Matlab – How does path retrieval work using imread and imwrite

imageMATLAB

I know how imread and imwrite works, but I don't know where do the function call the image file from? In other words, where do I store the image in order to call it using imread?

Best Answer

As Adam suggests you could change the Matlab working directory to the location of your images or what I tend to do is to get the user to select the file to be read using uigetfile

>> [fn,pn]=uigetfile({'*.TIFF,*.jpg,*.bmp','Image files'}, 'Select an image');
>> I = imread(fullfile(pn,fn));

or if you know the directory of to the images you want to read you could store it in a variable then you could get a list of images in that directory using dir

>> imageDir = 'c:\path\to\my\images';
>> imageList = dir(fullfile(imageDir,'*.tif')); % store all files with extension tif  
                                               % in a structure array imageList

from there you can loop through imageList and process each image found. Finally, you can use uigetdir to ask the user for the direcotory containing the image set.

Related Solutions

Android – Strange OutOfMemory issue while loading an image to a Bitmap object

To fix the OutOfMemory error, you should do something like this:

BitmapFactory.Options options = new BitmapFactory.Options();
options.inSampleSize = 8;
Bitmap preview_bitmap = BitmapFactory.decodeStream(is, null, options);

This inSampleSize option reduces memory consumption.

Here's a complete method. First it reads image size without decoding the content itself. Then it finds the best inSampleSize value, it should be a power of 2, and finally the image is decoded.

// Decodes image and scales it to reduce memory consumption
private Bitmap decodeFile(File f) {
    try {
        // Decode image size
        BitmapFactory.Options o = new BitmapFactory.Options();
        o.inJustDecodeBounds = true;
        BitmapFactory.decodeStream(new FileInputStream(f), null, o);

        // The new size we want to scale to
        final int REQUIRED_SIZE=70;

        // Find the correct scale value. It should be the power of 2.
        int scale = 1;
        while(o.outWidth / scale / 2 >= REQUIRED_SIZE && 
              o.outHeight / scale / 2 >= REQUIRED_SIZE) {
            scale *= 2;
        }

        // Decode with inSampleSize
        BitmapFactory.Options o2 = new BitmapFactory.Options();
        o2.inSampleSize = scale;
        return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
    } catch (FileNotFoundException e) {}
    return null;
}

Android: combining text & image on a Button or ImageButton

For users who just want to put Background, Icon-Image and Text in one Button from different files: Set on a Button background, drawableTop/Bottom/Rigth/Left and padding attributes.

<Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@drawable/home_btn_test"
        android:drawableTop="@drawable/home_icon_test"
        android:textColor="#FFFFFF"
        android:id="@+id/ButtonTest"
        android:paddingTop="32sp"
        android:drawablePadding="-15sp"
        android:text="this is text"></Button>

For more sophisticated arrangement you also can use RelativeLayout (or any other layout) and make it clickable.

Tutorial: Great tutorial that covers both cases: http://izvornikod.com/Blog/tabid/82/EntryId/8/Creating-Android-button-with-image-and-text-using-relative-layout.aspx

Best Answer

Related Solutions

Android – Strange OutOfMemory issue while loading an image to a Bitmap object

Android: combining text & image on a Button or ImageButton

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