This newly posted article from notateslaapp discusses dual repeater cameras as part of hw4 and the Highland/Juniper redesign.
Exclusive: Tesla's Model 3, Project Highland Exposed: What’s Changing
I'll also quote this relevant comment about the repeaters and add some thoughts:
Tesla's engineers must have decided that a side-facing camera integrated into the headlight assembly was just too prone to being obstructed by rain, snow and mud. A side-facing camera added to the repeater is better than nothing, but it doesn't seem like such positioning will significantly improve decision making when there's high speed cross traffic.
I wouldn't be so sure that the second camera in the repeater will be only side facing. I don't know for sure, but it makes complete sense to me that the second camera will be able to look forward along the fender of the car.
This would take care of what I think is one of the most dangerous present blind spots: the issue of seeing oncoming traffic when you are trying to turn left with another left turning car in the median turn bay facing you. This is already a problem for a human driver, but at least he can lean towards the driver window. The centralized windshield cameras cannot.
Peripheral forward l-looking cameras on the mirrors or in the headlight area would have been even better for seeing past such obstructions, but the repeater location is still a big advantage over the present central cameras. However, with the repeater location it's especially important that FSD should pose the car relatively straight when awaiting a left turn, so as not to have the cars on front fender obstruct the oncoming lane vew. (
one of the advantages of the headlight location is that the oncoming lane view is maximized for almost any left-turning pose angle of the ego car).
If the rear repeater camera sees straight back along the fender, and about 110° meaning a bit forward, then a roughly symmetrical front repeater camera could take in the view from straight forward along the fender back to an overlap region with the rear repeater camera. I would think that both of these would also see the ground for parking purposes.
This begs the question of what the pillar camera is then needed for. I think that even if the front and rear repeater cameras overlap, the pillar would still contribute its undistorted non-overlapped side view, also biased more for the upper vertical region and not the curb region. These pillar cameras are presently slightly mysterious because we don't get to see them in Sentry or Dashcam views, but apparently they're being kept in HW4, l so presumably they continue to be fairly important in FSD.
