I image with an ASIAIR PRO, ZWO EAF, and a Canon T3i among other equipment. All sub-exposures following the initial autofocus routine look good. However, all sub-exposures following a time- or temperature-triggered autofocus routine are pixellated and misaligned when displayed within the ASIAIR application for iOS. Unfortunately, the issue is persisted to the data files, which is evident within PixInsight. Additionally, the JPEG files that the ASIAIR PRO saves to the storage drive display a discoloration rather than the pixellated appearance.

The following image shows the display of a captured image that followed the temperature-triggered autofocus routine. Notice the purple pattern, which reminds me of a Bayer matrix. This is also how the resulting data file appears within PixInsight.

Pixelated image preview

The next image is of the JPEG that was written to the ASIAIR PRO storage device.

Discolored JPEG

The remaining two images show the display of a captured image and the resulting JPEG prior to the time- or temperature-triggered autofocus routine, which are the results that I expect to see before and after every autofocus routine.

Normal image preview

Normal JPEG

I am using the following software and hardware:

  • ASIAIR PRO iOS application (v 1.6.2)
  • ASIAIR PRO firmware (v 8.11)
  • iOS 14 (release OS version)
  • iOS 15 (beta OS version)

Do you know why this is happening?

  • w7ay replied to this.

    nickkohrn Pixelated image preview

    Probably Moiré pattern (a kind of beat pattern) that is caused by ASIAIR taking a short cut (or worse, not understanding the basic principles of image processing), and not properly low-pass filtering an undersampled image before it is resampled to fit the dimensions of the tablet display.

    Carefully pinch the tablet display to expand the magnification of the image by a few percent, if the pattern goes away, it is Moiré.

    https://en.wikipedia.org/wiki/Moiré_pattern

    (Notice especially the blueish example on the right, with the caption "Moiré pattern appearing on scaled camera captures of LCD screen.")

    If it is Moiré, it will again come back as you pinch to increase the magnification, then go away, and then come back again as the magnification continues to be increased. This effect will finally go away when you have magnified the image on the screen to the point where each pixel of the image is 2x larger than the screen pixel.

    Chen

        w7ay Ah, yes, that seems to be the issue as the pattern disappears when I pinch to zoom in and out.

        Based on my understanding of your description and referenced source, there is nothing that I can do to resolve this except to disable time- and temperature-triggered autofocus routines. 🙁

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