Column Profile Plot

A Column Profile plots the pixel values along a line parallel to the image columns. The column(s) to be plotted are located using the Image Cursor. This type of plot shows changes in image intensity, or pixel value, in the vertical direction. The X axis of the plot measures the row number in the image. A column profile plot can also be created using the Line Profile tool to draw precisely along a single column (hold down the Shift key while drawing).

World Coordinates

If the image has a World Coordinate System calibration, moving the plot pointer along the plot X axis reflects the world coordinate change in row number along the image Y axis. The same image pixel value applies at a given row number regardless of the plot Y value.

Types of Column Profile Plots

This command plots the following types of profiles:

Single Column
Averaged Column. Various methods are available for combining the columns; see Plot Averaging Mode.
Range of Columns showing multiple rows on the same graph.

If the Image Window contains an Image Set, Mira can make the above types of plots for the entire image set or for only the top image; this is controlled by the state of the Graph Image Set mode of the Image Window.

The Window Caption describes the type of plot that is displayed:

An Average Column Profile plot has the suffix [ACP] in the window caption.
A simple Column Profile of one column has the suffix [CP] in the window caption. This command is also operated using the 'V' (vertical, column) keystroke command when the Image Cursor is placed near the peak of a point source.

To plot a column profile:

Adjust the image cursor to cover the desired pixels.
Click the plot button or execute the menu command to create the plot.
Use the procedures below to plot a single column, averaged column, or range of columns.

Procedures

Plotting a Single Column

Set the command mode to Cursor Mode.
Click the mouse on the image to position the Image Cursor.
Adjust the corners or edges of the Image Cursor until it defines the region you wish to average. Combine moving and sizing operations to get the image cursor where you want it.
Execute the Plot > Column command in the menu or click the button to make the plot. Alternatively, you can use the 'v' (vertical, column) keystroke command when the Image Window has focus.
The Plot Bar world coordinates refer to the image along the plotted column.

Plotting an Average Column

Mira can combine the neighboring columns and plot the result as a single line of data. Mira provides different options for combining the adjacent lines to create the plot; see Plot Averaging Mode.

Set the command mode to Cursor Mode. If the image cursor is a rectangle, it outlines the region to be averaged into a single column. If it is a crosshair, the averaged region is the number of columns spanned by the crosshair. In both cases, the same number of columns will be averaged.
Combine moving and sizing operations to get the image cursor where you want it. Click the mouse on the image to position the cursor and adjust the corners or edges until it defines the range of columns to average.
Select the column combining method by choosing an option in the Combine Mode submenu of the buttons' drop menu or use the image Plot menu or Image Context Menu. The name in the menu adjusts to the selected method.
Execute the selected [Average Column] mode from the menu. The plot title depends on the currently selected Averaging Mode. Also see Plotting an Averaged Line.
The Plot Bar world coordinates refer to the image along the average column location.

Plotting a Range of Columns

This command plots all rows inside the image cursor box to view them simultaneously or as an animation.

Set the command mode to Cursor Mode. If the image cursor is a rectangle, it outlines the region of columns to be plotted. If it is a crosshair, the span of the crosshair defines the number of columns to be plotted. In both cases, the same number of columns will be plotted.
Combine moving and sizing operations to get the image cursor where you want it. Click the mouse on the image to position the cursor and adjust the corners or edges until it defines the range of columns to plot.
In the plotting menu set the Plot Series Mode to Overplot and then use the Range of Rows command. You can later change the Plot Series Mode from the Plot Window using its Context Menu.
The Plot Bar world coordinates refer to the image along each plotted column within the range.

Changing the Plot Appearance

After you have made the plot, the properties can be changed using the Plot Properties dialog. This includes properties such as the minimum and maximum extent of the axes, the tick marks, axis labels, fonts, colors, and more.