Measuring the Rotation Angle of an Object

Objective

Following this tutorial, you will learn how to use EasyGauge to measure the rotation angle of a CCD sensor package. As we only need to retrieve an angle value, it's not required to work in a calibrated field of view. All geometrical parameters and results will be express as numbers of pixels.

You'll need to load the source image (step 1), and attach a line fitting gauge (step 2). The inspection is automatically performed (step 3).

Line fitting gauge

Step 1: Load the source image

From the main menu, click EasyGauge, then New World Shape.

Keep the default variable name, and click OK.

From the Gauges tab, click the Open icon, and load the image file EasyImage\CCD.tif.

Keep the default variable name for the new image object, and click OK.

Step 2: Attach a line gauge to the image

In the Gauges tab of the world shape dialog box, right-click the world shape icon, select New > Line Gauge from the contextual menu.

Keep the default variable name, and click OK. The line location gauge appears on the image. It consists of the following elements:

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A blue line segment along which the transitions search is carried out.

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Five white handles, allowing the user to move and rotate the segment.

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A gray arrow, indicating in which direction the segment is traversed.

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Black and white rectangles, indicating which kind of transition is searched for.

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Green line, indicating the transition points found (if any).

Using the handles, move, rotate and extend the line gauge, so that it is positioned on the upper edge of the CCD package, with the gray arrow pointing downwards.

In the Measurement tab of the line gauge dialog box, choose 'White to Black' from the Type dropdown list and 'From Begin' from the Choice dropdown list.

Step 3: Perform the inspection

The image is automatically inspected. However, clicking Process in the world shape dialog box will insert the corresponding code into the script window.

Click the Results tab to retrieve the measured angle value.

To see the individual fitting points, select the Points checkbox under the Draw Samples area.