I am trying to convert data from a Keysight scope to .png Image. When I looked how to do it online, I stumbled the following code:
# Download the screen image. # -------------------------------------------------------- sDisplay = do_query_ieee_block(":DISPlay:DATA? PNG") # Save display data values to file. f = open("screen_image.png", "wb") f.write(sDisplay) f.close() The problem with code above is that I'm not sure what do_query_ieee_block is. I thought it was under pyvisa but couldn't find it there. After looking online, I understood that query_binary_values is more or less the same thing as pyvisa assumes that data is in IEEE.
According to this information, I wrote the following code:
import pyvisa import struct IDN="SomeScopeIDN" #something like 'USB0::0xhhhh::0xhhhh::MYdddddddd::0::INSTR' scope=pyvisa.ResourceManager().open_resource(IDN) binImage=self.scope.query_binary_values(":DISPlay:DATA? PNG") #This gets a list of floats byteImage=struct.pack('%sf' % len(binImage),*binImage) #Convert the list to bytes-like object path=r"c:\Users\user\Desktop\Scope_Image.png" with open (path,'wb') as f: f.write(byteImage) This creates an image, but the outcome is bad:
and from snipping tool:
As you can see, only the upper 10% of the image is fine but the rest is not (it will be mentioned that each time I retrieve new data from the scope I get a different area that is corrupted, which is between 50-90% of the picture. Most of the time the corrupted area is between 80-90%, as seen in the picture above).
So basically my questions are:
- Could it be that I don't read the whole data from the instrument? and if so, how can overcome this issue?
- Could it be happening because of packing in a wrong way? If so, what's the solution?
Источник: https://stackoverflow.com/questions/632 ... pted-image
