mobile image processing part1

Mobile image processing – Part 1 Mobile application development on Android  Project 1: “Hello Image”, reading/writing/modifying images  Project 2: “Viewfinder EE368”, processing viewf

Mobile image processing – Part 1

 Mobile application development on Android

 Project 1: “Hello Image”, reading/writing/modifying images

 Project 2: “Viewfinder EE368”, processing viewfinder frames

 Project 3: “CVCamera”, utilizing OpenCV functions

 Mobile application examples

Mobile landmark recognition

Mobile product recognition

Popular mobile platforms

Symbian

Apple iOS

Windows 7

Nokia N97

Android

Samsung Galaxy Tab

Spotlight on Android

 Open source mobile platform developed by Google

 Supported by Open Handset Alliance

 13 mobile operators

 18 handset manufacturers

 20 semiconductor companies

 16 software makers

 Uses an open-source, customizable Linux kernel and a

virtual machine designed for mobile hardware

 Largest share of smartphone market in the US

 Android Market now contains over 250k apps

Android software stack

[ Professional Android

Application Development ]

Linux Kernel

Programming in Java

 Android encourages high-level development

 Android uses Java as the main programming language

 Inherits basic classes from conventional Java

 String, Container, Math, IO, Network

 Adds new classes specific to mobile devices

 Camera, Telephony, Map, GPS, Speech

Android programming with Eclipse

Eclipse IDE

Android SDK

Java Runtime

program installation

and execution

system messages

programmer inputs

data and

Class tutorials for Android (1)

 Android tutorials designed specifically for mobile image

processing in the EE368 class

 Tutorial #1: Basic Android Setup

 Image processing-oriented introduction to Android

 Explains how to download and install the different software

packages (JDK, SDK, Eclipse) on your own computer

 Shows how to build and run a viewfinder app that computes color histograms in real time

 Tutorial #2: OpenCV for Android Setup

 Builds on core skills developed in Tutorial #1

 Explains how to download and install OpenCV for Android

 Shows how to build a more advanced viewfinder app that computes various image feature keypoints supported by OpenCV

Class tutorials for Android (2)

http://ee368.stanford.edu/Android

Support for Windows, Macintosh, and Linux in both tutorials

Eclipse IDE

Project files

Class hierarchy Text editor

Errors and warnings

Different perspectives

Structure of an Android Project in Eclipse

Programmer-defined Java files

Program new functions here

Auto-generated Java files Don’t edit anything here

Android library Don’t edit anything here

Resource files Edit layout, define constants, import external media files, change program permissions Java Native Interface files

C/C++ code

“Hello Image” project

 Goals of this project

 Learn how to create a new Android project

 Learn how to read/write images from/to SD card

 Learn how to access and modify image bitmaps

 Full source available on class website:

 http://ee368.stanford.edu/Android/HelloImage

Recommended project settings (1)

Recommended project settings (2)

HelloImage Activity class (1)

public class HelloImage extends Activity {

Bitmap myBitmap;

ImageView myImageView;

public void onCreate(Bundle savedInstanceState) { … }

private void processImage() { … }

private void brighten(int offset) { … }

}

Subclass of Activity class

will be visible on the phone

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

String imageFileName = “ /sdcard/test_vga.jpg ”;

File imageFile = new File(imageFileName);

} }

}

HelloImage Activity class (2)

onCreate called when the

application first starts

Load image from SD card

Display image

in viewer

private void processImage() {

brighten(50);

try {

String outputPath = " /sdcard/test_vga_output.jpg ";

int quality = 75 ; FileOutputStream fileOutStr = new FileOutputStream(outputPath); BufferedOutputStream bufOutStr =

new BufferedOutputStream(fileOutStr);

myBitmap.compress(CompressFormat.JPEG, quality, bufOutStr);

bufOutStr.flush();

bufOutStr.close();

} catch (FileNotFoundException exception) {

Log.e(" debug_log ", exception.toString());

} catch (IOException exception) {

Log.e(" debug_log ", exception.toString());

}

myImageView.setImageBitmap(myBitmap);

}

HelloImage Activity class (3)

Apply some image processing operation on the stored bitmap

Save the processed image to the SD card

Catch exceptions Show the image on the display

private void brighten(int brightenOffset) {

// Create new array

int width = myBitmap.getWidth();

int height = myBitmap.getHeight();

int[] pix = new int[width * height];

myBitmap.getPixels(pix, 0 , width, 0 , 0 , width, height);

// Apply pixel-by-pixel change

int index = 0;

for (int y = 0; y < height; y++) { for (int x = 0; x < width; x++) {

int r = (pix[index] >> 16 ) & 0xff ; int g = (pix[index] >> 8 ) & 0xff ; int b = pix[index] & 0xff ;

r = Math.max( 0 , Math.min( 255 , r + brightenOffset));

g = Math.max( 0 , Math.min( 255 , g + brightenOffset));

b = Math.max( 0 , Math.min( 255 , b + brightenOffset));

pix[index++] = 0xff000000 | (r << 16 ) | (g << 8 ) | b;

} // x } // y

// Change bitmap to use new array

myBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);

HelloImage Activity class (4)

Extract RGB Values

Pack RGB Values

Running the program on an Android device

0123456789ABC

“Hello Image” application running on device

http://ee368.stanford.edu/Android/HelloImage

Class Project: Plant Leaf Classification

D Knight, J Painter, and M Potter, Spring 2010

http://ee368.stanford.edu/Project_10

Class Project: Jigsaw Puzzle Solver

Mobile image processing – Part 1

 Mobile application development on Android

 Project 1: “Hello Image”, reading/writing/modifying images

 Project 2: “Viewfinder EE368”, processing viewfinder frames

 Project 3: “CVCamera”, utilizing OpenCV functions

 Mobile application examples