(ANNOUNCE) Gray-scale image widget for Tcl/TK

[Pierre-Louis Bossart]

I am pleased to announce the first release of my Tcl/Tk visu
extension. visu provides a new Tk widget called the pict widget. It is
an image widget, geared to gray-scale images. It can be downloaded at
the following location:
ftp://redhook.llnl.gov/pub/visu/visu-1.0.tar.gz
It will also be available from the archive soon:
ftp://ftp.aud.alcatel.com/tcl/extensions
Some test images can be downloaded at
ftp://redhook.llnl.gov/pub/visu/visu_images.tar.gz

I hope you find this extension useful. It was for me the best way to
display and interact with 2D and 3D images, without worrying about
writing a GUI in X/Motif. Please send your comments/ideas to
boss...@llnl.gov.

Pierre-Louis Bossart, PhD.
Lawrence Livermore National Laboratory
Non-Destructive Evaluation Section
L-416, 7000 East Avenue, Livermore, CA 94550
phone: 510-423-9350 fax: 510-422-7819 email: boss...@llnl.gov

PS: Here is summary of the main features provided by visu and the pict
widget:

A. File formats

The pict widget can be used to visualize images of the following types:
unsigned char, short, int or float;

For unsigned char images, there will be no normalization: the images
are mapped to the interval [0-255]. For other images, the images need
to be normalized. You can set the user max and user min values in
order to choose a proper dynamic range. If the values in the image
exceeds the user-specified ones, the dynamic range will be computed
from the image values, regardless of what the user typed in. The min
and max value show the actual dynamic range of the images.

visu supports the following file formats, with some restrictions:
VIEW (local LLNL format)
KHOROS1 (the map and location information are not read)
GIF (reads color image as gray-scale)
PPM/PGM (reads color image as gray-scale)

B. Display, Colormaps and overlays:

visu allows one to perform colormap manipulations and interactive
threshold. You can use one of the predefined colormaps to visualize
your gray-scale images in colors. The color tool lets you stretch or
compress the colormap in a non-linear way, e.g. when the transitions
between regions are not very important. Note that the data is not
changed when you change the colormap; only the colors displayed will
be affected.

Each image displayed may use either one of these colormap type:
0 (Shared): This is primarily for compatibility with the VIEW
software written at LLNL.

1 (Default Colormap): this is the default standard colormap.

2 (Shareable Private): A shareable colormap, different however from
the default one.

3 (Private Colormap): A non-shareable private colormap.

The colormap type can be set either with the mouse in the New menu, or
by setting the global variable Private_Colormap before you display the
image.

C. Overlays:

The color allocation can be used to display "semi-transparent"
overlays. This is a feature that was found very useful in our
interactive segmentation work. There is a restriction however: You
will need to display the window with a Private_Colormap, so that you
can use more color cells that with the default colormap.

Before you overlay anything over the active image, you will need to
enable the overlays. Do not worry about the color flash, it is
perfectly normal and cannot be avoided. Then you have a choice of
drawing a polygon, painting pixels, drawing a free-hand curve.

In addition, you can overlay another image on top on the active image.
The image to be overlayed is called a mask. Here is a summary of the
mask-related operations.

Create mask: creates a pict image, set its name. The number of
slices and current-slice are set to the same values as
the ones for the active image.
Get mask: Copies the active image overlays into mask_img.
Disp mask: Display mask_img.
Set mask: sets/changes which image is currently considered
as the mask.
Put mask: copies the mask and overlays it over the active image.
Save mask: saves the mask on disk.

Visu lets you set the Graphic Context values with the mouse. For
example, if you overlay two polygons with the GC set to xor, their
intersection will appear blank. Setting the GC to clear lets you
delete overlay pixels.

--
Lawrence Livermore National Laboratory
Non-Destructive Evaluation Section
L-416, 7000 East Avenue, Livermore, CA 94550
phone: 510-423-9350 fax: 510-422-7819 email: boss...@llnl.gov

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