How to use ZXing ("Zebra Crossing") library to get the location of three finder patterns (QR code)?

I am using the ZXing library to get information about the location of QR code.

Follow the javadoc[1], I import package: "com.google.zxing.qrcode.detector" and using class "FinderPatternInfo" in this package to get the location of QR code in pixel coordinate.

But, I don't know how to set up parameters of "FinderPatternInfo" class!!!

Code matlab version 2016a (javaclasspath add to matlab classpath.txt):

import com.google.zxing.qrcode.*;
import com.google.zxing.client.j2se.*;
import com.google.zxing.*;
import com.google.zxing.common.*;
import com.google.zxing.client.result.*;
import com.google.zxing.qrcode.detector.*;

jimg = im2java2d(img);                              % convert image to java
source = BufferedImageLuminanceSource(jimg);        % convert image to luminance source
bitmap = BinaryBitmap(HybridBinarizer(source));     % local threshold before convert image to bitmap

fp1 = FinderPattern;
P1 = fp1.getEstimatedModuleSize(bitmap);
disp(P1)

Thanks a lot!

[1] https://zxing.github.io/zxing/apidocs/