Rob's inverted platen build - 01
| Builder: | Rob |
| Forum Post: | Rob's inverted platen build |
| Material: | Wood & Acrylic |
| Platen Angle: | 120° |
| Camera Setup: | dual |
| Camera Models: | Canon PowerShot SD1100 IS |
|
Table of Contents
|
Rob's inverted platen build
Post by Rob » 29 Mar 2011, 18:09
Why I started a new build
So I was scanning a paperback the other day after doing some hardcovers, and I noticed a few things:
1. The spine on paperback books is not very solid. It twists a lot.
2. The spine is nevertheless tight.
3. The margins on the textblock sometimes go deep into the spine.
When putting the usual platen down onto the book, I found that I had to press down on the platen sometimes to get enough page to show up, to spread the pages out, and then the spine would twist a bit. Also, when lifting up the platen, the book had a tendency to flip a few pages in an effort to close up. I ended up having to lift the platen a little bit and sneak my hand in to hold the pages down.
Then I remembered that some other folks here had built scanners with inverted platens, like this one [built by Ahmad], and I realized that this would be ideal for paperbacks that don't have a lot of value. I can press the spine onto the platen as hard as I need to. I can hold the spine down evenly so that it doesn't twist. And paperbacks are light, so lifting the book, flipping a page, and putting it down again would take less effort than to lift the platen.
And so, I am now setting out to build an inverted platen scanner, with two cameras.
The first thing I did was to (horror!) remove the platen from my existing scanner, flip it over, and pop a book on it.
This platen was originally made from two picture frames.
I'm thinking of going out and finding some 1/8" panes of glass, because the picture frames are made of two 1/16" panes each. I think 1/16" is too flimsy for pressing down on, and I've noticed that dust tends to get in between the two panes of the platen where it's impossible to clean unless I take the platen apart.
Question
Post by steve1066d » 29 Mar 2011, 18:23
Hmmm… Maybe the thing to try is to make it so my scanner can lock in the "up" position, then press the paperback up against the platen (maybe raising my cameras a bit too).
I'm sure it is easier to press down instead of up, but it would avoid having to make a separate scanner.. something to try I guess.
Steve Devore aka steve1066d
Location: Minneapolis, MN
Answer
Re: Question Posted by steve1066d
Post by Rob » 29 Mar 2011, 18:38
That would be a neat idea: a convertible scanner. But not for me, yet! Also, you do not want to push the book upwards. I've done that sort of thing, and your back will kill you after 20 pages.
Rob
Location: Maryland, US
Top
Starting to make a platform
Post by Rob » 03 Apr 2011, 19:14
Today was a good day at NextFab. I'd count it as Rob 2, Robot Tools 1.
OK, so I need some kind of a platform to put my inverted platen into. Cutting a square hole into some plywood is a good start. I took some 1/2" plywood, and cut it to about 30" wide by 24", and then cut a smaller hole centered in the middle, just big enough for my platen: about 16.8" across by 15". The idea is to fit the platen into the plywood so that it doesn't move, yet can be removed for cleaning. If your hole is slightly too large, you can always add shims, but if your hole is too small, frowns all around.
Cutting a square hole in plywood can be done in several ways, according to Lewis at NextFab. The lowest-tech way is to drill holes at all four corners, then insert a jigsaw and cut your way around. The next step up is to cut out a template from MDF or plywood, and then use a router to route your way around the hole. This is also hellishly noisy. I really hate routers. The highest-tech way is to use a laser cutter, which I did at NextFab. This also gave the opportunity to add some personal touches.
Next, since the hole is designed to fit the platen, we need a little platform so that the platen doesn't fall through. Since the hole is 16.8" by 15", I told the laser to cut two additional strips, 2" x 16.8". Thank you, Robot!
Glue up and clamp hard on the underside. Here's the back view. I determined that my particular platen could use a 3/4" ledge to sit on, so that's how far the strips stick out.
And the front view, so you can see now how the platen will sit on the ledges thusly formed!
Success! Thank you, Robot!
Oh, and the one where the Robot Tools won?
I was drilling holes in plastic in the CNC (40 holes, to be exact), and it worked fine in the morning. But I did another run in the afternoon and the drill bit heated up, melted the plastic, and then got stuck in a hole.
The whole run was ruined. Up yours, Robot! I think that there has to be some kind of cooling that has to be turned on.
