NED
UME-0033-01
Sui74450T2
39
4.12 Pixel Correction
Generally speaking, image sensors (CCD, CMOS and so on) have fixed pattern noise
and photo response non-uniformity. When you use a lens, lens shadings and light
sources also can cause non-uniformity. The camera is factory set to the optimal
correction before shipping in order to provide images of high grade. The camera also has
a user white correction function in order to cope with lens shading and non-uniform
illumination.
Cal_bl : Output data of each pixel in perfect dark (digial)
Cal_wh : Output data of each pixel in uniform illumination (digial))
When Vin: Input data (digital), Vout: Output data (digital),
Vout
＝
(Vin-Cal_bl
）
×Cal_wh
to correct output data.
<Example> Pixel correction target level:192DN
Image“before”user arbitrary pixel Green line is Luminance Profile
is corrected.
Image“after”user arbitrary pixel Green line is Luminance Profile
is corrected.
Figure 4-12-1 Waveform and image before and after bit correction
target level
