drawing a line ROI on image in LabVIEW

[priya9129]

I am trying to draw a line ROI in the form of 'H' i.e a line whose end points are marked with perpendicular lines, on an image display in LabVIEW but unable to do so. I am only able to draw a simple line as ROI on the image display. Kindly help

[Gregory]

If you hold down "ctrl" as you draw your lines, you should be able to put multiple. I don't know what the actual ROI data will look like or if it will be useful if you need to use it for analysis, but if you just want to mark up your image, that should do it.

Edit: It looks like if you get the ROI through a property node, the "Contours" array will have 3 elements (one for each line). Each of those will have a 4 element "Points" array that is in the order [x1, y1, x2, y2]

[Gregory]

It dawned on me that you probably want those lines drawn automatically. You can do some trig and calculate line segments to add to the end of your ROI, but it's not an automatic tool.

[priya9129]

Is it possible to drag the ROI around the image? Also, I want to be able to change length of the ROI on the same image. Kindly suggest.

[Gregory]

Yes I have no trouble dragging the ROI around, just hover over it in a location where you get the four way arrow. To change the length you have to drag from one of the endpoints, have you tried it?

[priya9129]

Yes. Thank you for the suggestion. Also, is it possible to customize the shape of ROI( for example an 'H' shaped ROI ) in LabVIEW?

[Gregory]

Yes, there is a polyline tool. But again, you're going to have to do all the math for where you want the endpoints.