—Rob
Location: Maryland, US
Mounting the table top
Post by Rob » 10 Apr 2011, 21:25
The next step in the build is to mount the tabletop onto some legs. I wanted to make the height of the scanner comfortable for me while sitting. I should be able to hold my arms out straight ahead or slightly down and touch the top of the platen. For me, that makes the top of the platen about 29 inches from the floor, making the top of the table 21 inches from the floor.
I spoke with Lewis at NextFab for some advice, since I have no experience in building stable tables. The best I did was ten years ago when I took a 4' x 8' piece of plywood and stuck some 2" x 4" legs on. I added some bracing after I realized that it was unstable, and it sort of worked. But I wanted something a little more stable from the beginning.
He suggested building an "apron" around the bottom of the tabletop, made of 3/4" plywood, 3" wide. I decided to leave a 1" lip around the perimeter. My tabletop measures 30" x 23 1/2" — I cut the plywood to slightly under 24" because I didn't want to assume one edge was perfectly parallel with the axis of the laser. So I subtract 2" from each dimension to get 28" and 21 1/2". That latter dimension is very close to my desired leg height, so I decided to use 21 1/2" for the legs as well.
I cut two strips 3" wide and 28" long, then ten strips 3" wide and 21 1/2" long. Two of each go into the apron. Now, if you're not like me, you've discovered a little problem already. If I were to place the strips like this: |_| then I'd get 21 1/2" plus twice 3/4", which is 23". That gives a 1/4" lip, not the 1" I wanted! What I should have done was make the 28" strips smaller by twice 3/4", or 26 1/2".
So instead I just placed the strips alternately. I ended up with a lip of 5/8", which is fine. Just don't forget the thickness of the plywood strips!
To attach the strips, first mark a pencil line 5/8" from the edge (or however big the lip is) on the bottom of the tabletop. Run a thin bead of wood glue inside the line, and put the strip on top. Clamp in three places:
Now mark a pencil line 5/8" plus half of 3/4" along the top from the edge. More generally, lip plus half the apron plywood thickness. This is where your screws must go:
Drill pilot holes through the top — it helps to use a very small square to make sure you're drilling perpendicular to the top — then countersink for the screw heads, and screw together.
Once all four sides are on, use a looooooooong clamp to squeeze the sides together. Drill pilot holes, countersink, and screw:
Use only one screw at the top, because we will later be drilling holes through the apron near the corners.
We now have a very sturdy tabletop.
Rob
Location: Maryland, US
Building a table
Post by Rob » 10 Apr 2011, 21:35
For the legs, take a pair of the 21 1/2" strips.
Run a bead of wood glue along one edge, and place the other strip on it. Clamp, pilot holes, countersink, screws. Repeat four times.
Clamp each leg hard into an inside corner of the apron. I'm not going to glue the legs on, since I want to be able to remove the legs. Thus, after clamping, drill four holes through for bolts. I'm using 1/4" holes for 1/4" bolts. Make sure the bolts you get are 1/2" longer than twice the plywood thickness, 2" in my case. Make sure that when you drill the holes for the bolts, they will not interfere with each other.
Note that in the below pattern, the bolts will not hit each other.
Before you take the leg off, mark each leg and each corner with a letter so that you can put each leg into the same corner every time, otherwise the bolt holes won't line up.
The final result is pretty stable and somewhat Masonic even without bracing. (Bolts not shown)
The next step will be to add some bracing which will also serve the purpose of providing mounting points for cameras and lights.
Rob
Location: Maryland, US
Re: Rob's inverted platen build
Post by Rob » 11 Apr 2011, 18:14
Thanks! I'll post more pix next week, and hopefully by then I'll have gotten some bicycle brake cables to add remote triggering without having to use CHDK (but that is the subject of another post).
Rob
Location: Maryland, US
Suggestion: Using a single piece of plexiglass
Postby spamsickle » 11 Apr 2011, 19:46
"Rob wrote:I'm thinking of going out and finding some 1/8" panes of glass, because the
picture frames are made of two 1/16" panes each. I think 1/16" is too flimsy for pressing down
on, and I've noticed that dust tends to get in between the two panes of the platen where it's
impossible to clean unless I take the platen apart."
Perhaps you've considered and rejected my suggestion to use a single piece of plexiglass with a heat bend in the middle, but I'd like to suggest it again anyway. It would solve the "dust in the crack" pRoblem — no crack! I used 1/8" or 3/16", and still haven't gotten around to doing it again sideways "for real", but it's just a matter of clearing a block of space and time. I have the plastic, the heat gun, the suction cups, etc.
