ParameterValue<OverviewPolicy> policy = AbstractGridFormat.OVERVIEW_POLICY
            .createValue();
    policy.setValue(OverviewPolicy.IGNORE);

    // this will basically read 4 tiles worth of data at once from the disk...
    ParameterValue<String> gridsize = AbstractGridFormat.SUGGESTED_TILE_SIZE.createValue();

    // Setting read type: use JAI ImageRead (true) or ImageReaders read methods (false)
    ParameterValue<Boolean> useJaiRead = AbstractGridFormat.USE_JAI_IMAGEREAD.createValue();
    useJaiRead.setValue(true);

    GridCoverage2D image = new GeoTiffReader(f).read(new GeneralParameterValue[]{policy, gridsize, useJaiRead});
    /**
     * reproject to WGS84
     */
    CoordinateReferenceSystem targetCRS = CRS.decode("EPSG:4326");
    image = (GridCoverage2D) Operations.DEFAULT.resample(image, targetCRS);

    GridGeometry2D geometry = image.getGridGeometry();

    BufferedImage img = ImageIO.read(f);
    WritableRaster raster = img.getRaster();