How can I get an image back to labview from opencv dll code?

[BorisR]

Hello!
Can you explain, what is threshold1, threshold2 and kernel_size?

[udka]

Did you check the link earlier mentioned?
Those parameters define the threshold values of hysteris process(which is part of Canny Edge Detection)
For ref adding here: http://docs.opencv.org/2.4/modules/imgproc/doc/feature_detection.html?highlight=canny#canny
Read more here:https://en.wikipedia.org/wiki/Canny_edge_detector

[BorisR]

Thank you, I have understood it with your help!

[xiaoliumi]

It seems that LabVIEW can correctly pass color image to opencv via 2d uint32 array pointer. But it doesn't work when you pass a color image from opencv to LabVIEW。At LabVIEW side，it just shows what you pass out to opencv even if it's been changed a lot. In my experiment, it is true. Maybe there is something wrong in my code or some particular reasons I will never know. 

My environment:

LabVIEW 2017 64bit trail,

OpenCV 4.1.2,

windows 10 pro 64bit.

[peterchen33011]

This have solved my encountering issue. Thanks you so much.

Hsing-Yu Chen