https://sourceforge.net/p/mvacquire/home/Tutorial/Recent changes to TutorialenFri, 09 Dec 2011 12:52:09 -0000https://sourceforge.net/p/mvacquire/home/Tutorial/<pre></pre>Gregor ThalhammerFri, 09 Dec 2011 12:52:09 -0000https://sourceforge.net4369af9437892974ab70f368d43f52a01608e73ahttps://sourceforge.net/p/mvacquire/home/tutorial/**Please read tutorial.rst in the source code docs folder for up to date information!** # Tutorial The mv extension is designed to provide a very pythonic interface, such that it can be easily used in an interactive environment like an IPython shell. ## Initialization Necessary for all interaction is the :py:class:\`mv.DeviceManager\`. On loading the mv extension already creates an instance mv.dmg from mv import dmg ## Opening an imaging device In an IPython shell, try typing 'dmg.' and hit TAB: Installed devices (here: a BlueFOX USB camera and two virtual devices) are accessible as attributes of the device manager instance dmg. They are listed by their serial number. Acessing them opens a connection to the device, which is automatically closed when the object goes out of scope. More detailed information about the available devices is returned by :py:meth:\`DeviceManager.get\_device\_list\`. ## Getting an image Some background: For image acquisition the underlying C library uses so called 'request objects'. For each image one wants to acquire, such an request object needs to be placed into a 'request queue'. For this, use the :py:meth:\`\~mv.Device.image\_request\` method. After an image has been acquired (or an timeout elapsed), the request object is moved to the 'result queue'. To get a :py:class:\`\~mv.ImageResult\` object, use :py:meth:\`\~mv.Device.get\_image\`. This call blocks until a result is available, or raises an :py:exc:\`\~mv.MVTimeoutError\` if a given timeout has elapsed without a result getting ready. To actually get the image data, use :py:meth:\`\~mv.ImageResult.get\_buffer\`. This returns a \`memoryview\` object to a copy of the image data. From this you can obtain a \`numpy\` array with \`numpy.asarray\`. For subsequent image acquisition, the request object needs to be released, since only a limited number (default 4) of request objects is available. For this, free (delete) the image result object obtained by get\_image if you are done. A minimal command sequence might would be: dev.image_request() image_result = dev.get_image(timeout=1) #wait at most 1 second buf = image_result.get_buffer() del image_result img = np.asarray(buf) ## Changing camera settings *All* available settings (also called a :py:class:\`\~mv.Property\`) are organized in a tree like structure. They are accessible as attributes (of attributes of attributes...), e.g. >>> print dev.Setting.Base.Camera.Gain_dB 1.000 dB Code completion in ipython (with TAB key) displays a list of possible attributes while typing. Alternatively, you get a list of child settings with \`dir\` >>> dir(dev.Setting.Base.Camera) ['Aoi', 'BayerMosaicParity', 'ChannelBitDepth', 'FrameDelay_us', 'Gain_dB', 'ImageDirectory', 'ImageRequestTimeout_ms', 'ImageType', 'PixelFormat', 'PseudoFeatures', 'TapsXGeometry', 'TapsYGeometry', 'TestImageBarWidth', 'TestMode', 'UserData'] Accessing a setting as an attribute returns its value as Python int, long int, float, or bytes string, depending of the Property type. For changing the value of a setting use the :py:attr:\`\~mv.Property.value\` attribute: >>> testmv.dev.Setting.Base.Camera.Gain_dB.value = 10.0 >>> print testmv.dev.Setting.Base.Camera.Gain_dB 10.000 dB Setting a Property value with a string argument is also possible, this is especially useful for named integer properties.: >>> dev.Setting.Base.Camera.TestMode.value = 'MovingMonoRamp' >>> print dev.Setting.Base.Camera.TestMode MovingMonoRamp Gregor ThalhammerFri, 09 Dec 2011 12:44:17 -0000https://sourceforge.net31c60cf8b0f9613eda6079a78ad80d8e00c60fbb