I need to create an android application using OpenCV VideoCapture() method with python kivy framework. Please note I'm not going to use KivyCamera available on Kivy, because I need to draw some shapes on top of the video frame. I found a example from (Is there a way to integrate the imshow() function of OpenCV into kivy or kv file in python).Thanks for this Answer. However this is still not working after installing the APK in android phone, application launches but white background screen is displayed in camera section. This is working fine in windows PC. I tried videocapture(-1), videocapture(0), videocapture(1) nothing worked.
If somebody knows of an answer please help me.
main.py
import threading
from functools import partial
import cv2
from kivy.app import App
from kivy.clock import Clock
from kivy.graphics.texture import Texture
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
class MainScreen(Screen):
pass
class Manager(ScreenManager):
pass
Builder.load_string('''
<MainScreen>:
name: "Test"
FloatLayout:
Label:
text: "Webcam from OpenCV?"
pos_hint: {"x":0.0, "y":0.8}
size_hint: 1.0, 0.2
Image:
# this is where the video will show
# the id allows easy access
id: vid
size_hint: 1, 0.6
allow_stretch: True # allow the video image to be scaled
keep_ratio: True # keep the aspect ratio so people don't look squashed
pos_hint: {'center_x':0.5, 'top':0.8}
Button:
text: 'Stop Video'
pos_hint: {"x":0.0, "y":0.0}
size_hint: 1.0, 0.2
font_size: 50
on_release: app.stop_vid()
''')
class Main(App):
def build(self):
# start the camera access code on a separate thread
# if this was done on the main thread, GUI would stop
# daemon=True means kill this thread when app stops
threading.Thread(target=self.doit, daemon=True).start()
sm = ScreenManager()
self.main_screen = MainScreen()
sm.add_widget(self.main_screen)
return sm
def doit(self):
# this code is run in a separate thread
self.do_vid = True # flag to stop loop
# make a window for use by cv2
# flags allow resizing without regard to aspect ratio
cv2.namedWindow('Hidden', cv2.WINDOW_NORMAL | cv2.WINDOW_FREERATIO)
# resize the window to (0,0) to make it invisible
cv2.resizeWindow('Hidden', 0, 0)
# cv2.resizeWindow('Hidden', 200, 200)
cam = cv2.VideoCapture(0)
# start processing loop
while (self.do_vid):
ret, frame = cam.read()
# ...
# more code
# ...
# send this frame to the kivy Image Widget
# Must use Clock.schedule_once to get this bit of code
# to run back on the main thread (required for GUI operations)
# the partial function just says to call the specified method with the provided argument (Clock adds a time argument)
Clock.schedule_once(partial(self.display_frame, frame))
cv2.imshow('Hidden', frame)
cv2.waitKey(1)
cam.release()
cv2.destroyAllWindows()
def stop_vid(self):
# stop the video capture loop
self.do_vid = False
def display_frame(self, frame, dt):
# display the current video frame in the kivy Image widget
# create a Texture the correct size and format for the frame
texture = Texture.create(size=(frame.shape[1], frame.shape[0]), colorfmt='bgr')
# copy the frame data into the texture
texture.blit_buffer(frame.tobytes(order=None), colorfmt='bgr', bufferfmt='ubyte')
# flip the texture (otherwise the video is upside down
texture.flip_vertical()
texture.flip_horizontal()
# actually put the texture in the kivy Image widget
self.main_screen.ids.vid.texture = texture
if __name__ == '__main__':
Main().run()
buildozer.spec
[app]
title = OpenCVCam
package.name = opencvcam
package.domain = org.test
source.dir = .
source.include_exts = py,png,jpg,kv,atlas,xml
version = 0.1
requirements = python3,kivy,opencv,numpy,pyjnius,plyer,requests,urllib3,chardet,idna,pip,Image,PIL
orientation = portrait
# Android specific
fullscreen = 0
android.permissions = INTERNET, ACCESS_FINE_LOCATION, WRITE_EXTERNAL_STORAGE, READ_EXTERNAL_STORAGE, CAMERA
android.arch = armeabi-v7a
[buildozer]
log_level = 2
warn_on_root = 1
