NOMALIZE THE IMAGE
in [Matlab]
|
From: Steven Lord on 24 May 2010 09:23 "mops zaki" <zaki_achi(a)hotmail.com> wrote in message news:htdovp$4eo$1(a)fred.mathworks.com... > "Wayne King" <wmkingty(a)gmail.com> wrote in message > <htdo7e$ej4$1(a)fred.mathworks.com>... >> "mops zaki" <zaki_achi(a)hotmail.com> wrote in message >> <htdm05$kgj$1(a)fred.mathworks.com>... >> > i have to do normalization...for it first i have to calculate mean and >> > variance of the image >> > i use M = mean(I5(:)) ; to calculate mean...but the size of image >> > reduce to 1x1 after mean.. WAT I HAVE DONE WRONG >> > >> > MY FULL CODE IS.. >> > clear all >> > image=imread('0001hv1.bmp'); You should change this variable name; IMAGE is a function in MATLAB, and you may want to use it later on in your code. http://www.mathworks.com/access/helpdesk/help/techdoc/ref/image.html >> > %Designing guasian filter%%%%%%%%%%%%%%%%%%(LOW PASS) >> > sigma=0.8; >> > H=fspecial('gaussian',[5 5],sigma); >> > I5=imfilter(image,H); >> > figure(2),imshow(I5); >> > M = mean(I5(:)) ; >> > >> > HELP ME PLZ >> >> Hi, did you just intend to calculate the mean of each column in the >> image? Then, just enter: >> >> M = mean(I5); >> >> Your line M = mean(I5(:)); is equivalent to M = mean(mean(I5)); >> you're calculating the mean of the column means. That's why it's a >> scalar. >> >> Wayne > > > hi i want to calculate mean of whole image....ofter calulating mean i have > to subtract the mean image from the original one.... Okay, so you've done the first half of what you wanted. Now you need to subtract the mean _value_ (M) from the original image. If you intend something other than the mean value when you refer to "the mean image" then you need to clearly state what exactly you want when you use that phrase. -- Steve Lord slord(a)mathworks.com comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ To contact Technical Support use the Contact Us link on http://www.mathworks.com
From: mops zaki on 24 May 2010 09:48 "Steven Lord" <slord(a)mathworks.com> wrote in message <htdujg$c8b$1(a)fred.mathworks.com>... > > "mops zaki" <zaki_achi(a)hotmail.com> wrote in message > news:htdovp$4eo$1(a)fred.mathworks.com... > > "Wayne King" <wmkingty(a)gmail.com> wrote in message > > <htdo7e$ej4$1(a)fred.mathworks.com>... > >> "mops zaki" <zaki_achi(a)hotmail.com> wrote in message > >> <htdm05$kgj$1(a)fred.mathworks.com>... > >> > i have to do normalization...for it first i have to calculate mean and > >> > variance of the image > >> > i use M = mean(I5(:)) ; to calculate mean...but the size of image > >> > reduce to 1x1 after mean.. WAT I HAVE DONE WRONG > >> > > >> > MY FULL CODE IS.. > >> > clear all > >> > image=imread('0001hv1.bmp'); > > You should change this variable name; IMAGE is a function in MATLAB, and you > may want to use it later on in your code. > > http://www.mathworks.com/access/helpdesk/help/techdoc/ref/image.html > > >> > %Designing guasian filter%%%%%%%%%%%%%%%%%%(LOW PASS) > >> > sigma=0.8; > >> > H=fspecial('gaussian',[5 5],sigma); > >> > I5=imfilter(image,H); > >> > figure(2),imshow(I5); > >> > M = mean(I5(:)) ; > >> > > >> > HELP ME PLZ > >> > >> Hi, did you just intend to calculate the mean of each column in the > >> image? Then, just enter: > >> > >> M = mean(I5); > >> > >> Your line M = mean(I5(:)); is equivalent to M = mean(mean(I5)); > >> you're calculating the mean of the column means. That's why it's a > >> scalar. > >> > >> Wayne > > > > > > hi i want to calculate mean of whole image....ofter calulating mean i have > > to subtract the mean image from the original one.... > > Okay, so you've done the first half of what you wanted. Now you need to > subtract the mean _value_ (M) from the original image. If you intend > something other than the mean value when you refer to "the mean image" then > you need to clearly state what exactly you want when you use that phrase. > > -- > Steve Lord > slord(a)mathworks.com > comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ > To contact Technical Support use the Contact Us link on > http://www.mathworks.com > sir it mean that I5(x,y) is my original image i want to subtract mean i.e M(M=mean(I5(:)); from my image I5... i.eA=(I5(x,y)-M)^2; it give nothig 1x1 is size... reqardz zaki
