Panoramic/Stitched Images

3. Choosing Panoramic Stitching Software

There is quite a choice of Panoramic software available with which you can stitch images together. In common with other types of software some work much better than others, whilst the price difference is also quite large, ranging from those that are free up to some that cost in excess of £400. Quite often basic Panoramic software comes bundled with digital cameras, scanners, and printers. The two main problems that exist are that it is either very basic, mostly designed to do very limited stitching of no more than two or three horizontal shots, and often not doing it very well either, or it's extremely expensive and very complicated, both of which rather puts people off trying to take stitch images. 

We confess to not really paying a lot of attention to taking stitch shots in our early days of digital camera ownership for precisely these reasons. The programs we tried often couldn't assemble a simple stitch of two images, and if they did the results weren't brilliant, while the investment needed to see if the dearer programs worked better was so much that it just couldn't be justified. So we rather forgot about it and concentrated on other things. Every now and then we'd give it another go, usually with the same mixed results, and most often when we'd got a new piece of equipment that had another stitch program bundled with it.

In more recent times we came to the conclusion that being able to stitch images together, consistently and reliably, was something that would be a distinct advantage to us, and so we spent some time investigating all the available options, both software and hardware. The problem usually is, as most would probably agree, that you would like to try something to see if it is of interest or use, yet you find that considerable cost will be involved just to find out, without any prior knowledge of whether it will be money well spent or not.  

Eventually we came up with a reasonably low cost solution that suited us, purchasing the best software we could find that worked consistently well, and designing and building our own equipment, a Panoramic head.  We managed to juggle this around so we built the head as we evaluated the software, and didn't purchase the software until we had discovered which one worked best in unison with it. This seemed to be a satisfactory solution to the problem. Little cost was involved in building the head, just some time and effort.

Software options

Panoramic software has come a long way since it's inception when it was just looked upon as a means of stitching two or three images together to produce a Panorama. This was of course the initial ambition, to be able to produce Panorama's easily using an ordinary digital camera rather than an expensive special purpose Panoramic camera. To start with programs simply stitched images together by matching points in adjacent images. There was no blending of exposures or warping to correct perspective, so only two or sometimes three images were used, and the results were mixed and varied. Then warping of images began along with the introduction of Apple's Quicktime VR format, which took things a stage further and introduced the idea of wrap around 360° cylindrical and spherical images, whether they were viewed on screen or printed. 

A related concept, the exact opposite of Panoramic imaging, has now arrived in the shape of Object VR. As the name implies this is concerned with taking multiple shots of objects and then assembling a VR tour around them. In this case instead of the camera rotating through 360°, the object does. As such only small items can be used at present and the equipment and software used is very expensive. Generally it's used in studio's whilst hooked up to a computer. Web selling and the recording and archiving of antique objects, pottery etc, are the main reasons for it's development and use. With the popularity of auction sites such as E-bay we think it won't be long before cheaper equipment and software arrives.

The software you choose to use to generate Panoramas depends to a great extent on what you hope to achieve. There is an awful lot of Panoramic software around, some from quite well known names, Ulead, Corel, etc and others from firms that specialize in Panoramic and VR software, VRworx for example, whilst a lot has also come and gone. In the past we have often gone by other peoples recommendations for software, which is great for discovering what is available, but we have sometimes come unstuck in that they failed to mention, or were unaware of, some problem that existed with it. Software that runs perfectly on one persons computer, might not run on another due to different hardware or software specifications. Quite often you discover that certain programs can't work with particular graphic cards or other hardware or software. Today we rarely buy software without testing it first, so only those that provided trial versions are considered.

Part of the problem of choosing which software to use is the difficulty in discovering not only what limitations the software might have but also how well it does what it is supposed to. Most Panoramic software claims to be able to stitch Panorama's. But the idea of what constitutes a Panorama varies greatly depending on your viewpoint. Some programs only do limited stitching and can't cope with full 360° cylindrical or spherical stitches. Others can only work with images from cameras that use 'normal' focal lengths, say 35mm upwards. Wider or more highly distorted views, like those from fish-eye's, can't be used. Some can only open images taken in a set sequence or in a specific manner.

