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Messages - foobar

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31
NiNeff is correct, the image sensor digitizes an entire row at once and then reads it out 16-pixels at a time to the FPGA. While the first row is being read out to the FPGA, the second row of the image can then be digitized. The time that it takes to digitize a row can be adjusted by playing with the timing parameters of the image sensor but reducing the time allowed for this operation causes a loss of image quality.

The fastest framerate at any resolution is achieved when the row readout time is equal to the row digitization time, so that we minimize the time that the image sensor is idle. And the best quality is achieved when the row readout time is long enough to allow for the maximum digitization timing (approximately 922us per row).

On the 0.3.1 release of the Chronos 1.4, the fastest row digitization time is approximately 255us, which is equal to the time it takes to read out 336 pixels. This is why there is no performance benefit to reducing the horizontal resolution below 336 pixels. On the 0.3.2 release we have managed to reduce this time to 244us, which is why we now list 320x96 as the minimum resolution for that release.

32
Would you be able to share a screenshot of the Trigger I/O Settings window to show how you have the triggers configured? That might help us in trying to reproduce the problem you're seeing.

33
When you were using the v0.3.2 software update, did the issue occur at full-frame (1280x1024) and low gain, or did this banding appear only at the higher gains and/or smaller frame sizes? There have been reported problems at high gains using the new black calibration routines on v0.3.2 that I am presently working on.

To completely revert from v0.3.2 back to v0.3.1, you will also need to restore your factory calibration (in particular, the /opt/camera/cal/lux1310Offsets*.bin files will have been overwritten by the v0.3.2-beta software).

Regarding the issue with the power button and 'no batt' indication, I will have to try out reverting a camera from v0.3.2 to v0.3.1 and investigate the issue further. It is likely there are some files that may need to be deleted from the SD card to revert from v0.3.2 to v0.3.1 after the changes to the power controller for the automated power-on and power-off features.

34
Chronos User Discussion / Re: Maze artifact with 1.4
« on: June 22, 2019, 07:48:16 PM »
This is a known issue in versions v0.3.0 and earlier, and it is caused by the FPGA sometimes loosing the first pixel of a frame when shooting in 12-bit raw mode. The result is that the whole image gets offset relative to its bayer battern resulting in demosaic artifacts and color corruption. There was a discussion about the changes to 12-bit raw mode in the v0.3.1 beta software thread, which you can read here.

As part of the resolution of this issue, the bit packing order also changed between v0.3.0 and v0.3.1, so if you are using custom software to convert the 12-bit raw files you will also need to account for that change after updating the software. However, I do recommend using CinemaDNG for raw shooting as it requires fewer tools to process in Adobe Premier or Davinci Resolve.

35
Software Dev / Re: Chronos V0.3.2 Beta
« on: June 10, 2019, 12:10:00 PM »
Thank you so much, that does clearly demonstrate an issue with the new calibration routines when operating at high gains. I've been able to reproduce the problem and I'll be looking into it.

36
Software Dev / Re: Chronos V0.3.2 Beta
« on: June 08, 2019, 11:07:16 AM »
Can you attach some images to show us what the banding looks like at higher gains and framerates? Does the banding appear to change either for better or for worse after attempting a black cal at those settings?

37
Software Dev / Re: Chronos V0.3.2 Beta
« on: June 07, 2019, 03:19:30 PM »
Because this update includes some major changes to the calibration routines of the camera, for the best results we recommend re-generating your factory calibration after applying the update. You can do this by navigating to the factory screen and tapping the "Black Calibrate All Resolutions" button.

This procedure should be performed only once the camera has warmed up to its normal operating temperature, and the lens or body cap is in place.


38
In this release we are making changes to improve the camera's image quality by addressing the vertical banding issue that some users have reported and adding some new features to the power controller to make unattended operation of the camera a little easier.

Note that this update will affect your camera's factory calibration, you should back up your factory calibration before applying this update if case you have to revert back to v0.3.1 at a later time.

