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Thread: Telecam Time!

  1. #1
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    Telecam Time!

    OK, as I've mentioned before, I've got a reversing camera package which I've just recently commissioned in the Green Machine. To retain that authentic "period" look (with lots of "original features" ), I am using a 5" monochrome CRT instead of your more commonplace LCD TFT display, but the camera is a standard 1/3" CCD board camera in a waterproof housing with a built-in microphone and 6 IR LEDs for night-time illumination.

    In common with nearly all cameras of this type, it is designed for reversing applications, not rear vision in the absence of an interior rear view mirror, which is my intended use. This means that the camera has a very wide Field of View (FOV), which is great for capturing all the objects that may be immediately behind you, but I am finding that it is a lot less satisfactory in the rear vision role.

    I think the original lens has a FOV of around 120° - initially I thought it was great; the monitor could see beyond the range of both my exterior mirrors, as well as all points between.

    But out on the road it was less advantageous - any car that appeared to be at a safe distance was in fact right on my bumper (trying to see if there is a makers badge somewhere, a common experience ), and any car that could be discerned approaching in the monitor was in fact too close for a safe overtaking manouvre. My sooper-dooper telecam was rapidly becoming an expensive distraction rather than a safety feature

    However, I do have another CCD board camera using the same type of lens mounting (the lens screws into a casting mounted over the CCD chip and is held in place with a small grubscrew), so I carefully dismantled the camera unit on the car, removed the lens and compared it with my spare.

    The spare lens has a longer focal length, which reduces the FOV, but also increases the effective size of objects in the monitor. It is also physically longer, so I've had to space the CCD board in the housing to stop the lens fouling the outer coverglass, but it does fit, and properly focussed (I had to do this with the camera in bits looking at distant objects in the monitor and adjusting the lens before locking it down) I now have a FOV of around 78°.

    Its still not enough. I can see in the monitor everything I can see in the exterior mirrors and then some, and cars on my tail still look like they are travelling at a safe distance. The only improvement has been in the resolution of distant vehicles, which has improved, but not to the point where I can establish closing speeds prior to commencing overtaking or changing lanes.

    So I think I need a narrower FOV still - and this time I will have to pay for it (about £10 a throw by mail order). The next size up (down) is a 53° FOV, followed by a 40° FOV. I know that some of you are using telecams out on the roads, what FOV have you found works for you? Does it allow you to dispense with the interior rear view mirror altogether, or do you find that (as I am at the moment) you have to retain it as a back-up?

    I'm going to get some pictures together of my installation, but for the moment words will have to do. The monitor positioning is only temporary at the moment, as the dashboard will be replaced, but I'm quite pleased with my interim arrangement (made up of pop-rivets, ali sheet and black-painted cardboard and gaffer tape for the surround/sunshield). At least that bit works fine, and the microphone option has possibilities...

    Let's hear some experiences from our more seasoned telecammers!

    Lauren
    only Pythagoras can save me now!

  2. #2

    Re: Telecam Time!

    Lauren, was there a question on the way? or just your findings so far? I have a camera fitted but like yourself think it will be more for reversing rather than rear view (it was cheap so suspect it will be just a glorified parking sensor that can see). however I saw a Lambo (I think) in the south of France a few years ago and that had a rear view camera, do you think it was in place of the mirror or just for parking again. Do you know what camera would be a good one to get for the application we are trying to use it for? My one has 9 ir led's for night vision (think it goes black and white when in this mode).

  3. #3

    Re: Telecam Time!

    What the F**p went on there, I read your post but when I submitted my one your original post grew to twice the size, will now have another read to see what the rest said and see if it answers my post.

  4. #4
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    Re: Telecam Time!

    Sorry BBC, if its a lengthy discourse I like to post a bit first and then edit as I go along!

    I suppose its more of an observation really - I was wondering if the current clutch of Supercars with zero rear vision and built-in telecams were set-up differently. I guess they must be - and with systems like the BMW IR night vision overlayed onto the windscreen via the HUD, the camera optics need to match the drivers forward view exactly - no comedy fish-eye lens would work.

    I was hoping that somebody had already settled on a suitable camera lens specification, but if not I don't see why the results of my on-going exercise can't be shared - most CCD cameras use this type of lens and so could be changed/optimised at little additional expense.

    The IR LEDs provide illumination with a range of 2-3 metres. CCDs are sensitive into the near infra-red range so will still work in low-light conditions. The LEDs only produce one wavelength so if you are relying purely on them (complete darkness) the image will be monochrome.

    TG tested the Gumpert Apollo the other night, which has no rear window. At all - so it has a rear view telecam. I was trying to make out how wide the FOV was when Hamster pointed it out, but the image only seemed to show clouds. Also I've noticed works Ferrari F430 GT cars have LCD telecams fitted, if you are relying on those to check that its all clear to overtake the car in front you don't want a camera with a reducing lens on it!

    I'm sure there's some useful experience out there. I know Rick had a telecam on his Sterling, and Mike's purple thingy has a camera prominently fitted on the roof.

    Lauren
    only Pythagoras can save me now!

  5. #5

    Re: Telecam Time!

    Right, now I see, your first post stopped about 4 paragraghs from the end, so in a nut shell you are asking for help and didn't have the answer to our issues.
    I have an added issue in that there is no rear screen to view through whatsoever (fabricated rear hatch instead of the louvers and filled in window tunnel, now a large rear glove box/storeage area with lid) so will be relying on the wing mirrors and the camera for vision, so a good effective camera would be a very useful addition.

