Summary

Typically, Whole Scan Images (Deep Zoom, SVS, and SZI) are composed of square image tiles that are 256×256 pixels in size. This size was historically chosen as a best case size for images served from a web site.

uScope Navigator v4.6 adds a Tile Size option under Program Options — Whole Scan Image Options where you may specify the following tile sizes:

• 256×256 (default),
• 512×512 (4× fewer tiles),
• 1,024×1,024 (16× fewer tiles),
• or 2,048×2,048 (64× fewer tiles).

There are a few trade-offs to consider when changing the tile size from the default.

Advantages of Increasing the Tile Size

• Process time is reduced. But, not much after increasing tile size to 512×512.
• Reduced disk space consumption.
• Disk operations that Copy, Archive, or Move the Deep Zoom folder complete faster.

Disadvantages of Increasing the Tile Size

• The Deep Zoom image viewer may perform more slowly.
• Render speed in the Deep Zoom image viewer is decreased. Render lag is apparent with 2,048×2,048 sized tiles.
• SVS or SZI images may not work in all image viewers. Although, they worked in our limited testing.

Details

A typical problem with Deep Zoom pyramid images is that the number of tiles gets very large (over 1,000,000 tiles) for typical (15mm×15mm) whole slide scans. Copying, archiving (zipping), or moving a Deep Zoom folder can take a very long time when the number of tiles is large. This problem does not exist with SVS or SZI images since they are single-file image formats.

Increasing the tile size, for the most part, offers significant benefits with regards to file operations (copy/move). If you rarely move Deep Zoom images around your computer network, increasing the tile size may not be justified.

Increasing the tile size from 256×256 to...

• 512×512
  reduces the number of tiles by a factor of four (4). So, a 1,000,000-tile Deep Zoom image is reduced to 250,000 tiles.
• 1,024×1,024
  reduces the number of tiles by a factor of sixteen (16). So, a 1,000,000-tile Deep Zoom image is reduced to 62,500 tiles.
• 2,048×2,048
  reduces the number of tiles by a factor of sixty-four (64). So, a 1,000,000-tile Deep Zoom image is reduced to 15,625 tiles.