model is a specification of a 3-D coordinate system and a subspace within the system

where each color is represented by a single point (Gonzalez and Woods, 1992).

 The current implemented system is using HSI as the color space. The main reason

behind the selection of HSI model is that it correlates well with human color perception.

Hue is defined as color attribute that describes pure color (pure red or green etc.),

whereas saturation gives a measure of the degree to which light is added with a hue

component. However, as all images from the camera were encoded in composite video

format, it was converted to RGB tri-stimulus format in the imaging board. Then the

image was converted later to HSI equivalent in software for further analysis. A composite

video signal contains all of the brightness, color, and timing information for the picture.

In order for the color information to be combined with the brightness and timing,

information must be encoded. There are three main color-encoding systems in use

throughout the world: National Television System Committee (NTSC), Phase Alternation

by Line (PAL) and Systeme Electronique Couleur Avec Memoire (SECAM). The camera

utilized for this experiment used NTSC format.

 3.5 Development of the Fruit Counting Algorithm

 The steps in the fruit recognition algorithm are to identify fruits from an image and

process the results to remove noise and to improve precision in counting the number of

fruit. Segmentation or binarization is an image-processing step used to separate obj ects of

interest from background. In this research, the object of interest was a citrus fruit and the

background included citrus leaves and branches. The simplest way to segment an image

is by a gray level threshold or global threshold. This operation requires that the obj ect of

interest and backgrounds have different levels of brightness or completely different

colors. Unfortunately, the fruit portion, the leaf portion, and the background are not easily