Image analysis programs?

[ergospherical]

I have taken some photos (with my phone) of some optical phenomena in the lab. I'd quite like to analyse the distances between some features of the image. In school I remember using a piece of software which allowed you to choose an origin point / setup coordinate axes, select a scale (i.e. 1 cm real life = x pixels) by using a reference length in the image, and then determine distances by clicking between points. Might anybody know what this program is (or a similar program that I could use)? Many thanks.

 

[kuruman]

I was intrigued by your request so I did a little bit of web research and I found this. I have not used the kind of program you describe but I have used Google Sketchup extensively in the past (last time was about 10 years ago) and I think that the limited (but free) version will work for what you want to do. Of course you will have to know an actual calibration distance but that is always the case for programs of this sort. This method, however, may not be as accurate when you have objects at different depths.

 

[ergospherical]

This might work, yes! The images are at normal incidence and aren't taken too close to the screen, so it should work alright.

It's one of those simple but mundane tasks which I could, in principle, do by hand, but at the cost of a good 20-or-so minutes of time and slightly reduced precision.

 

[anorlunda]

I think the search term you want is
https://duckduckgo.com/?q=Photogrammetry+software&ia=web
There appears to be a lot of software, including free, and open source.

Photogrammetry is the analysis of aerial or satellite photos.

 

[Andy Resnick]

I have taken some photos (with my phone) of some optical phenomena in the lab. I'd quite like to analyse the distances between some features of the image. In school I remember using a piece of software which allowed you to choose an origin point / setup coordinate axes, select a scale (i.e. 1 cm real life = x pixels) by using a reference length in the image, and then determine distances by clicking between points. Might anybody know what this program is (or a similar program that I could use)? Many thanks.

Fiji, which used to be called ImageJ:

https://fiji.sc

It's free and easy to use. For your application, all you need is the basic installation.

 

[robphy]

In intro physics, we have used
https://physlets.org/tracker/

As @Andy Resnick says, one could use https://imagej.net/software/fiji/
which is based on https://imagej.net/software/imagej2/ ,
which is based on the original https://imagej.net/software/imagej/

Another interesting option may be
https://automeris.io/WebPlotDigitizer/