  6. #6
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    Re: Telecam Time!

    Hmm, I see. A bit like an Ultima GTR then. Looks like we are both searching for a suitable solution then.

    I got a volunteer to stand at various points behind the car so I could see by how much the FOV needs to be reduced. This, plus parking in the road to see what does and does not need to be seen in the monitor suggests that reducing the FOV by another 20° would be about right, so I would need the 53° FOV lens, but I might just go for broke and buy that and the 40° just in case. Or should I try the 30° lens as well?

    This is where you can't beat real on-the-road experience, which was my reason for posting. SOMEBODY must have had this trouble before!

    Lauren
    only Pythagoras can save me now!

  7. #7

    Re: Telecam Time!

    Hmmm...I can't tell you what my FOV was with my little evilBay setup, Lauren. My foggy memory wants to say it was 110 degrees, as it was the most common camera listed (read: cheapest ). My monitor left A LOT to be desired - a micro 2" screen that fit neatly in the center vent between the dash pods. I did have the camera mounted on the top louvre, so I was able to see the very edge of the spoiler I had fitted, which was exactly what I wanted. It was more of a back-up camera more than anything else. During the day my monitor was very hard to read, so I relied on my mirrors. But at twilight and night was when the monitor/camera really came into play. The camera had no IR capabilities, but even at very low light I could see more than I was able to from the mirrors. Judging closing speeds wasn't really an issue, since I was also relying on my mirrors rather than the monitor solely. At night, the camera picked up headlights long before my mirrors, and apart from the glare (non-adjustable monitor), was an asset when trying to switch lanes.

  8. #8

    Re: Telecam Time!

    i have sat in a box ready to fit a different camera but to the same design, i also have a 7" w/screen monitor as well. The difference in picture is total and the current drain amazing. When I get round i will post, as it is the list of to do's.
    http://jimsnova.page.tl/
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  9. #9
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    Re: Telecam Time!

    Well, I found a source of CCD board camera lenses at £7 a pop (plus the dreaded VAT of course), so I have ordered a 53° FOV and a 42° FOV lens. I don't think I need anything less than that, but we shall see.

    Lauren
    only Pythagoras can save me now!

  10. #10
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    Re: Telecam Time!

    Right - my current installation, this time with pictures!

    So, when you open up a standard CCD (Charge-Coupled Device) reversing camera, this is what you find...

    The imaging chip is covered by a cast aluminium housing which is threaded to take the lens assembly. As you know, after trying the standard 120° FOV lens fitted in my camera, I found it impossible to use as a replacement for the interior rear view mirror - you could see everything when it was close up, but any cars in the distance were impossible to detect due to their small size.

    So I raided my electronic spares box and came up with a 78° FOV lens and tried that instead. Better, but still not good enough. By looking at the monitor and comparing the display to what I could also see in the exterior rear view mirrors, I reasoned that something of the order of 50° FOV would suffice.

    Replacement board camera lens are available in a number of focal lengths, so I selected two that I hoped would fit the bill, with focal lengths of 6mm (52° FOV) and 8mm (42° FOV). They look like this...

    Sorry about the small size of the image, I tried to take pictures of my own camera and lens but they didn't come out too well

    Anyway, on the basis that I might as well try the narrowest FOV first, I installed the 8mm lens. The result is pretty much right on the money, with the camera "handing over" the rear view to the mirrors at the extremes of vision, with a small overlap. But I'm getting a little ahead of myself - here is the camera back in place above what used to be my rear window aperture...

    I used a small block of UPVC to space the bracket away from the fibreglass, to get the camera positioned so that it looks through the louvre slats at the right point.

    When the louvre is in place, it looks like this...

    Notice I placed the camera on the offside rear, so that it covers slightly more of this side of the car than the nearside. This works very well on the road for RHD cars (and in the UK where undertaking is illegal), but there is essentially no blind spots between the camera FOV and the nearside mirror anyway.

    The six little dots either side of the central lens are the IR LEDs. I haven't used the system in full darkness yet, but the early signs are that they don't have enough range for effective night-time illumination.

    Now, you can't see anything without a monitor of some kind, so I need to put in a picture of my much hacked-about dashboard. Those of a nervous disposition should look away now, but it does fulfil its primary role of putting all my instruments and functions in the right places

    I moved my centrally-mounted ventilators down to make way for the monitor (a 5" monochrome CRT in this case). It needs to be mounted as high as possible so that it is as close to the driver line of sight as possible. I also angled the monitor towards the driver. The monitor is mounted on a yoke, which I attached to an aluminium bridge attached to the underside of the dash with self tappers. The surround is made from cardboard covered in gaffer tape (to give it the right texture ) and then sprayed satin black. I have left the buttons and potentiometers exposed for the moment, but in future I will probably conceal them or bring the functions out to remote switches. The monitor is wired into the ignition-controlled supply.

    Yesterday I felt sufficiently confident in the effectiveness of the system to remove my suction-cup interior mirror altogether and rely solely on the telecam for direct rear view. I did a 260 mile round trip to Holdenby House in Northamptonshire to attend the MITCAR show. Apart from minor issues with direct sunshine obscuring the view, the system works so well now (after adjusting the exterior mirrors to complement the camera view) that I won't be looking back

    Lauren
    only Pythagoras can save me now!

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