OT - digital camera fault

[Peter.]

Looking for ideas on this.

I have a small digital camera (Sanyo xacti) which has developed a fault. When I take video it saves to the card perfectly, but when I take photos they save with lines across them. On the LCD display the picture is perfect, but once the photo is taken there's a short review on the LCD where the lines are apparent and they are there once saved also.

I have formatted the card and re-set the camera to factory but the fault persists. Any clues as to what might be wrong?

[winchman]

Well, it's not just your camera that's doing it.

http://www.google.com/search?q=digital+camera+horizontal+lines&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

There may even be an answer somewhere in all those hits.

[Grind Hard]

All the sensor chips come out of the same factory... made from the same cut-rate material. Manufactured with the same discounted quality standards. Sold to assembly "concerns" at the lowest price where they are soldered to shoddy boards with less than pure solder... then sent to other assembly "concerns" where they are fashioned into cameras and programed with software that makes them "unique."

Then we pay a 1,000,000,000,000,000,000,000,000,000,000,001% markup use it for a few months then bitch when it fails.


...same thing happened to my Sony camera. Seems there is a batch of bad chips/boards floating around out there. As they age you get lines.... and they age quite rapidly due to poor material and workmanship. But hey! At least they saved .000000003 cents per unit.

[J Tiers]

if you buy a decent camera, the problems grindbastard alludes to will not exist. Camera companies, (not Kodak, but real companies like Canon, etc) have extremely tight QC.

Even so, I had, not horizontal, but IIRC vertical lines in my Canon... and they showed up on the display also. Plus a color was missing.

Problem was a connector, I believe, and Canon fixed it absolutely free, including all shipping, despite the camera being long off warranty.

Good companies give that level of service.

Lines of any sort suggest a cyclical problem such as a bad address line in the camera somewhere (depends on the device). Something that recurs every X number of stored pixels, or every time that address line combination comes up, etc.

Check for recalls. Evan it was, I believe, who pointed out a link to the recall for the Canon model I had.

[Peter.]

Hmm, thanks for the replies.

I did think at first it was the sensor but as I said the display is perfect on the LCD befroe the picture is taken, and video comes out nice and clean too. Here is a frame from some video I took the same day as the above photo:



As you can('t) see - no lines on the video. Surely that rules out the sensor?

[rohart]

Camera take four pixels in a square, balled a Bayer pattern, and use this for interpolation.

The Bayer pixels are monochrome, but different colours, if that makes sense.

For example:

RBGBRBGB
BGBRBGBR

is one possible pattern.

Each four pixel pattern is then combined with neighbouring pixel squares to make squares of full RGB,

so the above pattern becomes

rgbrgbrgbrgbrgbrgbrgbrgb
rgbrgbrgbrgbrgbrgbrgbrgb

This is for the full size photo image.

For the video image, it can't afford the time or the space to store the full sized image, so it will use a diffreent algorithm, and the above pattern will become

RGBRGBRGBRGB
RGBRGBRGBRGB

with less processing.

In between all of these processing stages you could have a dry joint on a path between chips, or the video and photo processing chips may be on different cards with bad cables between them.

At the beginning of the digital revolution, whole camera ranges came out with errors like this showing up because of insufficient testing of late revisions of the firmware basically the algorithms had errors in them.

[Evan]

As you can('t) see - no lines on the video. Surely that rules out the sensor?

Not at all. Video is displayed at a different resolution than stills. The image is resampled to a lower resolution to produce the video image frames. That eliminates lines that appear to be occurring every other scan line (interlacing or combing). I presume that the camera has settings for different "quality" levels for still images. The line artifacts will probably disappear on lower resolution settings for stills since they are also resampled which effectively averages the good scan lines with the missing lines.

They don't show on the LCD since the LCD doesn't have the same resolution as the sensor chip. Again, the sensor image is resampled to fit the resolution of the LCD. The lines are probably not caused by the sensor itself but by the software that does the Bayer interpolation of the sensor image.

Look for a firmware update for the camera. The problem is called "combing".

[aboard_epsilon]

Hmm,
Denford Viceroy 280 Synchro (11 x 24)
Herbert 0V adapted to R8 by 'Sir John'.
and a Rolls Royce Phantom

all the best.....markj

[J Tiers]

One assumes the camera was not expected to do that.

Possibly there is a firmware update that correts it...... but firmware tends not to change in production by "natural variations"...... meaning that their protos should have done the same thing, and an excessively high res presumably would not have been specified, unless the problem was non-existent in a properly working camera.

I still lean towards an issue with the hardware.

That said, it may be that some hardware variation issue is bringing it up in production, where it was Ok in testing. In that case, new software will probably simply cut out the highest res...... Which you can do on your own.

Try the next lower res and see if it is corrected.