diff --git a/README.md b/README.md
index b669dac..f86ae12 100644
--- a/README.md
+++ b/README.md
@@ -6,35 +6,33 @@ Overview
 
 This is the python3 wrapper for AprilTag implemented in cv2cg.
 
-Currently it is tested under Windows10(VC2017, x64), OpenCV3.4.7(official prebuilt version), and python3.6 in Anaconda3.
+Currently it is tested under Windows10(VC2017, x64)/Ubuntu 18.04, OpenCV3.4.7(official prebuilt version),
+and python3.7/3.6 in Anaconda3.
 
 Version
 -------
 
-0.0.4
+0.0.5
 
 Installation
 ------------
 
 ### Install from Pip
 
-For Linux and Windows users, simply run the following command:   
+For Linux and Windows users, download the proper wheel file from https://github.com/ai4ce/pyAprilTag/releases,
+then simply run the following command under the same folder of the wheel file to install:   
 ```
-pip install pyAprilTag
-python -m pyAprilTag.demo
-# expected output:
-#[ 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
-# 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39]
+pip install pyAprilTag-0.0.4-cp37-cp37m-win_amd64.whl
 ```
 
 ### Install by Compiling from Source
 
-For Mac users, you need to compile from source. **First install the C++ version of OpenCV 3.4.x.**
-Then: 
+Following is for Mac users who need to compile from source, or other users who want to try installing from source. 
 
-0. clone repository recursively:   
+0. clone repository **recursively**, and install pre-built opencv 3.4.7 for python from conda-forge:   
     ```
     git clone --recursive https://github.com/ai4ce/pyAprilTag.git
+    conda install -c conda-forge opencv=3.4.7
     ```
 
 1. prepare your build environment:   
@@ -44,18 +42,26 @@ Then:
     "C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Auxiliary\Build\vcvars64.bat"
     ```
 
-2. **Check the setup.py file, modify the OpenCV include and libs path according to your system.**   
-
-3. compile the project:   
+2. compile the project and you are done:   
     ```
     pip install -e .
     ```
+   
+Usage
+-----
 
-4. Enjoy!   
-    ```
-    python -m pyAprilTag.demo
-    ```
+```
+python -m pyAprilTag.demo
+# expected output:
+#[ 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
+# 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39]
 
+python -m pyAprilTag.demo_plt
+python -m pyAprilTag.demo_calib
+python -m pyAprilTag.demo_calib_by_photo #remember to remove the calib_log folder in the current working directory
+python -m pyAprilTag.vdemo_cv
+python -m pyAprilTag.vdemo_plt
+```
 
 Contact
 -------
diff --git a/python/pyAprilTag/vdemo_cv.py b/python/pyAprilTag/vdemo_cv.py
index 3ed305c..876d4fa 100644
--- a/python/pyAprilTag/vdemo_cv.py
+++ b/python/pyAprilTag/vdemo_cv.py
@@ -29,6 +29,7 @@
 
 # Read until video is completed
 cnt = 0
+cv2.namedWindow('Frame', cv2.WINDOW_NORMAL)
 while cap.isOpened():
     # Capture frame-by-frame
     ret, frame = cap.read()
diff --git a/setup.py b/setup.py
index b36d52b..ec8ea00 100644
--- a/setup.py
+++ b/setup.py
@@ -38,9 +38,11 @@ def get_conda_opencv_info(sys_name):
     except ImportError as e:
         print(str(e))
         print('Please install opencv for python in your current Anaconda environment via the following:\n'
-              'conda install -c conda-forge opencv')
+              'conda install -c conda-forge opencv=3.4.7')
         exit(-1)
 
+    assert(cv2.getVersionMajor() == 3) #currently we do not support opencv4
+
     if sys_name == 'Linux':
         opencv_lib_dir = os.path.abspath(os.path.join(os.path.dirname(cv2.__file__), *(['..'] * 2)))
         available_opencv_libs = glob.glob(os.path.join(opencv_lib_dir, 'libopencv*.so'))
@@ -60,14 +62,18 @@ def get_conda_opencv_info(sys_name):
     available_opencv_libs = [os.path.splitext(os.path.basename(it))[0].lstrip('lib')
                              for it in available_opencv_libs]
 
-    opencv_libs = [lib for lib in required_opencv_modules if lib in available_opencv_libs]
+    if sys_name == 'Windows':
+        opencv_libs = [lib for lib in available_opencv_libs
+                       if any([lib.startswith(it) for it in required_opencv_modules])]
+    else:
+        opencv_libs = [lib for lib in required_opencv_modules if lib in available_opencv_libs]
     return opencv_lib_dir, opencv_inc_dir, opencv_libs
 
 sys_name = platform.system()
 opencv_lib_dir, opencv_inc_dir, opencv_libs = get_conda_opencv_info(sys_name)
-# print(opencv_lib_dir)
-# print(opencv_inc_dir)
-# print(opencv_libs)
+print(opencv_lib_dir)
+print(opencv_inc_dir)
+print(opencv_libs)
 
 extensions = [
 Extension('pyAprilTag._apriltag',
@@ -82,7 +88,7 @@ def get_conda_opencv_info(sys_name):
 
 setup(
     name="pyAprilTag",
-    version="0.0.4",
+    version="0.0.5",
     author="Chen Feng",
     author_email="cfeng@nyu.edu",
     description="python wrapper for AprilTag implemented in library cv2cg",
@@ -92,6 +98,7 @@ def get_conda_opencv_info(sys_name):
     package_data={'pyAprilTag': ['data/*.png', 'data/**/*']},
     include_package_data=True,
     license="BSD",
-    cmdclass={'build_ext': BuildExt},
-    ext_modules=cythonize(extensions, compiler_directives={'language_level' : sys.version_info[0]})
+    cmdclass={'build_ext': build_ext if sys_name=='Windows' else BuildExt},
+    ext_modules=cythonize(extensions, compiler_directives={'language_level' : sys.version_info[0]}),
+    install_requires=['opencv>2,<4',]
 )
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