Artsnova Digital Art and Space

A Binary Mona Lisa

I recently came across an article about teaching computers to appreciate art - at least that was the title of the news story. The story actually dealt with a software program under development that would be able to analyze a work of art and associate it with an artist in its database. The software would also be used to spot art forgeries.

The program was created by Daniel Keren, a professor from the Department of Computer Science at the University of Haifa in Israel. The software works by subdividing known paintings by an artist into discrete blocks. Each of these blocks is then mathematically reduced to a formula. The multiple formulas can then be combined and compared with one another. The underlying program logic is that these sets of formulas will uniquely describe the artist that created the associated works of art.

Models were created for five artists - Vincent van Gogh, Rembrandt van Rijn, Salvador Dali, Rene Magritte, and Wassily Kandinsky - using 15 painting per artist. The program was then tested against another 15 paintings from each artist to see if the program could correctly associate a painting with an artist. The program was able to correctly associate a painting with its artist 86 percent of the time.

Over the course of the article it becomes clear that the program has a very long way to go in order for it to be considered truly functional. I am skeptical as to the program’s chances of ever surpassing, or even equalling the judgments of the art specialist. While this program could develop to the point where it becomes a more useful tool, I can not see it ever reaching a state of reliability such that it becomes the arbiter of authenticity. I am even more skeptical of the ability to apply the program’s technique to the analysis of digitally created art since digital brushwork does not have the same characteristics of traditional brushwork.

If you would like to know more about this program, see the article Teaching a Computer to Appreciate Art

Binary Mona Lisa

Since this post is about software “appreciating” art, I decided to create an image reflective of the subject. The image used to illustrate this blog entry is a digitally manipulated rendition of that most famous of paintings, the Mona Lisa, also known as La Gioconda, painted by Leonardo da Vinci slightly more than 500 years ago. The woman in the portrait is said to be the wife of Francesco del Giocondo.

Ad Astra, Jim

Photoshop FITS Liberator screen shot

A new version of the free ESA/ESO/NASA FITS Liberator plugin for Photoshop was released earlier this month. This plugin makes it possible to open FITS files with Photoshop. For you Photoshop users who are not familiar with FITS, the Flexible Image Transport System is the standard file format for astronomical data, like that of the Hubble Space Telescope for example. For more FITS information visit my Making Astronomical Art with your PC Resources page which I created for students in the astronomical art class I taught at the Adler Planetarium.

According to the release notes, the following enhancements are in this new release:

1. Universal Binary for Mac allows native CS3 operation on Intel-based systems
2. Flip image checkbox allows image orientation to be selected on import
3. Stretch Root functions now operate antisymmetrically about x=0
4. Version 1.1 of the Astronomy Visualization Metadata (AVM) standard is fully supported. For more information see http://www.virtualastronomy.org
5. Improvements to importing coordinate metadata from the FITS header

I went to the version 2.2 download page and downloaded this new version. There is also a Photoshop action called Colour_composite.atn that can be downloaded. This action automates the production of color images from the individual RGB grayscale layers. I’ve never used their action preferring to use one I created myself. I installed the plugin without difficulty. On opening a FITS file (M27 for the curious among you) I observed that the main dialog for this new version was essentially the same with the only modifications being to the Stretch Function dialog (item 3 in the list above) and the addition of a Flip Image option (item 2 in the list above).

You can learn more about the plug-in, how to use, and even get some sample FITS files from the ESA/ESO/NASA Photoshop FITS Liberator Home Page.

Ad Astra, Jim

3D object created in CB Model Pro

This last week I learned of and downloaded a new 3D modeling program. The beta version of CB Model Pro is a free download that can be used indefinitely if you fill out the online registration.

CB Model Pro sports a very simple user interface. It operates by deforming the surface of either the supplied primitives or very simple imported objects. The supplied primitives are the sphere, cylinder, cone, cube, sheet, and torus. 3D object operations that are available are Point Pull, Flatten, Bend, Neck, Scale, and Poke. The degree of deformation applied by these tools is controlled by two simple sliders. There is also a Mirror option so that operations performed on one side of the object are mirrored on the other side.

In addtion to modeling, you can also paint your object. This is accomplished either by applying an image to the model or by using the paintbrush tool.

Once finished with your 3D model, you can export it as either an obj, stl, wrl, or 3dxml object. However, for the stl and 3dxml formats, only the 3D mesh is exported. The CB Model Pro web site has a gallery of sample textured objects to give you an idea of what can be done with the product.

If you have questions about the program, you can turn to the 12 page PDF for program documentation. There is a forum for the software advertised on the web site but stupidly they have chosen to restrict both read and write access to only those people who have previously purchased software from SolidWorks. Definitely not a bright marketing move.

The Pluses

Okay it’s free. It’s also a very simple program to learn and use. I created the object in the picture used to illustrate this article in minutes using only the Neck tool and application of a texture image.

The Minuses

It would be nice if you were able to name your saved models - rather than having the program arbitrarily assign names like file1.cb3d Precision of manipulation is really not there. It is a simple tool that performs simple tasks to create simple objects. You start with a primitive, select an operation, click somewhere on your primitive and drag. And a forum closed to everyone except owners of SolidWorks software is not at all helpful.

