It is to note that the CCD continues to be photo-sensitive during the shift operation i.e. for a time T

5.3. Multi frame acquisition

Up to 4 images can be acquired and stored in the CCD frame store in a fast sequence without intermediate read-out. The CCD frame store

is organized in 4 CCD frame store elements (FS1-FS4), thereby each CCD frame store element can store one frame/image. The first

captured image initially occupies 3 frame store elements as for a single-frame acquisition (see section 5.2 and Figure 8). epc901 automati-

cally detects a multi-frame acquisition when detecting the second SHUTTER signal without prior read-out. Upon the second shutter the

first image is shifted to a single frame store element (see (2) in Figure 9). The frames are shifted from the CCD pixel field to and through

the CCD frame store in a FIFO-manner i.e. the first captured image is the first one read out. The read-out is described in more detail in

section 5.4. As soon as 4 frames have been captured without prior read-out, at least one read-out has to be issued prior the next shutter in

order to make FS1 available again. Excessive shutter pulses are ignored.

SHUTTER

READ_CLK

T

SHIFT

T

CDS

T

SHIFT

T

SHIFT

T

CDS

T

CDS

(1)

(2)

(3)

(4)

DATA_RDY

Figure 9: Illustrative example of multi-frame acquisition and read-out

5.4. Image readout

After one or more images have been captured, the first image (FIFO) can be read out through the video interface on the pins VIDEO_P

and VIDEO_N. The read-out is controlled by the READ pin. The following timing diagram shows its usage:

READ

VIDEO_P/N

T

RD_PULSE

T

RD_CLK

T

H,VIDEO

T

CDS

N

Pre-loading of

internal pipe-line

DATA_RDY

ANA_TEST0

1

2

3

P

0

P

1

P

2

P

3

P

N

READY goes low when the readout of

the last stored frame begins

(rising edge indicates readout of the last pixel in a frame)

Figure 10: Image readout timing of one frame

frame in the CCD frame store is sampled pixel-wise onto a capacitor array thereby the pixel charges are converted into pixel voltages

© 2016 ESPROS Photonics Corporation

Characteristics subject to change without notice

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