Ideas and open points for visualization postprocessing

PNG images for the Web

On Web PNG images there are suggestion for obtaining nice images especially from Postscript.

Quick and dirty MPEG1 builder

Use ImageMagick:

convert frames*jpg movie.mpg

Optimizing JPEG images

Just found an utility that unfortunately works only on Windows. The good news is that convert produces already clean JPEGs.

Unsharping for thumbnail images

Downscaling produces soft images. Try to use unsharp filter like:

-unsharp 6x3+1+0

Select the best filter for downscaling

Draw your conclusions from the test page.

Common operations for chemistry visualization

• Add a chart below
• Picture in picture (to highlight a detail)
• Multiple views
• Smoothing

Histogram hyperbolization

How to implement it for images?

Relief shading of DEM images

Kernel: [-200, -100, 0 // -100, 0, 100 // 0, 100, 200]

Image comparison by image swapping

Take a look at the Noise Reduction Tool Comparison page (using IE!) and see how simple is to compare two images by flipping back and forth between them.

Astronomy images processing

Here are the only techniques I have found useful for sci viz:

• Interpolation, upscaling splines vs. linear extrapolation.
• Set limits for colormap (the range of linear relationship).
• Gamma.
• Unsharp masking.
• Blinking images for comparison.

GIMP tutorials and resources

Take a look at: GIMPguru, GIMP Savvy.

Animation formats for Web

Investigate the use of mencoder to create Flash movies

Make background transparent

convert -fuzz 1% -draw "matte 0,0 floodfill" input.img output.img

but this does not work on Win!

Complex draw commands in file for batch processing

-draw @draw_file where draw_file contains:

    font Candice
    font-size 72
    gravity center
    fill white
    stroke black
    text 0,0 "Candice"

Draw text on image

See the script above.

Best color for drawing text on a certain area

convert logo: -resize 1x1 -negate -monochrome txt:- | awk '/^0/ {print $NF}' Anyway, see the script!

Convert EPS to PNG

If you convert directly EPS to PNG the result is far from optimal. It is better to use eps2png or peps. Both use Ghostscript for the actual conversion.

Other themes

• Image formats
• icms image example
• containers/codecs
• player on Linux
• page on formats
• page on postprocessing for the web

The magnifying lens filter

Used by the filter page. Make it standalone.

Simulate transparency

Suggestion from the VMD maillist:

composite -dissolve 60 -gravity South molecule.tiff water_shell.tiff -matte output.tiff

For details look at dissolve example.