Output depends on the brightness of the pixels in the bitmap. Brightness is defined as the sum of the red, green, and blue values for a pixel (or the grayscale value for black-and-white drawings). One path is created containing all regions that are darker than the Threshold setting. This works well for black-and-white line art.

Brightness. From left to right, the Threshold is 0.4, 0.5, and 0.6.

Brightness for a color drawing. From left to right, the Threshold is 0.4, 0.5, and 0.6.

Output depends on differences in brightness between adjacent pixels. A path is created between areas with changes that exceed the Threshold setting.

Edge detection. From left to right, the Threshold is 0.1, 0.5, and 0.9.

Edge detection for a color drawing. From left to right, the Threshold is 0.1, 0.5, and 0.9.

Output depends on changes in color between adjacent pixels. The Number of Colors gives the number of different colors that were used in looking for edges. Only one path is created; what is inside and outside of the path is based on whether the index of the color is even or odd.

Color Quantization for 4, 6, and 8 colors (from right to left).

Color Quantization for 4, 6, and 8 colors (from right to left).