JVC GR-DVM80 Camcorder User Manual


 
EN23
Description of Progressive Scan CCD
Progressive Scan is a special image sensing method which, unlike conventional interlace scanning, is able to
pick up all the lines of picture information in one Scan. Since the Progressive Scan CCD is capable of
outputting 60 full Frames* per second twice the amount of conventional systems it is able to deliver a
high quality picture even when its output signal is converted to a format that can be viewed on a TV screen.
*A NTSC TV screen image is composed of 30 Frames per second. 1 Frame is made up of 2 Fields.
Scan C
Scan A
1 Frame
Scan B
Skip
Scan D
Skip
Scan A
1. Regular shooting of moving images
Records 30 odd and 30 even image Fields, for a total
of 60 per second. Since there is a time lag between
an odd and even Field, when they are combined to
make 1 Frame the part of the image that is moving
appears as image jitter. However, during normal
playback, the moving picture looks smooth and
natural.
2. Progressive mode shooting of moving images (Progressive Mode Recording pg. 22)
Scan A is recorded, divided into an odd- and even-number Field, and then Scan B is skipped. Scans C and D
are handled in the same way as Scans A and B, as illustrated below, thereby recording 30 Frames per second.
Since each recorded odd- and even-number Field originates from the same Scan there is no time lag between
them, and so when they are combined into a Frame and a still image is displayed on a TV or PC monitor the
picture does not look jittery. However, when moving images are played back, the picture can look unnatural.
Even-number
Field
30 Frames per second
Odd-number
Field
Odd-number
Field
Even-number
Field
Scan B