IMAQdx producing two timestamps: IMAQdxReceiveTimestamp and IMAQdxTimestamp

[czarv10]

Hi,

I'm producing images with the IMAQdx icons. Following the examples in the link below I am able to acquire the timestamps for my images. However, two sets are produced: IMAQdxReceiveTimestampHigh ( and the corresponding Low) and IMAQdxTimestampHigh (/Low) so four keys total.

Does anyone know what the difference is?

Thanks,

Link: http://digital.ni.com/public.nsf/allkb/D0488009D5AC87CF862579BA007B5F9B

[ChrisStrykesAgain]

czarv10,

The Receive timestamp simply indicates when the packet is read by the system, not the actual moment at which the image is acquired. Without knowing the specifics of your camera, my assumption is that the other timestamp signifies the actual moment of acquisition as logged by the camera itself. (Some cameras support this attribute and others do not.) 

Could you clarify which camera you are using?

[czarv10]

I'm using an IR camera, the FLIR A2600sc. I'm inclined to agree with you for the following reasons: in order to get a sensible timestamp I had to extract the tick frequency (the timestamp is measured in "ticks" apparently) using the appropriate attribute. Furthermore there is another attribute you can set " Receive time stamp mode " which when set to "none" suppresses the generation of the "receivetimestamphigh" but still allows the "timestamphigh" key to be generated.That same attribute has two other settings: "system time" and "tick count." However, none of this is mentioned in the camera's manual.

Do you happen to know what the timestamps are relative to? Right now I'm just substracting them all from the first image to make sense out of them.

It's all a bit frustrating but I have no good reference on any of this.

[ChrisStrykesAgain]

The Recieve Timestamp is defined with either the system time or the "tick count," which is the number of "ticks" elapsed since the system was started. For a Windows machine each tick is one millisecond. Note: This timer does eventually roll over, but if I remember correctly it takes somewhere around 50 days to do so. Additionally, even though it's measuring in milliseconds, you will likely not get true millisecond resolution.

I cannot speak with detail to the actual time stamp key, however. All I can find is the following link which implies it is somehow defined by the PC clock: http://www.flir.com/thermography/americas/us/view/?id=46798&collectionid=521&col=45868

FLIR technical support may be able to shed further light on the issue.