Posted by
Gluender-3 on
URL: http://imagej.273.s1.nabble.com/Method-to-get-zoomed-in-or-zoomed-out-AWT-image-from-and-ImagePlus-or-ImageWindow-tp3688583p3688593.html
Bill,
the picture elements of a digital image are samples and as such they
are numbers that have no extent. Mathematically they are
delta-functions with a certain integral value that denotes the value
of a pixel.
The way e.g. a digital camera captures images can be described by
averaging the analog image in the sensor plane by the light sensitive
area of a single photo sensitive element of the sensor. This low-pass
filtered image then is sampled by a 2D array of delta-funktions. Now
why is that?
The description takes into account that each of the photo sensitive
elements of the camera sensor delivers a single value (photo-current
or electric charge) according to the _mean_ light intensity that is
collected by is tiny area. This averaging means a low-pass filtering
of the light distribution in the sensor plane of your camera.
>Dscho-
>
>I've addressed my original problem by using ImageProcessor.resize().
>
>But I'm stuck mentally on your argument about the squares. What's
>the alternative? Circles? I thought that the pixels in our cameras
>were actually squares. Are they a different shape, either
>physically or functionally? Does anyone do math to account for
>their actual shape? Maybe in astronomy?
>
>Very interested in the details of what's correct, even if my own
>imaging never reaches the precision needing this sort of rigor.
>
>Thanks,
>Bill
>
>Johannes Schindelin wrote:
>>Hi,
>>
>>On Tue, 13 Apr 2010, Michael Schmid wrote:
>>
>>
>>>On 13 Apr 2010, at 18:21, Johannes Schindelin wrote:
>>>
>>>
>>>>For zooming in, I am not aware of an appropriate upsampling
>>>>plugin, but I am sure there is one.
>>>>
>>>For zooming in (enlarging), simply use Image>Adjust Size
>>>(ij.plugin.Resizer) with Bilinear (faster) or Bicubic (better)
>>>interpolation.
>>>
>>
>>Only if you ignore my comment about pixels not being little
>>squares, of course.
>>
>>Ciao,
>>Dscho
HTH
--
Herbie
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