Measuring Images


Mira provides many tools for measuring and quantifying images, including distance and angle, statistics, photometry, shape measurements, and others.

Measurement procedures are operated through buttons, menu commands, and command toolbars. Measurements share a common user interface in terms of how the target object is marked and how the results are displayed in a Grid Control (also called a "report" or "table") You can also create a scatter plot, including error bars, from two columns in a table of measurements. Other types of plots and point samples are also useful for quantifying images.

Measurements are divided into classes according to whether they use the Image Cursor or the Mouse Pointer to mark locations. All measurements that use a toolbar use the mouse pointer. Conversely, all measurements that use the image cursor operate from a button (or a duplicate entry in a menu). All Command Toolbars all have a similar interface

Measuring a Single Image or Image Set

Most measurements offer the option to measure one or all of the images of an Image Set. If an Image Set is open in the Image Window, you can choose whether to measure only the currently displayed member of the image set or to repeat the measurement for all images of the image set. This is done using the Measure Image Set button in the Image Set Flags group on the Image Bar. When the button face shows a "1", then only the current (one) image is measured, otherwise, the entire image set is measured.

Measurements that use the Image Cursor

These commands list their results in a Report Window or a Measurement Pane (the default for a new Mira installation). They also have menu commands in case the button is not accessible.

These commands can also be operated using a single keystroke command.

Centroid: Reports a high precision position for a peak or trough.

Statistics: Reports statistics inside a rectangular region. Use the Statistics Properties to select the statistical estimator and set its parameters.

Measurements that use the Mouse Pointer and a Toolbar

These commands list their results in a Measurement Pane:

Distance & Angle: Measures the distance and angle between two points.

Aperture Photometry: Makes photometric measurements of stars and other objects.

Measurements that use the Mouse Pointer

Image Coordinate Readout: The "live" cursor in the image window measures image coordinates and values.

  

Tip

The difference between measurements made by the mouse pointer and image cursor is generally as follows:

Measurements that use a window toolbar use the mouse pointer to mark or drag markers on the image.

Measurements that use menu commands and buttons on the Image window or main toolbar use the Image Cursor as a position reference.

Related Topics

Contents, Grid Controls, Measurement Panes, Report Windows, Command Toolbars, Image Windows, RGB Image Commands, Create Plot from Table Data, Create Chart from Table Data, Open Table in Excel, Image Tool Keystroke Commands