Flashing Lights on prototypes ?

[rak2]

Have noticed in some of the videos that either the headlights or taillights appear to be flashing in a strobe like fashion. Is this a designed feature or just an optical illusion ? If it's intentional what modes/circumstances would activate the strobing? rak2

Sponsored

 

[Administrator]

Explanation from online:

"The electronic signal that controls LED and HID headlights isn't a constant flow of energy, it's a frequency. Mind you, too fast for the human eye to notice, but a camera, due to recording at a specific frequency as well, will in many cases see the blinking."

 

[BOLD Renegade93]

Have noticed in some of the videos that either the headlights or taillights appear to be flashing in a strobe like fashion. Is this a designed feature or just an optical illusion ? If it's intentional what modes/circumstances would activate the strobing? rak2

It's because they are LEDs. Basically they work by turning on and off at a rate faster than our eye can detect. A camera can see them flashing at that speed, hence why we see it when watching videos. If you were there live, you wouldn't have seen the flashing, unless you're some type of cyborg...

 

[frinesi2]

LEDs are PWM (pulse width modulation) controlled to make them brighter. Essentially they're flashing at a frequency high enough that human eyes can't perceive it. When they're recorded by a camera, the differences in frequencies means they're on for some frames and off for other frames.

Fun fact - LED traffic lights and signage can cause big problems for vision-based autonomy systems because of this.

 

[Ocnorb]

Not gonna lie, it really bothers me. And it doesn't have to be this way. I have plenty of fancy LED Flashlights that have no visible PWM, even on camera.

 

[rak2]

[OP] Thanks everyone. Don't get out much these days and was thinking that I'd missed something new.

 

[broncobob94]

Not gonna lie, it really bothers me. And it doesn't have to be this way. I have plenty of fancy LED Flashlights that have no visible PWM, even on camera.

okay.

 

[Orbiter]

The stroboscopic effect

LED lights are flashing at a certain frequency, and your camera records at ~30 frames per second. When the LED lights up aligned with when the camera takes a snapshot creates the flashing effect in the video (which itself is playing at the recorded frequency).

 

[broncobob94]

There is a lot more to this, a couple of things to add as to why an engineer might decide to PWM your headlights. Software can control the intensity. Maybe the same bulb is used for both headlights and brights, which saves on costs and our dollar to buy the truck. Perhaps Bronco has a vision system (via safety system camera) and can dimm the drivers side light when it senses headlights via oncoming traffic at night (or auto dimm). Lots of other scenarios you could imagine (we don't really know the fine details yet with Bronco)....another thing is heat, a pwm signal means the light is on less which reduces heat and extends bulb life, ballast life, and anything else between it and the power source. probably more reasons to ellaborate on but it's more than just an annoying camera flicker for the sweet videos we'll be taking. I'm sure I've missed some other obvious ones but you could imagine the advantages to having anything controlled (via controller --> logic) PWM

Sponsored