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ALTRES AJUSTAMENTS:
DETALL
Els ajustaments de Detall
Si incrementem el Detail level ( menú DSR400), donant-li
valors positius, aquest nivell de senyal afegida augmenta en les
vores hotizontals i verticals.
En canvi si li donem valors negatius la imatge obté una
aparença més “soft”.
Detail és una funció utilitzada per
ajustar la sensació de nitidesa de la
imatge o per contra la seva suavitat,
que funciona afegint senyal elèctrica
“blanca” o “negra” en les transicions
entre llum i foscor de les imatges
originals.
Els ajustaments de detall
• Aquesta qüestió no és tan simple:
• En afegir senyal estam també afegint soroll, i les vores poden no veure’s tot el
contrastades que desitjaríem.
• Aquest soroll és més visible a les zones fosques
• En les zones d’altes freqüències poden aparèixer defectes com el Cross color
• En realitat amb un sol control sols es pot afectar a un rang de freqüències relativament
amplies i no a patrons fins a l’hora.
28 The Basics of Camera Technology
Camera Functions
Crispening
As mentioned in the section on Detail Level (refer to “Detail
Level” ), detail signals are used to raise the contrast at the
dark-to-light and light-to-dark transitions, making the edges
of objects appear sharper both horizontally and vertically.
Simply put, detail correction makes pictures look sharper
than the actual resolution provided by the camera. However,
since detail correction is applied to the entire picture, its use
also emphasizes the noise of the picture, especially when the
detail level is high.
Crispening is a circuit implemented to avoid detail signals
being generated around noise. By activating the Crispening
function, detail signals with small amplitudes, which are most
likely caused by noise, are removed from the signal.
As shown in the figure below, in the Crispening process, only
detail signals that exceed a designated threshold are utilized
for image enhancement. Conversely, the detail signals with
small amplitudes are regarded as noise and removed.
Crispening allows detail to be adjusted without worrying
about its influence over noise.
Cross Color Suppression
Cross color is an artifact seen across very fine striped pat-
terns when displaying a composite signal feed on a picture
monitor. It is observed as a rainbow-like cast, moving across
the stripes. To understand how cross color occurs, it is
worthwhile to review the composite signal (refer to “Color Sig-
nal Forms” ).
A composite signal is formed by combining the chrominance
and luminance signals together so their spectrums inter-
leave. In the early days of color broadcast, the composite
signal introduced the benefit of transmitting a color signal
within the same bandwidth as a black and white signal. How-
ever, a drawback was seen on the TV receiver side. Since all
video signals must be decoded into their R, G, and B compo-
nents for display on a color video monitor, the composite sig-
nal first requires to be separated into its chrominance and
luminance components (known as Y/C separation). This is
where the problem occurred. Although many techniques
have been developed to separate the composite signal into
its luminance and chrominance components, none have
been complete even with the most advanced technology.
Cross Color Suppression technology - incorporated in the lat-
est Sony professional video cameras - presents a solution to
the limitations of Y/C separation on TV receivers. Cross
Color Suppression refers to a digital filtering process, which
eliminates any luminance components that may result in
cross color prior to outputting the composite signal. These
frequency components are eliminated from the Y/R-Y/B-Y
signals within the camera head by using sophisticated digital
three-line comb filtering (NTSC/fine line/PAL). This allows
the composite signal to be easily separated back into its
chrominance and luminance components at the TV receiver.
This results in greatly reduced cross color and dot crawl (dot
noise appearing at the boundaries of different colors) than
normally observed.
Crispening level
Cross Color Cross Color Suppression ON
Altes freqüències Baixes freqüències
