Reset properties while acquisition in Hamamatsu camera service

[erinpougheon]

Fixes #194.

Changing the Hamamatsu Camera service so we will be able to change certain properties without having to stop the acquisition.

[erinpougheon]

With inspiration from the FLIR camera (and Alied Vision Camera), I changed the way properties are created, so they can all be changed without having to stop mannualy the acquisition.
I will have to run some tests to verify when the Hamamatsu Camera will arrive (and also to be sure which property needs the acquisition to be stopped to be modified).
I had to make a distinction in the _create_propery method for the exposure time property, due to units that are used.
I have a doubt on how I'm using the getattr in the setter and getter (see l.29, 31, 47, 49).

A software review can be done, knowing this will require to be tested.

[ivalaginja]

Looking good! I think I know what tripped you over with the getters and setters, so here comes a solution.

[ivalaginja]

Since property_name is a string, we cannot call it - this is exactly why we use gettattr(). And property_name is a property of dcam.DCAM_IDPROP, so that is what we have to call getattr() on.

The correct way to write this is, for a getter:

return self.cam.prop_getvalue(getattr(dcam.DCAM_IDPROP, property_name))

and for a setter:

self.cam.prop_setvalue(getattr(dcam.DCAM_IDPROP, property_name), value)

[erinpougheon]

thank you, I changed that and I understand better now !

[ivalaginja]

I didn't point this out in the AV PR, but since this function _create_property() is specific to Hamamtsu cameras because of the getters and setters, lets call property_name -> hamamatsu_property_name instead. It's a bit long, but helps for understanding.

Also, could I maybe ask you to do a code-sneak and also replace that variable in the AV service with av_property_name?

[erinpougheon]

Done for both services ;)

[ivalaginja]

This looks good to me now! We will just put this PR on standby until we can test it on hardware.

[ivalaginja]

@erinpougheon since the camera delivery will be delayed, could you maybe post a brief bullet-point list here what needs to be done in terms of tests once we have the new camera to wrap up this PR?

[erinpougheon]

Once the camera arrives:

• Determine which properties can be changed on the fly (go and test in an
ipython terminal, with the service open in another terminal). You need to
have to access the camera, try to change one of the properties, and then
check if it has changed. The properties to test are : exposure time, gain,
brightness, width, height, offset on x, offset on y.
• Check if the properties are well ’sorted’ in the Hamamatsu properties
branch on catkit2 (in this PR). 2 categories : the properties
that can be changed without having to stop the acquisition, or the ones
that can not.
• Test the service in the catkit2 branch, so see if we are now able to change
these properties

[ivalaginja]

As an update, we received the new camera and will be integrating it in the following weeks, which means we will be able to address this PR.

[ivalaginja]

We got our new camera and @johanmazoyer is working on it now.