www.gusucode.com > images 案例代码 matlab源码程序 > images/BasicImageImportProcessingAndExportExample.m
%% Basic Image Import, Processing, and Export % This example shows how to read an image into the workspace, adjust % the contrast in the image, and then write the adjusted image to a file. %% Step 1: Read and Display an Image % Read an image into the workspace, using the |imread| command. The example % reads one of the sample images included with the toolbox, an image of a % young girl in a file named |pout.tif| , and stores it in an array % named |I| . |imread| infers from the file that the graphics file format % is Tagged Image File Format (TIFF). I = imread('pout.tif'); %% % Display the image, using the |imshow| function. You can also view an % image in the Image Viewer app. The |imtool| function % opens the Image Viewer app which presents an integrated environment for % displaying images and performing some common image processing tasks. The % Image Viewer app provides all the image display capabilities of % |imshow| but also provides access to several other tools % for navigating and exploring images, such as scroll bars, the Pixel % Region tool, Image Information tool, and the Contrast Adjustment tool. imshow(I) %% Step 2: Check How the Image Appears in the Workspace % Check how the |imread| function stores the image data in the workspace, % using the |whos| command. You can also check the variable in the % Workspace Browser. The |imread| function returns the image data in the % variable |I| , which is a 291-by-240 element array of |uint8| data. whos I %% Step 3: Improve Image Contrast % View the distribution of image pixel intensities. The image |pout.tif| is % a somewhat low contrast image. To see the distribution of intensities in % the image, create a histogram by calling the |imhist| function. (Precede % the call to |imhist| with the figure command so that the histogram does % not overwrite the display of the image |I| in the current figure window.) % Notice how the histogram indicates that the intensity range of the image % is rather narrow. The range does not cover the potential range of [0, % 255], and is missing the high and low values that would result in good % contrast. figure imhist(I) %% % Improve the contrast in an image, using the |histeq| function. Histogram % equalization spreads the intensity values over the full range of the % image. Display the image. (The toolbox includes several other functions % that perform contrast adjustment, including |imadjust| and |adapthisteq|, % and interactive tools such as the Adjust Contrast tool, available in the % Image Viewer.) I2 = histeq(I); figure imshow(I2) %% % Call the |imhist| function again to create a histogram of the equalized % image |I2| . If you compare the two histograms, you can see that the % histogram of |I2| is more spread out over the entire range than the % histogram of |I| . figure imhist(I2) %% Step 4: Write the Adjusted Image to a Disk File % Write the newly adjusted image |I2| to a disk file, using the |imwrite| % function. This example includes the filename extension |'.png'| in the % file name, so the |imwrite| function writes the image to a file in % Portable Network Graphics (PNG) format, but you can specify other % formats. imwrite (I2, 'pout2.png'); %% Step 5: Check the Contents of the Newly Written File % View what |imwrite| wrote to the disk file, using the |imfinfo| function. % The |imfinfo| function returns information about the image in the file, % such as its format, size, width, and height. imfinfo('pout2.png')