how would i go about resizing an image of unknown dimensions to a specific dimension and saving it?

[manurizzo]

I'm acquiring images with a NI-PCIe 1427 (and Uniq UF-1000 camera) and saving them with "imaq write file". Acquired images always have a fixed dimension of 11.29x8.47cm.

Since this value doesn't correspond to "number of pixels multipled pixel dimension (in micron usually)", I would like to know if this is a value imposed by labview (and then it can be changed) , or if it is a hidden zoom I didn't consider.

Thank you all for your useful help,

Emanuele

[Nate.H]

Dear Emanuele,

Where are you reading the image dimensions?

The image size should be settable through the camera attributes for you camera either by mode switches or serial commands, at least from what I read in the camera spec sheet here:

http://www.uniqvision.com/spec/uf1000&1000cl.pdf

The IMAQ image display indicator does contain a zoom feature, but this will not affect the actual image size, just the way it is displayed in the indicator.

Does the image size change when you change the frame rate settings either by using the mode switches or the serial commands?

Best Regards,

~Nate

[manurizzo]

Dear Nate,

image size does not depend from frame-rate.

In addiction it seems to me that via mode switches I can only affect resolution (and obvoiusly frame rate).

Do you think it's right for me to have an expected dimension equal to "number of pixels multipled pixel dimension (in micron usually)",

or am I completely wrong??

I read the dimensions with Photoshop, but I've also tried to print the image for measure the real dimensions.

I think that if this lack cannot be related to the software, maybe it could be due to a wrong "focal distance",

and, actually, I'm reconsidering all these parameters.

Thank you for your suggestions.

Sincerely,
Emanuele

[Nate.H]

Dear Emanuele,

I am not sure that I understood your question correctly. In my previous post, I was referring to the fact that your camera seems to have set framerate/resolution settings:

108 x 80 resolution at 1000 FPS
160 x 120 resolution at 600 FPS
210 x 165 resolution at 500 FPS
320 x 240 resolution at 400 FPS

If it is valid to expect an image size to equal the # of pixels in a dimension multiplied by the size of the individual pixel in whatever units you are using for that dimension. By this reasoning though, would not different resolutions result in different image sizes?

I am curious, where are you quoting that expected dimension relationship from?

This equation relates some of the relevant parameters in determining a field of view of a camera, and there is more detail in the Vision Concepts Manual

focal length = (sensor size × working distance) / field of view

 Have you seen this KnowledgeBase?

Calculating Camera Sensor Resolution and Lens Focal Length
http://digital.ni.com/public.nsf/allkb/29D716D6F4F1FBC386256AE700727AF6?OpenDocument

I believe it may be of some use to you in reconsidering your other parameters such as working distance and focal length.

I hope this helps,

~Nate