For a project to reassemble the parts from an old Lenco turntable I thought it might be worthwhile trying a scan of the stamped steel top-plate then convert it to vector (and then to cad). In a test using a flat ruler I discovered that there is considerable distortion that varies with the location on the scanner so that even if the scan of a 10" ruler is printed so the ruler image is 10" long, some segments of the ruler length are shorter than actual and some are longer.
Does anybody know about this technology and how to identify a flatbed scanner that will actually produce correct scaling across the entire image?
Thanks
Does anybody know about this technology and how to identify a flatbed scanner that will actually produce correct scaling across the entire image?
Thanks
Hi Pano,
No, I'm not sure, but the scanner I have is a very cheap Cannon that runs entirely on USB power and sounds like it just barely has the power to move the sensor across the frame. I think it's because of that I'm looking at the scanner first.
I was told by a salesman at a local store that anything but paper thin flat images won't scan with millimeter to millimeter accuracy unless the scanner has a focussing lens, and that type costs $700+. I don't know enough about the technology to agree or disagree with him.
Maybe it's best is to take the plate to a graphics repro house and ask them to scan it.
No, I'm not sure, but the scanner I have is a very cheap Cannon that runs entirely on USB power and sounds like it just barely has the power to move the sensor across the frame. I think it's because of that I'm looking at the scanner first.
I was told by a salesman at a local store that anything but paper thin flat images won't scan with millimeter to millimeter accuracy unless the scanner has a focussing lens, and that type costs $700+. I don't know enough about the technology to agree or disagree with him.
Maybe it's best is to take the plate to a graphics repro house and ask them to scan it.
I also use a Canon USB scanner (CanoScan Lide 60). This type has very small depth of field, and suitable for scanning paper images and text only. Also the absolute constant speed of the cart is not guaranteed, neither the same scale in the horizontal and in the vertical direction. Perhaps a more powerful office laser printer/scanner is better (as it should be).
You might have a digital camera or phone with a good camera , make a high res picture with a tripod or some other fixture and you can do anything with the produced Jpeg with various software and it will be linear !
Cheers ,
Rens
Only by making digital lens correction. All camera lenses distort to some extent
Well, that's one way to do it.I was thinking more using the rulers in an image program. Do you have anything like that?
heh heh, Yeah, I thought you might say that.
I don't have any graphics programs with that capability. I was thinking of getting AutoCad but when I saw the $4K price tag I nearly fell over. So then I downloaded DraftSight, a freeware cad program, but it won't open any of the files I can produce. (sigh)
(I actually did what KMossman suggested and got a graphics house to scan the plate yesterday, but as mentioned above the DraftSight can't open the pdf or tiff files I received.)
I'll have to think this out a bit. I see myself getting sucked into searches for and education on graphic software when what i really want to do is build a turntable.
Yup! That's the one I have. Really great for scanning printed stuff straight into emails etc. and . . . . I guess that's what it's good for.
If you send me the image (TIFF) I will see what I can do with it (no promises).
If you want to do it yourself, there is a freeware program called Wintopo that can work very well for raster to vector conversions. I think illustrator and some freeware like inkscape might do some simple raster to vector as well.
Pano, Ron,
Thanks for your very kind offers. If I may have a rain check I might take you up on it but I have a speaker project I need to finish in the next week as the shop I've been renting bench space in is closing down.
It will be at least a week before I can think about this again. If OK with you I'll post again or PM when things are done.
. . . And thanks again!
Thanks for your very kind offers. If I may have a rain check I might take you up on it but I have a speaker project I need to finish in the next week as the shop I've been renting bench space in is closing down.
It will be at least a week before I can think about this again. If OK with you I'll post again or PM when things are done.
. . . And thanks again!
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