ajdelange

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Cameras don't need to be as wide out as a mirror for the same view.
So the driver with a mirror at A would not be able to observe a motorcycle at C but a camera mounted at B would?

CTMirrors1.jpeg


What you aren't telling us is that for the light to bend around the corner of the trailer there has to be a tremendous mass (about like Jupiter's) in the back of the trailer (General Theory). I think this would adversely effect towing range.


This is why a curved mirror doesn't need to be as far out as a flat mirror.
It doesn't matter whether the objects at A and B are curved mirrors, flat mirrors or the Hubble telescope. No light traveling in a straight line from anywhere in the shaded triangle can reach them. This should be intuitively obvious but if it isn't go sit in your car for a few minutes. Most have a flat mirror on the driver side and a curved one on the passenger side. Can you see an object located at X?


The path for a camera is curved (wide angle lens).
No!!! Light travels in straight lines except in extremely intense gravitational fields or where the refractive index of the medium changes along the propagation path. In a camera lens the rays are refracted at places where there are discontinuities in refractive index but they remain rays (i.e. travel in straight lines). Lenses are designed using "ray tracing".
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hridge2020

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So the driver with a mirror at A would not be able to observe a motorcycle at C but a camera mounted at B would?

CTMirrors1.jpeg


What you aren't telling us is that for the light to bend around the corner of the trailer there has to be a tremendous mass (about like Jupiter's) in the back of the trailer (General Theory). I think this would adversely effect towing range.


It doesn't matter whether the objects at A and B are curved mirrors, flat mirrors or the Hubble telescope. No light traveling in a straight line from anywhere in the shaded triangle can reach them. This should be intuitively obvious but if it isn't go sit in your car for a few minutes. Most have a flat mirror on the driver side and a curved one on the passenger side. Can you see an object located at X?


No!!! Light travels in straight lines except in extremely intense gravitational fields or where the refractive index of the medium changes along the propagation path. In a camera lens the rays are refracted at places where there are discontinuities in refractive index but they remain rays (i.e. travel in straight lines). Lenses are designed using "ray tracing".

Lane position.png
 

ajdelange

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The guidance a motorcyclist should take from No. 61 is to not ride in the shaded triangle! If you can't see the tractor's mirrors or cameras they can't see you. Don't some trucks have signs on the back that say "If you can't see my mirrors I can't see you."?

Regulatory bodies contemplating allowing vehicles with cameras instead of mirrors should think about marking the cameras in such a way that following traffic can determine with certainty where the cameras are located for just this reason.
 

Dids

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So the driver with a mirror at A would not be able to observe a motorcycle at C but a camera mounted at B would?

CTMirrors1.jpeg


What you aren't telling us is that for the light to bend around the corner of the trailer there has to be a tremendous mass (about like Jupiter's) in the back of the trailer (General Theory). I think this would adversely effect towing range.


It doesn't matter whether the objects at A and B are curved mirrors, flat mirrors or the Hubble telescope. No light traveling in a straight line from anywhere in the shaded triangle can reach them. This should be intuitively obvious but if it isn't go sit in your car for a few minutes. Most have a flat mirror on the driver side and a curved one on the passenger side. Can you see an object located at X?


No!!! Light travels in straight lines except in extremely intense gravitational fields or where the refractive index of the medium changes along the propagation path. In a camera lens the rays are refracted at places where there are discontinuities in refractive index but they remain rays (i.e. travel in straight lines). Lenses are designed using "ray tracing".
Side view mirrors are not for seeing behind you. You are misunderstanding what OP is talking about. He wants to see the side of his trailor so that he can clear obstacles on turns etc. It is true that being further out does narrow the cone behind you but it is not true that you have to be further out to see along side of a long vehicle. Also I never said the light curves around the trailor. I said the path curves which it does in a lens. In any case... I will use the side view cameras and rear view camera and you can add side view mirrors and enjoy your narrower cone, which is behind you.
 
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ajdelange

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Side view mirrors are not for seeing behind you.
They aren't? I didn't know that and use them for that purpose all the time! Should I not do that? The rear view mirror in the X isn't very effective as the rear window is so small. How should I check behind me?

You are misunderstanding what OP is talking about. He wants to see the side of his trailor so that he can clear obstacles on turns etc.
I checked the OP. It asks about the appearance.

It is true that being further out does narrow the cone behind you but it is not true that you have to be further out to see along side of a long vehicle.
Yes but that is done so the driver can see behind him better. Were that not the case who would buy this sign?

Untitled 2.jpeg


($7.34 in 7 X 10. Other sizes available).

Also the diagram makes it quite clear that the mirror has to be further out to show the entire side of a trailer in a turn to the passenger side.


