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Old 05-22-04, 05:28 PM   #1
MikeC
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Join Date: Jan 1997
Location: Virginia
Posts: 5,359
Arrow AquaMark 3 image quality comparison

The following information is based on various image quality tests that I ran last night. I really didn't have a plan of attack when I started, but I knew it was going to be related to the Radeon X800 Pro and the stories we've been reading in regards to texture filtering. This series of tests may not lead to anything, but I have some free time this weekend and I felt this would be an interesting experiment.

The weapon I ended up choosing was AquaMark3. Last year Alexander Jorias of Massive Development provided nV News with a key that unlocks all of the features in AquaMark3. One test in the licensed version is a screen capture test. The test accepts a user-supplied frame interval setting and screenshots are taken at the interval provided (for example, take a screenshot every 10, 50, 100, 500, or 1000 frames). AquaMark3 also has application control over antialiasing and anisotropic texture filtering.

All of the graphics options in AquaMark3 were configured to their maximum setting and I adjusted the level of texture filtering for each test. I selected a number of frames that are good examples to use for conducting image quality comparisons.

I then used the The Compressionator tool to compare the screenshots from AquaMark3, which I converted from TGA to PNG format. The screenshots were not altered in any other way. The Compressionator can be used to identify the differences between two images. In fact, you can download and install The Compressionator and use the images from my tests to run comparisons.

The example below is a comparison of trilinear filtering on the left and 2X anisotropic filtering on the right. The middle section shows the differences, which are often subtle and requires the difference brightness level to be adjusted before the differences become visible. In this example, the difference brightness was increased to 400%. The Compressionator also has a zoom in/out feature.



The Compressionator is also able to quantify the differences as it provides the following statistics for a comparison.



Although I'm not familiar with the measurements that take place, I do know that similar images have a lower error deviation than images that are vastly different. Taking all of the information, I developed the following chart, which lists the mean square error for each image quality comparison.

The mean square error of 2.52 from the example above was based on a comparison of trilinear filtering and 2X anisotropic filtering from frame 300.



Below are the links to the various AquaMark3 screenshots, which range in size from 700 KB to 1.2 MB. Increase the brightness on your monitor if they are too dark. I hope to install the Radeon X800 Pro in one of my other PCs this evening and conduct the same tests.

Cheers,
MikeC


Frame 200:



Trilinear - 2X Anisotropic - 4X Anisotropic - 8X Anisotropic

Frame 300:



Trilinear - 2X Anisotropic - 4X Anisotropic - 8X Anisotropic

Frame 900:



Trilinear - 2X Anisotropic - 4X Anisotropic - 8X Anisotropic

Frame 1700:



Trilinear - 2X Anisotropic - 4X Anisotropic - 8X Anisotropic

Frame 2400:



Trilinear - 2X Anisotropic - 4X Anisotropic - 8X Anisotropic

Frame 2500:



Trilinear - 2X Anisotropic - 4X Anisotropic - 8X Anisotropic

Frame 2600:



Trilinear - 2X Anisotropic - 4X Anisotropic - 8X Anisotropic

Frame 3500:



Trilinear - 2X Anisotropic - 4X Anisotropic - 8X Anisotropic

Frame 3900:



Trilinear - 2X Anisotropic - 4X Anisotropic - 8X Anisotropic

Frame 4000:



Trilinear - 2X Anisotropic - 4X Anisotropic - 8X Anisotropic

Frame 4300:



Trilinear - 2X Anisotropic - 4X Anisotropic - 8X Anisotropic
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