also, I'd like to extract the raw IR, depth and color streams with maximum resolution as possible

PS: now I'm using the R200 for this same case, but to use it in a short range I need to reduce the stream resolution to very low size (240x380)

tks

[MartyG · Accepted solution]

Both cameras work well outdoors and have little difference in terms of resolution sets and accuracy. The best depth resolution you can get on both cameras is 1280x720.

The main distinguishing points relevant to your project are:

1. The minimum depth range of the D415 is 0.3 m and the minimum of the D435 is 0.2 m.

2. D435 has a wider field of view and so will find it easier to keep the driver's head in its view.

3. D435 is better at tracking moving objects because of a faster 'global shutter'

Edit: I should add that you will need to combine the camera's SDK 2.0 with other software platforms such as OpenCV, as SDK 2.0 does not have face landmark tracking built into it like the old RealSense SDKs for the R200 did.

[PSnip]

Hi Marty,

I think one additional item to keep in mind for such applications may be that most users report D415 to be giving better performance than D435 for short range, and for smaller objects. What do you think?

I don't have D415, so I have so far not made any comparison with D435, but almost every user who has compared the two, suggest D415 to be much better for short range.

Another important point, though both D435 & D415 have 1280x720 depth resolution. The resolution of IR camera is 1920x1080 on D415, but only 1280x800 on D435.

Note that Depth is computed by D4 Vision processor, based on the IR Camera imaging. So input to D4 processor is very different in case of D435 vs D415.

So far I have assumed that this difference is what leads to better short range resolution on D415. What do you think?

Best Regards,

PS

[MartyG]

The resolution chart for the two cameras gives an IR resolution of 1280x720 for both cameras, In Calibration mode though, the D435 has 1920x1080 instead of the D415's 1280x720 though.

I'm wary of putting too much emphasis on the D415 / D435 image quality issue. Though feedback strongly suggests that the depth image on D415 is better, it is easy to become automatically negative about the D435 without considering its merits. A doom-based viewpoint can become a self-fulfilling prophecy.

Yes it is true, the D15 excels at scanning smaller objects.

[RRibe8]

tks a lot MartyG

but one point that I'd like to emphasis is about depth details.

I saw that pixel from D415 is 1.4mm

and so we can get more details from the object.

I'd like to get more details from the face.

even in this case the D435 can get better results than D415?

[MartyG]

You can use Visual Presets to change the balance of the camera's settings, so you can get more detail at the cost of lower accuracy, or higher accuracy at the cost of lower detail.

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

Like with the R200 / SR300, the D415 and D435 will have areas where one is the better choice for a certain application than others. For example, the R200 could scan larger objects and full human bodies, but had the drawback of lacking the hand joint tracking that the SR300 supported. Over time it will become clearer what the specific strengths and weaknesses of rthe D415 and D435 are compared to each other.

For example:

The D415 excels at scanning small, static objects.

The D435 excels at scanning larger, moving objects and has less blind-spots in its vision because of its wider field of view.