Saturday, June 25, 2016

OpenGL and OpenCV with python 2.7 - part 002.

I deal today with opencv and I fix some of my errors.
One is this error I got with cv2.VideoCapture. When I  try to used with load video and createBackgroundSubtractorMOG2() i got this:

cv2.error:   C:\builds\master_PackSlaveAddon-win64-vc12-static\opencv\modules\highgui\src\window.cpp:281:  error: (-215) size.width<0 amp="" cv::imshow="" function="" i="" in="" size.height="">
You need also to have opencv_ffmpeg310.dll and opencv_ffmpeg310_64.dll into your Windows C:\Windows\System32, this will help me to play videos.
Now make sure you have the opencv version 3.1.0 because opencv come with some changes over python.
C:\Python27\python
Python 2.7.8 (default, Jun 30 2014, 16:08:48) [MSC v.1500 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>import cv2
>>>print cv2.__version__
3.1.0

You can take some infos from about opencv python module - cv2 with:

>>>cv2.getBuildInformation()
...
>>>cv2.getCPUTickCount()
...
>>>print cv2.getNumberOfCPUs()
...
>>>print cv2.ocl.haveOpenCL()
True

You can also see some error by disable OpenCL:

>>>cv2.ocl.setUseOpenCL(False)
>>>print cv2.ocl.useOpenCL()
False

Now will show you how to use webcam gray and color , and play one video:
webcam color

import numpy as np
import cv2
cap = cv2.VideoCapture(0)
while(True):
    ret, frame = cap.read()
    cv2.imshow('frame',frame)
    if 0xFF & cv2.waitKey(5) == 27:
        break
cap.release()
cv2.destroyAllWindows()

webcam gray

import numpy as np
import cv2
cap = cv2.VideoCapture(0)
while(True):
    ret, frame = cap.read()
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    cv2.imshow('frame',gray)
    if 0xFF & cv2.waitKey(5) == 27:
        break
cap.release()
cv2.destroyAllWindows()

play video

import cv2
from cv2 import *
capture = cv2.VideoCapture("avi_test_001.avi")
while True:
    ret, img = capture.read()
    cv2.imshow('some', img)
    if 0xFF & cv2.waitKey(5) == 27:
        break
cv2.destroyAllWindows()


Wednesday, June 22, 2016

OpenGL and OpenCV with python 2.7 - part 001.

First you need to know what version of python you use.
C:\Python27>python
Python 2.7.8 (default, Jun 30 2014, 16:08:48) [MSC v.1500 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>

You need also to download the OpenCV version 3.0 from here.
Then run the executable into your folder and get cv2.pyd file from \opencv\build\python\2.7\x64 and paste to \Python27\Lib\site-packages.
If you use then use 32 bit python version then use this path: \opencv\build\python\2.7\x86.
Use pip to install next python modules:
C:\Python27\Scripts>pip install PyOpenGL
...
C:\Python27\Scripts>pip install numpy
...
C:\Python27\Scripts>pip install matplotlib
...

Let's see how is working OpenGL:
C:\Python27>python
Python 2.7.8 (default, Jun 30 2014, 16:08:48) [MSC v.1500 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import OpenGL
>>> import numpy
>>> import matplotlib
>>> import cv2
>>> from OpenGL import *
>>> from numpy import *
>>> from matplotlib import *
>>> from cv2 import *

You can also use dir(module) to see more. You can import all from GL, GLU and GLUT.
>>> dir(OpenGL)
['ALLOW_NUMPY_SCALARS', 'ARRAY_SIZE_CHECKING', 'CONTEXT_CHECKING', 'ERROR_CHECKING', 'ERROR_LOGGING', 'ERROR_ON_COPY', 'FORWARD_COMPATIBLE_ONLY', 'FULL_LOGGING', 'FormatHandler', 'MODULE_ANNOTATIONS', 'PlatformPlugin', 'SIZE_1_ARRAY_UNPACK', 'STORE_POINTERS', 'UNSIGNED_BYTE_IMAGES_AS_STRING', 'USE_ACCELERATE', 'WARN_ON_FORMAT_UNAVAILABLE', '__builtins__', '__doc__', '__file__', '__name__', '__package__', '__path__', '__version__', '_bi', 'environ_key', 'os', 'plugins', 'sys', 'version']
>>> from OpenGL.GL import *
>>> from OpenGL.GLU import *
>>> from OpenGL.GLUT import *
>>> from OpenGL.WGL import *

If you are very good with python OpenGL module then you can import just like this example:
>>> from OpenGL.arrays import ArrayDatatype
>>> from OpenGL.GL import (GL_ARRAY_BUFFER, GL_COLOR_BUFFER_BIT,
... GL_COMPILE_STATUS, GL_FALSE, GL_FLOAT, GL_FRAGMENT_SHADER,
... GL_LINK_STATUS, GL_RENDERER, GL_SHADING_LANGUAGE_VERSION,
... GL_STATIC_DRAW, GL_TRIANGLES, GL_TRUE, GL_VENDOR, GL_VERSION,
... GL_VERTEX_SHADER, glAttachShader, glBindBuffer, glBindVertexArray,
... glBufferData, glClear, glClearColor, glCompileShader,
... glCreateProgram, glCreateShader, glDeleteProgram,
... glDeleteShader, glDrawArrays, glEnableVertexAttribArray,
... glGenBuffers, glGenVertexArrays, glGetAttribLocation,
... glGetProgramInfoLog, glGetProgramiv, glGetShaderInfoLog,
... glGetShaderiv, glGetString, glGetUniformLocation, glLinkProgram,
... glShaderSource, glUseProgram, glVertexAttribPointer)

Most of this OpenGL need to have a valid OpenGL rendering context.
For example you can test it with WGL ( WGL or Wiggle is an API between OpenGL and the windowing system interface of Microsoft Windows):
>>> import OpenGL
>>> from OpenGL import *
>>> from OpenGL import WGL
>>> print WGL.wglGetCurrentDC()
None

Now , let's see the OpenCV python module with s=one simple webcam python script:
import numpy as np
import cv2
cap = cv2.VideoCapture(0)
while(True):
    ret, frame = cap.read()
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    cv2.imshow('frame',gray)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break
cap.release()
cv2.destroyAllWindows()
This is result of my webcam: