Color detection for curves

Color detection

Instead of manually defining curves and selecting data points, you can use the Color detection feature to perform this task automatically.

Color and Sampling

The Color and Sampling options allow you to select a curve and extract data points from it. You can fine-tune data point extraction using the Tolerance and X sampling sliders.

Procedure

1. On the Color detection page, click directly on the curve whose data points you want to detect.

The Curve color box changes to the color of the selected curve and the Tolerance and X sampling sliders are activated. Figure 5: Color detection

Note If you want to change to a different curve, click the Curve color box again to reset the selection, and click on a different curve.

2. Use the Tolerance slider to adjust the sensitivity of the color detection.

Moving the slider to the left decreases sensitivity; to the right increases sensitivity. You can use your mouse cursor, or the arrow keys on your keyboard to do this. You will notice that the higher you set the tolerance the more points you add to the curve, but if the tolerance becomes too high, the detection process can start to include points outside the target curve. Note You can define detection areas to limit the area of the image used for data point extraction, as described below.

3. Use the X sampling slider to adjust the number of points detected on the curve.

You can use your mouse cursor, or the arrow keys on your keyboard to do this.

4. When you have set the tolerance and sampling for your curve, click Validate.

The curve is added to the Curves list with the extracted data displayed in the Data table. You can then manually add, move or delete points as required.

5. Click the Color detection button again if you want to detect a new curve.

You are prompted to either remove all detected points or to create a new curve.

If you select Remove all points, you return to the Color detection page. If you select Create new curve, the detected curve is added to the list, and you return to the Color detection page.

Image trims

You can limit the detection of data points to specific areas of your image, either to include a region, or to exclude it.

Two methods are available for defining regions to include or exclude:

• rubber-band rectangle

• highlight with a brush

You can use these two methods in conjunction to define multiple detection areas. In other words, you can use the brush method in one area of the graph, and the rectangle method in another.

Note

If you define multiple detection areas, each area must either use Include or Exclude mode (see below). You cannot define one zone to include data points and another to exclude data points simultaneously.

When a zone is defined, it is highlighted in white, and the rest of the image appears in grayscale.

Figure 6: Image trims

Click the Image trims toggle to enable the Image trims tools and modes. The following tools are available:

• Tool: use the icons to select either the rubber-banding or the brush method.When you select the brush method, you can adjust the brush size.

• Mode: When set to Exclude, no data points are extracted from the selected area. Include has the opposite effect.

• Area:

Clear: click this button to remove any currently-defined areas.

Invert: click this button to invert the area being defined. That is, data points are either detected within the area defined, or outside the area defined.