Fast Precision Perspective Correction

[Harrie]

Hi, I’m new with Affinity Photo and I’m really impressed by all the features and possibilities. There’s only one thing that I’m not able to do: Fast Precision Perspective Correction which is needed to correct the perspective fault due to an incline (angle) of the camera. I cannot get beyond the iterating proces of slide the four corner until the result is more or less satisfying.

If you do some mathematics you can find a desired correction at the top of the picture of:

(cos(𝛂)xcos(𝛃)/cos(𝛂+𝛃))-1 and at the bottom: 1-(cos(𝛂)xcos(𝛃)/cos(𝛂+𝛃)). In which: 𝛂=angle of the camera and 𝛃=half of the angle of view (= arctan(h/2f) in which h=censor height and f=focus length).

So the desired correction can be calculated precisely as a function of the angle of the camera, if know what focus length was used.

My question: Is there a possibility to construct a procedure, macro or filter to do fast precision perspective correction with the existing tools and features in Affinity Photo?

Vergrotingsfactor.key

[h_d]

Hi @Harrie and welcome! You've uploaded your diagram as a Keynote presentation which means that the many PC-using members of this forum won't be able to open it (unless they have iCloud). I've taken the liberty of uploading a screenshot:

Hopefully someone will come along and help with the algebra - it's beyond me!

Cheers,

H

[Callum]

Hi Harrie

Welcome to the forums

Unfortunately there is no straightforward way of performing this operation within the app. However if you are trying to correct a tilt or incline you could try playing with the distort correction options found within the develop persona.

Thanks
C