On 10/30/06, Mike Hord <mike.hord@gmail.com> wrote:
> I have raw image data, stripped from an isochronous FireWire
> stream, that I'd like to view.
>
> Has anyone had any experience with making this happen?  The
> data is 8-bit grayscale- it should be amazingly easy to do this,
> but it's turning out harder than I'd have suspected.
>
> Note that there isn't any file header data or anything- it's from a
> 1024x768 pixel detector, and I have exactly 512 packets of 8-bit
> data, 1536 bytes per packet.  AIUI, it doesn't even match the
> .raw image format.
>
> I'd hate to have to write a program to do this.
>
> Mike H.

Here's what I'd do:

1) Use a raster editor (the Gimp) to make a 1024*768 greyscale image.
2) Save the image as a MS-bitmap (.bmp) file, no compression.
3) The image is a little bigger than the pixel count:

[markrages@midwesttelecine ~]$ echo $(( 1024*768 ))
786432
[markrages@midwesttelecine ~]$ ls -l test.bmp
-rw-rw-r--  1 markrages markrages 787510 Oct 30 13:22 test.bmp

This is because the bmp format tacks a header on the front.  We will
reuse this header with the image information.

4) Assuming your packets are numbered packet001...packet512, assemble
the image like this:
( head -c $(( 787510 - 1024*768 )) test.bmp && cat packet??? ) > out.bmp

This is for a Unixy system like Linux or MacOS.  For Windows, consult
your shell documentation, but the idea should hold.

Regards.
Mark
markrages@gmail
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