android图像处理之灰度化

package com.scy.grayvalue2;import java.io.File;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.OutputStream;import android.os.Bundle;import android.os.Environment;import android.app.Activity;import android.graphics.Bitmap;import android.graphics.Bitmap.Config;import android.graphics.BitmapFactory;import android.util.Log;import android.view.Menu;import android.widget.ImageView;/** * 思路如下：      1.读取or照相，得到一张ARGB图片。      2.转化为bitmap类，并对其数据做如下操作：         A通道保持不变，然后逐像素计算：X = 0.3×R+0.59×G+0.11×B，并使这个像素的值新R，G，B值为X，即：         new_R = X, new_G = X, new_B = X         例如：原来一个像素是4个byte，分别为ARGB，现在这个像素应该为AXXX。       3.将上一步骤得到的bitmap图像写到输出流里面，并保存为图片。或者直接显示在ImageView上。 * @author scy * */public class MainActivity extends Activity {private byte[] rawData;private ImageView imageView;    @Override    public void onCreate(Bundle savedInstanceState)     {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        imageView = (ImageView)findViewById(R.id.image);        //将bitmap转换成一个伪灰度图，再转化成一个byte[]        //将byte[]转换为bitmap//Bitmap bitmapOrg = BitmapFactory.decodeByteArray(rawData, 0, rawData.length);        Bitmap bitmapOrg = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);Bitmap bitmapNew = bitmapOrg.copy(Config.ARGB_8888, true); //Bitmap bitmapNew = bitmapOrg.copy(Config.ARGB_8888, true);if(bitmapNew == null)Log.i("TAG", "null");Log.i("TAG", "copy end");/** * 一种简单的灰度化算法，但是这种方法需要修改每个点的像素，如果一张图片比较大，则这个处理速度就堪忧了 * 往往需要创建一个线程来处理 */        for(int i = 0;i<bitmapNew.getWidth();i++)        {        for(int j =0;j<bitmapNew.getHeight();j++)        {                int col = bitmapNew.getPixel(i, j);//获取点（i，j）处的像素                //分别获取ARGB的值                int alpha = col&0xFF000000;                int red = (col&0x00FF0000)>>16;                int green = (col&0x0000FF00)>>8;                int blue = (col&0x000000FF);                //用公式X = 0.3×R+0.59×G+0.11×B计算出X代替原来的RGB                int gray = (int)((float)red*0.3+(float)green*0.59+(float)blue*0.11);                //新的ARGB                int newColor = alpha|(gray<<16)|(gray<<8)|gray;                //在点（i,j）处设置新的像素                bitmapNew.setPixel(i, j, newColor);                //Log.v("tag",  Integer.toHexString(col));          }        }        Log.i("TAG", "pro end");        sendMsg(bitmapNew);        /*        File file = new File(Environment.getExternalStorageDirectory()+File.separator+"gray"+number+".jpg");        OutputStream out;try {out = new FileOutputStream(file);if(bitmapNew.compress(Bitmap.CompressFormat.JPEG, 100, out))Log.i("TAG", "success");out.close();} catch (FileNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();} */}private void sendMsg(Bitmap bitmapNew){imageView.setImageBitmap(bitmapNew);}}/** * drawableToBitmap *//* public static Bitmap drawableToBitmap(Drawable drawable) {                Bitmap bitmap = Bitmap                        .createBitmap(                                        drawable.getIntrinsicWidth(),                                        drawable.getIntrinsicHeight(),                                        drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888                                                        : Bitmap.Config.RGB_565);        Canvas canvas = new Canvas(bitmap);        //canvas.setBitmap(bitmap);        drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());        drawable.draw(canvas);        return bitmap;} *//** * Bitmap2Bytes *//* private byte[] Bitmap2Bytes(Bitmap bm) {ByteArrayOutputStream baos = new ByteArrayOutputStream(); bm.compress(Bitmap.CompressFormat.PNG, 100, baos);  return baos.toByteArray(); }*//** * Bytes2Bimap *//* private Bitmap Bytes2Bimap(byte[] b) {    if(b.length ==0)    {    return null;    }return BitmapFactory.decodeByteArray(b, 0, b.length);  }*/

最后介绍了几种图片转换方法。

下面是另外一种灰度化方法：

package com.scy.grayvalue;import java.io.File;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import android.os.Bundle;import android.app.Activity;import android.graphics.Bitmap;import android.graphics.Bitmap.Config;import android.graphics.BitmapFactory;import android.graphics.Canvas;import android.graphics.ColorMatrix;import android.graphics.ColorMatrixColorFilter;import android.graphics.Paint;import android.view.Menu;import android.widget.ImageButton;import android.widget.ImageView;public class MainActivity extends Activity  {private Bitmap bitmap,buffer;private ImageView imageView;    @Override    public void onCreate(Bundle savedInstanceState)     {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);                         bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);        buffer = convert2Gray(bitmap);       /*        //创建八位图        buffer = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Config.ARGB_8888);        //将八位图作为画布        Canvas canvas = new Canvas(buffer);        Paint paint = new Paint();        paint.setColorFilter(filter);                canvas.drawBitmap(buffer, 0, 0, paint);        canvas.save();         */        imageView = (ImageView)findViewById(R.id.image);        imageView.setImageBitmap(buffer);         /*        File file = new File("/mnt/1.jpg");        FileOutputStream os = null;        try{os = new FileOutputStream(file);bitmap.compress(Bitmap.CompressFormat.JPEG, 80, os);os.flush();os.close();} catch (FileNotFoundException e){e.printStackTrace();} catch (IOException e){e.printStackTrace();}*/                    }private Bitmap convert2Gray(Bitmap bitmap){        /**         *  [ a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t ] When applied to a color [r, g, b, a],          *  the resulting color is computed as (after clamping)          *  R' = a*R + b*G + c*B + d*A + e; G' = f*R + g*G + h*B + i*A + j;          *  B' = k*R + l*G + m*B + n*A + o; A' = p*R + q*G + r*B + s*A + t;          */        ColorMatrix colorMatrix = new ColorMatrix();        /**         * Set the matrix to affect the saturation(饱和度) of colors.          * A value of 0 maps the color to gray-scale（灰阶）. 1 is identity         */        colorMatrix.setSaturation(0);        ColorMatrixColorFilter filter = new ColorMatrixColorFilter(colorMatrix);                Paint paint = new Paint();        paint.setColorFilter(filter);                Bitmap result = bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Config.ARGB_8888);        Canvas canvas = new Canvas(result);        canvas.drawBitmap(bitmap, 0, 0, paint);        return result;}}