Also I never said the light curves around the trailor. I said the path curves which it does in a lens.
If the path isn't the path of the light what is it the path of? The only thing I know of that moves through a lens is light and it does so in straight lines.
 

Dids

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u14l5b1.gif

Hmm. The blue line is straight and parallel but funny how the straight lines turn red and intersect. Did they bend? Maybe it's a black hole. You use math which is a very precise language but like the scalpel in the hands of a surgeon with Parkinsons the result isn't a successful surgery. Its hamburger. With precise tools you cannot skip small details like completing the image path to the eyes of the driver. The reason mirrors are placed outboard for long vehicles is not to provide a better look behind the vehicle, it is so that the angle of the mirror in relation to the drivers eyes allow the driver to see what is beside his vehicle for the whole length. Indeed placing it forward on the vehicle allows shorter outboard with the same size mirror and the same view. I'm guessing if you can see behind your car with the side view mirrors that you can also see your car in the mirrors and that you cannot see a car that is beside you. Lucky for us FSD is coming.
 

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This is a whole lot of talk about mirrors vs. cameras. I don’t really have a dog in the fight except that the CT will already be super wide. For argument’s sake I use side mirrors to see what is on the side of me. At the end of the day a mirror will always work and a camera can at least possibly turn off. Luckily we can always turn around like in the old days :)
 

Zhe Wiz

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Mirrors break, I’ve seen plenty.
 

Jhodgesatmb

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You are stating the obvious, but mirrors don't lose power. Anyway, I never said I have a preference, only that mirrors cannot lose power (except to turn them I guess). As a mirror they won't fail. That is why I mentioned always being able to turn around and look. If I am a government agency I will look for redundancy in lieu of a mechanical solution, so if Tesla (or any other manufacturer) can provide camera redundancy, then maybe the powers that be will grant them a waiver. I don't know.
 

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Looks like Tesla might have the camera cleaning issue sorted already : )

Tesla Patents Frickin' Laser Beams That Clean a Car's Glass
The technology could ensure cameras used for the Autopilot driver-assist system have a clear view of the road.
16f63cdc-f6f1-41da-ae08-c3124a955056_1543373149.jpg

By Eric Tingwall
NOV 29, 2019

-pm-1574895282.png?crop=0.879xw:0.852xh;0.0544xw,0.png

Tesla
  • Tesla has filed a patent for the process of cleaning a vehicle's glass surfaces using laser beams.
  • The laser cleaning process could clean dirt and other debris blocking the view of a camera used for advanced driver-assistance features.
  • Tesla also says the lasers could be used to clean the surfaces of solar panels.
 

Jhodgesatmb

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This was talked about some time ago in the wiper thread along with another patent application Tesla filed for a novel windshield wiper idea. Personally I think I’d be more comfortable wiping the camera lens clean. Any laser capable of removing dirt could do harm.
 

ajdelange

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u14l5b1.gif

Hmm. The blue line is straight and parallel but funny how the straight lines turn red and intersect. Did they bend?
Yes, but they didn't curve. Looking at this and the post I originally responded to

Cameras don't need to be as wide out as a mirror for the same view. A mirror reflects light to your eyes... so the path is from object to mirror to your eyes ( is the to your eyes part of the path that dictates the need for the mirror to be wide out) This is why a curved mirror doesn't need to be as far out as a flat mirror. The path for a camera is curved (wide angle lens).
It appears that you aren't 100% on what "curved" means. Here are a couple of definitions:

to have or take a turn, change, or deviation from a straight line or plane surface without sharp breaks or angularity

a continuously bending line, without angles. [emphasis mine]



Maybe it's a black hole. You use math which is a very precise language but like the scalpel in the hands of a surgeon with Parkinsons the result isn't a successful surgery. Its hamburger.
WTF? Over.
Where's the math?

With precise tools you cannot skip small details like completing the image path to the eyes of the driver.
It appears that you think the path from a mirror to the driver's eye has something to do with the discussion at hand. It doesn't. Light from an object, which travels only in straight lines, and which is blocked from reaching the collector (mirror or lens) cannot be observed with either.

I've put the onward paths from the collector aperture in the diagram and I've drawn it in such a way that it shows what happens with either a lens or a mirror. First consider the curved surface closest to the letter A to be a curved, silvered surface. A light ray from X strikes that silvered surface at some point such that the incidence angle is equal to the angle between that point and the driver's eye. Note that this surface does not have to be curved but if it is flat it's normal must bisect the angle between the incident and the reflected ray which reaches the driver's eye. A ray from C cannot reach the driver's eye because it is blocked by the back of the trailer. Move the mirror closer to the vehicle if you want or closer away. The concept remains the same.

