White Papers

Compression and Losses

A wide spread myth is the statement that JPEG compression is always bad and details get lost; although unfortunately, this is true with most scanners that do the compression in the host PC. Image Access scanners compress to JPEG inside the scanner, utilizing a customized set of parameters to ensure the best possible compromise between noise suppression and JPEG artifacts. The result is a decently compressed file (1:10 - 1:25) with no visible JPEG artifacts - nearly as high quality as a TIFF raw file but with significantly reduced noise. The experienced reader will understand the following diagram after considering the following statements:

• Every optical system has a resolution limit (MTF).
• Compressing areas above the MTF adds noise, no content.
• Discarding areas below the MTF reduces high frequency details.
• A customized JPEG parameter set preserves more details.
• Our scanners all have a highly optimized JPEG compression engine developed by Image Access and tailored towards the camera properties.