Published on Mar 13 2020 by cartowall.
Do you want to help improve the CartoWall photo base but don't know how? In this guide we show you how step by step. Let's go!
What you need:
Photo camera with zoom and tripod (recommended).
Tajo Gomer's sample photos, so you can play with them on Image Composite Editor.
We make them available to you under the Creative Commons with Attribution license.
Digital images are made up of pixels (the little squares we see when we zoom in excessively on an image), and the more pixels we have, the more details we will be able to distinguish in the image when we zoom in. The number of pixels in an image is given by its resolution, usually expressed in megapixels (1 megapixel = 1 million pixels). For example, an image of 10 megapixels is composed of 10 million pixels.
Today, advances in technology have made it possible for virtually anyone with a mobile phone in their pocket to have a camera capable of capturing images of even several tens of megapixels. It is not uncommon to find a mid-range smartphone capable of taking pictures with a resolution of up to 48 megapixels.
Now, when the number of pixels in an image is very high (in the order of 1000 megapixels), we can start talking about gigapixels images. Namely, 1 gigapixel is equal to 1000 megapixels (1 gigapixel = 1 billion pixels), and many of the pictures that we have published in CartoWall have a resolution of this order. That's why you can see the anchors and the route slopes when you zoom in.
Gigapixel photos are obtained as a result of joining tens, hundreds and even thousands of conventional photographs. So, if you have a zoom camera, tripod (if possible) and a half-decent computer, we have good news for you: you can take GigaPixel photos and publish them on CartoWall! Let's get started.
Choose a place where you can see the whole wall you are going to photograph, place your tripod there and level it correctly. You can also take photos without a tripod, but it will be more difficult and you will have to take great care not to get lost on the wall. For example:
Now, adjust your camera settings to the scene conditions (zoom, focus, exposure, aperture and white balance). First adjust the zoom so that the wall anchors are visible (if your zoom is not that good, don't worry, it'll still be a good shot). Then adjust the aperture and ISO so that we don't need a long exposure time (the shorter the exposure time, the less likely it is that a picture will be shaky). Generally, very bright scenes go well with a low ISO value, while low light scenes require high ISOs.
Of course, there is the option to do everything in Automatic mode, but it is not recommended since we will obtain discordant results between the different photographs and surely the quality will not be the best possible.
Everything is ready to start taking pictures. The idea is to cover the whole scene with as many photos as necessary, being very important that there is an overlap between photos of approximately 30%, both horizontally and vertically. Here are some examples, where you can see the horizontal overlap:
We recommend that you make horizontal sweeps in order, so it will be harder for you to get lost and end up ruining your work. We usually start at the base of the wall, and from here we make successive horizontal sweeps until we reach the sky.
Take as many photos as you need, no matter how many, and repeat those that raise questions about their quality. By the way, do not neglect the parts where there is vegetation, as these will also appear in the final result. If we don't take them, the resulting photo will be incomplete.
Finally, don't waste your time taking pictures where there is only sky: the software that joins the pictures is not able to join sky as it cannot find any specific details to connect the pictures with. The sky will be added "artistically" to the final photo in the last step.
You have two options to approach the gigapixel photo stitching process:
You do the assembly and send us the result. If you choose this option, keep reading.
There are many programs that allow you to join multiple photographs into a single giant picture (a process known as stitching). We will be using Image Composite Editor (ICE), developed by Microsoft. It is a program that, although limited in terms of configuration options, is very intuitive and offers very good results. Download it here (Windows only).
With ICE, the stitching process is fully automatic: we simply import the JPEGs, the software identifies the common features in the overlapping photos, adjusts the geometry of each photo as needed and joins them together. Depending on the number of photos, the process may even take hours, but since it's automatic, you can go to the climbing wall while the computer is working.
Steps to follow:
Start ICE, click the "New panorama from images" button, select all the images you want to combine and click NEXT.
Click on NEXT to start the image projection phase:
Now we enter the CROP phase, where we can select the part of the image we want in the final result. In the example we are only interested in the area relative to the Tajo Gomer, what is outside the box will be removed from the final result:
If we want we can click on the "Autocomplete" button so that the program automatically draws the parts that have no image. Warning: this is a very slow process that will not always give good results, as you can see in the following image:
As shown below, the resulting image has a total of 479.06 MegaPixels (almost half a GigaPixel). In File format we choose PNG, to avoid quality losses, and click on Export to Disk... It only remains to indicate the name of the file where we want to save our image and wait for the export to be completed.
The resulting image will probably need some touch-ups. For example, it is common to have to correct, or even draw, the sky in the photo. Options:
You make the adjustments. If you choose this option, you will need to use Photoshop.
It's hard to do this using any other program, because of all the ones we've tried, this software is the only one that allows you to work with gigapixel images without problems, as long as you have a large amount of RAM (at least 16GB) and free space on your hard disk (we recommend a 1TB SSD or M2 drive). A powerful processor won't hurt either. Once you open the image in Photoshop, the Clone Stamp and the Spot Healing Brush will be your allies.
And that's all. Come on, grab some pictures so we can post them on CartoWall! I'm sure the experience will be worth it.