Scanning Large Plan Sheets At Home

[thibaultron]

Part 01

 

Most of us don’t have very large format scanners at home. One that could scan a large plan sheet.  Nor do we necessarily have even paid access (or the money for same) to a commercial one. Thus we are stuck will our standard 8 ½ by 11+ scanner. As some will note, scanning in the plans can add distortion from the scanner itself, as can the process of combining them. If you are careful to check for this, some corrections can be made using a photo editing program. For most of us, any distortions are quite small, and probably less than a real wooden ship varied from the original plans, just due to the fact wood is a flexible and changing media and measurements were not all that precise and the ship could settle during framing and construction. You, of course, can redraw the plans by hand, or use the drawing directly to build your model, but many times CADing the plans works as well or better.

 

There is a way to scan in a large sheet one section at a time and combine them into a single scanned sheet. Why would you need a complete scan of a sheet if you have the original? There could be several reasons. Here are my typical ones.

 

1.       I want to rescale the drawing.

2.       There are larger scale detail drawings on the same plans sheet, and you want to make scale drawings as templates. For instance. The plans for Model Expos’ Willie Bennett, has 1/32^nd scale main drawings, and 1/16^th scale detail drawings on the same sheet.

 

 

3.       There are many parts on the model that are copies of the same part, (blocks, anti-aircraft guns, cleats) that can easily be copied and moved with CAD.

4.       You want to print a copy of a section, and build the model on it rather than the original plans.

5.       There is missing information on the plans. A section that has been ripped out and lost, too few frames drawn. I have a drawing I’m working on from an “Out Of Production” kit (manufacturer is no longer in business) where the fore frame line drawings are close and the stern lines completely factious, I assume to keep someone from building the boat from only the plans. The bulkheads were precut in the kit. On another boat I’m drawing, the masts are shown broken off just above deck, with no spar information supplied. Using the short length of fore stay shown, and an old woodcut, I found after a couple years of searching, I was able to determine the mast length for both the fore and main masts. The woodcut showed that the foremast ended just above the fore stay fitting. Not a very hard example, but the plan sheet was too small to draw the masts or sail plan, so CAD was helpful.

 

 

6.       You need to check some of the drawing against anther area, and want to trace it out in CAD. A case I run into frequently is the frame lines not matching the body lines, or offset table.

7.       The various views differ. I’m drawing up a Santa Fe business passenger car, for 3D printing. After scanning in the drawing and starting to CAD I found that the overhead and two side views in the original drawing were slightly different lengths (yes all 3 views differed by several inches). In the case of this drawing, several of the dimensions given were also wrong!

 

8.       You want to compare the plans to photographs (as above) of the original prototype. Again with the train car above, the side views had the windows slightly incorrectly placed. Also using the photographs in direct comparison I was able to correctly place all of the several hundred rivets, precisely. The pictures at the very top and bottom are the sides for a version of the car, after AC was added in the 50s. Those pictures are the sides from a kit.

9.       You want to make bulkhead drawings from the offset or frame drawings. It is easy to copy, mirror  the one side and place the “other” side once one is done. Here is an simple example:

 

10.   You need to have  CAD files for a laser cutter, or 3D printer.

 

Anyway, on to how to do it.

 

1.       Scan the drawing in sections, allowing an inch or 2 of overlap (top bottom and sides).

a.       Shown is an example of two overlapped scans. As you can see, both scans have hefty amount of overlap. The overlap shown is far more than needed, but that is alright.

 

2.       Save each scan as a separate file. It is best to save them as .TIF or .TIFF files, with no compression. Many other types, such as .JPG or .JPEG, compress the file EACH time you save it! This causes the final file, after several iterations, to be quite blurry.

3.       Now there are two ways to get the scans into one picture for your CAD or graphics file.

a.       You can lay each picture onto a larger graphic editor blank “Canvas”, aligning each by hand. This can be difficult, because as you move the original around for the scans, you will rotate it slightly as it is moved. This means you also have to custom rotate each pane to a common angle, as well as line them up.

                                                               i.      This is easier if you are lining them up in a CAD program, as long as each is prerotated using the CADs ability to measure angles. After finding how much the pane is off by, use the graphics editor to correct the pane angle. You can then place all the scans in the CAD window, mark common points and move the panes to mate at those points. I can give examples of this using DesignCAD, if you want, later.

b.      You can use a Graphics Editor program to combine them automatically (Called a Panorama or Composite). Most graphics programs can do this with photographs, but many not so well with drawings. I have had poor luck with Photoshop and GIMP. The best two I have found are Microsoft Live Elements  (Photo Gallery) and Microsoft ICE (Image Composite Editor). Both are free.

                                                               i.      The Live Elements app Photo Gallery can be used to create a panorama from drawing scans. This is a 32bit program and can stumble on larger files or a large number of files. Note that, with Gallery, the files must be in the User’s “Pictures” directory. MS no longer supports this program, and has taken it off their site, but a full download is available at;

 

https://web.archive.org/web/20170112124505/http://wl.dlservice.microsoft.com/download/C/1/B/C1BA42D6-6A50-4A4A-90E5-FA9347E9360C/en/wlsetup-all.exe

 

                                                             ii.      The ICE is a free, current, download and is 64bit (There is no telling with MS, how long they will support it, though, as with Live Elements) At:

 

https://www.microsoft.com/en-us/download/details.aspx?id=52459

 

c.       Be sure to carefully check the final “Stitched” drawing, things can and have gone wrong with my files.

