Face detection not working in android studio - python-3.x

Question

I'm new to android studio and want to do face detection. The face detector code uses opencv and is written in python. I'm using chaquopy as the python SDK. When i run the app, the face is not detected. It is not showing any error also. Can someone help me out. Below is my MainActivity.java code:
public class MainActivity extends AppCompatActivity {
Button btn;
ImageView iv;
// now take bitmap and bitmap drawable to get image from image view
BitmapDrawable drawable;
Bitmap bitmap;
String imageString="";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn = (Button)findViewById(R.id.submit);
iv = (ImageView)findViewById(R.id.image_view);
if(!Python.isStarted())
Python.start(new AndroidPlatform(this));
final Python py = Python.getInstance();
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// on click over button, get image from image view
drawable = (BitmapDrawable)iv.getDrawable();
bitmap = drawable.getBitmap();
imageString = getStringImage(bitmap);
// now in imagestring, we get encoded image string
// now pass this input string to python script
PyObject pyo = py.getModule("myscript");
// calling the main function in python code and passing image string as parameter
PyObject obj = pyo.callAttr("main", imageString);
// obj will return value ie. our image string
String str = obj.toString();
// convert it to byte array
byte data[] = android.util.Base64.decode(str, android.util.Base64.DEFAULT);
// now convert it to bitmap
Bitmap bmp = BitmapFactory.decodeByteArray(data, 0, data.length);
//now set this bitmap to imageview
iv.setImageBitmap(bmp);
}
});
}
// function to convert this image into byte array and finally into base 64 string
private String getStringImage(Bitmap bitmap) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);
// store in byte array
byte[] imageBytes = baos.toByteArray();
// finally encode to string
String encodedImage = android.util.Base64.encodeToString(imageBytes, android.util.Base64.DEFAULT); // Base64.DEFAULT
return encodedImage;
}
}
and the below shown is my python script "myscript.py"
import numpy as np
import cv2
import io
from PIL import Image
import base64
import face_recognition
def main(data):
decoded_data = base64.b64decode(data)
np_data = np.fromString(decoded_data, np.uint8)
img = cv2.imdecode(np_data, cv2.IMREAD_UNCHANGED)
img_rgb = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
img_gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
face_locations = face_recognition.face_locations(img_gray)
for(top,right,bottom,left) in face_locations:
cv2.rectangle(img_rgb, (left,top),(right,bottom),(0,0,255),8)
# convert this image to PIL
pil_im = Image.fromarray(img_rgb)
#convert this image to byte
buff = io.BytesIO()
pil_im.save(buff, format="PNG")
#converting to base64
img_str = base64.b64encode(buff.getvalue())
return ""+str(img_str, 'utf-8')
My minSdkVersion is 16 and targetSdkVersion is 30.
I'm not understanding what is the problem with this code. Can someone help me.
Thanks in advance.