CTMirrors1 2.jpeg

Now let the mirrored surface be the front surface of a simple camera lens. An incident ray from X impinges on this surface and is refracted as it propagates (in a straight line) through the glass and then is refracted again at the rear surface from which it travels (in a straight line) to the CCD. As with the mirror, a ray from C cannot reach the lens and cannot be imaged by the CCD. Thus, whether the ray from the mirror to the eye is shown

The reason mirrors are placed outboard for long vehicles is not to provide a better look behind the vehicle,
Were that true there would be no reason for a truck driver to purchase a sign cautioning following drivers to stay far enough behind that they are out of the C zone and can, consequently, see his mirrors. Thus it is demonstrably not true.

.. it is so that the angle of the mirror in relation to the drivers eyes allow the driver to see what is beside his vehicle for the whole length.
It should be clear from the diagram that as drawn the driver, be he using camera, flat mirror or curved mirror can see the whole side of the trailer and the road further behind him than X. It should also be clear that if he move the mirrors or camera in the subtense of the side of the trailer on his retina or on the CCD of the camera is lessened so that he cannot see as much detail (the image of the leading edge and trailing edge are merging) while at the same time X is moving backward. It should also be clear that if the mirrors are moved in to a distance half the width of the trailer from the vehicle axis that he will not be able to see the sides at all. It should also be clear that in none of these cases does it matter in the least whether the sensor is a mirror or a camera.

Indeed placing it forward on the vehicle allows shorter outboard with the same size mirror and the same view.
It should also be clear that if you move the mirror forward to the front of the vehicle you would have to move it outboard to position E in order to have the same angular subtense of the side of the truck and same size rear blind zone and you would have to make it larger whereas if you move it all the way to the back you can move it inboard to position D (though clearly it would have to be a camera and you wouldn't be able to see the side of the car).


I'm guessing if you can see behind your car with the side view mirrors that you can also see your car in the mirrors and that you cannot see a car that is beside you. Lucky for us FSD is coming.
Remember that there is an image world behind the mirror and the mirror is a small aperture in a wall that gives you a view on that world. You chose the part of that world you want to see by tilting and/or rotating the mirror and positioning your head. In the X the mirror (and thus the window) are too small to let you see what's behind you well and at the same time a car that is closing from behind unless you move your head around a bit. This is the oft discussed X blind spot. The solution to this problem is supposed to be the sonic sensors which, if they detect the approaching vehicle will image it on your driver display and if it is really close make all kinds of noises. But the sonic sensors are pretty short range. The cars really need another radar in the back,
 
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Dids

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Yes, but they didn't curve. Looking at this and the post I originally responded to
Zoom in. Way in, on the word refraction. You will find the curve matches the curve of the lens.
Where's the math?
Your drawing uses geometry?

Were that true there would be no reason for a truck driver to purchase a sign cautioning following drivers to stay far enough behind that they are out of the C zone and can, consequently, see his mirrors. Thus it is demonstrably not true.
The sign is for when they are backing up. Frequently accompanied by a beep beep beep sound.
It should also be clear that if you move the mirror forward to the front of the vehicle you would have to move it outboard to position E in order to have the same angular subtense of the side of the truck and same size rear blind zone and you would have to make it larger whereas if you move it all the way to the back you can move it inboard to position D (though clearly it would have to be a camera and you wouldn't be able to see the side of the car).
You are still mistakenly believing that the side mirrors are for capturing the rear of the vehicle. They are for capturing the lane next to the vehicle, for the length of the vehicle. Look at the orientation of a mirror on a big rig sometime. Notice its larger on the vertical than the horizontal. If seeing around to the back was important don't you think it would be different?
are too small to let you see what's behind you well and at the same time a car that is closing from behind unless you move your head around a bit. This is the oft discussed X blind spot.
That blind spot is in reference to reverse. You will notice you are not held responsible for anything that occurs behind you but are at fault for failure to yield on a lane change.
If your mirrors are adjusted in too far you will not be able to change lanes at speed forcing you to slow down to change lanes. Are cars coming up behind you real fast? Is that why you are fearful and want to see behind you? Adjust your mirrors out so that when you are looking at the mirror anything beside you is either in the mirror or in your field of view without having to turn your eyes or head further. Now you will be able to maintain speed and change lanes and you dont have to worry about what is behind you because the other drivers arent having to slam on the brakes. Now the only thing you need the rear view mirror for is the cops cause you speeding along!
 

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Yeah, mirrors suck, to get all scientific about it............they also fail, just in a few different ways than cameras...........
 
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