Unexpected cumulative sharpening effect in LabVIEW image processing

[jaywai88]

I’m trying to implement some basic image post-processing (brightness, contrast, and sharpening) in LabVIEW. Brightness and contrast behave as expected, but I’m running into a strange issue with sharpening. Specifically, it seems like the sharpen operation is being applied cumulatively. After the first run, the processed image is reused as the input for subsequent runs, instead of starting from the original image each time. This causes the sharpening effect to compound and produce unexpected results.

Based on my code, the algorithm should always take the original image (stored in imaqImage "untitled1") as input. However, it looks like the processed result is being written to a different image (untitled), and that version keeps getting reused and further processed.

What’s confusing is that the overall structure is very similar to my brightness and contrast implementation, which works correctly and does not show this cumulative behavior.

I’m not sure what I’m missing here—could this be related to how IMAQ image references are handled or overwritten internally? Any help or pointers would be appreciated.

 

[raphschru · Accepted solution]

Hi jaywai88,

You are applying the convolution to the original image:

When you only wire the "Image Src" input, IMAQ filter VIs modify the source image.

However, if you specify a second image for the "Image Dst", the filter is applied to it instead of the source image.

To correct your issue, also wire your "processed" image reference to the "Image Dst" input of the IMAQ Convolute VI:

Regards,

Raphaël.

[jaywai88]

Oh yes, I see. Thank you very much