Diagonal striping on XL1 at DVinfo.net

Bill Heaner · January 20th, 2003, 01:58 AM

Anyone know what causes the diagonal striping betweens lines of contrast? For example, a sharp color next to white produces this striping when the camera is moving in a pan. Is this just typical of 4:1:1 video or are there prosumer camcorders that have resolved this problem?

Don Palomaki · January 20th, 2003, 06:02 AM

Only seen during pans or fast moving objects? Sounds like an interlace artifact.

Jeff Donald · January 20th, 2003, 06:14 AM

Does it look like this? If so, it's as Don guessed, interlace artifact. You might want to search the topic using the search button in the upper right. The lines are more pronounced on a computer monitor because of the nature of the display.

Jeff

Bill Heaner · January 20th, 2003, 01:10 PM

Thanks for the comment, but, no, the artifact is seen during normal playback through the camera on a tv.

Andre De Clercq · January 20th, 2003, 02:48 PM

If you see this "striping" only on slightly oblique area's while panning /tilting you probably see the "stairstepping" which relates to the sampling and (interlaced) line structure character of DV.
Longer shutter time settings reduce this effect by introduction of some extra motion blurr.

Don Palomaki · January 20th, 2003, 03:31 PM

Can you post a captured frame with a sample of the effect for us to see.

Bill Heaner · January 21st, 2003, 11:50 AM

Don,
Thanks for your input...I'll work on getting a sample for you to take a look at. However, I am interested in the response from Andre. The "stairstepping" effect is what is happening and seems to relate to sampling. I will try the longer shutter speeds and post the results.

Andre,
Is this something that you see on your video? Also, do you know at what sampling rate this digital stairstepping smooths out? I came from an analogue (beta and 16mm film) background and do not like this problem that I am seeing with these 4:1:1 cameras.

Thanks a lot (Don, Andre and Jeff) for your thoughts on this. I am about to start work on a documentary series using digital for the first time and want to make sure that I understand the image limitations.

Andre De Clercq · January 21st, 2003, 03:08 PM

Bill,
Sampling rates are fixed in DV. Yes I can see stairstepping in DV images. This belongs to the often mentioned "edge business" in digital images and manifests itself in different ways like stairstepping, twitter, straddling, moire ...all belonging to the domain of spatio-temporal aliasing effects. Reducing resolution also reduces aliasing effects and motion blurr is one of the ways to get this (if there is motion!). So keep your shutter at 1/60 when panning.tilting.

Bill Heaner · January 21st, 2003, 07:51 PM

Many thanks Andre...sounds like you understand this issue. I'll keep your advice in mind.

Thanks again.

January 20th, 2003, 01:58 AM	#1
Bill Heaner New Boot Join Date: Jan 2003 Location: Draper, UT Posts: 7	Diagonal striping on XL1 Anyone know what causes the diagonal striping betweens lines of contrast? For example, a sharp color next to white produces this striping when the camera is moving in a pan. Is this just typical of 4:1:1 video or are there prosumer camcorders that have resolved this problem? __________________ Bill

January 20th, 2003, 01:10 PM	#4
Bill Heaner New Boot Join Date: Jan 2003 Location: Draper, UT Posts: 7	Thanks for the comment, but, no, the artifact is seen during normal playback through the camera on a tv. __________________ Bill

January 21st, 2003, 11:50 AM	#7
Bill Heaner New Boot Join Date: Jan 2003 Location: Draper, UT Posts: 7	Don, Thanks for your input...I'll work on getting a sample for you to take a look at. However, I am interested in the response from Andre. The "stairstepping" effect is what is happening and seems to relate to sampling. I will try the longer shutter speeds and post the results. Andre, Is this something that you see on your video? Also, do you know at what sampling rate this digital stairstepping smooths out? I came from an analogue (beta and 16mm film) background and do not like this problem that I am seeing with these 4:1:1 cameras. Thanks a lot (Don, Andre and Jeff) for your thoughts on this. I am about to start work on a documentary series using digital for the first time and want to make sure that I understand the image limitations. __________________ Bill

January 21st, 2003, 07:51 PM	#9
Bill Heaner New Boot Join Date: Jan 2003 Location: Draper, UT Posts: 7	Many thanks Andre...sounds like you understand this issue. I'll keep your advice in mind. Thanks again. __________________ Bill

January 20th, 2003, 06:02 AM	#2
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,487	Only seen during pans or fast moving objects? Sounds like an interlace artifact.

January 20th, 2003, 06:14 AM	#3
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	Does it look like this? If so, it's as Don guessed, interlace artifact. You might want to search the topic using the search button in the upper right. The lines are more pronounced on a computer monitor because of the nature of the display. Jeff

January 20th, 2003, 02:48 PM	#5
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	If you see this "striping" only on slightly oblique area's while panning /tilting you probably see the "stairstepping" which relates to the sampling and (interlaced) line structure character of DV. Longer shutter time settings reduce this effect by introduction of some extra motion blurr.

January 20th, 2003, 03:31 PM	#6
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,487	Can you post a captured frame with a sample of the effect for us to see.

January 21st, 2003, 03:08 PM	#8
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	Bill, Sampling rates are fixed in DV. Yes I can see stairstepping in DV images. This belongs to the often mentioned "edge business" in digital images and manifests itself in different ways like stairstepping, twitter, straddling, moire ...all belonging to the domain of spatio-temporal aliasing effects. Reducing resolution also reduces aliasing effects and motion blurr is one of the ways to get this (if there is motion!). So keep your shutter at 1/60 when panning.tilting.