Summary

If want to play with creating simple 3D objects in an intuitive manner then give CB Model Pro a try.
Ad Astra, Jim

NASAView JPEG vs GIF of a Mars Reconnaissance Orbiter HiRISE image

For those wanting to work with the raw data files returned by various NASA planetary missions the first order of business is to convert the data from its native PDS (Planetary Data System) IMG format into something usable by standard image processing software, like Adobe Photoshop. The NASA PDS Software Download site provides a variety of software packages for use in processing various NASA data products. For Windows users the only program available there for converting IMG files is NASAView. The most recent version of NASAView is 2.14 and was released in June 2007. Earlier versions of NASAView supported saving IMG files only as GIFs. Recent versions have included the option to save to JPEGs.

By design, GIF files are limited to 8 bits of color information per pixel. In the case of PDS IMG files, this means that each image is limited to a palette of 256 gray levels with 0 representing black and 255 representing white. Because the PDS IMG files from earlier missions contained only 8 bits of information per pixel, there was no data lost in the translation from IMG to GIF.

But what about when saving the IMG file as a JPEG. I do not know what the rationale was for adding the ability to save JPEGs. Perhaps so people could easily have an image that was more web friendly in terms of the file’s size. I strongly advise against ever saving an IMG file as a JPEG in NASAView. The reason is because of the JPEG compression. Unfortunately NASAView does not give the user any control over the level of compression. From what testing I have done, it appears that NASAView defaults to a quality setting of 75%. While this may be fine for dumping an image on the web, it fails when it comes to producing quality print images, especially if you want to enlarge the image.

To illustrate the impact of JPEG compression in NASAView take a look at the image at the top of this article. This is a 300% magnified view of a segment of a Mars Reconnaissance Orbiter HiRISE image. On the left is the JPEG version and on the right is the GIF version of the same area, only mirrored. The JPEG artifacts are obvious and take the form of square blocks. Of course there is a significant difference in file size. Whereas the GIF version is just about 7 megabytes, the JPEG version is just over 1 megabyte. Another differences between the JPEG and GIF versions are that the JPEG version is brighter than the GIF version.

In closing, my advice is that if you are using NASAView to convert IMG files to a standard graphic format file, never ever use the “Save JPEG” or “Save JPEG AS” options. If you need a JPEG version, then save your file as a GIF and use another pieces of software to do the conversion to JPEG so that you can control the amount of image compression used. Hopefully in the future a more robust version of NASAView will be released which offers Window’s users greater control on output file format and quality.
Ad Astra, Jim

Which Flag Do You Prefer? Before and After Using Serif PanoramaPlus 1

I was in a local bookstore last week going through the magazine section and pulled the current issue of the astronomy magazine BBC Sky at Night. I’m in the habit of going through all the astronomy magazines in search of interesting articles. Unfortunately for Sky at Night I’ve never came across an article in their magazine that would make it worth its price. Looking at the May 2007 issue, it wasn’t what was inside the magazine that grabbed my interest but what was on the CD that comes with the magazine.

The CD has a full version of Serif’s PanoramaPlus, version 1. This program automates the creation of panoramic images given a list of individual source images. Previously I had created my panoramas by using Adobe Photoshop’s Transform Tool and layer masks. Needless to say the Transform Tool is definitely suboptimal - especially when it comes to altering the geometry of the individual images. While I wasn’t thrilled that as a part of the software activation process I had to call the UK offices of Sky at Night, I figured that would be cheaper than going out and buying the software. What bugged me about this is that for all other magazines containing CDs with full versions of software being offered, I’ve never had to make a phone call to activate the product: either it was ready to go or all I had to do was point my browser at the specified web page to complete the registration.

Fortunately the software did have a one time use without registering so that I could fire it up and test it out. I fed the program a total of 11 images from an Apollo 16 EVA to merge. Their combined file size was 8.5 megabytes. PanoramaPlus quickly stitched them together and as far as I could tell from the software’s preview window, had done a good job of it.

The final step was to export the newly created panorama. Therein lies the source of my disappointment. The only export format available was to save as a jpeg. Not only that but there was no option to specify image quality and no documentation identifying what compression setting the software was using. The other shock was the size of my new panorama - just 3000 pixels wide. PanoramaPlus had taken 11 separate images with a combined width of 25,740 pixels and combined file size of 8.57 megabytes and created a panorama just 3000 pixels wide with a file size of 880K.

As a before and after comparison I took the American flag from the panorama and enlarged it to match the flag in one of the source images. The comparison of the two flags is shown at the top of this article. Note that the image shown is a scaled down version of the full size comparison. On the left is the original source flag image and on the right is the flag image from the PanoramaPlus panorama, upsized to match the size of the original flag. The qualitative difference is obvious.

Going to the Serif web site, I see that they are now on version 3 of the software so it is probably no longer the same product. Bottom line: if you’re thinking of buying the May 2007 issue of Sky at Night because of the PanoramaPlus version 1 software, don’t - big mistake. And the special upgrade offer they are running in the magazine: if you’re in the U.S. and paying in U.S. dollars, the standard price for the software is cheaper than the Sky at Night special “discount.”
Ad Astra, Jim