Why wouldn’t you just make a camera mount that can clamp onto one of the two gas pipes and can gimbal for a good view? Seems a lot more flexible and easier to get right the first print.
I don't know this exact meter, but I had a little optical sensor on my meter for years. There was a dial that rotated once per a given volume, it had a black part and a white part. This way a single led and light detector could measure exact revolutions and be able to read out the value. This way it didn't have to read the numbers, which is much harder and can't measure small increments very well.
My meter got replaced with a smart kind years ago, so now I simply have a port that can be read out directly with way more information. But my janky led and light detector thing worked very well for years. Since this was years ago it ran a very simple PIC micro, nothing like a full fledged ESP platform.
If you're already using an esp32 why not just get a simple ultrasonic sensor and measure flow on an indoor inlet pipe? You may need to know the pressure (probably 1.7 kPa) and temperature but that should be possible to calibrate against your meter readings
Then your project just becomes a simple pipe clamp that can be indoors
Afaik scanning will require extra tuning steps. Alternatively you can take rough measurements of few cross sections, then print them on paper, cut the contours and check how it fits, make adjustments and repeat until you are satisfied
Electricity and Gas Inspection Act
R.S.C., 1985, c. E-4
Offences and Punishment
Marginal note: Falsification and meter frauds
30 Every person who
(a) except as authorized by or under this Act, makes, causes or procures to be made, or assists in making any certificate required under this Act or purporting to be a certificate so required or any stamp, seal, label, tag or mark prescribed for the purposes of this Act or purporting to be a stamp, seal, label, tag or mark so prescribed,
(b) knowingly sells, utters or disposes of, lets, uses, lends or exposes for sale any meter with any stamp, seal, label, tag or mark thereon made or obtained by means of the commission of an offence under paragraph (a) or section 32 or made or affixed by way of the use of anything so obtained,
(c) in relation to the administration of this Act, knowingly
(i) makes any false representation,
(ii) makes or causes to be made any false entry in any register or record,
(iii) makes or causes to be made any false document or makes any alteration, false in a material respect, to the form of a copy of any document, or
(iv) produces or tenders any document containing false information,
(d) for a fraudulent purpose,
(i) repairs or alters, or causes to be repaired or altered, or tampers with or does any other act in relation to a meter, or any wires or pipes leading to a meter, so as to cause the meter to register with an error, or
(ii) replaces any meter with a meter calculated to mislead, or
(e) with intent to defraud, obtains, consumes, uses, supplies or sells electricity or gas in relation to which any meter
(i) registers with an error caused by an offence under paragraph (d), or
(ii) in the case of commission therewith of an offence under subparagraph (d)(ii), is calculated to mislead,
is guilty of an indictable offence and liable to imprisonment for a term not exceeding five years.
1980-81-82-83, c. 87, s. 30
Hope you get the scans you need, and that it's worth 5 years for whatever you're trying to do.
A clearly-labeled plastic box smaller than the actual metal meter is not likely to cause this law to be invoked, since there is no way in hell that a reasonable person could mistake it for the real thing. It would be like mistaking a Tonka toy for actual construction equipment.