Digital Outback Photo
- Photography using Digital SLRs

 

Workflow Technique #071

Stitching with Realviz Stitcher 4.x (PC & Mac)

review by Jim Collum

 
 

The race for megapixels continues. “Resolution isn’t everything.” “Having a 16Mpixel sensor does not guarantee a good image.” These are true statements, and Uwe repeats them to me all the time. I come from a 4x5” film world. I chose that route 20 years ago, because detail is a vital part of how I see things. I prefer a tactile image. One that has an almost 3 dimensional quality to the texture. As a result, I’m on a constant search for “enough detail”. The largest I typically print is 30x40 (although I have printed 40x50” images from a Betterlight scanning back), so this is my goal. 30x40” prints with no visible digital artifacts. Uwe doesn’t really believe me though... he doesn’t think I’ll ever be happy... give me 100Mp, and I’ll be looking for 200. (He’s probably right... just don’t tell him)

There are already a few articles on how to capture the stitched image. I prefer flat stitching... which involves keeping the lens stationary and moving the sensor around the film plane. The most common method I use is with a Canon Tilt/Shift lens, by capturing three overlapping images: left, middle right. The important thing for quality flat stitching, is to ensure minimal parallax errors (read here how to avoid parallax).

This review is based on the version 4.04 of Stitcher.


I use one of two methods of stitching. My initial method involved bringing each image into Photoshop as a layer, and then creating the seam following detail where it wouldn’t be noticed. This method becomes more troublesome when using 16 bit images. The general manipulation of the 3 layers slows down a lot. It is also *very* cumbersome when attempting to combine a 5x5 matrix of images taken with the Canon 1Ds Mk II mounted on a Sinar view camera.

Since I’d much rather be photographing than playing in Photoshop, I have always been on the lookout for an automated method of doing this. There are many stitching programs on the market, both free and as products. I tried most of them, and was always able to find the seams. Most will work if you downsize the image to 1024 pixels for display on a monitor, but none really held up to scrutiny at 100% enlargement (this is necessary for me, since most of my images are printed at greater than 16x20). The program that held up best was Realviz. It was also one of the easier to work with.

Realviz allows you to do more than just flat stitches. It’s a VR creator’s dream. For my purposes, this additional functionality just got in the way. Once ignored, the use became much easier for me.


The Realviz Interface


The following is a quick overview of how I normally interact with Realviz. It in no way even begins to document all of the features and capabilities the product has. My sole purpose in using it is for flat stitching. If you are using a Pano head, then I’d recommend getting the demo version and trying it out. A word of warning though, the demo version is 4.0.1, and there are numerous, aggravating bugs that have been fixed in 4.0.3. Their site doesn’t allow access to any of the upgrades unless you’ve purchased the product.


After starting the program, you are presented with a dual screen view of your project. The top portion (stitching window) is used for the combining of individual images, while the bottom (image strip) is where you can drag/drop each individual one (loading is also possible from the file menu).



If you are doing flat stitches, then you need to set that in the Properties dialog box. This has to be done prior to dragging any of the images into the stitching window. Forgetting to do this will result in a projected panorama, rather than a flat. (If you’re image in the stitching window has curved edges, then you have this setting wrong).



Creating the stitched image is as easy as dragging an image from the Image Strip and dropping it into the Stitching window. If an image has been joined successfully, then you’ll see a green square in the upper corner. A red means that you haven’t joined it yet.


Here is an example of all three images joined successfully. If the images to be joined are lacking in detail (a lot of sky would do it), then Realviz will tell you that, and ask if you want to force a joining. This requires more manual control on where the images will join.


When manually stitching in Photoshop, there are times that the exposure in one more of the images differs slightly. This requires some careful curves adjustments on each of the layers to make sure that this isn’t visible in the final image. Realviz makes this much easier. After the images are fully joined, you just select “Equalize All Images” and voila.



Realviz gives you a plethora of options. I’m only going to outline those necessary for my workflow. I set Sharpen to none (I prefer to use Uwe’s EasyS sharpening toolkit). The type of panorama is Planar (with other options being Cylindrical QTVR, Cubic QTVR, Cylindrical, Cubical, Spherical, Shockwave3D and VRML). Mixing option is used to combine the images along the seams when there’s a difference between them (possibly due to parallax). Method 1 has worked for me. Lanczos5 is the highest quality, but slowest, interpolation method used during the seam creation.

Mixing Options

Let's say you have a line in the overlapping part of two images, which should become 1 line in the resulting image:

Method 1: Stitcher tries to match the lines into one line when combining the images; this is called warping and can mean that the line becomes curvy, if there are parallax problems

Method 2: Stitcher just blends the two images as is, so if you have a parallax problem you will see in the result two lines instead of one.

 

There are a number of output options as well. I normally use either Tif or PSD. The advantage to PSD is that Realviz will output each image into a layer, and supply the layer mask necessary to combine the images, forming the final panorama. This takes a lot more time, and more disk space (these files grow very quickly), but it offers the most control over the images. I will use TIF first, and if there are any artifacts around seams, then I’ll rerun it with PSD as my output option.


Select the Render Area tab to highlight the area you wish to render. I normally leave a little white space around it, and remove it later in Photoshop. I find that cropping in Photoshop is more accurate.


One useful option that is new in 4.0.3 is “Use strip” under the TIFF Options. Early releases of Realviz had problems with the program crashing when attempting very large panoramas. The “Use strip” option will help with this, however it does increase the length of time necessary to render the final image.



Here is the final output image, produced by Realviz ( output using TIFF). Not much can really be told by examining web versions of stitched images. Of course you can’t see seams in the image posted here. The real test is to examine it at 100%. My advice is to download the demo version and give it a try yourself. I have noticed an improvement in 4.0.3 in both memory management and joining of images and the seams produced. It is unfortunate that you can only download 4.0.1 and unless bought, a user doesn’t have access to maintenance releases (4.0.3 is the most significant).

Best you download the demo and then apply the following 4.04 patches:

Mac: ftp://ftp.realviz.com/private/ST4/Stitcher404PatchEN.dmg.gz

PC: ftp://ftp.realviz.com/private/ST4/Stitcher4-0-4_patch.exe


Finally, here’s an example of what can be done. I wouldn’t begin to attempt this using Photoshop and layers, and combining them by hand. Each of these images is a full frame from a Canon 1Ds Mk II (16.7Mp). I used a Sinar 4x5 view camera and an attachment (read more info here) to capture 25 images (5x5). The final rendered image is about 180Mp, and took about 3 hours to render (using a dual Xeon 2.2Ghz processor).



Like I said above, I’m a detail person. I sell large images (up to 40x50). Although not perfect (slight parallax errors can still produce artifacts around seams), I have found it the best tool on the market for my workflow.


Stitcher Express ($120 list price)

Drawbacks compared to Stitcher 4 are:

- only 8 bit support (that maybe a big one for some users)
- no panorama conversion tool
- very limited stencil tool compared to Stitcher 4
- limited export format support
- no hotspot editor
- limited interpolation methods
- no templates or batch rendering
- no render sets

You can find a comparison here.

 


A special deal for DOP readers

Buy Stitcher 4.0 (actualy version 4.04) at $290.

Order here: http://www.realviz.com/purchase/buyonline/index.php

and enter at checkout the discount code: "OBPSOD15". The offer will be valid till end of June.

 
 
 
 

   

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