Question: What do you call the square brackets used to target a barcode/QR scanner? I thought this would be called "reticle," but when I Google the term, all I see are circles with crosshairs. Is there a more precise term, especially in the context of a digital device/camera, or is reticle the word?

![scanner target](https://i.stack.imgur.com/vYbtD.jpg)

Answer: 
Well going to the actual source of QR codes - the company who invented them ([Denso Corporation](http://en.wikipedia.org/wiki/Denso)) don't seem to have given that a particular name at all.

The products that they sell refer to that roughly in equal measure as the '[Reading Area](http://www.denso-adc.com/products/gt15)' or the '[Scanning Area](http://www.denso-wave.com/en/adcd/product/qrcode/handy_terminal/bht-800q.html)'.

Even the actual patent for QR codes: ([Optically readable two-dimensional code and method and apparatus using the same](http://worldwide.espacenet.com/publicationDetails/originalDocument?CC=US&NR=5726435A&KC=A&FT=D&ND=7&date=19980310&DB=EPODOC&locale=en_EP)) doesn't detail the actual guide lines, only going as far as to state that it is an 'image pickup device'. 

You could *possibly* refer to it as a 'CCD Area', as a CCD (Charge-Coupled Device) is the type of image sensor that QR codes use (see this patent: [Optical information reading apparatus](http://www.freepatentsonline.com/y2006/0054844.html) - also from Denso) but that's not really the most intuitive term.

So basically, it seems like the specific term is still up-for-grabs. Reticule, 'Reading Area' or 'Guidelines' or whatever makes the most sense to the user really.
Cross hairs are meant for aiming (centering) and are not usually interactive.

The rectangular visualization's primary purpose is not centering of focus, but selecting the relevant part of the image for scanning. Theoretically user can change both size and location in the screen, therefore this is not a common cross hair.

The rectangular visualization enables the user to see and modify the "region of interest". (See definition of "region of interest" or ROI here [[Wikipedia]](http://en.wikipedia.org/wiki/Region_of_interest), [[Mathworks]](http://www.mathworks.com/help/toolbox/images/f19-13234.html), [[Wolfram]](http://library.wolfram.com/examples/roi/)).

I found that this rectange is refered to as ["**viewfinder box**"](http://acer-tr.custhelp.com/app/answers/detail/a_id/16483/~/how-to-install-a-printer-with-acer-print), ["**viewfinder rectange**"](http://areacellphone.com/2010/05/howto-download-install-android-apps-using-qr-codes/), ["**viewfinder area**"](http://www.quickmark.cn/en/Info/android.asp), ["**crosshair box**"](http://www.cadtutor.net/forum/archive/index.php/t-17689.html) (or ["annoying yellow box around crosshair"](http://forums.steampowered.com/forums/showthread.php?t=1718837) in non-QR usage), however a more correct term (which is commonly used in image processing) would be "**region of interest**".

Relevent queries:

[viewfinder box](https://www.google.com/search?q=%22viewfinder+box%22+qr&hl=en&tbm=isch)  

[viewfinder rectangle](https://www.google.com/search?q=%22viewfinder+rectangle%22+qr&hl=en&tbm=isch)  

[viewfinder area](https://www.google.com/search?q=%22viewfinder+area%22+qr&hl=en&tbm=isch)