Operation Manual

4.5 Correction

_____________________________________________________________

Cautions

This procedure should only be done by suitably-trained service engineer.

_____________________________________________________________

Cautions

If the exposure for the corrected images are collected by wrong exposure setting, for example, (A).

Over-exposure than or under-exposure (B). Foreign object is put on the surface (C) collimator of

Xray tube is not open to the full field of FPD. It may lead to image artifact.

_____________________________________________________________

Cautions

Do not expose to any X-ray during dark image collection.

_____________________________________________________________

4.5.1 Collect images

When the program is executed, the corrected images are collected in sequence. The images with

X-ray radiation and without X-ray radiation are collected in reasonable amounts according to the

environment. At least 5 flat field images are recommended for calibration. Radiation quality of the

light image shall be in the range of 30000±3000lsb.(The exposure condition is adjustable based on

each customers.) The images with X-ray radiation and without X-ray radiation are collected in

reasonable amounts according to the environment. Next, the offset map (D) and the gain map (G)

are calculated. And use the following algorithm to correct for raw images.

- C = corrected image

- R = raw image

- F = flat field image

- D = dark field or dark frame

- m = image-averaged value of (F-D)

- G = Gain =