Anyway, here's the link to the mock-up:
One suggestion for "impossible" paperbacks.
The right slab of plastic on that nifty frame you've got there looks like it would be "plug and play".
spamsickle
Answer: Using a single piece of plexiglass
Post by Rob » 12 Apr 2011, 09:19
Spam — thanks for reminding me of your work! I'll have to get some acrylic and practice bending it under heat. Your results definitely speak for themselves, and if I can get the acrylic to behave, I'll certainly upgrade my platen!
Rob
Location: Maryland, US
Suggestion: Using a circular saw
Postby jck57 » 12 Apr 2011, 14:12
"Rob wrote:Cutting a square hole in plywood can be done in several ways, according to Lewis at
NextFab. The lowest-tech way is to drill holes at all four corners, then insert a jigsaw and cut
your way around. The next step up is to cut out a template from MDF or plywood, and then use a
router to route your way around the hole. This is also hellishly noisy. I really hate routers.
The highest-tech way is to use a laser cutter, which I did at NextFab."
Carpenters use circular saws [http://www.ehow.com/video_4417355_cutting-windows-circular-saw.html] to cut out windows.
jck57
Answer: Using a circular saw
Post by Rob » 12 Apr 2011, 15:05
Not a technique I would try. Granted, if you're expert, you can do it, but if you've only picked up a circular saw a few times… it can go very wrong very quickly!
Rob
Location: Maryland, US
Suggestion: Using a single piece of plexiglass part 2
Post by spamsickle » 12 Apr 2011, 16:33
"Rob wrote:I'll have to get some acrylic and practice bending it under heat."
My current plan is to tape the acrylic to a table top with the "bend line" on the straight edge of the table. I'll do a bit of math, and have a platform built of books to the height I want the bending side to stop. Run the heat gun along the bend line to soften it, then bend to the proper angle. I'm still going with something a lot more obtuse than 90 degrees; I guess a 90-degree angle would make the platform unnecessary. My main concern is that the heat-softened "bend line" will be too wide, and I'll get an S-bend rather than a V-bend. If I was bending up rather than down, that wouldn't be a concern, but I can't think of a convenient way to suspend my stop plane.
Let me know if you try it first, or have any ideas. Maybe I should start a "heat bending" thread…
spamsickle
Answer: Using a single piece of plexiglass part 2
Post by Rob » 14 Apr 2011, 09:34
Oh, my thought was to suspend the acrylic in the middle from a long thin tube, and then heat the top, allowing it to flop down. If the plan works, the acrylic should bend itself, and stop when the ends hit the table.
Rob
Location: Maryland, US
The mount for the camera
Post by Rob » 16 Apr 2011, 22:12
Parts needed
Parts needed for this step:
* Four 4" angle brackets, found in the door hardware section at my Home Depot
* Four 1 1/2" long 1/4" hex bolts
* Four 1/4" nuts
* Sacrificial piece of wood, at least as long as your scanner is wide
* Optionally, four 1/4" washers
Tools needed
Tools needed for this step:
* 1/4" spade bit
* Small square
* Drill
* Ruler
* Three clamps
* Pen or pencil
* Optionally, some sandpaper
Next step is the mount for the camera. There are many camera mounts: the original "Six Degrees of Awesome" design from Instructables (formalized here). Or, use some old gooseneck lamps and mount your cameras on those (article here for Make Magazine subscribers, but you can just bodge one together).
Or any of the numerous other solutions that just involve bolting this thing to that other thing.
My solution involves going to Home Depot (or your local hardware megastore equivalent) and getting some 4" angle brackets (or your local metric equivalent). Get at least four.
I'll mount one on each side underneath the top inside the apron to provide a convenient attachment point.
First, take one of the brackets and measure the distance from the side to the middle of the hole. Then add a little more.
Set up a ruler so that you can scribe a line along the inside of the apron at this distance.
Mark out the locations of the legs so that you can avoid them. In retrospect, I would probably have scribed the line further in, to provide more room. We learn by making mistakes. Oh well.
Next, put your angle bracket almost right up against the leg, and mark the center of each hole. Move it over about halfway, and mark the holes again. Now march your way across the top, marking the centers. In this way, you will get holes exactly spaced for your bracket.
Now, drill the holes. Use a 1/4" bit, which matches the 1/4" bolts you'll use (or whatever your metric equivalent is). Preferably a spade bit because those are longer, and you'll need the length due to the apron being in the way. Also, clamp some wood against the top. The drill will splinter the plywood at the exit point, but clamping some sacrificial wood there will help drastically reduce the splintering. Also, use the small square as before to help make your drill bit perpendicular.
