Opened 7 years ago

Last modified 7 years ago

#281 new Data problem

Hawk framerate reported incorrectly in header file / Hawk dropping every second frame

Reported by: mggr Owned by: mggr
Priority: immediate Milestone:
Component: Data collection Keywords:
Cc: benj Other processors:

Description (last modified by mggr)

While in Ethiopia, Phil and Ben noticed the Hawk running at half the framerate it's been told to. It still records the inputted framerate in the header file, which means that az* calculates things wrong.

It looks like a timing offset if compared to itself, but if compared to the Eagle files the Hawk lines are half the length.

Halving the framerate in the header file for the affected lines makes them process correctly.

Change History (4)

comment:1 Changed 7 years ago by mggr

  • Owner changed from gaew to mggr

Wrote a script to scan header files for the problem (hdr_fps_check.py). Resulting run:

Hawk lines affected, flight
      1 078c
      1 152a
     12 252a
      7 252b
     11 268a
      7 268b
      8 268c
      4 277
     11 278a
      8 278b
      9 278c
     26 280a
     10 280b
      4 281
     23 285

Interestingly, Eagle has one framerate doubled line too:

  • uk/GB08_12-2009_152a_Borth_Bog/eagle/VNIR152-09-2.hdr
  • uk/GB08_12-2009_152a_Borth_Bog/hawk/Hawk152-09-2.hdr (ditto Hawk)

Anyway, basically seems to have started in earnest from 252 onwards.. I'll put notes in all the affected tickets.

comment:2 Changed 7 years ago by mggr

  • Cc benj added

comment:3 Changed 7 years ago by mggr

  • Summary changed from Hawk framerate reported incorrectly in header file to Hawk framerate reported incorrectly in header file / Hawk dropping every second frame

According to Specim, the instrument may be skipping every other frame (e.g. catching the rising but not falling part of a pulse). This would lead to every second frame being dropped.

Not sure there's a lot we can do about this until Specim deliver a fix (apparently soon).

comment:4 Changed 7 years ago by mggr

  • Description modified (diff)

Corrected attribution of problem finding.

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