Long-time store mode – Hitachi HV-D25 User Manual
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Long-Time Store Mode
In case that illumination on the subject is insufficient, just increasing the gain of the camera may cause an increase in noise,
resulting in an unclear image. In such a situation, it is advisable to select the long-time store mode using the external
memory. Thereby, the image can be brighter and clearer according to the stored amount of image. This camera is provided
with two kinds of image store functions (CCD MODE:FLD/FRM in SUB MENU 1). When one of these image store
functions is used, video signal output is delivered from the camera with the timing shown below.
Since the degree of after-image increases for a moving subject because of image storing, it is recommended to use the
image store function when taking a still picture or scene.
CCD line A
Even field
odd field
Field store mode
Aa
Aa
Ab
Ab
Ac
Ac
Ad
Ad
Ba
Ba
Bb
Bb
Bc
Bc
Bd
Bd
Ab+
Ab+
Bb
Bb
Ac+
Ac+
Bc
Bc
Aa+
Aa+
Ba
Ba
VD signal
Store charge
on CCD line A
Video signal
Store time: 1/15 s (Example)
WE signal
In the field store mode, both the CCD lines
A and B are read out simultaneously. After
completion of storing, video signal output is
made on the next field. Immediately before
the field on which video signal output is
made, the WE signal is delivered from the
D-SUB connector equipped on the rear
panel.
Even field
CCD line B
CCD line A
CCD line B
Store charge
on CCD line B
CCD line B
Even field
Frame store mode
Aa
Aa
Ab
Ab
Ac
Ac
Ad
Ad
Ba
Ba
Bb
Bb
Bc
Bc
Bd
Bd
Ab
Ab
Ac
Ac
Aa
Aa
Store charge
on CCD line B
Video signal
Store time: 1/15 s (Example)
WE signal
Ba
Ba
Bb
Bb
Bc
Bc
In the frame store mode, each of the CCD
lines A and B is read out individually.
Therefore, the vertical resolution is superior.
After completion storing, video signal output
is made between two fields. Immediately
before the field on which video signal output
is made, the WE signal is delivered from the
D-SUB connector equipped on the rear panel.
VD signal
CCD line A
CCD line B
CCD line A
Even field
Odd field
Odd field
Store charge
on CCD line A