Re: To Jan Crittenden: HVX-200 Green Screen Halo Problem

[Per Holmes] "I should only add, that the halo could also be caused by the pixel shifting process. As I understand it, the native CCDs in the HVX are actually not very high resolution, and the higher resolution is gained by interleaving these signals, which logically implies that some technical assumptions about being made about a certain chroma value the same way 4:2:2 makes assumptions about chroms"

Hi Per,

Your explanation of the Pixel Shift says that you believe that there is a actual pixel to pixel match up somewhere, this is not true. What comes off of the CCD is an ANALOG signal, the offset is made to capture the areas of the green CCD which are non-photosensitive, the registers, and this is done with the red and blue CCDs. They are then clocked back into time and a snapshot is taken at 1080P. It is at this time the signal is changed into the digital domain. And BTW, this process is practiced by a good number of manufacturers in their Standard Def Cameras and have been doing so since 1990 or so and also in a couple of the small HD cameras but only on the Horizontal Domain.

As many have pointed out in this thread, Green screen with the HVX200 is a real breeze. There is something in your process, setup, lighting, or whatever that is causing your problem. I suggested that you back off your detail, and while you feel that might have been a "is the power on" sort of a remark, I note that Barry Green, who is one person that I feel probably knows the camera better than I do, also suggested the same along with another reference to a customer that does a lot of green screen work with the HVX200. And your reply to him is that there are lots of people all over the internet that are having a problem. Hmm, I have not found them. Would you post a couple of those threads?

In the meantime my offer to the fellow above with my frame grab is open to you as well, just send me an email with your email address in it and I will upload it to yousendit.com.

Best regards,

Jan







Jan Crittenden Livingston
Product Manager, HPX500, HVX200, DVX100
Panasonic Broadcast & TV Systems