From: Steven Lord on 24 May 2010 10:07 "mops zaki" <zaki_achi(a)hotmail.com> wrote in message news:hte02n$jck$1(a)fred.mathworks.com... > "Steven Lord" <slord(a)mathworks.com> wrote in message > <htdujg$c8b$1(a)fred.mathworks.com>... *snip* >> >> > %Designing guasian filter%%%%%%%%%%%%%%%%%%(LOW PASS) >> >> > sigma=0.8; >> >> > H=fspecial('gaussian',[5 5],sigma); >> >> > I5=imfilter(image,H); >> >> > figure(2),imshow(I5); >> >> > M = mean(I5(:)) ; *snip* > sir it mean that I5(x,y) is my original image Incorrect. Your "original image" is either the variable named image (that I advised you to rename) or I5 -- I5(x, y) is some subset of the elements in the image after it has been filtered. > i want to subtract mean i.e M(M=mean(I5(:)); from my image I5... > i.eA=(I5(x,y)-M)^2; > it give nothig 1x1 is size... That's correct, assuming x and y are scalars; in that case that code operates on _one element_ of I5. If you want to operate on _all elements_ of I5 then do so. A = I5-M; -- Steve Lord slord(a)mathworks.com comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ To contact Technical Support use the Contact Us link on http://www.mathworks.com
From: Walter Roberson on 24 May 2010 10:14 mops zaki wrote: > sir it mean that I5(x,y) is my original image i want to subtract mean > i.e M(M=mean(I5(:)); from my image I5... > i.eA=(I5(x,y)-M)^2; > it give nothig 1x1 is size... I5(x,y) is not your original image: it is one pixel out of your individual image. Use I5 instead of I5(x,y) to do the whole array at once. (And when that gives an error message, look for the documentation about "array power" at http://www.mathworks.com/access/helpdesk/help/techdoc/ref/arithmeticoperators.html )
From: ImageAnalyst on 24 May 2010 10:43 mops: One thing to be aware of is that you'll need to convert your image do floating point if you want the difference image to be correct. If you don't, it will stay as uint8 and it will clip values to 0 and you'll have an incorrect image. Run this demo and you'll see what I mean: (IMPORTANT: BE SURE TO JOIN THE "message = sprintf(...." LINE WHICH WILL GET SPLIT INTO MULTIPLE LINES BY THE NEWSREADER!!!) % function test() % Change the current folder to the folder of this m-file. % (The line of code below is from Brett Shoelson of The Mathworks.) if(~isdeployed) cd(fileparts(which(mfilename))); end clc; % Clear command window. clear; % Delete all variables. close all; % Close all figure windows except those created by imtool. imtool close all; % Close all figure windows created by imtool. workspace; % Make sure the workspace panel is showing. fontSize = 20; % Read in standard MATLAB gray scale demo image. grayImage = imread('cameraman.tif'); subplot(2, 2, 1); imshow(grayImage, []); title('Original Grayscale Image', 'FontSize', fontSize); set(gcf, 'Position', get(0,'Screensize')); % Maximize figure. % Calculate the mean gray level of the entire image. meanGrayLevel = mean(grayImage(:)) % Calculate the difference with the result being a uint8 image. uint8SubtractedImage = grayImage - meanGrayLevel; subplot(2, 2, 2); imshow(uint8SubtractedImage, []); title('Difference uint8 Image', 'FontSize', fontSize); % Calculate the mean after subtraction. % It should be zero, but it won't be. meanGrayLeveluint8 = mean(uint8SubtractedImage(:)) % Calculate the difference with the result being a uint8 image. dblSubtractedImage = double(grayImage) - meanGrayLevel; subplot(2, 2, 3); imshow(dblSubtractedImage, []); title('Difference double Image', 'FontSize', fontSize); % Calculate the mean after subtraction. It will be zero. meanGrayLevelDouble = mean(dblSubtractedImage(:)) % Display results. message = sprintf('The mean of the original uint8 image = %.2f\nThe mean of the uint8 difference image = %.2f\nThe mean of the double difference image = %.2f', ... meanGrayLevel, meanGrayLeveluint8, meanGrayLevelDouble); msgbox(message);
First
|
Prev
|
Next
|
Last
Pages: 1 2 3 Prev: How to Solve This Code ??? Next: save contour plot as image |