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Raspberry Pi HQ Camera with 16mm lens (?)

Everything camera related. Includes triggers, batteries, power supplies, flatbeds and sheet-feeding scanners, too.
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kay
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Joined: 23 Jun 2021, 13:39
Number of books owned: 300
Country: Switzerland

Raspberry Pi HQ Camera with 16mm lens (?)

Post by kay »

Hi everyone!

I'm planning on building the archivist to digitise my grandpa's library containing old persian books. I'm planning to purchase two Raspberry Pi HQ Cameras to use due to their ease of programming and availability in my region. However, I don't know which lens to purchase alongside the cameras.

Currently, I'm looking at the 16mm telephoto lens which is one of the two lenses recommended with a Pi HQ Camera (the other one is a wide angle with a lot of distortion that I've discarded). Due to the crop factor of the Pi HQ sensor, the effective standard focal length of the 16mm telephoto is 88mm on a standard sensor. Since this is a fixed focal length lens I'm not sure if the distance in the archivist (between the camera mount and platen) will allow me to capture the full page without any cropping.

Sadly, I have no experience dealing with cameras and lenses. On the Swiss pi-shop website where I'm buying from, there are also other Arducam lenses that have no reviews. I'm not confident in buying the recommended ones, let alone the unreviewed Arducam cameras.

If anyone can please recommend a further course of action I'd be very grateful. I've already made posts on the raspberry pi reddit, discord server and forums, but no one seems to be familiar with this. Thank you!
BillGill
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Re: Raspberry Pi HQ Camera with 16mm lens (?)

Post by BillGill »

I can't really comment on the Raspberry PI camera, but I have had some slight success with fixed focus cameras. You may need to change the mounting distance so that the camera will cover the full page. Too close and you get cropping, too far and you get overscan and lose resolution. I'm not sure how you would go about modifying the mounts on the archivist to change the distance.

Bill
kay
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Joined: 23 Jun 2021, 13:39
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Country: Switzerland

Re: Raspberry Pi HQ Camera with 16mm lens (?)

Post by kay »

Hey Bill!

Thank you for the input! I was wondering if you by any chance knew the distance between the platen and the camera mount? I think this would greatly help me in identifying whether the lens I'm buying would need to be modified to build the archivist. Do you think it would be hard to reposition the camera mount?

Thanks!
- kay
BillGill
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Re: Raspberry Pi HQ Camera with 16mm lens (?)

Post by BillGill »

Another thing I'm not familiar with is the Archivist. I have been building my own and cutting to fit. So I don't really know how much work it would be to change the mounts. The latest one I built is my 'Tower Scanner'. You can find a discussion on it at viewtopic.php?f=14&t=3467

Bill
murgen
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Re: Raspberry Pi HQ Camera with 16mm lens (?)

Post by murgen »

I used to have an old standard build 1rst generation an my focus was at 53cm.
http://www.critiqueslibres.com/blog/?attachment_id=1784

I am not sure if you need this 16mm. I think the 6mm should be ok but will not swear, just a feeling.
Here is an example of such a build https://www.youtube.com/watch?v=3S1MQM8B-DU
And the resulting image should be fine for scan. https://drive.google.com/drive/folders/ ... DRiTuv7KLS
In all case let us know the result. I decided to rebuild a scan machine and this time I will go for rasberry pi 4 + rasberry camera to have a direct view/input of the image and automated trigger. The lens 6mm vs 16mm is still unknown at this moment.

Why do I go for the raspbbery ?
Here is my old construction, http://www.critiqueslibres.com/blog/?p=1625 canon a800 + chdk with bike brakes as triggers. It worked for 2 years before I had issue with one camera. Never replaced it due to the difficulty linked to find camera that support chdk at small prices.
The main reason I go for the rasberry is that I feel I can keep the setup stable for years to come.
By stable, I mean that if I have a broken gear, I can replace it without being obliged to redevelop a whole system due to new camera. chdk = maintenance pain
murgen
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Re: Raspberry Pi HQ Camera with 16mm lens (?)