Even with the sacrificial piece of wood, I had to sand the top a little to remove the smaller wood splinters.
Use 1 1/2" long 1/4" bolts, with optional washers. See? The bracket fits. Why? SCIENCE!
Rob
Location: Maryland, US
Mounting the other brackets and your cameras
Post by Rob » 16 Apr 2011, 22:27
Parts needed for this step:
* Two 1/4" wingnuts
* Two 1/4" thumbscrews, 1" to 1 1/2" long. You can probably substitute hex bolts here.
* Two nylon standoffs with 1/4" or slightly larger inner diameter, 1/2" long. Any outside
diameter is fine.
* Two 1/4" split washers
* Two 1/4" wingscrews, 1/2" long (note: these fit into your camera, so make sure you get the right
size)
* The other angle brackets you didn't use from the last step
Tools needed for this step:
* Optionally, two pliers
This step involves mounting the other brackets and your cameras so you can admire your handywork. Attach the wingnuts, thumbscrews, split washers, and nylon standoffs as depicted. You can orient the angle brackets any way you wish.
The reason for the split washers is that they provide a force pushing all the parts together. The nylon standoff allows you to rotate the parts even when everything is tightened together. This means you can adjust the thing to the right angle, and not worry about it moving.
Use the pliers on the thumbscrew and wingnuts to loosen, if you can't loosen them with your fingers.
Using the wingscrews to mount your cameras to the angle brackets.
At this point, if you have CHDK-compatible cameras, you can just hook up the cables and go scan some paperbacks. However, I'll be building a version of kusnick's remote trigger using bicycle brake cable (see this thread). Also, I'll be trying to build Spam's bent acrylic platen. So watch the space below for more!
Rob
Location: Maryland, US
Bending an acrylic sheet
Post by Rob » 18 Apr 2011, 16:38
Parts you will need for this step:
* Sheet of 1/4" clear transparent acrylic, 18 3/4" x 15" or other size for your custom scanner; see text below.
Tools you will need for this step:
* Two adjustable-angle clamps (such as this Rockler Clamp-it Set)
* Alternative to the above, two wooden triangles with one angle being 120 degrees
* Two identical pieces of 3/4" plywood, 18" x 15"
* One strip of 3/4" plywood, 18" x 2"
* Two wood screws, at least 1 1/2" long
* Screwdriver
* Non-permanent marker
* Square
* Acrylic strip-heater at least 24" long (such as this Craftics heater)
Here's how to bend an acrylic sheet to make a Spamsickle-type bent acrylic platen. First, size your acrylic sheet correctly for a 120-degree bend. If your opening is W inches wide by H inches high, your acrylic sheet should be 1.15 W - 0.56 by H.
Why? SCIENCE!
Next, take your plywood sheets and your clamps, set your clamps to 120 degrees, and make a little tent:
Here I'm using a different kind of adjustable angle clamp, which I couldn't find online.
Anyway, this tent will be your form for the acrylic. Next, take your acrylic, and place two small dots using the marker on either side of the acrylic, halfway along its long side.
This is where you're going to bend the acrylic, so the dots serve as alignment markers.
Balance the acrylic on the form so that your center dots are centered along the seam, and use the square to make sure it is parallel to the form's sides. Now carefully tilt the acrylic over so that it ends up flat on one side, sticking up in the air on the other.
Draw a line where the acrylic ends, and screw your small 2" strip to the form:
The idea is that once your acrylic is heated up, you can just set the acrylic against the strip, and bend at the right place to the right angle.
Now lay out your strip heater. Professional acrylic strip heaters are big long solid things that you can either lay your acrylic on top of, or lay on top of the acrylic. The cheaper wire heaters are designed to sit on top of the acrylic. Here is the important part: the side of the acrylic closer to the heater is the WARM side, and other side is the COOL side. Remember this.
Lay out the acrylic and the strip heater so that you are heating along the line connecting your marked alignment dots.
Wiggle the acrylic gently every so often to see how pliable it gets. You don't want it to be too hard. Soft is good. The softer the better. Chances are the cheap wire heater will not heat the acrylic up so much as to get it really soft.
