chapter 27: contrast

There are two image quality properties that allow detail to be seen on a radiographic images, What are they?

IR exposure and contrast

What is bit depth?

The number of bits available to store each pixels value. Every device in the imaging chain (Detector, Computer, Monitor) Has its own bit depth which determines its grayscale

Grayscale:

The number of shades of gray a system can represent, It is determined by depth

Grayscale formula?

Grayscale = 2^n

• n = bit depth

Grayscale example.

• if the bit depth is 6, how many shades of gray

2^6 =64 shades of gray

Grayscale

• clinical DR detectors typically capture how many bits?

14-16 bits

Grayscale

• Display monitors typically show how many bits?

Display monitors typically show 8-10 bits (but some medical grade monitors go higher)

Dynamic range-

The range of IR exposure that the detector can capture and convert into signal values