*1stD image quality

Started Mar 28, 2004 | Discussions thread
*isteve Veteran Member • Posts: 9,509
Re: Increased sharpness

Pretty much, yes. Its why of you overdo it you get white or black halos around high contrast edges...

mikiw wrote:
And what is "increase the contrast"? does it mean that colors
brighter from a given threshold becomes brighter (i.e., increased
numerical values of the RGB channels), and colors darker from that
same threshold are made darker?

*isteve wrote:
They all work the same basic way - they increase the contrast
between neighbouring pixels above a certain brightness threshold
over a certain radius relative to the pixel.
Where sharpening algorithms differ is in which areas of the picture
they alternatively select to sharpen or smooth. For instance,
selecting only edges and sharpening those has no effect on noise
(only noticeable on flat colour areas) but makes high contract
edges sharper. However it does little for small low contrast detai
(grass, distant leaves etc). Some digicams reduce apparent noise by
actually smooting those areas making things worse.
Starting with an unsharpened baseline and applying different levels
of sharpening to edges and selected areas of a picture is the only
way to do it properly but its time consuming. Alternatively Focal
Blade and other sharpening tools allow you to set the edge ask
intensity and set different levsl of sharpening for edges and
surfaces, as well as altering the intensity and colour of the
"halo" you get when sharpening. So far I have had excellent results
from Focal Blade.

mikiw wrote:
Hi guys,
Any of you Electrical Engineers or Mathematician knows what does
the mathematical algorithm for sharpening? how it differs from PS's
Unsharp Mask

Richard N. Allen wrote:

Thanks Jim.

Earlier this afternoon, I went back over some of the 1stD reviews
and they all mentioned image softness. So, I changed the sharpness
to "hard" and it did improve the situation. I guess it's going to
take me a little time to adjust to the camera's quirks.


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