Camera parameters have no effect

The following is my code, i need to have a solarized effect but the parameter's not getting set.What could be the problem??

package com.android;

import java.io.IOException;
import java.util.List;

import android.app.Activity;
import android.content.Intent;
import android.content.res.Configuration;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.PixelFormat;
import android.hardware.Camera;
import android.hardware.Camera.PictureCallback;
import android.hardware.Camera.Size;
import android.os.Bundle;
import android.util.Log;
import android.view.Surface;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Button;

public class CameraActivity extends Activity implements SurfaceHolder.Callback{
private Camera camera=null;
private SurfaceHolder surfaceHolder = null;
private boolean previewRunning = false;
private Button btnDone,btnCapture,btnRetake;
private Bitmap mBitmap;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().setFormat(PixelFormat.TRANSLUCENT);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.camera_screen);
SurfaceView surfaceView = (SurfaceView) findViewById(R.id.surface);
surfaceHolder = surfaceView.getHolder();
surfaceHolder.addCallback(this);
surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
surfaceHolder.setFixedSize(getWindow().getWindowManager()
.getDefaultDisplay().getWidth(), getWindow().getWindowManager()
.getDefaultDisplay().getHeight());

btnCapture =(Button) findViewById(R.id.btnCapture);
btnDone =(Button) findViewById(R.id.btnDone);
btnDone.setVisibility(View.INVISIBLE);
btnRetake =(Button) findViewById(R.id.btnRetake);
btnRetake.setVisibility(View.INVISIBLE);

btnCapture.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
btnDone.setVisibility(View.VISIBLE);
btnRetake.setVisibility(View.VISIBLE);
btnCapture.setVisibility(View.INVISIBLE);
camera.takePicture(null, picCalBac, picCalBac);
}
});

btnDone.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent=new Intent(CameraActivity.this,BrailleReaderActivity.class).putExtra("mBitmap",mBitmap);
startActivity(intent);
finish();
}
});

btnRetake.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (previewRunning) {
camera.stopPreview();
}
Camera.Parameters parameters = camera.getParameters();
parameters.setColorEffect(Camera.Parameters.EFFECT_SOLARIZE);
camera.setParameters(parameters);
try {
camera.setPreviewDisplay(surfaceHolder);
} catch (IOException e) {
Log.d("IOException", e.getMessage());
}
camera.startPreview();
previewRunning = true;
btnDone.setVisibility(View.INVISIBLE);
btnRetake.setVisibility(View.INVISIBLE);
btnCapture.setVisibility(View.VISIBLE);
}
});
}

Camera.PictureCallback picCalBac = new PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
if (data != null) {
mBitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
}
}
};

@Override
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
if (previewRunning) {
camera.stopPreview();
}
Camera.Parameters parameters = camera.getParameters();
List<Size> sizes = parameters.getSupportedPreviewSizes();
Size optimalSize = getOptimalPreviewSize(sizes, w, h);
parameters.setPreviewSize(optimalSize.width, optimalSize.height);
parameters.setColorEffect(Camera.Parameters.EFFECT_SOLARIZE);

setCameraDisplayOrientation(CameraActivity.this,0,camera);

camera.setParameters(parameters);
try {
camera.setPreviewDisplay(surfaceHolder);
} catch (IOException e) {
Log.d("IOException", e.getMessage());
}
camera.startPreview();
previewRunning = true;
}

public static void setCameraDisplayOrientation(Activity activity,
int cameraId, android.hardware.Camera camera) {
android.hardware.Camera.CameraInfo info =
new android.hardware.Camera.CameraInfo();
android.hardware.Camera.getCameraInfo(cameraId, info);
int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();
int degrees = 0;
switch (rotation) {
case Surface.ROTATION_0: degrees = 0; break;
case Surface.ROTATION_90: degrees = 90; break;
case Surface.ROTATION_180: degrees = 180; break;
case Surface.ROTATION_270: degrees = 270; break;
}

int result;
if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
result = (info.orientation + degrees) % 360;
result = (360 - result) % 360; // compensate the mirror
} else { // back-facing
result = (info.orientation - degrees + 360) % 360;
}
camera.setDisplayOrientation(result);
}


private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) {
final double ASPECT_TOLERANCE = 0.05;
double targetRatio = (double) w / h;
if (sizes == null) return null;

Size optimalSize = null;
double minDiff = Double.MAX_VALUE;

int targetHeight = h;

// Try to find an size match aspect ratio and size
for (Size size : sizes) {
double ratio = (double) size.width / size.height;
if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue;
if (Math.abs(size.height - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
}
}

// Cannot find the one match the aspect ratio, ignore the requirement
if (optimalSize == null) {
minDiff = Double.MAX_VALUE;
for (Size size : sizes) {
if (Math.abs(size.height - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
}
}
}
return optimalSize;
}

@Override
public void surfaceCreated(SurfaceHolder arg0) {
camera = Camera.open(0);
}

@Override
public void surfaceDestroyed(SurfaceHolder arg0) {
camera.stopPreview();
previewRunning = false;
camera.release();
}
}