Mitsubishi Electric KD Series, User Manual

Page: 27 / 118

© Mitsubishi Electric Corporation
27
【
White correction
】 【
CIS output and signal processing function
】
2. White correction
CIS output corrected by Dark correction is affected by the
sensitivity of the CMOS sensor, the imaging efficiency of
the lens, and the illumination intensity. White correction
enables this product to correct these variations and to
provide a uniform output, when a uniform-reflectance chart
is scanned.
White correction corrects the white output (DVEp (n))
acquired in an actual scanning operation by using the white
correction data (DVEp0(n)) acquired in scanning another
object having an uniform reflectance.
CIS output corrected by White correction, DVp’(n) is
calculated by the following formula.
Target value can be set by register value. There are
several methods to create White correction data. Refer to
Function specification for further detailed information.
Original data of white output
scanning white chart
Pixel
C
IS
o
u
tp
u
t
DVEp0(n) : n
th
pixel output
Target value
Pixel
C
IS
o
u
tp
u
t
CIS corrected data scanning reference
white chart
DVp’(n) =
×
Target value
DVEp(n)
DVEp0(n)
2-3 Definition
DVp’(n) =
×
Target value
DVEp(n)
DVEp0(n)
TM-XJ959A
CIS corrected data scanning reference
white chart