View Full Version : I really need a help on image processing
newrule 03-15-2011, 07:39 AM Hi all, I was having a tutorial for image processing. The problem is I'm so stuck with the questions. Well, maybe it is so easy peasy for some of you. I'm such a newbie on this field. :argh: :argh: :argh:
the tutorial question:
an example:
sensorData[0] represents cell [0,0];
then
sensorData[0] = 50;//red
1)if sensorData[0] is for cell[0,0], then what is the corresponding sensorData array index for the following:
a) cell[12,25]
b)cell[25,25]
c)cell[5,5]
2) whats the general equaltion for mapping array index for sensorData array with cell[..,..] array
pls guys..pls..I'm so stuck..
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ndeboar
03-17-2011, 04:16 AM
You are probably best asking your tutor, that's what they are there for.
ThE_JacO
03-17-2011, 05:09 AM
Sounds like a simple serialisation question, and faster/slower array walking.
IE: If you have an NxM two dimensional array, and the first digit of a look-up is the position in X on the table, the second its Y, it will be an X fastest array(every increment in x corresponds to M increments along the Y serie).
The conversion is a simple serialisation of that table into a one dimensional sequence.
In general to answer that you need to know how you are serialising, but assuming the standard NxM X faster than Y, you can use something like:
i = X*M + Y
Basically that means every time you advance in X, you advance in the serie by the length along X (or the number of Y entries in that X), then add the Y to find the offset within that line.
That's columns then rows, if you scanline top to bottom then usually X will be slower than Y, as a hop down by one line will be N pixels on X jumped.
edit: btw, if you're already finding it an obstacle to map a 2d table to a serie, and you're taking programming classes, you might want to go back to some fundamentals in a hurry. This isn't really image manipulation specific, this is very, very simple arithmetics behind data models and data management ABC.
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