iPhone to trinocular microscope for low-latency visual feedback system - Page 1
Forum section: electronics / projects

author: lynaghk
author_rank: Contributor
timestamp: November 27, 2021, 07:29:58 am
content: I'm experimenting with small actuators and curious if I can use the 240 fps capabilities of an old iPhone (model A1662) with a trinocular microscope (Amscope SM745NTP-B 7X-45X) for a low-latency closed-loop feedback system.This is my first microscope, and my understanding is that I'll need to:1. mount the iPhone to the 23mm photo port somehow (presumably my resin 3d printer will get involved)2. either get optics to reduce the image down to the iPhone's camera OR be okay with losing most of the field of viewAside from saving money by using an extra phone, my hunch is that it'll be lower latency to do image analysis on the iPhone rather than any $300 combination of AliExpress/Amazon USB+HDMI+computer kit?That said, I'm a microscope / optics newbie, and I haven't seen any prior art about throwing cell phones onto trinocular microscope photo-ports, so perhaps this is a terrible idea?My backup plan is a Raspberry Pi HQ Camera, which I've seen folks mount to trinocular scope ports.What do y'all think --- iPhone <-> trinocular photo port possible?How would I go about calculating/measuring the optics I'd need to buy or build?

author: magic
author_rank: Super Contributor
timestamp: November 27, 2021, 10:31:15 am
content: I'm not familiar with stereoscopes, but if they are anything like biological scopes, you will need an eyepiece there in order to use a fixed-lens camera. Without an eyepiece, only a bare sensor camera could work, such as dedicated microscope cameras or DSLR/MILC or a webcam with lens removed (waring: extreme crop factor). A fixed lens camera peeking down the tube will see the same view that you can see with your own eye, which is a distant objective with a bright spot in its center - not very useful at all.I suppose you have some eyepieces at hand already, so go ahead and experiment.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 27, 2021, 12:50:29 pm
content: Is there already an iOS app that does the analysis you want? Apple is very unfriendly towards writing your own apps for your own devices.

author: lynaghk
author_rank: Contributor
timestamp: November 27, 2021, 06:42:43 pm
content: Thanks magic, that makes sense. The scope is still in the mail, but when it arrives I'll try moving one of the eyepieces into the photo tube and see if I can get a decent image on the phone. Will update the thread with details.NiHaoMike, I pay Apple $99/year for a developer license so I can write my own apps for my own devices =DIt may also be possible to access the camera from a website (no Apple permission needed), though it's unlikely all of the camera control knobs re: focus, white-balance, etc. will be accessible there.

author: magic
author_rank: Super Contributor
timestamp: November 27, 2021, 07:21:47 pm
content: https://www.microscopy-uk.org.uk/mag/artjan14/pvb-digistereo.pdfpage 8,9Apparently I wasn't wrong and those scopes are indeed mostly identical. Regarding field of view, if the smartphone has a wide angle lens, the image may not fill the frame, just like looking into a scope IRL. I suppose you could experiment with some smartphone teleconverters / telephoto adapters / addon lenses, whatever they call them. These reduce the camera's FOV and increase magnification, but they may also vignette when combined with the eyepiece if they are too bulky. I honestly have no clue. I suppose eyepieces with long eye relief may be advantageous in such application, if you can find them.