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Using SORAA Snap System Beam Spreader - Uneven Lighting

Posted: 11 Mar 2019, 20:09
by camwow13
So I just completed a DIY build of the plywood Archivist book scanner. Yay!

I stayed almost entirely to spec as I was lucky enough to have friends with easy access to laser and CNC cutters. One area I strayed\experimented was using the Soraa 00329 60 Degree Beam Spreader ( in place of the lenticular lenses. They actually fit the stock Archivist parts, snapping perfectly on top of the GX5.3 holder inside the light mount holes. To the naked eye these work really well, turning the narrow beam into a much wider and softer light.

One of my primary scan subjects is a giant stack of yearbooks, many of which have large, dark, shiny pages. I gave my scanner with its fancy snap lenses a run with some worst case scenarios and was disappointed to find it had rather uneven lighting.

Here are a few examples: Note that both the left and right pages get progressively brighter as you move out from the center, going from slightly too dark to too bright. I tried rotating the spreaders and even doubled them up with a single light for a test without luck. Looks like I'll be acquiring a set of lenticular lenses instead.

If anyone sees something dumb I might be doing feel free to correct me as I'm pretty clueless when it comes to lighting!

Re: Using SORAA Snap System Beam Spreader - Uneven Lighting

Posted: 11 Mar 2019, 21:56
by Konos93a
put the light higher and maybe you need stronger one .
try the glass- lens of cameras distance be one that when odd and even pages get cropped fit in the same size
put a glass mirror in front of your glass and calibrate the camera so you can see from the centre the lens from the screen.
zoom more the camera

nice work by the way

Re: Using SORAA Snap System Beam Spreader - Uneven Lighting

Posted: 13 Mar 2019, 15:39
by camwow13
I experimented with making the light higher, I think it helped, but it makes the thing even bigger than it already is and a little precarious haha. I'm going to get the lenses it was designed to be used with and try those out. It should work fine with those. Definitely need to do the fine calibration steps. I'm still waiting for a second matching camera to come in then I'll get everything dialed in. And thank you, I think it turned out pretty good considering how many times I messed up during construction. First time building something like this.

Re: Using SORAA Snap System Beam Spreader - Uneven Lighting

Posted: 13 Mar 2019, 18:25
by Konos93a
what camera will you use ?

about light . when you capture photos you will realize that the higher is the light , the more outside it will get from the centre of the page .
try to get so high that the light source reflection in the captured photos will get outside and something more from the content of the page.

about the size of the scanner . personally i set it on the top of my fringe .and built something like big desk so the fringe skeleton not to accept the weight.

maybe you will need stronger light .i use a 30 watt flood light . white colour 88cm from the corner of the 2 glass . ... nation.gif ... age_id=236 go to 0.41 about the light use subs even though , i dont explain so much

Re: Using SORAA Snap System Beam Spreader - Uneven Lighting

Posted: 13 Mar 2019, 22:04
by camwow13
I'm using dual Sony A6000's, they're overkill but they'll be able to do a nice job with the yearbooks I'm going after.

I think my light and height will be fine, I built my archivist to almost the same specs as the kit so the given lights and lenticular lenses should work as advertised on the guide. I'm using two 410 lumen SORAA bulbs that are throwing out a lot of light.

I'm afraid I'm nowhere near as creative as you when it comes to building things. That's an impressive build you put together.

Re: Using SORAA Snap System Beam Spreader - Uneven Lighting

Posted: 14 Mar 2019, 11:49
by Konos93a
ok you will be ok with your lights
your camera gives you many options.

check this video you i build that because i had light issue that i couldn't avoid for a4 books.

for smaller books result is acceptable for me

if you wanna not put out from the position your camera then use a way to trasfer photos and charge your camera.

can you charge your camera with a usb cable for smartphones and capture photo?

you can use sd cable ,if you cannot trasfer your photos while the camera is on your scanner

also how many dpi your photo is . you can find that buy right click on an image ans see the details.

built and use a scanner is 80 % internet 10 % hardware 10% software. you will have perfect results

Re: Using SORAA Snap System Beam Spreader - Uneven Lighting

Posted: 14 Mar 2019, 20:45
by camwow13
It does look like you're getting good results with your setup.

