What is blooming?
Blooming is the overflow of charge from one pixel to another. It should not be confused with purple fringing. Blooming is a more serious concern with CCD devices, where can flow down a readout column creating a distinctive white streak, as seen here or on this NASA composite from Mars. Blooming can be mitigated in CCDs through the use of an anti-blooming gate, which bleeds off excess charge. However, such structures do rob photosensitive area from each pixel. From reading Sony’s CCD datasheets, it appears that the interline transfer area of interline transfer CCDs may be usable as a kind of antiblooming device during exposure. (There are references to sweeping the blooming signal before reading the exposure from the chip.) I’d welcome additional insights on this. CMOS sensors are inherently resistant to blooming, in part because they are not designed to transfer charge from one pixel to the next, as is the case with CCDs.
