Recent Posts

81

Electronics / Re: sensor Signal−to−Noise Ratio

« Last post by Daniel Aharoni on April 26, 2018, 04:25:04 PM »

Hi Stephan,
Thanks for posting this information. We have never measured the Photon Transfer Curve ourselves but I will try to get around to doing so soon. Can you upload a plot of your measurements?

82

Electronics / sensor Signal−to−Noise Ratio

« Last post by Stephan on April 24, 2018, 06:18:13 PM »

Hi all

I was wondering whether someone ever characterized the noise of the sensor used on the miniscope, for example by measuring the Photon Transfer Curve (https://www.adimec.com/how-to-measure-the-photon-transfer-curve-for-ccd-or-cmos-cameras/).

Plotting the log of the  Standard Deviation versus the log of the average effective signal , one would expect to see a region where the photon shot noise is dominant, and the slope of the curve is equal to 0.5.

I measured this curve and identified a portion of the curve where the slope is 0.5 (STD~(MEAN)^(0.5)). This was roughly between the values 1 and 50 (at gain 4x). But to my surprise there is also another portion (much larger) which has a very different regime. In this portion, extending from the values 50 to ~200, I see the STD varying linearly with the MEAN.
Finally the curve ends as expected (values 200-255): the STD drops to zero as the pixels saturate.

I do not understand the linear relationship between STD and MEAN at the intermediate light levels.
Did anyone ever made this measurement? Did you observe the same thing?

Thanks for your help,
Stephan

83

Optics / Re: Miniscope for Bioluminescence imaging

« Last post by Dmitrijs on April 23, 2018, 07:00:54 PM »

Hi Daniel,

Thank you so much for your response! Could you suggest any particular more sensitive sensor brands/vendors worth considering?

Ideal case scenario would be to be able to increase the sensitivity while keeping the miniscope design alternations to the minimum, especially on the electronics side.

84

Optics / Re: grin lens for gofoton

« Last post by Daniel Aharoni on April 22, 2018, 06:04:49 PM »

Hi Richardson,
We have used a bunch of their ~1mm diameter relay lenses which pretty good success. I know multiple groups have been testing their 2mm objective GRIN lenses but we personally haven't had a chance yet.

85

Optics / Re: Miniscope for Bioluminescence imaging

« Last post by Daniel Aharoni on April 22, 2018, 06:02:59 PM »

Hi Dmitrijs,
I haven't heard of anyone doing this yet but it is a really interesting application for Minsicopes. From what I have seen so far with bioluminescence, the MT9V032 likely won't be sensitive enough but there are some much more sensitive CMOS sensors on the market that could fit in the Miniscope form-factor.

86

Optics / Miniscope for Bioluminescence imaging

« Last post by Dmitrijs on April 21, 2018, 01:33:03 AM »

Hi,

Did anyone try using the miniscope to do bioluminescence imaging? Would default MT9V032C12STM sensor be sensitive enough?

Thank you!

87

DAQ Software/Firmware / msCam Frame retrieve error

« Last post by hansu47p on April 17, 2018, 09:26:23 AM »

Hi,

My name is Su and I need your help.
I have been using the miniscope with the version3 DAQ with Dell computer (Windows 10) which had been working fine, but suddenly stopped working as the video stream is lost (the red screen of Doom appears with the message of 'frame retrieve error).
All 3 LED lights come on the DAQ PCB and the red light on CMOS sensor and the blue LED are also on when I plug the scope in. I am using the proper USB 3.0 cable (1m long) and when the miniscope is plugged in I still see the miniscope driver on Device manager. I have tried 3 different DAQ, 2 USB cables and 2 different miniscopes but it still shows the msCam frame retrieve error.
Is there any suggestion on what would have been a problem?
Thank you!

88

Data Analysis / Re: Error in msExtractFiring and additional basic questions for analysis

« Last post by kjlawlor on April 16, 2018, 08:56:43 PM »

I am getting the same error in regardsto undefined function or variable 'C1'. Was this issue ever resolved? Thanks!

89

General Discussion / Can GCaMP signals pass through the corpus callosum?

« Last post by Yujin Han on April 16, 2018, 01:31:16 AM »

Hi, I'm trying to image hippocampal area just underneath the corpus callosum.
But I found out, in that case, recommended lens implantation site would be 'in' the corpus callosum.
So I'm wondering if the GCaMP signals from the ROI can pass through and reach the lens implanted in the corpus callosum without significant loss.

Is there anyone who could give me some advice?

Thanks!

90

Data Analysis / Re: Sample Workshop data stats

« Last post by Daniel Aharoni on April 14, 2018, 02:22:07 PM »

Hi and sorry for the issue and delay in responding. The link looks to now be working.