Unfortunately the A6000 does not charge via USB when powered. That feature came in later, newer, more expensive cameras. From my limited testing it also doesn't do dual tethering very well.

An SD cable is an interesting idea, I'll look into it. At the moment I'm going to be using a labor intensive process of shooting both cameras with an IR remote, and removing them to offload photos and replace batteries. Once I have the actual scan process figured out more I'll look into getting power adapters, extensions, or a raspberry pi to make life easier.

Not sure what the DPI is, will depend on the size of the book and how I frame it with the zoom on the kit lens. With 24 megapixels capturing the platen I should have more than enough for most of the subjects I'm shooting.

Re: Using SORAA Snap System Beam Spreader - Uneven Lighting

Posted: 14 Mar 2019, 20:45
by duerig
konos92a, your scanner is looks really good. I get mad scientist vibes off of it in the best possible way.

Just to be clear, though, looking at the image metadata generated by the camera won't give you an accurate idea of what the DPI is. That is a piece of metadata which every camera adds but which is usually set to a single flat value. The camera doesn't know what you are taking a picture of. If you take a photo of a billboard, the true number of pixels per inch of text is going to be vastly different than if you are zoomed all the way in on a little pocket book.

To actually get an accurate DPI value, you will want to take a picture of a physical reference like a ruler at a particular distance and zoom level with the camera. Then you can see how many pixels (dots) are in an inch.

However, even that won't give you a complete picture. Based on the quality of your camera, the lens, and the image sensor, adjacent pixels in the sensor will have leaked light between them. So there is a limit to how fine of detail they can resolve before things become a gray blur. A DSLR and a point and shoot camera may have the same sized images (like 20 Megapixel). But the higher quality DSLR will actually capture finer detail and yield crisper letter edges. If you want to quantify the difference, you can purchase a DPI chart which consists of a series of black lines that get slimmer and slimmer and closer and closer together as you move across it. At some point, your camera will stop showing the distinct lines and instead show that gray blur. Then the chart lets you match that point to an actual DPI value.

-Jonathon Duerig

Re: Using SORAA Snap System Beam Spreader - Uneven Lighting

Posted: 14 Mar 2019, 20:47
by duerig
Get power adapters right away. Taking cameras off mounts to change batteries is really terrible. I had to do that on my first setup and I still get nightmares. :)

Re: Using SORAA Snap System Beam Spreader - Uneven Lighting

Posted: 17 Mar 2019, 10:37
by Konos93a
to be honest duerig with his post clarified for me what dpi is?
anyway for more informations i think that link is good

From an older post in threat a small story for my scanner
also you can find which is the best glass-lens distance with abbyfinereader. there is a command detect optimal resolution. the more it gives you the better the image. if you have a 2 camera diybookscanner the cropped images even or odd should have the same size. my images usually are 510 or 540 suggested dpi i can go better (640 ) but i have light problems and need to change other camera position . so i let it just more that 500 and cropped pages on the same size for the context of the page. scan tailor experimental rescale them on the same size but odd or ever pages will have darker letters if you have much different lens-glass distance on your cameras. more than 300 suggested dpi gives you he same ocr results . more than 500 suggested dpi looks the same with for your eyes . "

now i use scan tailor advanced because it has many more options than experimental and the output seem better to me. but no rescale in the same sizes so evens content is a little bigger in even than odds pages.

finally every english reader has 2 benefits . firstly ocr in english is the easiest thing you can actually works perfect. no tones , clear letters although image can be blur and you larger word packache . >=5 mp ,ocr has the same results .

secondly about books . every book printed after 2011 in english can be found on Libgen . so no scan needed for newer books in english.

i see u have kindle install Koreader