How best to stitch a large scan?
Dec 6, 2023 07:53:41 #
I have a large CAD drawing but my scanner is only 8.5x14". So I would scan sections of the drawing separately. How would I best stitch them in PS? It appears that the agorithm in PS is good for when you pivot the camera on the tripod but not so much when stitching the sections like I do with the scan.
Dec 6, 2023 09:07:30 #
BebuLamar wrote:
I have a large CAD drawing but my scanner is only 8.5x14". So I would scan sections of the drawing separately. How would I best stitch them in PS? It appears that the agorithm in PS is good for when you pivot the camera on the tripod but not so much when stitching the sections like I do with the scan.
Not sure about your scanner capability wise.
But provide the following:
What is the size of the "CAD drawing"?
What is the drawing of?
That will help with getting a response.
Dec 6, 2023 09:25:28 #
BebuLamar wrote:
I have a large CAD drawing but my scanner is only 8.5x14". So I would scan sections of the drawing separately. How would I best stitch them in PS? It appears that the agorithm in PS is good for when you pivot the camera on the tripod but not so much when stitching the sections like I do with the scan.
Scan in using an overlap of about a third for each scan. The use Lightroom Classic to stitch them togather. I regularly use this method for scanning in old maps.
Dec 6, 2023 09:40:52 #
Architect1776 wrote:
Not sure about your scanner capability wise.
But provide the following:
What is the size of the "CAD drawing"?
What is the drawing of?
That will help with getting a response.
But provide the following:
What is the size of the "CAD drawing"?
What is the drawing of?
That will help with getting a response.
It's an E size drawing of mechanical parts and thus I don't want any geometric distortion (unlike stitching a landscape some distortion is OK).
Dec 6, 2023 10:01:43 #
Modnar wrote:
Scan in using an overlap of about a third for each scan. The use Lightroom Classic to stitch them togather. I regularly use this method for scanning in old maps.
For accuracy your scanner and any PS type program is inadequate.
You cannot place the drawing accurately enough as you are proposing.
Go to a shop that scans drawings for Architects or contractors and they can do it as 1 drawing easily. Well worth the cost if any modicum of accuracy is desired. Or if there is an Architect or good engineering firm nearby you might be able to sweet talk them into scanning the drawing for at least cost.
I know that I would when I did my own. But today I just provide a digital file and require the contractor to make the prints and many AHJ won't take prints for review and only digital files.
Good luck.
Dec 6, 2023 11:53:54 #
BebuLamar wrote:
I have a large CAD drawing but my scanner is only 8.5x14". So I would scan sections of the drawing separately. How would I best stitch them in PS? It appears that the agorithm in PS is good for when you pivot the camera on the tripod but not so much when stitching the sections like I do with the scan.
Beware. The scanner will not give you what you would think. I tried to stitch a several row x several column scan of a detailed map of the Antarctic Peninsula and I never did get it correct. I did then revert to photographing it hanging on a wall with a high end camera. Results were good. HTH
Dec 6, 2023 13:21:05 #
BebuLamar wrote:
I have a large CAD drawing but my scanner is only 8.5x14". So I would scan sections of the drawing separately. How would I best stitch them in PS? It appears that the agorithm in PS is good for when you pivot the camera on the tripod but not so much when stitching the sections like I do with the scan.
Why not photograph it - doing copies I tend to like photo images rather than scans
Dec 6, 2023 13:47:01 #
stan0301 wrote:
Why not photograph it - doing copies I tend to like photo images rather than scans
A sheet that large, to get a somewhat undistorted image would need a large distance from the camera to the image and most all lenses have barrel or pincushion distortion that even corrected in PS will not be accurate.
Dec 6, 2023 16:55:26 #
Architect1776 wrote:
A sheet that large, to get a somewhat undistorted image would need a large distance from the camera to the image and most all lenses have barrel or pincushion distortion that even corrected in PS will not be accurate.
I copied a 30" x 45" Antartica Map by photographing Several rows of images and then stiching. LrC did a wonderful job of correcting for lens distortion. Distance was only 7 feet with a 100mm lens
Dec 6, 2023 20:09:06 #
A lot depends on scanner software. The process is called Tiling , My Image Print software RIP for my printer can do it. It basically allows a 17" printer to print any size, kind of like wall paper.
I realize you are doing basically the opposite, but to get maximum accuracy I think you need software that can scan with that purpose in mind.
When you just scan separate pieces and then bring those into a stitching program you almost always get some distortion. (That's why there is a 'blend control)
It costs you only time to try it, people above have reported success so you MAY get results that work, but the most foolproof way is to bring it to people who do it every day, and they can probably make copies for you
I realize you are doing basically the opposite, but to get maximum accuracy I think you need software that can scan with that purpose in mind.
When you just scan separate pieces and then bring those into a stitching program you almost always get some distortion. (That's why there is a 'blend control)
It costs you only time to try it, people above have reported success so you MAY get results that work, but the most foolproof way is to bring it to people who do it every day, and they can probably make copies for you
Dec 7, 2023 07:40:14 #
Thank you everyone! I decided that that best thing to do is to redraw the drawing. It takes time but the result would be perfect.
Dec 7, 2023 15:15:48 #
The CAD program should be able to produce any sort of image or file that your scanner would create. And you would have an original rather than a copy.
Dec 7, 2023 15:35:57 #
twowindsbear wrote:
The CAD program should be able to produce any sort of image or file that your scanner would create. And you would have an original rather than a copy.
Not to original scale
Dec 7, 2023 17:20:50 #
Architect1776 wrote:
Not to original scale
Well the original drawing is scale 1:1 and it has all the dimensions.
Dec 7, 2023 17:33:18 #
BebuLamar wrote:
Well the original drawing is scale 1:1 and it has all the dimensions.
Go for it.
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