How to remove the frame of a photo taken with android studio

The problem I have is that when you take a photo from my application and I proceed to save it, it is stored with a frame on the sides.

I wanted to know how I can delete this framework.

I leave my code

private void openCameraIntent() {
    Intent pictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    if (pictureIntent.resolveActivity(getPackageManager()) != null) {

        File photoFile = null;
        try {
            photoFile = createImageFile();
        } catch (IOException e) {
            e.printStackTrace();
            return;
        }
        Uri photoUri = FileProvider.getUriForFile(this, getPackageName() + ".provider", photoFile);
        pictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoUri);
        ivimagen.setImageURI(Uri.parse(imageFilePath));
        ivimagen.buildDrawingCache();
        startActivityForResult(pictureIntent, 1);
    }
}

private File createImageFile() throws IOException {
    // Create an image file name
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    String imageFileName = "JPEG_" + timeStamp + "_";
    File storageDir = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
    File image = File.createTempFile(
            imageFileName,  /* prefix */
            ".jpg",         /* suffix */
            storageDir      /* directory */
    );

    // Save a file: path for use with ACTION_VIEW intents
    imageFilePath = image.getAbsolutePath();
    return image;
}