Removing Objects from Photographs in Gimp

withoutThe title says GIMP but I’ll cover other packages in here – read on. Normally I put photos in my blogs and leave the reader to wonder how i made them. I’ve uploaded approaching 8,000 photos to Flickr over time and that’s just a small selection of the pics I’ve taken over the past 50 years (digital since 1998) – that’s a lot of photo clean-ups.

From the dawn of digital photography I’ve been trying out different tools to enhance my pictures and in these pages I’ll describe some of them.

Anyway, here’s a quick tip. Let’s say you’ve taken a holiday photo and there’s something (or someone) in the photo you want to remove. Perhaps an unwanted tree, animal or sign.  As you can imagine – not that simple because the information BEHIND that object – was never photographed. Depending on the background however it may be possible to make a convincing show of removing the object.

Take a look at the photo to the right – this is a bunch of us this summer, at the annual Galera wine tour in Spain. In this instance there wasn’t anyone I wanted to remove – but for the purpose of this demo I’ve removed one of our friends. This took all of a minute – let’s see how this was done.

Now you COULD fork out large sums for Photoshop, spend a lot of time mastering it and suffer monthly or annual charges to help make millionaires out of the designers. I know several photographers who are happy to do this – and several who are not – their results are not that different.

Photoshop is good and is often referred to as the industry standard, but like Microsoft Word – few of the more advanced features are likely to be used by your average hobbyist and so it really is worth looking at the alternatives unless you’re really committed.

I’ve discussed mobile phone packages in a separate blog entry as it is often far more convenient to edit photos on the phone and anyone who under-estimates the power of modern mobiles is in for an eye-opener – for now – another program that has been around for a long time and also handles plug-ins (that is, pieces of (often free) software that you can add to enhance the package) is called Gimp.

The Rise of the Gimp

Gimp is free and unlike Photoshop, is available to run natively on PC, Mac and Linux – it is a VERY good photo package and plug-ins make it even better. Like Photoshop, it takes some mastering but simple tricks are easy to do. Let’s see one of them in action. Installing Gimp on Windows is easy – like most PC programs – just visit here and install it. https://www.gimp.org/downloads/ – it is probably easy to install on Macs too but I only use Windows and Linux – and I have had it running on Linux too.

So now you have Gimp, you can pull in photos and do wonders with them. If you’re interested in having a go, visit this page and get the free “plug-in” I use to remove objects. https://www.youtube.com/watch?v=2yGYLSs40Og

When you follow the link on the site, the file RESYNTHESIZER will download automatically. Unzip the file and you’ll find a load of files therein– these simply need copying into the Gimp plug-ins directory and that’s it. Takes longer to discuss than to do. In my case the directory to store these files is at c:\users\gimp-2.8\plug-ins – yours will be similar but with your Windows username instead. Drop the files in that directory and start up Gimp and you’re good to go. This applies to pretty much all plug-ins for Gimp (and there are LOTS) – download, unzip – move into plug-ins directory – run. Easy.

Once inside Gimp you need to use the lasso tool to roughly highlight the object you want to remove – make sure you completely envelope said object.

Gimp

Hopefully you can see our friend with the pink shirt has a set of dotted lines around her – I simply did that manually using the lasso tool – that’s one of the tools on the top right that is highlighted above – and looks like a lasso. If you’re a little unsteady – zoom in first.

Once that’s done if you select the top menu FILTERS then ENHANCE then HEAL SELECTION – you’ll end up with a dialog box. The menu item and the dialog box come from the plug-in, picked up automatically by Gimp.

Heal Selection

There really isn’t much to this – the program looks at the pixels surrounding your selection for a given radius which you control (too big and it gets messy, too small and you can start to see patterns – EXPERIMENT) – I just used the defaults in this case. Press OK and VOILA. One missing person as in the photo at the top. 

Once you know what has been done you can save the file or if you’re not entirely happy, go back and tweak what you’ve done with other replacements – either way, with natural scenes it is usually quite easy to completely eliminate some parts of the image convincingly.

The technical paragraph – you can skip over this if you like: This kind of tool works best with natural scenes. as it happens, much of nature is either random, or fractal. So if you were to look at the dirt in the photo here I’d call that largely random. Hence a program that can take somewhat random selections of pixels from the area surrounding an object to be removed – can often do a good job – it might not work so well in a structured environment with lines and bends such as inside a building. But it costs nothing to try. Picasa’s “retouch” tool is better able to blend in such backgrounds – oh and both this Gimp plugin AND Picasa’s retouch tool are EXCELLENT for removing blemishes on old photos. That will be the subject of a separate blog.

Android mobile Tools

If you prefer processing your photos on the go – and in particular for Android phone users – there are free tools such as Touch-Retouch – very handy when you are taking pics on the road and just need a quick fix. See this excellent short video tutorial.

I use mobile tools on a daily basis saving hours of work – you can see most of my photos here – some where taken on top-notch cameras, some on a mobile phone – many were processed using the tools I discuss above – here’s  a selection

And Finally – Photoshop

Oh and just so the Photoshop guys don’t get missed out – if you’re using a modern Photoshop – simply use the “spot healing tool” on your image…

Image 1

The tool is not un-similar to that on Picasa and the plug-in for Gimp but possibly even easier to use. It can be used just like a paintbrush – cover the object or objects you wish to remove and….

Removed

As you can see – I got carried away. Look for any obvious repeating patterns you’ve left in the removal process and remove those too.

Anyway – enjoy.

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