reading jpegs faster

[John W. Eaton]

On 22-Jan-2010, David Grundberg wrote:

| I'm reading 10 megapixel jpeg files alot. Unfortunately it me takes 9 
| seconds to load such files with imread on the tip. I think that is too 
| long time. Is someone experiencing the same problem as me? Or does it 
| have to do with my configuration?
| 
| I've written a function file in C++ that loads the same file in about 1 
| second.

Doesn't the GraphicsMagick library ultimately use libjpeg?  What
causes it to be slow?  Rather than writing a special case for jpeg
files, I think it would be better to find out why imread is slow and
fix that.  It's possible that would improve the performance of
Octave's imread function for all image formats, not just jpeg files.

jwe