                                                               i.      Sometimes the process just fails spectacularly.

                                                             ii.      Sometimes the panorama is distorted.

d.      If difficulties arise try:

                                                               i.      Checking that your overlap is OK.

                                                             ii.      Make sure that all the images are correctly oriented to each other, all right side up, or all upside down.

                                                            iii.      Perhaps stitch the scans in smaller groups, then stitch the larger groups together.

                                                           iv.      Try a different program.

 

Here are some examples with the two programs.

 

 

Photo Gallery

 

Note make a copy of the directory you want to combine the pictures in, in that same directory. Sometimes Gallery modifies the files in the original directory also! Then copy the “Copy” directory to “Pictures”.

Now that the directory is in Pictures, Start Photo Gallery, and select the directory you will be using.

 

 

Then select all the images you want to combine

 

 

Select “Create” Then “Panorama”

 

 

 

The program will then start the process.

 

 

 

And proceed to the next step.

 

 

 

When it is done (if it competes, otherwise you will get an Error message), you are asked to save the Stitched file. Note a name is generated for the panorama, change it if you like.

 

 

 

 

[thibaultron]

Part 02

 

Select “Save”, and the file will be saved, when that is done, the finished file will be displayed.

 

 

Don’t worry that it is not square in the “Frame”, you can fix later with a graphics program. In this case it is also upside down. That must have been how I scanned it, or at least how Gallery saw the best way to combine the files.

 

In any case, copy the stitched file to your original directory. I generally delete the directory file in “Pictures”, just to save disk space.

 

 

ICE is a bit simpler. Note: You can use any directory with ICE.

 

Start ICE

 

This screen will be displayed

 

 

Select “New Panorama From Images”.

 

 

 

Go to your directory and select the images.

 

 

This screen will be displayed, with your images displayed.

 

 

 

Select “Next”

 

 

 

The process then starts.

 

 

The process continues.

 

 

 

The finished panorama is displayed.

 

 

 

 

Select “Next” again and the “Crop” screen is displayed.

 

 

 

Select “Next” and the “Save Image“ Screen will be displayed.

 

 

In the “Image” area select the box in the “Image Format” section, then “TIFF”.

 

 

 

Then select “Export to disk”. The file will be saved.

 

 

 

The save screen will be displayed, notice that ICE also supplies a name, if you want to use it.

 

 

Select “Save” and the file will be saved.

 

 

 

 

Edited December 28, 2020 by thibaultron
Remove duplicate image

[thibaultron]

Part 03

 

Then close the program, then when it has finished, select “Discard Project”.

 

 

Now you can use a graphics editor to finalize the panorama.

As another note: ICE saves the composite as a compressed .TIF file. So the first thing you should do is open it with your graphics editor, and save it as an uncompressed TIF file, before you further work on it.

 

I’ll show an example using my very old copy of Paint Shop Pro 9. No explanation, other than the pictures, as your program will be different.

 

 

 

 

 

 

 

 

 

 

I then rotated it to level. In this case 1.75 degrees left. Yes, I cheated and had previously used my CAD program to find that angle.

 

 

Then cropped it

 

Now I have a nice composited digital plan file.

 

Not all the drawings inside the plan are square with the border, so use an internal drawing line as your reference to “level” the whole drawing. This was the case with this plan, so I used one of the center lines. Check several center or baselines to make sure the drawing is not bowed or otherwise not correct. On this drawing the deck center line is bowed (by about 1”) but all the other base and center lines are straight to within the width of the drawn line. The original drawing must have this error, and it is not due to the compositing.

[druxey]

Whew!  An exhaustive if not exhausting tutorial on compositing multiple images and trying to eliminate distortion. Thanks for taking the time to show us how you deal with this issue.

[mtaylor]

Ron,

Check with a local builders exchange service.  They have the large format copiers.  The last batch I had done for around 15 prints plus a thumbdrive was around $20.  Just offering another alternative method.

[thibaultron]

I'll look, thanks.

[Dr PR]

Ron,

 

I used your technique to scan several hundred blueprints on microfilm from the National Archives.

 

The microfilm scanner at our library produced images that were far too coarse for scanning the full 35mm film frames, resulting in images too blurry to read the fine print. I optically enlarged the images and scanned each 35mm frame  in six overlapping scans and pasted them together in Photoshop. Some of the largest blueprints (12' x 3') were photographed in six frames producing 36 scanned images.

 

The original photo equipment generated some spherical distortion in the images on microfilm, and the microfilm scanner at the library added even more distortion. I had to do a lot of image straightening and stretching to get back the original rectangular shapes. But then they all went together pretty smoothly.

 

The resulting images are really good. I can read the finest print, and can even see the tiny pencil dots the draftsman used to center circles and align lines of text!

[niwotwill]

Ron thanks for taking the time too present your methods it gives me another alternative to get large files scanned. As a follow on to Marks post I have found that at a local engineering copy center they can scan drawings up 34" by 44" (E size) and adjust scale to meet your needs. The output can be most formats including tiff. 

 

Thanks for sharing your method

Stay well and stay safe

Will 

[Duck]

Ron, Thanks for taking the time to share your approach!  Another alternative is the business center at a Staples store.  They have large format scanner and can usually complete a few scans while you wait.  Last time I had some drawings scanned it was less than $2 each.  They also have self service copiers than can scan up to 11x17.  Bring your own flash drive.

 

Paul