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From: Jeprol on 25 Mar 2010 16:00
ImageAnalyst <imageanalyst(a)mailinator.com> wrote in message <916f1bb4-51f7-4967-ac56-3dabbb1ec971(a)q16g2000yqq.googlegroups.com>...
> Jeprol
> To subtract images:
> diffImage = image1 - image2;
>
> Seems rather obvious once you see it, doesn't it?
>
> And you can look in the help for rgb2hsv().

thanks for your idea. i have another question. how to count or detect whether there is an edge in image or not? I mean, after we detect the edge in the image, what is the process involve to know whether there is edge or not? i hope you have an idea to be shared to me. thanks.
From: Rob Campbell on 25 Mar 2010 17:30

> thanks for your idea. i have another question. how to count or detect whether there is an edge in image or not? I mean, after we detect the edge in the image, what is the process involve to know whether there is edge or not?


How about this?
http://blogs.mathworks.com/steve/2006/06/02/cell-segmentation/
http://www.mathworks.com/products/image/demos.html?file=/products/demos/shipping/images/ipexwatershed.html
From: ImageAnalyst on 25 Mar 2010 18:59
On Mar 25, 4:00 pm, "Jeprol " <jeprolll_...(a)yahoo.com.my> wrote:
> thanks for your idea. i have another question. how to count or detect whether there is an edge in image or not? I mean, after we detect the edge in the image, what is the process involve to know whether there is edge or not? i hope you have an idea to be shared to me. thanks.
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Well if an edge detection algorithm said that there was an edge there,
of some strength, then obviously it thinks there is an edge there.
Now a different edge detection algorithm may agree or disagree, or
disagree about the strength of the edge. And you may have yet a
different opinion. Who's to say which one is "correct"? Well I guess
since the edge detection is supposed to be doing the job for you, I
guess you're the ultimate judge. So you looking at the edge and
saying whether you believe it or not is the process.

From: Walter Roberson on 25 Mar 2010 19:11
ImageAnalyst wrote:
> On Mar 25, 4:00 pm, "Jeprol " <jeprolll_...(a)yahoo.com.my> wrote:
>> thanks for your idea. i have another question. how to count or detect whether there is an edge in image or not? I mean, after we detect the edge in the image, what is the process involve to know whether there is edge or not? i hope you have an idea to be shared to me. thanks.
> -----------------------------------------------------------------------------------------
> Well if an edge detection algorithm said that there was an edge there,
> of some strength, then obviously it thinks there is an edge there.
> Now a different edge detection algorithm may agree or disagree, or
> disagree about the strength of the edge. And you may have yet a
> different opinion. Who's to say which one is "correct"?

The one that embeds complete real-world physics of reflection and refraction
and textures and shadows and color gradients, is able to detect the angle of
illumination of the sun, deduce latitude and longitude and time of day, knows
how car windows and mirrors and sides and hoods reflect sunshine (potentially
defused by clouds), does a light polarization assessment to determine whether
the illumination is direct or indirect, and so on.

That one.

Didn't you whip that one up in the last 3 days of your final year project,
like everyone else does?? Or at least everyone who doesn't instead choose to
do OCR of hand-written Urdu ?
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