If you Have a photshop Newer version is better,
- Resize The image, ENLARGEMENT (Range 2x to 6x)
- Resample with : Bicubic Smoother
- Filter : Noise > Reduce Noise
- Duplicate Layer
- Filter : Other > High Pass (Usually Radius 3.5 to 9.0)
- High Pass Layer > Use Hard Light or Overlay
- Save Image and Done