How to activate the frame memory?
A. Asynchronous Reset Mode (Select switch on back plate for ASYNC)
When External VINIT is high ( 5V), the TM-9701 expects the async pulse input. It resets at the negative
going pulse edge and captures the frame regardless of the shutter speed (fast or slow mode). The video is
kept and output continuously during VINIT high. When the next VINIT pulse comes in, the next image is
captured. If the switch is MAN (manual shutter) mode, the video output is real time. Because of the
progressive scan to interlace scanning, the interlace video reacts slower to moving objects than with normal
interlace cameras. (It converts 30 Hz frame into 60 Hz rate and since moving objects are captured at a slow
rate, 60 Hz scanning cannot show faster motion.)
B. Integration
Activate ENINT (Enable Integration) of 31-pin connector (#22) by connecting to 0V (TTL GND) then input
INTEG CONT as active low. During low, the TM-9701 keeps integrating and, upon the rising edge of the
INTEG CONT pulse, it captures the frame and keeps it until next end of integration.
9. Progressive Scanning
Standard TV system scanning is 525 line interlace scanning as specified in RS170. Every other horizontal
line (ODD lines and EVEN lines) are scanned at a 60 Hz rate per field, and completes scanning with two
fields (one Frame) at 30 Hz rate. Because of the interlace scanning, vertical resolution of CCD cameras is
limited at 350 TV lines regardless of horizontal resolution. When electronic shutter is applied, the CCD can
hold only one field of charge at each exposure. Therefore, the vertical resolution of the electronic shutter
camera is only 244 TV lines.
The TM-9701 uses a state-of-the-art CCD called a "Progressive scanning interline transfer CCD" which
scans all lines sequentially from top to bottom at one frame rate (30 Hz). Like a non-interlace computer
screen, it generates a stable crisp image without alternating lines and provides full vertical TV resolution of
484 instead of 350. The interline transfer architecture is also important to generate simultaneous shuttering.
This is different from full frame transfer architecture which requires a mechanical shutter or strobe light in
order to freeze object motion.
The TM-9701 outputs the progressive scan image with electronic shutter in three different formats:
i) Progressive Scanning Analog Output (refer to P.5 for jumper setting)
Straight forward signal output without going through 8-bit A/D, D/A converter. It is useful for higher gray level
resolution than 8-bit (256 levels). It is a real-time CCD output through normal analog video processing into
75Ω1Vp-p output format.
ii) Progressive Scanning Digital and Analog Output (refer to P.5 for jumper setting)
The CCD signal goes through A/D and D/A converters. The frame memory is capable of capturing async
and integration video without having special frame grabbers. The analog output is the same as 75Ω, 1Vp-p
format at 30Hz rate available from BNC and 12 pin connector. The digital output is available from 31-pin
connector with EIA-422 format.
iii) Interlace Scanning Output (Digital and Analog)
By setting switch on the back plate to interlace mode, the TM-9701 outputs normal RS-170 video for
standard monitor display or general purpose video frame grabbers. (Set jumpers W4 ON side). Since the
interlace mode must use a frame memory, it can output captured images of async and integration video. The
first field after asynchronous reset is the previous image. The second field is an even field, and the third field
is an odd field. In orer to capture full frame, the frame grabber must capture the 2nd and 3rd fields. (See
page 2, Fig. 2) Option 51 provides continuous (uninterrupted) video sync output for asynchronously
captured images.
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