Stitcher by RealViz

If you are interested in panoramic images one program that is often mentioned on websites that deal with the subject or sell equipment is Stitcher by RealViz. This appears to be the Panoramic equivalent of Photoshop with many options. The only drawback is that like the full Photoshop CS it is quite expensive, although a cheaper more basic version, Stitcher Express is also available. Trial versions are available for download, which is always useful for evaluation purposes. You may have more luck with them than we have had, for regrettably we have never been able to persuade the trial versions we have tested to produce a fully rendered finished stitch we could examine. The program has always crashed at some stage, and despite some investigation we have never been able to determine why this should be. Others seem to have no problems and we have seen good stitches produced using them. 

Trial downloads of  the latest versions of Stitcher 5 or Stitcher Express are available from  www.realviz.com  or www.red-door.co.uk   Currently Stitcher 5 costs around £350 and Stitcher Express £65. 

Adobe Photomerge

Several programs we have tried have cried enough and given up at some stage, but it has usually been after we had completed a basic three shot stitch and then asked them to do more than they were evidently capable of in terms of the number of images they could open and merge. And this is a problem with many. They have very limited options and can only work with small numbers of identically sized images, at full resolution. Which isn't of much use for multiple row and 360° panoramic images. They can also place huge demands on the amount of free hard drive space they need to render finished stitches. Adobe's Photomerge is one example. This started out in Elements but is now also included in CS. It offers simple automatic stitching of images but tends to be unpredictable and erratic in use and often has trouble merging and blending images together even when these are relatively simple. It can't apply perspective correction over 120° or output a 360° stitch.

As an example here is a stitch of just three shots taken of a Christmas scene display in a shopping centre using Photomerge. Because the display was located on a lower floor between escalators and upper floor, a stitch was considered the best way of obtaining a final image. The images are 6mp size produced using a DSLR with a 36mm [equiv] focal length lens and taken in the portrait orientation.

The first image is planar and the second planar with perspective correction enabled. A cylindrical stitch was attempted but was so bad it's not worth including. Even with these you can see that the program hasn't quite managed to stitch all the elements together properly or blend the images overall. The one stitched using the perspective correction is better with regard to the upper floor merging of elements, but we had to open the finished stitch in Photoshop and apply additional perspective correction before cropping so the side elements were upright. 

Each stitch took around 10-15mins to render. Overall, the time taken from choosing the shots to merge, to the final cropped image was around 30mins a time. Worthwhile if a decent final image resulted, but here, really, just a waste of time and effort.

PTGui & Panorama Tools

By comparison now take a look at this stitch of the same three shots. This was produced using the program we discovered a while ago and now use, PTGui, and was produced completely automatically. This is a plain planar image and all we have done is crop it in PTGui as nothing else was needed. It took between 7-10mins to do. Files can be rendered at the resolution of your choice. There is a range of pre-set sizes (maximum, print, web) or you can enter any pixel size you want, in a variety of file formats, JPEG, TIFF, or Photoshop PSD, blended as a single file or in layers. There is also a tool that tells you how much hard drive space is required for rendering the file size chosen, and whether you have enough.

PTGui is not free, but it was developed from Panorama Tools which is. You may see many references to Panorama Tools on the web. It is a set of powerful Java tools and Photoshop plug-ins originated by Helmut Dersch. Many small free applications have been developed around it. PT lens, a lens distortion correction program  www.epaperpress.com and Pano2QTVR, a program to convert panoramas to Quicktime VR format  www.pano2qtvr.com  are two.

PTGui started life as a graphical user interface for Panorama Tools as they are quite difficult to use, hence the name. It has now developed into a powerful application in it's own right, and no longer needs Panorama Tools, although if installed they can be used with it. (Panorama Tools must be installed for PT lens and Pano2QTVR to work). PTGui is available from  www.ptgui.com  as a fully working 30 day trial download, all stitches being watermarked.

The latest version, 5.6, currently costs € 59 plus 19% tax for those living in the EU, around £50. 

Generally we have found it to be a program that has almost as many options as Stitcher 5 from RealViz. It can be used in simple or advanced modes and switching between the two at any stage is easily done. The only option not available is to output files in the Quicktime VR format. However Pano2QTVR neatly solves this problem for those who require it. As with most software it benefits from some time spent familiarizing yourself with it, and the options that it has, but you can use it straightaway in the simple mode. Basically the simple mode chooses the settings to use automatically whilst the advanced mode allows these to be altered if needed. We hardly use anything other than simple mode, there's usually no need.

On the next page we will look at creating Panoramas