The Point-To-Point Caliper module allows to take point to point measurements on the current image.
To get the distance between two points, provided the module was calibrated beforehand, the user simply do a click and drag (left mouse button) from a start point to and end point. The module will draw a line between the two points and the measured value will be shown. The measurement line will stay visible until it is redrawn by doing a new click-drag action or removed by clicking without dragging or by pressing the [Clear] button.
The "Draw Overlays" section is used to determine when the overlay burning is taking place.
When done "At grab level", the overlays will be written on the images as soon as they are received from the camera. "On displayed frames" will show the overlays on images received from the camera but after any saving process occured. It will also show overlays on images read from a sequence file. Finally, "On exported frames" will apply overlay to any images exported from a sequence, regardless of the destination format (seq, avi, bmp, jpg, etc).
Checking the "Lock Overlay" checkbox will make the module ignore mouse clicks and actions.
In the Units edit box, type the abreviation used for the measurements. It can be : pixels, mm, m, cm, km, %, or anything else.
In the precision box, type the number of digits to show after the point in measurements.
[Clear] will erase the current measurement line.
While the "Calibrate" tab is the active tab, the module is in calibration mode. Quit calibration mode by selecting any another tab. Calibration mode, to set reference values. The measurement line will use those reference values to compute its real length.
To calibrate, first select one of the 3 calibration methods available. Any measurements will be done using the currently selected calibration method. Here is how to proceed for each.
This tab control how the various overlays are drawn.