    +----------------------------------+
   ++                                  ++
   |     Chronos V0.3.2 Changelog       |
   ++                                  ++
    +----------------------------------+


Notable Changes:
  • Automatic ADC calibration during black calibration, which should reduce column banding across a wider temperature range.
  • Add a storage tab to the util menu to view, eject and format the attached storage devices.
  • Speed boost at most resolutions, with a top speed of 1069fps at 1280x1024, and 40420fps at 320x96.
  • Configurable automated power-on and off depending on the AC adaptor status.

Minutae:
  • Factory black calibration is now user accessible from the Factory tab of the util window.
  • The software update button has been moved to the storage tab of the util window.
  • Shipping mode to disable power-on by battery until an AC adaptor is attached.
  • Add a watchdog to reboot the camera in case of power-on boot failure.

Fixed Bugs:
  • Memory leak in the M3 video coprocessor which could lead to a crash after lots of H.264 encoding.
  • Ignore video which was recorded during black calibration.
  • Changes to exposure may be overwritten during black calibration.

Known Issues:
  • After applying this update, software versions v0.3.1 and earlier may no longer be able to receive battery data or utilize the power button.

Updating Your Camera:
  • Extract the .zip file into the root directory of a FAT32 formatted USB drive.
  • Turn on your camera and insert the USB drive.
  • From the main window, tap the Util button to open the utility window.
  • As a precaution, tap the Backup Calibration Data button on the utility window before starting the update.
  • When the backup is completed, a pop-up window will be displayed.
  • Tap the Done button to close the pop-up window.
  • From the utility window, tap the Apply Software Update button to begin the software update.
  • A warning message will be displayed, tap the Yes button to confirm and begin the update.
  • During the update, the screen will go blank and an Applying Update message will be displayed.
  • After approximately 60 seconds, the update will be complete and the camera will restart.

39
Chronos User Discussion / Re: Segmented recording problem
« on: June 07, 2019, 02:37:17 PM »
I've often found that the last segment when in segmented recording mode is effectively not usable and this is just due to the way that the camera operates.

When you start recording in segmented mode the video memory is divided into segments and the camera starts saving frames into the first segment. At each application of the trigger signal, the camera starts saving frames into the next segment. When the camera is saving frames to the final segment and it receives a trigger event it loops around and begins overwriting the first segment again. This process continues until you exit recording mode using the red button on the top of the camera, or the "Stop" button.

To summarize, the sequence of events is something like this:
  • Press the recording button to begin recording, the camera is now saving frames into segment 1.
  • Generate a trigger on the BNC port, the camera terminates segment 1 and is now saving to segment 2.
  • Generate a trigger on the BNC port, the camera terminates segment 2 and is now saving to segment 3.
  • Generate a trigger on the BNC port, the camera terminates segment 3 and is now saving to segment 4.
  • Generate a trigger on the BNC port, the camera terminates segment 4 and is now saving to segment 1, which overwrites the first thing we recorded.
  • Press the recording button to exit recording mode, the camera terminates segment 1.

As a workaround, you should be able to use the BNC trigger three times for the first three segments and then use the red trigger button to terminate the fourth segment.

40
Chronos User Discussion / Re: Filename time stamp question
« on: May 09, 2019, 08:03:13 PM »
The automatic filename is the time at which the recording was saved to storage medium.

41
Chronos User Discussion / Re: Chronos 1.4 screen upgrade?
« on: April 16, 2019, 05:50:36 PM »
Our initial tests have shown that the backlight on the new LCD does consume a bit more power than the older unit, but I would expect the difference in runtime to be very small. It's the FPGA and CPU that consumes the lion's share of the power budget. If I had to take a guess, it might reduce your battery life by about 5 minutes or so from a full charge.

42
Chronos User Discussion / Re: Chronos 1.4 screen upgrade?
« on: April 12, 2019, 01:00:50 PM »
The screen and rear bezel that will be used on the Chronos2.1 can be swapped onto a Chronos1.4 as a drop-in replacement. I don't have any idea of what the pricing for such an upgrade would be.

