Line Profile

A line profile track is a tool for measuring brightness and other pixel data along a line on a video image. At each pixel point along the line, it can average the image pixels above and below the line to reduce noise and/or increase sensitivity.

1. Marking the Line Profile

Click and drag the mouse (crosshair cursor) to mark a line profile. The line is drawn as a narrow rectangle that surrounds the pixel points analyzed by the line profile tool.

Drag either end of the line parallel to change its length. Drag the center of the line to position it.

2. Adding Spread

To increase the number of pixels sampled for a smoother average you can give the line profile a spread (s). Select the line and enter the desired spread in pixels in the field on the toolbar.

The spread pixels extend to both sides of the pixelpoint. Thus, for a given pixel point, the total number of pixels sampled (i.e., width of the line profile) is 1 + 2s. The outline of the line profile shows all pixels included in the average.

3. Rotating the Line Profile

When the "Rotates" box on the toolbar is checked, the line profile rotates along with the coordinate axes so the line stays parallel to the x-axis. This is useful when measuring spectra that have been inadvertently captured with a tilted camera, for example.