#Matlab 2012 freezing when saving pictures code
Now we have to code the behavior of our program: We do not need other modifications for the moment, so just save the window.Īs you did with the push button, select the static text, choose "Property Inspector" and modify "string" and "tag" NOTE: The string text is optional, the tag is not!
"Type element" + UNDERSCORE + "what this element does".
My convention is to define tags in the format
#Matlab 2012 freezing when saving pictures free
NOTE: while you can be highly free to chose your own texts for the string field, I suggest you to be consistent in choosing the tag field. For example, when you want to write in a particular text box, you need its tag! Within the program, you need this tag in order to refer to a certain element. The tag field is the name that the GUI object (button, graph, text.) has within the application and MUST be without spaces and unique within the GUI. The string field is the text that will appear on the button and it's for the user interaction and must have a meaningful content like "exit", "clear graph", "save" etc. So if you execute this code you are going to have on screen and on disk two images, that I can’t dsiplay here because they are bmp files.Here we want to modify two properties: string and tag. Imwrite(noisy,'lsb_watermarked_noise.bmp','bmp') Noisy = imnoise(watermarked_image,'gaussian') Watermarked_image(ii,jj)=bitset(watermarked_image(ii,jj),1,watermark(ii,jj)) % set the LSB of cover_object(ii,jj) to the value of the MSB of watermark(ii,jj) % title the message object out to cover object size to generate watermark % determine the size of message object to embed % determine the size of cover image used for embedding
% conversions needed to spread the image values on a 256 gray-scale % read the message image you want to hide in the cover image % read in the cover object you want to use for embedding %Project: Tutorial on Least Significant Bit Substitution The code is heavily commented, so I think that further explanations are not needed. We will try also to add an WGN (white gaussian noise) to the image then after these operations we will write to file the results. Ok, now (as always) a lot of code about LSB watermarking and few words about it 😀 Briefly with the following code I will try to embed the MSB of the baboon image into the picture of Lena by exploiting the LSB embedding technique. For my code I used two bitmap image, unfortunately wordpress doesn’t allow me to publish bmp images, so I’m just going to put here the links for getting the images from the web: If your image is for example in gray scale, you can make changes to the value of the LSB without any perceptible distortion for the human user therefore you can think of taking the LSB of an image (the cover image) and change its value in every pixel with the MSB of another image, that we would like to embed in a secret/non perceptible way in the cover image).
The idea behind this watermarking technique is the following: if you see you image as a matrix NxM (where N and M are the dimension of the image) you can represent the value of the pixel in the position (i,j) as a binary number this binary can be then divided in all of its bit, so that you will have a most significant bit (the one that contains quite a lot of information, and a least significant bit that contains few information). One of the first lab lessons was about LSB (least significant bit) replacement. Basically the lecture are focused on digital watermarking (on images and audio files), and cryptography. Lately at university, I have been following the “Data Hiding” course.
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