This app is capable of setting scale for image by specifying known distance for pixel width with unit.
Download the file "Set Image Scale.opx", and then drag-and-drop onto the Origin workspace. An icon will appear in the Apps gallery window.
With a matrix window activated, click the app icon to bring up the dialog, then in the upper preview panel, move and resize the rectangle to match the desired scale bar on image. Then in the bottom setting area, provide the known distance of the scale bar and unit, and choose Width for horizontal scale bar or Height for vertical scale bar. If you have a factor, you can also give a factor, and then click OK button to set scale for the image.
1. Known Distance: Specify the distance of scale bar you know in real world.
2. Unit of Length: Specify unit of distance.
3. Width (pixels): If the scale bar is horizontal in the image, choose this for number of pixels of the known distance.
4. Height (pixels): If the scale bar is vertical in the image, choose this for number of pixels of the known distance.
5. Factor: If there is a factor for the scale, use it, otherwise, let it be 1.
6. Scale: Show the scale information for the current settings.
7. OK: After settings done, clicking this button, the specified unit will be put for X and Y of the image, and the XY mapping is calculated using the scale of current settings.
8. Cancel: Clicking this button will do nothing but close the dialog.