43
Chronos User Discussion / Re: Problem saving No storage device found
« on: March 31, 2019, 03:57:43 PM »
You can also try saving the footage to a USB drive as long as it's formatted as FAT32 or Ext2/3, that might provide you with another mechanism to save the footage if something has gone awry with the SD card slot. To know more about why the SD card was not being detected correctly, we would have log into the camera via to SSH (using the micro-USB port) and check into what the kernel thinks of the SD card. If you can manually mount the SD card using the Linux mount command then the UI should still be able to save footage to it.

If you're on one of the 0.3.1 software releases, and you have SSH access to the camera, then you can also use the /opt/camera/cam-recover tool to extract footage from a camera isn't able to save via the normal method (be warned that this option is quite slow).

44
Awesome, I'm glad to hear that the camera worked out well for you.

- We were shooting with natural light (large outdoor scenes) with many parts of the field of view not being well lit, especially later in the evening.   This resulted in pronounced vertical sensor banding.   I was unable to get rid of the banding despite numerous and frequent black calibrations.   Black cals were done at power-up and at regular intervals throughout the day, but they did not have a noticeable effect on the image.   Topaz denoise worked well for the most part to correct for this in post, though some shots were unsalvageable.

We have spent a bunch of time recently looking over and revising the calibration procedures on the camera lately and we will be rolling out some changes during the transition to Debian that will hopefully improve the vertical banding issue. The cause of the vertical banding is that the ADC calibration of the sensor is temperature-dependent, and as the temperature of the camera drifts away from what it was calibrated at the gain of the ADC channels become slightly mismatched.

- The most difficult part of the workflow was focusing.  The edge highlight function is not reliable enough to depend on in production.  I ended up using trial and error, importing the video to a computer each time to check the focus, then marking the focus ring on the lens when I got it right.  The screen has a lot of noise in lower light, making focusing in those conditions, even using an external monitor, next to impossible.   I also had weird depth of field issues I'd never seen before.   At infinity, with the foreground all the way to objects about a mile distant in focus, the most distant objects were noticeably out of focus (including clouds in the sky and a city skyline backdrop).   I could not fix this problem.   It may be with my lens or possibly a backfocus problem, but I'm not really sure.  Anyone have any ideas?
This does sound like the backfocus has been set incorrectly on your camera and/or lens, and is preventing you from being able to reach infinity focus. If you loosen the set screw on the bottom of the camera you can rotate the CS ring to adjust the backfocus of the camera.

A big request for future firmware would be the ability to pinch and zoom on the screen to enlarge objects to make focusing a little easier, plus maybe a "temporary max exposure" button to brighten the image temporarily for focusing purposes without resetting the resolution/framerate. 
I'd love to see this get implemented too, but it's been on my feature wishlist for a while and unfortunately I just haven't had much time to work on it. As an interim solution, some of our users have recommended setting the image sensor to  a smaller resolution, but leaving the expousre and framerate the same, this will effectively crop the sensor down a smaller area and making it a lot easier to get your focus set right. Once focus is set, you can then switch back to 720p for the real shot. It's a bit of a bandaid, but it does help.

45
Software Dev / Re: Saved file's owner/group/permissions.
« on: March 18, 2019, 05:07:15 PM »
Hey Nick,

We also ran into this issue a short while ago and we already have a fix for it in our development builds, the underlying problem is that the directories for DNG and TIFF recordings were created without execute permission, which prevents anyone from being able to browse the directories even though they may have read permission on the contents. To repair a directory that was saved with this bug, you can simply use the chmod tool to add the execute bit to the directory (eg: chmod +x directoryname) at which point you should be able to browse its contents.

If you would like to apply a slightly more permanent fix to your camera, you can grab the latest and greatest development builds from our chronos-updates repository and follow the README to build a release package that can be applied to your camera. This particular issue affects the /opt/camera/cam-pipeline program, so you can also apply the update by overwriting that particular file on your SD card with one downloaded from our github.

Note that files will still be created with the UID and GID of the root user, meaning that you will need root permissions to modify them once moving the disk to another PC for viewing, but all users should be able to browse and open the files.

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