In any case, when you've determined that you can bend the acrylic easily, take the acrylic and lay it down on the form, WARM SIDE UP. That is, if your heater was on top of the acrylic, just pick the acrylic up and put it down on the form the same way. If your heater was under the acrylic, pick the acrylic up, flip it over, and set it down on the form. The reason for this is that the outside bend of the acrylic requires more stretchy material, and hence that side needs to be warmer. If you mess up and do it the other way around, your bend will still work, but you'll end up with a bunching of material on the inside, which will distort your book in all the wrong ways.
Bend it gently.
Hold it down while it cools. If you bent it the right way, the acrylic should not spring back when you let go. Anyway, once it is cool to the touch, take it off the form, and fit it in your scanner. You may have to shim the sides a small bit.
Rob
Location: Maryland, US
Adding a different place for mounting the camera
Post by Rob » 08 May 2011, 20:49
Parts you will need for this step:
* Eight 1 1/2" long 1/4" hex bolts
* Eight 1/4" nuts
* Two strips of 3/4" plywood, 3" x 20-1/2"
* Sacrificial piece of wood, at least 20-1/2" long
Tools you will need for this step:
* Tape measure
* 1/4" spade bit
* Small square
* Drill
* Pen or pencil
* Three clamps
* Optionally, a level
* Flat black spray paint
In this step, we're going to add a different place for mounting the camera. The problem that I found with mounting cameras near the "roof" is that the angle of the camera to the platen is so far off perpendicular that it adds significant keystoning to the image, and that's no good.
Here's the geometry:
You can use the tape measure to draw a kind of virtual line perpendicular to the platen, and from this you can see where you want your camera to end up. Mark that position on the legs.
The next step is to use the rest of the tools and parts to add cross-braces to the sides.
Drill holes for the angle brackets just as in previous steps.
Then clamp the result to the legs. You can use the level to make sure the cross brace is nice and straight. Drill two holes through each end. It doesn't matter where, as long as the holes aren't in a straight line. Bolt together.
You may have noticed that I spray-painted the angle bracket holder flat black. This is important, because with this style of scanner, everything that isn't black is going to reflect against the platen. Interestingly, the wood doesn't seem to add any reflections.
It seems that only stuff within the volume of the scanner will reflect.
You will need to light the platen from the front, not from directly underneath as you would think based on the other kind of scanner. See where the lights are in the first picture? That's where the lights need to be. You might be able to eliminate some shadows by lighting also from the back, but I've found that the shadow isn't so bad, especially when the end result is going to be bilevel.
If you have cables running to the cameras and they are not black, put a black cloth under the scanner, and run the wires underneath that.
Next will cover the results from this scanner!
Rob
Location: Maryland, US
Using ImageMagick
Post by Rob » 08 May 2011, 21:52
Getting the most out of your inverted-platen scanner
Things you will need:
* ImageMagick
* Some program that will let you pick out coordinates of points on your image.
Photoshop does it, but I'm not sure what else does.
* Scan Tailor or BookScanWizard
One of the advantages of an inverted-platen scanner is that the platen does not move relative to the camera. This means you can take all of your pictures, and as long as the camera doesn't change location or orientation, the same exact keystoning will happen to every image. Also, the spine of the book will be (approximately) in the same position in every image. This lets you do some very simple yet powerful image cleanup before turning Scan Tailor or BookScanWizard loose on your images.
Here's a sample image.
The first step will be to rotate and dekeystone the image all at once. Select an image that has a full page of text.
Determine the coordinates of the points at either end of the topmost and bottommost full line. Use the bottoms of the lines rather than the tops.
Write down the coordinates. Making a little diagram helps.
While you're at it, calculate the long and short sides of your text block using the good ol' Pythagorean Theorem. My sample image has a long side of 1854 and a short side of 1199. The particular side you measure doesn't matter much.
Also, take a ruler and measure one of the sides. Divide the number of pixels by the measured size, and you get the dpi of the image. Notice that my dpi ended up being 353, which is really not too bad!
Now, here's what you want to end up with:
So we have four source points and four destination points.
Let's label the destination points UL, UR, LL, and LR (upper left, upper right, lower left, and lower right). Let's also label the source points ULs, URs, LLs, and LRs — but ULs is not the upper left of the image but of the page. Thus, in the example above,
ULs = 2388, 500
URs = 2432, 1712
LLs = 536, 578
LRs = 582, 1776
The question is, what should UL, UR, LL, and LR be? First, let's set UL = LLs. Why?
Because this is the source point with the lowest x and y coordinates. Note that if your image is of the opposite page, you will pRobably end up setting UL = URs.