Post by murgen »

This is my previous post reposted with the images embedded:

I have completed my proof of concept for this raspberry HQ camera 16mm lens (Long post).
The goal : setup a tethered control set of camera for the smallest budget possible, without compromising the PDF quality. the goal is 200€, but I can't do it less than 400€ for dual cameras.
I choose the raspberry pi 4 (65€) with the HQ camera (60€) and 16mm lens (60€).
Here is the raspi 4.
IMG_20210709_110647.jpg
There is a hint here that point to an IT guy.

Here are the source of the build for my proof of concept :

My pi 4 https://shop.mchobby.be/fr/kits-raspber ... 21167.html
The HQ camera https://shop.mchobby.be/fr/pi-camera/18 ... 18365.html
The lens https://www.amazon.fr/gp/product/B08CXH ... UTF8&psc=1
Tripod https://www.amazon.fr/gp/product/B005KP ... UTF8&psc=1
Flexible cable 1m https://shop.mchobby.be/fr/pi-camera/12 ... 12714.html

Total cost are : 83.48 + 59.96 + 59.99 + 19.99 + 4.78 = 228.2 € vat inclusive.

1m cable is too short, I should take the 2m, specially when I will have 2 HQ camera.
To complete my camera build up, I will order the multi camera adaptor https://shop.mchobby.be/fr/pi-camera/20 ... 20337.html 47,63€ + another 2m flexible cable (2x7.77€) + second tripod (19.99€), second HQ (59.96€), second lens
16mm (59.99€) = 203.11 to complete the dual camera setup.

The complete build up will be : 228.2 + 203.2 = 431.4 € VAT inclusive (I don't pay the VAT, the costs are on my society :p)

The other cheap option of a tethered setup would be a PI 3 with 2 cheap smartphone in USB. This setup may cost slightly less, but the tethering is an issue. I have to toss cost for 2 remote control Bluetooth gear.
There is no really cheap tethered option with Canon CHDK. The cheapest, CHDK supported but non DSLR, still sold are the Canon IXUS 185 at 145€ a piece and you still play with memory cards. This is something I don't consider anymore, it is tethered or nothing.

Now, the important thing, for the raspberry pi 4 setup cost, what did I achieved ? Well, to my to my delight, I could produce a scan 100% correct with ABBY 14 and get the images correctly.
Keep in mind this is only a proof of concept, my lighting is deficient (a 17w led bulb in my office ceiling) but the HQ camera still did an amazing job.
raspi 4, the beast in action :
IMG_20210716_124043.jpg
The picture Image is out of a big book (h 31cm - w 22cm)
0001.jpg
Two columns text with an image embedded
0003_80.jpg
A full two columns text page to stress HQ camera dpi/OCR capability
0004_t2000.jpg
The tripod with HQ camera + lens 16mm
IMG_20210716_124007.jpg

closer look
IMG_20210716_124035.jpg
A look to raspi terminal while taking shots to demonstrate how easy it is to script
IMG_20210716_124129.jpg
View of the image just before snap
IMG_20210716_124140.jpg
A regular book, this is piece of cake for OCR
0001_t1000.jpg
Image processing in ABBY14 result is net
IMG_20210716_130647.jpg

Text recognition, the dpi of the HQ camera was enough to deliver 100% OCR
IMG_20210716_130844.jpg
The two column text OCR was also wonderful
IMG_20210716_130934.jpg
I even tested a color shot despite my lighting was only a LED 17w in ceiling.
0005_color.jpg
I excluded from this POC any art color reproduction, but the camera HQ delivered promising result. I will leave to other people to decide if the costly DSLR setup is still required. But for monochrome scanning, magazines and OCR purpose, the tethered raspberry pi 4 + HQ camera is up to the task.

I put the raw images in a pdf, so you can have a closer look to the PI 4 HQ camera :
spoc_rasp4_hq_camera.pdf
(466.34 KiB) Downloaded 76 times
The last 3 pages are the same, but taken with a snap duration of 2s, 1s, 500ms.
This was to assert the loss of the camera HQ quality when you venture out of the default.

That's it for now. I have to order the second batch of stuff to complete the setup, remount my 7 years old scan machine http://www.critiqueslibres.com/blog/?attachment_id=1784 , install and perform my first dual tethered scan.
TS Zarathustra
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Re: Raspberry Pi HQ Camera with 16mm lens (?)

Post by TS Zarathustra »

These scans look very nice, especially considering the lighting issue.
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