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Android Application Options for Comptuer Vision
OPTION 1 using built in camera app and Bitmap to do your own image processing
step 1: Use Camera to take picture and its is saved into a file on phone --
// MOST LIKELY INSIDE AN ACTIVITY CLASS ---class variables that are useful
File fileURL; // represent File of where we will store image we will take with camera
String mCurrentPhotoPath; //represents File location of the fileURL as a String
private static final int CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE = 100;ImageView mImageView; //NOTE you will need to create this image by done line of code like this in the Activities
//onCreate method
// mImageView = (ImageView) findViewByID(R.id.imageViewDisplay);// where imageViewDisplay is the ID of the XML ImageView specfied in Android GUI layout
//method to take a picture using Built-In camera app and store in specified location
void takePicture()
{
//get the picture taken by external existing Camera App right//away at start...could do instead as a result of Event handling
// create Intent to take a picture and return control to the calling application
//Create Intent LAUNCH built-in camera app
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);//setup File URL for location for image
fileURI = getOutputMediaFileUri(); // create a file to save the image
//save location also as a String
mCurrentPhotoPath = fileUri.toString();intent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri); // set the image file name
// start the image capture Intent-- this asks Android System to start the build in Camera App and return
// when done to this activity by calling the below method onActivityResult(**) method
// the name CAPTURE_IMGE_ACTIVITY_RESUEST_CODE is a made up value used in the onActivityResult
startActivityForResult(intent, CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE);}
//method to generate a FILE to store the image in with naming IMG_timestamp**.jpg
/** Create a File for saving an image */
private static File getOutputMediaFile(){// To be safe, you should check that the SDCard is mountedi
// using Environment.getExternalStorageState() before doing this.File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), "MyCameraApp");
// This location works best if you want the created images to be shared
// between applications and persist after your app has been uninstalled.// Create the storage directory if it does not exist
if (! mediaStorageDir.exists()){if (! mediaStorageDir.mkdirs()){
Log.d("MyCameraApp", "failed to create directory");
return null;
}
}
/ / Create a media file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());File mediaFile = new File(mediaStorageDir.getPath() + File.separator + "IMG_"+ timeStamp + ".jpg");
return mediaFile;
}
}
step 2: when camera App is done taking picture it will call onActivityResult -- this is where you call your method to process the image
//NOTE: parameter mCurrentPhotoPath is the path to the file stored on your phone containing the image --see above.
//camera App is done taking picture and returning to this application's Activity by calling the onActivityResult method
onActivityResult( int requestCode, int resultCode, Intent data) {
if (requestCode == CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE) //if returning from the request above to take picture
if (resultCode == RESULT_OK) { //if everything went okay
// PROCESS the image
Bitmap newBitMapImage = processImage(this.mCurrentPhotoPath);
//display the processed image if you wish in the Activites ImageView GUI widget referred to as mImageView
mImageView.setImageBitmap(bitmap); //display image we are working on in the ImageView Widget
} else if (resultCode == RESULT_CANCELED) {
// User cancelled the image capture -- do whatever is appropriate here
} else {
// Image capture failed, advise user -- do whatever is appropriate here
}
step 3: process the image by first read the file where image stored into a Bitmap then create your own processing routines
private BitMap processImage(String mCurrentPhotoPath) {
// Get the dimensions of the View - NOTE: assumes the Activity has a ImageView object mImageView
int targetW = mImageView.getWidth();
int targetH = mImageView.getHeight();
// Get the dimensions of the bitmap –NOTE: assumes mCurrentPhotoPath is location of image you took
BitmapFactory.Options bmOptions = new BitmapFactory.Options();
bmOptions.inJustDecodeBounds = true;
BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
int photoW = bmOptions.outWidth;
int photoH = bmOptions.outHeight;
// Determine how much to scale down the image
int scaleFactor = Math.min(photoW/targetW, photoH/targetH);
// Decode the image file into a Bitmap sized to fill the View
bmOptions.inJustDecodeBounds = false;
bmOptions.inSampleSize = scaleFactor;
bmOptions.inPurgeable = true;// READ in the picture we took prior to this method call from the mCurrentPhotoPath location
Bitmap bitmap = BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
//process the image as you wish
/* NOTE: bitmap.getWidth() = with get number of columns/width of imagebitmap.getHeight() = height/ number of rows of image
bitmap.getPixel(c,r) = pixel at row r and column cbitmap.setPixel(c,r) = set the pixel at row r and column c
*/
for(int i=0; i<bmp.getWidth(); i++){
for(int j=0; j<bmp.getHeight(); j++){
int p = bmp.getPixel(i, j); //do whatever you want with pixel p like p = ****** bitmap.setPixel(i,j,p);
} }
//Note rather that changing the values of bitmap you can create a second BitMap object and set its new pixel values to show the altered image that is up to you.
return bitmap;
}