UL = 536, 578
Now it is just a matter of adding the short side pixel distance to x:
UR = 1735, 578
And then adding the long side pixel distance to y:
LL = 536, 2432
LR = 1735, 2432
Now we will use ImageMagick to map
ULs -> UL,
URs -> UR,
LLs -> LL,
and LRs -> LR.
Do the one image you picked out first, as follows:
Code: Select all
convert input.jpg -virtual-pixel black +distort Perspective "ULs,UL URs,UR LLs,
LL LRs,LR" +repage -density dpixdpi output.jpg
For my page, this command line looks like this:
Code: Select all
convert Rob_inverted_platen_01_0006.JPG -virtual-pixel black +distort Perspective
"2388,500,536,578 2432,1712,1735,578 536,578,536,2432 582,1776,1735,2432"
+repage -density 353x353 output.jpg
And the result:
I've taken the liberty of drawing a line right around the middle of the platen bend.
Measure this using the coordinate measuring program. Mine came out to (about) 528.
Exactness isn't quite necessary, but you might err on the side of caution, because we're going to use ImageMagick again to get rid of the opposite partial page:
Code: Select all
convert output.jpg -crop +528+0 +repage output2.jpg
The above removes stuff on the left. To remove stuff on the right starting from X, use this instead:
Code: Select all
convert output.jpg -crop Xx0+0+0 +repage output2.jpg
There! Now we have a nice single page. This makes it easier for Scan Tailor and BSW to deal with.
Next, delete output.jpg and output2.jpg. Create a directory called, say, "fixed_images".
Now, if you're on OSX or Linux, running the command on every image is easy:
Code: Select all
for i in *.JPG
do
convert $i -virtual-pixel black +distort
Perspective "2388,500,536,578 2432,1712,1735,578 536,578,536,2432 582,1776,1735,2432"
+repage -density 353x353 -crop +528+0 +repage fixed_images/$i
echo $i
done
In Windows, it's a little more weird (and this may not work, since I don't use Windows):
Code: Select all
FOR %%i IN (*.JPG) DO 'convert %%i -virtual-pixel black +distort Perspective
"2388,500,536,578 2432,1712,1735,578 536,578,536,2432 582,1776,1735,2432" +repage
- density 353x353 -crop +528+0 +repage fixed_images/%%i'
If it doesn't work, ask on the forum for anyone who can get it to work. Or download and install Cygwin, which will let you run Unix-type commands on Windows. Then you can use the OSX/Linux commands above.
Anyway, your resulting images are now in fixed_images. Do the whole thing again for the images from your other camera (measure, dekeystone, crop), and point ST or BSW at your resulting images. After ST or BSW finishes up with the images, they are nice and clean:
Anyway, that's it. Good luck, and have fun scanning!
Rob
Location: Maryland, US
Top
Re: Rob's inverted platen build
Postby daniel_reetz » 09 May 2011, 08:08
Brilliant tutorial, Rob! And great results.
daniel_reetz
Location: City of Angels
Beginning-to-end time for scanning a 290-page paperback book
Post by Rob » 29 May 2011, 22:45
I finally got off my lazy fundament, and decided to scan a 290-page paperback. It took me 21 minutes. That's 13.8 pages per minute (or 6.9 dual images per minute), which means I picked up the book from the platen, flipped the page, put the book back down on the platen, adjusted the position to roughly center the page (using the monitor attached to the camera) and pressed the button all, on average, every 8.7 seconds. Wowzers!
Measuring a left and a right page for dekeystoning and cropping took about 10 minutes.
Actually dekeystoning and cropping took 50 minutes.
Here is the end-to-end time for one 290-page paperback book:
#Scanning: 21 min
#Check images, retake pix: 15 min
#Measure page images: 10 min
#Dekeystone and crop (ImageMagick): 50 min
#Rename for correct page order: 5 min
#ScanTailor to Margins step: 10 min
#Correct content, margins (ScanTailor): 4 min
#Output to 600dpi B&W (ScanTailor): 21 min (no dewarping necessary)
#Adobe AcRobat combine files: 8 min (result: 12.9MB)
#Adobe AcRobat ClearScan OCR: 31 min (result: 7.2MB)
#Scan front cover, back cover, spine. Dekeystone, rotate, crop. Add via AcRobat: 15 min
(result: 10.9MB)
Total time: 190 min
Computer processing time: 120 min (63%)
Human time: 70 min (37%)
Rob
Location: Maryland, US