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# Image Intensity

Asked by M@lik Ali on 4 Jun 2012
Latest activity Commented on by Image Analyst on 11 Feb 2014 at 11:04

Hi all, Can any one tel me the command in matlab to calculate the intensity of image.

Jean on 5 Jul 2013

Does anyone further know how to do this for a specific area of pixels? For example, image(100:1:200,100:1:200) for a 100 by 100 pixel area, and get the intensity in this area as an average?

Image Analyst on 5 Jul 2013
```meanGrayLevel = mean2(yourImage(100:200,100:200));
```

Don't use "image" as the name of your variable since it's a function.

## Products

Answer by Image Analyst on 4 Jun 2012

The mean of a particular pixel is just simply the pixel value, since there is only one sample - nothing really to take the mean of:

```intensityValue = grayImage(100, 230);
meanIntensityValue = mean(grayImage(100, 230));
```

Here, of course meanIntensityValue will equal intensityValue.

To get the mean of all the pixel values in the entire image, you can do any of these:

```meanIntensityValue = mean2(grayImage);
meanIntensityValue = mean(grayImage(:));
meanIntensityValue = mean(mean(grayImage));
```

Iain on 25 Jun 2013

Yes. Both should work. (Though, you have a spare "=" in the first one).

Mona on 26 Jun 2013

Thank you so much

Image Analyst on 26 Jun 2013

Please mark the discussion as "Answered" if you're done with it. Unless you want to open a can of confusing worms about how the units of an image are not really intensity.

Well, the intensity of the image is the average of the intensities of all pixels in an image (unless you're doing anything more specific than that). So if you do

```mean(imagefile(:))
```

you should get the intensity of the image.

## 1 Comment

M@lik Ali on 4 Jun 2012

But actually i want to calculate the intensity value of all elements of the images.

someone told me like

```intensityValue = grayImage(100, 230);
```

But in i have to calculate the intensity value of each pixel or total image, i think i can do it by calculating the intensity of each pixel and then add it but i am not sure.

Answer by Saranya on 30 Jan 2014

hi image analyst i want to measure the intensity profile for gray scale image.. can you help me..?

Image Analyst on 3 Feb 2014

Yes. improfile() can take arguments that are the endpoints of the line.

Jensa on 11 Feb 2014 at 4:00

Hi Image Analyst...Can you help me to find the density profile for my chromosome image..Attaching the image along with this.. http://postimg.org/image/pe5ozahzb/e770bd0c/

Image Analyst on 11 Feb 2014 at 11:04