Activity 12 | Color Image Segmentation

It is a common problem in image processing when the region of interest is more than a problem of separating it from a background, or an application of threshold especially when the image involves a great variety of colors. In this activity the region of interest is isolated from the image by image segmentation using color in such a way that different brightness levels are not a problem by converting the RGB color space of the image to the Normalized Chromaticity Coordinates or NCC which is shown in Figure 1.

Figure 1. Normalized Chromaticity Coordinates

Image segmentation can be done in two ways. First is the parametric segmentation and second is non-parametric segmentation. Parametric segmentation involves the use of image patches of the color of the ROI and its histogram. The ROI can be isolated by doing histogram backprojection to the image using the histogram of the patch of the ROI. Figure 2 shows the original image used for this activity while Figure 3 shows the patches used and the resulting image after applying histogram backprojection to the image using the histogram of the color patch.

Figure 2. Original image. Hibiscus.