JP2013029520A - Appearance quality measurement method for polished rice and unpolished rice - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for measuring appearance quality of polished rice etc., that can determine quality of each of respective sample grains even if tens of samples are successively supplied during determination on appearance of polished rice etc., in which a computer system automatically determines appearance quality of a polished or unpolished rice sample and displays the quantity and constitution ratio thereof when the sample is supplied.SOLUTION: An appearance quality measurement method for polished rice and unpolished rice includes the processes of: photographing polished rice etc., placed on a sample table by a camera; saving an original image in a data format corresponding to an RGB or YUV model by a frame grabber; binarizing the saved image; generating a two-dimensional image in a contour form from the binarized image; making the two-dimensional image three-dimensional, and extracting a border line; separating images of the polished rice etc., which are in contact with each other with reference to the border line, and labeling the respective images; and analyzing the respective labeled images and determining the proportion and quantity of one or more of complete rice, powdery rice, broken or moth-eaten rice, cracked rice, discoloring rice, etc.

Description

The present invention relates to a method for evaluating the appearance quality of white rice and brown rice, and in particular, complete rice contained in a certain amount of rice, powdery rice, waste rice, colored rice, cracked rice, etc. The present invention relates to a method for measuring the appearance quality of white rice and brown rice that can automatically determine the proportion and the proportion of completely brown rice and powdery brown rice, waste rice, colored brown rice, immature brown rice, etc. contained in brown rice.

  It has only been over 20 years since the Republic of Korea has been able to eat as much rice as possible while having a long history of rice cultivation. However, recently, with the absolute decline in rice consumption, the amount of rice stock in Korea has been increasing rapidly due to the increase in the amount of imported goods and annual harvest (Minimum Market Access). It is a fact. As a result, the amount of rice stock in the Republic of Korea exceeded 10 million 俵 at the end of 2005. In addition, the cost of Korean rice is significantly higher than rice produced in the US and China, and its price competitiveness is low.

  On the other hand, the development of the national economy of Korea and changes in the diet of the people have recently increased the preference for high-quality rice, increasing the need for high-quality rice production. In particular, in order to protect Korea's rice, the most important issue is to produce high-quality rice that meets consumer preferences, as South Korea's rice is less price competitive than foreign-produced rice. Was raised.

  In the end, nutrition and taste are regarded as important for the quality of rice. However, depending on how the rice is used and the main body handling the rice, the appearance of the rice is often subject to quality evaluation. What is related to the appearance quality of such rice is the ratio of complete rice, waste rice, powdery rice, colored rice, etc. contained in the rice. These are known to affect not only the merchantability of rice but also the taste of rice. The agriculture and forestry department in the Republic of Korea divides rice quality into three grades (Agricultural and Forestry Department Notification No. 2005-59). Each grade is categorized based on the appearance quality of the rice, such as the content of moisture, waste rice, powdery rice, damaged grains, heat damaged grains and foreign matters.

  On the other hand, the appearance quality of rice is generally evaluated by the examiner's eyes. However, the results obtained based on visual judgment are generally affected by the inspector's proficiency level and personal prejudice, fatigue, illumination type, brightness, and the like. For these reasons, determination is not objective and quick determination is difficult, and much labor and time are consumed. Therefore, there is a demand for development of a mechanical device that can quickly and objectively evaluate the appearance quality of rice.

  Currently, in foreign countries, machinery is used to take an image of rice while supplying rice one by one, analyze the image with a computer, and evaluate the appearance quality. However, although these devices are faster than the visual judgment, there are problems that the required time is relatively long, the accuracy is low, and the price is high.

  Machine vision is a combination of image processing technology and pattern recognition technology with computer technology. Machine vision is a high-potential technology that can be used in agricultural food processing processes, and many studies have been conducted to apply machine vision to quality inspection and grading of agricultural foods. Conventionally, quality inspection of agricultural foods has been dependent on visual inspection, but in most cases, visual inspection requires a long time, requires many personnel, and tends to reduce the accuracy of work. In contrast, inspection of agricultural foods using machine vision has proven to be much more consistent, convenient and cost-effective (Lu et at., 2000; Tao et al., 1995).

