I have done an implementation of this paper from CG&A for image reconstruction.

Original and a greyscale from CIE luminance

8x magnification - greyscale

8x scale using gimp

DDT method (8 passes using yms optimisation)

8x magnification - colour

8x scale using gimp

DDT method (8 passes using yms optimisation)

DDT method (3 passes using yms optimisation)

Photo from a recent shuttle mission

original photo

zoomed section original

4x magnification using gimp

DDT method (8 passes using yms optimisation

A simple example

Original

My implementation

Gimp version

Another edge-directed algorithm on the same image

Icon  Name                    Last modified      Size  Description
[DIR] Parent Directory - [IMG] costfunc.png 30-May-2002 21:10 3.4K [IMG] flow.png 09-Jun-2002 21:35 53K [IMG] flowerg-gimp.png 25-Jun-2002 21:53 50K [IMG] flowerg.png 09-Jun-2002 21:35 8.9K [   ] imagefilt-rob.tar.gz 06-Jan-2003 13:57 37K [IMG] lisa-gimp8.png 08-Jun-2002 14:51 310K [IMG] lisa-gimp8c.png 08-Jun-2002 14:32 710K [IMG] lisa-scale10.png 08-Jun-2002 14:32 762K [IMG] lisa-scale11.png 08-Jun-2002 14:46 763K [IMG] lisa-scale12.png 08-Jun-2002 14:48 19K [IMG] lisa-scale14.png 08-Jun-2002 15:16 349K [IMG] lisa-scale4.png 08-Jun-2002 12:13 62K [IMG] lisa-scale5.png 08-Jun-2002 12:14 415K [IMG] lisa-scale7.png 08-Jun-2002 13:03 398K [IMG] lisa.png 08-Jun-2002 12:14 34K [IMG] s110-zoom-ddt.png 08-Jun-2002 15:48 2.1M [IMG] s110-zoom-gimp4.png 08-Jun-2002 15:50 1.8M [IMG] s110-zoom.png 08-Jun-2002 15:50 247K [IMG] s110e5004.jpg 08-Jun-2002 15:52 1.4M [DIR] t/ 30-Mar-2010 20:10 - [IMG] thigh.png 12-Jun-2002 11:39 306K [IMG] thigh2.png 12-Jun-2002 11:40 284K [TXT] truck-distance-8pass..> 11-Jun-2002 07:13 681 [TXT] truck-distance-8pass..> 11-Jun-2002 07:13 340 [TXT] truck-yms-8pass.txt 11-Jun-2002 07:13 340 [IMG] truck.png 11-Jun-2002 07:30 224K