本文将介绍C/S模式的图像处理系统。C/S的框架已经在[1]中作了简单的介绍。[2]中介绍了如何搭建基于android和WAMP5的B/S模式的本机测试平台。本系统是在[4]中介绍的基础上开发的，有关图像显示和本地图像处理的框架可以参看[4];
@author:郑海波 zhb931706659@126.com
转载请声明：http://blog.csdn.net/nuptboyzhb/article/details/7945249
实验结果展示：（图像的DCT变换）
实验平台：
服务器：Windows 7+Apache+MySQL+PHP
客户端：Android
开发工具：Eclipse+ADT+AVD
我们先看客户端(Client)的android开发
1.图像处理框架：
本次试验的图像处理框架我们依然使用[4]的实验平台。该实验平台已经实现了图像的打开，保存，摄像，截屏，显示和简单的图像处理算法等功能。
我们本次试验，需要用到该框架的图像打开，显示，保存等基本功能。
2.客户端的核心
在客户端，C/S模式的核心就是如何将本机数据发送到服务器，并从服务器中下载处理完后的数据。由于连接服务器，发送，接收等需要较长时间，因此
我们将其过程封装到一个AsyncTask派生的类中，代码如下：
[java code]
public class ServerTask extends AsyncTask<String, Integer , Void>
{
public byte[] dataToServer;
//Task state
private final int UPLOADING_PHOTO_STATE = 0;
private final int SERVER_PROC_STATE = 1;
private ProgressDialog dialog;
//upload photo to server
HttpURLConnection uploadPhoto(FileInputStream fileInputStream)
{
//final String serverFileName = "test"+ (int) Math.round(Math.random()*1000) + ".jpg";
final String serverFileName = "test.jpg";
final String lineEnd = "\r\n";
final String twoHyphens = "--";
final String boundary = "*****";
Log.e("msg","begin HttpURLConnection......");
try
{
URL url = new URL(SERVERURL);
// Open a HTTP connection to the URL
final HttpURLConnection conn = (HttpURLConnection)url.openConnection();
// Allow Inputs
conn.setDoInput(true);
// Allow Outputs
conn.setDoOutput(true);
// Don't use a cached copy.
conn.setUseCaches(false);
// Use a post method.
conn.setRequestMethod("POST");
conn.setRequestProperty("Connection", "Keep-Alive");
conn.setRequestProperty("Content-Type", "multipart/form-data;boundary="+boundary);
DataOutputStream dos = new DataOutputStream( conn.getOutputStream() );
dos.writeBytes(twoHyphens + boundary + lineEnd);
dos.writeBytes("Content-Disposition: form-data; name=\"uploadedfile\";filename=\"" + serverFileName +"\"" + lineEnd);
dos.writeBytes(lineEnd);
// create a buffer of maximum size
int bytesAvailable = fileInputStream.available();
int maxBufferSize = 1024;
int bufferSize = Math.min(bytesAvailable, maxBufferSize);
byte[] buffer = new byte[bufferSize];
// read file and write it into form...
int bytesRead = fileInputStream.read(buffer, 0, bufferSize);
while (bytesRead > 0)
{
dos.write(buffer, 0, bufferSize);
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable, maxBufferSize);
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
}
// send multipart form data after file data...
dos.writeBytes(lineEnd);
dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);
publishProgress(SERVER_PROC_STATE);
// close streams
fileInputStream.close();
dos.flush();
Log.e("msg","upload finished!");
return conn;
}
catch (MalformedURLException ex){
Log.e(TAG, "error: " + ex.getMessage(), ex);
return null;
}
catch (IOException ioe){
Log.e(TAG, "error: " + ioe.getMessage(), ioe);
return null;
}
}
//get image result from server and display it in result view
void getResultImage(HttpURLConnection conn){
// retrieve the response from server
InputStream is;
try {
is = conn.getInputStream();
//get result image from server
resultForWebImage = BitmapFactory.decodeStream(is);
is.close();
IsShowingResult = true;
Log.d("msg","download finished!");
} catch (IOException e) {
Log.e(TAG,"getResultImage:"+e.toString());
e.printStackTrace();
}
}
//Main code for processing image algorithm on the server
void processImage(String inputImageFilePath){
publishProgress(UPLOADING_PHOTO_STATE);
File inputFile = new File(inputImageFilePath);
try {
//create file stream for captured image file
FileInputStream fileInputStream = new FileInputStream(inputFile);
//upload photo
final HttpURLConnection conn = uploadPhoto(fileInputStream);
//get processed photo from server
if (conn != null){
getResultImage(conn);
//String download="http://10.10.145.154/EE368_Android_Tutorial3_Server/computeSIFTOnSCIEN.php";
}
fileInputStream.close();
}
catch (FileNotFoundException ex){
Log.e(TAG, "processImage"+ex.toString());
}
catch (IOException ex){
Log.e(TAG, "processImage"+ex.toString());
}
}
public ServerTask() {
dialog = new ProgressDialog(SystemMain.this);
}
protected void onPreExecute() {
this.dialog.setMessage("Photo captured");
this.dialog.show();
}
@Override
protected Void doInBackground(String... params) { //background operation
String uploadFilePath = params[0];
processImage(uploadFilePath);
//release camera when previous image is processed
mCameraReadyFlag = true;
return null;
}
//progress update, display dialogs
@Override
protected void onProgressUpdate(Integer... progress) {
if(progress[0] == UPLOADING_PHOTO_STATE){
dialog.setMessage("Uploading");
dialog.show();
}
else if (progress[0] == SERVER_PROC_STATE){
