QueryFrame returns the previous queried frame

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Joined: Mon Sep 19, 2011 3:36 pm

QueryFrame returns the previous queried frame

Post by DArren » Mon Sep 19, 2011 3:57 pm

Hi there

I am using EmguCV 2.3.0 and am querying frames at random intervals from a Capture to be saved to hard drive. The problem is when I call the Capture.QueryFrame() or Capture.QuerySmallFrame() it is delayed by a frame.
To make this more clear: I start the program and query a frame pointed at my face. My face appears in the .jpeg. I then point the camera away from my face and query another frame, and my face appears in the .jpeg again. I then point it back at my face once more, query a frame and the .jpeg contains the image pointed away from my face.
There appears to be a 1 frame delay in a query. Is there some underlying buffer? What is causing this? And most importantly: how can I solve this problem without querying multiple frames for a single captured image?

Another question I have is that when I set the webcam resolution to 1600x1200, the program and computer begins to lag - even without making use of the images or querying frames. Is that caused only because I create a Capture and keep it in memory? Is there a way to lessen the affects of this?

I appreciate your help greatly,

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