**4.1.3 Determining number**

138 Advanced Topics in Measurements

calibration of the program. For this purpose software needed a calibration ruler or a

Surface areas describe as the boundries between structures. Surface area measurement of the different part of plant such as leaf projection area and fruit projection area is important for process engineering of agricultural products. So scientist use different methods for measuring areas of plant parts and one of them is image processing and analysis techniques. We need to slice products in to the pieces (Sum of these piece area give us the total surface of the agricultural product.) or select the boundries of the agricultural products for surface area measurements (Fig. 2.). They use the surface area measurements for estimating product

Fig. 2. Apple area measurement (Selection method) by using Myriad Image Analysis

dimensions help us to measure lenght of agricultural products easly (Fig. 3.).

Length measurement is usually applied in objects that have one more long dimension in comprision of others. For small objects such as seeds, lenght measurement can be done by using mage analysis and processing techniques. Photographic enlargement of the

calibration plate. Second step was true selection of images.

diameter, weight, fruit volume and pesticide usage estimation.

**4. Measurement types** 

Software.

**4.1.2 Length measurement** 

**4.1 Global measurement types 4.1.1 Surface area measurement** 

> In the area of machine vision, blob detection refers to visual modules that are aimed at detecting points and/or regions in the image that are either brighter or darker than the surrounding (Fig. 4.). There are two main classes of blob detectors (i) differential methods based on derivative expressions and (ii) methods based on local extrema in the intensity landscape. With the more recent terminology used in the field, these operators can also be referred to as interest point operators, or alternatively interest region operators.

Fig. 4. Counting the number of droplets by using ImageJ Software.

Machine Vision Measurement Technology and Agricultural Applications 141

The CIE 1976 (L\*, a\*, b\*) colour space, showing only colours that fit within the sRGB gamut (and can therefore be displayed on a typical computer display). Each axis of each square

The location of features was also needed for identify of the results. There are several definitions of location and pixels in an ordinary image For instance, the x,y coordinates of the midpoint of a feature can be determined simply from minimum and maximum limits of the pixels. Normally, starting from the top left corner of the array, the pixel addresses themselves (Fig. 7.). Global coordinate system gives us information about real pixel

ranges from -128 to 128 ( Fig. 6.) (Anonymous, 2011c).

**4.2.2 Determining location** 

Fig. 7. Set of RGB coordinate points.

dimensions values.

Also determination of the numbers of objects is important for agricaltural applications. We can determine specicif gravity, thousand grain weight, number of droplets in spraying and etc. For example, the numbers of the droplets on a leaf in pesticide application is an important parameter for determining optimum pesticide usage in agricultural products. Because pesticides effects enviroment and using them in high dozes caused to air, soil and water pollution.