if (dialog.isShowing()) {
dialog.dismiss();
}
dialog.setMessage("Processing");
dialog.show();
}
}
@Override
protected void onPostExecute(Void param) {
if (dialog.isShowing()) {
dialog.dismiss();
if(IsShowingResult){
ShowImage(resultForWebImage, 2);
IsShowingResult=false;
}
}
}
}
此时，我们只需要在适当的时候，启动这个任务。当用户点击send按钮时，启动服务：
[java code]
sendBtnListener=new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if(myBitmap!=null){
mClientForWeb.compressByteImage(myBitmap, 75);;
ServerTask task = new ServerTask();
Log.e("msg","new ServerTask finished!");
task.execute(Environment.getExternalStorageDirectory().toString() +mClientForWeb.INPUT_IMG_FILENAME);
}
}
};
服务器端的PHP代码和matlab代码
1.服务器端的执行流程
首先，PHP获取到客户端发送过来的数据，然后在PHP中调用matlab代码对数据进行处理。PHP将处理后的结果再发回给客户端
2.本次试验
本次试验我们将实现图像的DCT变换。也即是：对客户端发送的图像做DCT变换，然后将变换后的图像发回给客户端。
如下图：
[图]
3.matlab的执行方式
我们用命令行的方式执行matlab代码，参见[3]。在PHP中，我们只需要用exec函数调用相应的指令即可。
4.PHP代码
[php code]
<?php
#-------------------------------------------
# EE368 Digital Image Processing
# Android Tutorial #3: Server-Client Interaction Example for Image Processing
# Author: Derek Pang (dcypang@stanford.edu), David Chen (dmchen@stanford.edu)
#------------------------------------------
#function for streaming file to client
function streamFile($location, $filename, $mimeType='application/octet-stream')
{ if(!file_exists($location))
{ header ("HTTP/1.0 404 Not Found");
return;
}
$size=filesize($location);
$time=date('r',filemtime($location));
#html response header
header('Content-Description: File Transfer');
header("Content-Type: $mimeType");
header('Cache-Control: public, must-revalidate, max-age=0');
header('Pragma: no-cache');
header('Accept-Ranges: bytes');
header('Content-Length:'.($size));
header("Content-Disposition: inline; filename=$filename");
header("Content-Transfer-Encoding: binary\n");
header("Last-Modified: $time");
header('Connection: close');
ob_clean();
flush();
readfile($location);
}
#**********************************************************
#Main script
#**********************************************************
#<1>set target path for storing photo uploads on the server
$photo_upload_path = "./upload/";
$photo_upload_path = $photo_upload_path. basename( $_FILES['uploadedfile']['name']);
#<2>set target path for storing result on the server
$processed_photo_output_path = "./output/processed_";
$processed_photo_output_path = $processed_photo_output_path. basename( $_FILES['uploadedfile']['name']);
$downloadFileName = 'processed_' . basename( $_FILES['uploadedfile']['name']);
#<3>modify maximum allowable file size to 10MB and timeout to 300s
ini_set('upload_max_filesize', '10M');
ini_set('post_max_size', '10M');
ini_set('max_input_time', 300);
ini_set('max_execution_time', 300);
#<4>Get and stored uploaded photos on the server
if(copy($_FILES['uploadedfile']['tmp_name'], $photo_upload_path)) {
#<5> execute matlab image processing algorithm
#example: Compute and display SIFT features using VLFeat and Matlab
$command = "matlab -nojvm -nodesktop -nodisplay -r \"ImageDCT('$photo_upload_path','$processed_photo_output_path');exit\"";
exec($command);
#<6>stream processed photo to the client
streamFile($processed_photo_output_path, $downloadFileName,"application/octet-stream");
} else{
echo "There was an error uploading the file to $photo_upload_path !";
}
?>
5.Matlab代码(实现DCT变换)
[matlab code]
function ImageDCT(input_img_path, output_img_path)
%-----------------------------------------
% @Author: ZhengHaibo zhb931706659@126.com
% Android Tutorial : Server-Client Communication
%------------------------------------------
% INPUT:
% input_img_path - input image path
% output_img_path - output image path
%------------------------------------------
tic;
if nargin < 2
input_img_path =('./upload/test.jpg');
output_img_path =('./output/test.jpg');
end
if(isempty(input_img_path))
input_img_path =('./upload/test.jpg');
end
if(isempty(output_img_path))
output_img_path =('./output/test.jpg');
end
% --------------------------------
% Load an image
% --------------------------------
InputImg = imread(input_img_path);
GrayInputImg=rgb2gray(InputImg);
DCT_Result=dct2(GrayInputImg)*4;
imwrite(uint8(DCT_Result), output_img_path,'Quality',100);
toc
end
实验结果展示：
[图]
Reference:
[1]PHP学习之初：基本语法 http://blog.csdn.net/nuptboyzhb/article/details/7912483
[2]基于android和WAMP5的B/S模式的本机测试平台（android+web）
http://blog.csdn.net/nuptboyzhb/article/details/7932234
[3]命令行方式执行matlab代码 :http://blog.csdn.net/nuptboyzhb/article/details/7943910
[4]Android图像处理系统1.4图像的锐化-边缘检测 :http://blog.csdn.net/nuptboyzhb/article/details/7926735
[5]斯坦福大学EE368实验室：http://www.stanford.edu/class/ee368/index.html