Sony ICX274AQ Camera Accessories User Manual


 
17
ICX274AQ
Center scan and AF modes
Description of Center Scan and AF Mode Operation
The center scan and AF modes realize high frame rates by sweeping the top and bottom of the picture with
high-speed transfer and cutting out the center of the picture.
The various readout modes during center scan and AF operation are described below.
AF modes
AF mode (1), (2): The output method is the same as readout in 2/8-line readout mode.
Center scan modes
Center scan mode (1): The output method is the same as 2/4-line readout mode.
Center scan mode (2): The output method consists of 2-line addition readout whereby the signals for only
two out of four lines (3rd and 4th lines, 7th and 8th lines, and so on) are read out,
the vertical register is shifted by 2 bits, and then the signals of the remaining two
out of the four lines (1st and 2nd lines, 5th and 6th lines, and so on) are read out
and added within the vertical register.
Center scan mode (3): The output method is the same as progressive scan mode.
The readout method, frame rate, number of output lines and other information for each readout mode are
shown in the table below.
Undesired portions (Swept by vertical register high-speed transfer)
Picture center cut-out portion
Mode
Frame rate (frame/s)
Progressive scan mode
2/8-line readout mode
2/4-line readout mode
2-line addition mode
Center scan mode (1)
Center scan mode (2)
Center scan mode (3)
AF mode (1)
AF mode (2)
Progressive scan
2/8-line readout
2/4-line readout
2/4-line readout
2/4-line readout
2-line addition readout
Progressive scan
2/8-line readout
2/8-line readout
None
None
None
Vertical 2-line
None
Vertical 2-line
None
None
None
9.99
29.97
19.98
19.98
29.97
29.97
29.97
59.94
119.88
14.985
29.97
19.98
19.98
29.97
29.97
29.97
59.94
119.88
1220
305
610
1220
434
434
444
170
43
1220
305
610
1220
568
568
580
235
75
Number of output
effective pixel data
lines
Readout method
Addition
method
28.6MHz 36MHz 28.6MHz 36MHz