Image center of Intel D455

[JuanDYB]

Hi,

I wanted to know where is the image center of the Intel D455 (not the complete camera, just the D450 module).

Since there are multiple streamings (rgb and depth) and they have to be aligned in processing phase, I supose that the center or focal point it's not the position of the rgb lens.

I have seen multiple holes in the back part of the module and suposed that one of them is the reference to use as focal point.

With regards,

[MartyG-RealSense]

Hi @JuanDYB On RealSense 400 Series cameras such as D455, the 0,0,0 origin point of depth is the center-line of the left infrared sensor, whilst the origin point of RGB is the center-line of the RGB sensor.

However, it should not be assumed that the center of the image will coincide with (0, 0, 0). Instead, it depends on the sensor. The principal point (the center of projection) may not be exactly the center of the sensor. Often, there is a small offset.

[JuanDYB]

So, the center of the rgb image is the point of the RGB sensor if I understand well. But it's possible to have some offset. I have asked because I have seen the holes in the back part of the module and maybe because of processing and alignment of Depth image to RGB image.
Thanks!

[MartyG-RealSense]

The back part of the module has no role in the generation of images. The sensors on the front of the module (and the center-point of their lenses) are the important parts.

Each sensor has a 'field of view' (FOV) that determines how much of a scene it can see at once without moving the camera, like looking through the viewfinder of a photographic camera. The field of view size can be different for depth and RGB, though on the D455 model the field of view size is similar for both.

When performing depth to color alignment, the FOV size of depth is automatically resized to match the FOV size of the RGB sensor. The origin point of depth also changes to the center of the RGB sensor.