Hi Mark,
Sorry to intercept this thread.
Actually it is not a limit of channel access to support passing compressed NDArrays.
The NDPluginStdArrays could just copy the compressed bytes to output. The client
will look at the $(P)$(R)Codec_RBV record to handle it accordingly.
I have experimented this idea before the introduction of NDCodec plugin. I image
this has only got easier.
Best
Xiaoqiang
On 1/24/20 12:44 AM, Mark Rivers via Tech-talk wrote:
Hi Randall,
You can't pass the JPEG image over EPICS Channel Access, but you can pass it over pvAccess. The NTNDArray that your pvAccess client receives will be the JPEG compressed image.
What type of client are you running, and how will you display it?
There are examples of receiving JPEG compressed NTNDArrays in the ImageJ EPICS_NTNDA_Viewer.java in ADViewers
https://github.com/areaDetector/ADViewers/tree/master/ImageJ/EPICS_areaDetector
and in a new Python viewer that Marty Kraimer is writing:
https://github.com/mrkraimer/PY_NTNDA_Viewer
These viewers first decompress the JPEG images before displaying them.
Mark
-----Original Message-----
From: Tech-talk <[email protected]> On Behalf Of Randall Cayford via Tech-talk
Sent: Thursday, January 23, 2020 5:29 PM
To: [email protected]
Subject: Getting images from area detector plugins
We’re trying to connect to a gige camera with areadetector (using ADaravis). We would like to access the camera images via a pv that returns a jpeg of the image rather than an uncompressed byte stream.
We’ve got the camera connected, we’ve got an NDPluginCodec setup that takes the images and apparently is producing compressed jpeg images. We can enable acquisition and watch the MEDM screen show frames arriving and degree of compression, etc.
Our problem is: how do we access those images? There doesn’t seem to be any PV that returns the jpeg. Perhaps we’re supposed to pass the output of the codec to something else but we can’t seem to find anything that tells us how to do that.
Help would be appreciated.
Randall Cayford
ALS at Lawerence Berkeley Lab
- Replies:
- Re: Getting images from area detector plugins Mark Rivers via Tech-talk
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- CAS-client thread issues in areaDetector IOC Wlodek, Jakub via Tech-talk
- RE: CAS-client thread issues in areaDetector IOC Mark Rivers via Tech-talk
- Re: CAS-client thread issues in areaDetector IOC Wlodek, Jakub via Tech-talk
- Re: CAS-client thread issues in areaDetector IOC Michael Davidsaver via Tech-talk
- Getting images from area detector plugins Randall Cayford via Tech-talk
- RE: Getting images from area detector plugins Mark Rivers via Tech-talk
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