  When machine vision is used, an image is captured by a camera and converted into a digital image that can be recognized by a computer, and an image analysis process that analyzes the digital image and extracts necessary information. be able to.

  Whether or not the image capture is successful is basically related to appropriate lighting. Illumination characteristics vary depending on the characteristics of the object and the image capturing apparatus used. Various types of lighting devices such as fluorescent lamps, halogen lamps, and LEDs can be used as the lighting device, and methods such as front lighting, rear lighting, and slant lighting are used depending on the direction in which the object is illuminated with light. An image device scans an image formed on a sensor such as a point sensor, a line sensor, or a surface sensor using an optical device such as a photodiode or a CCD (Charge Coupled Device), and converts the image into an electric signal. The analog image signal obtained here is spatially sampled in the x and y directions and then converted to a digital image signal by A / D conversion. The image data after A / D conversion is stored in a frame buffer as a single image frame. The frame buffer can be imaged and displayed in real time.

  The purpose of applying machine vision is to extract necessary information from the obtained image. For this purpose, an operation for processing an original image obtained by machine vision into a format related to a desired signal is performed. This is called image processing. That is, various operations are performed to remove noise contained in the image, extract features of the image, and the like. In such an image processing process, information included in the image is not converted, and techniques such as contrast enhancement, corner enhancement, noise removal, sharpening, and enlargement are used to emphasize important features of the image.

  Image segmentation is an operation for separating a target object from a background in order to extract necessary information from an image. For example, the background is separated from the rice image and only the rice image is extracted. The image after image division is expressed in a form suitable for post-processing. There are two types of expression methods: external characteristic (boundary) expression and internal characteristic (pixel) expression method. In these methods, an image is displayed using a two-dimensional mathematical expression or function or a special indicator. An image in a two-dimensional space can be displayed as a region, a boundary line, or a contour line. A region is a part of an image in which parts having similar or identical properties such as outline, wood grain, and color are displayed separately. The boundary line is a boundary line that is embossed from the process of obtaining the contour of the object or obtained by various partitioning methods.

  An image processor is dedicated hardware that executes specific image processing at high speed, and performs basic functions such as image capture, image storage, low-level image processing, and image display. Necessary for image processing, processing a large number of images, or processing images accurately and at high speed. Most image processing digitizes one screen in unit frame time (about 1/30 second).

  Much research has been done to measure and classify morphological, optical and organizational properties of grain using machine vision. Zayas (1996) et al. For wheat variety identification, Ruan (1997) et al. For measuring the degree of wheat rot infection, Ni (1997) et al. For corn particle size measurement, and Xie and Paulsen (1997) for maize. For whiteness measurement, Ni et al. (1997) used to identify corn grains and swarf grains, Steenhoek and Precetti (2000) used to classify corn size, Liu et al. (1997) used to measure rice bran accuracy, and Yadav And Jindal (2001) applied machine vision to measure the quality of rice milling and Majumdar (1997) and others identified wheat, oat, oat and rye.

  However, in these studies, the appearance was photographed while manually aligning the grains under the camera to ensure that the individual grains were scattered widely without touching each other. In order to solve such problems, Casady, Paulsen (1989), Jayas (1999) and others developed a device that automatically supplies grains one by one, but the measuring device is complicated and expensive, and it is long to measure. There is a problem that it takes time.

  In order to solve such a problem, the appearance of the grains supplied in contact with each other is photographed with a camera, and then the images of the individual grains from the overall image are softwareized. Development of image processing algorithms to extract and analyze necessary information by separating them is being sought. The development of such algorithms is expected to contribute to the automation and simplification of grain inspection equipment using machine vision.

  As a study on this, Shatadal et al. (1995) used Mathematical Morphology to find the boundary line of the contact part by eroding the grain image and then dilating it. An image processing algorithm was developed. According to this algorithm, the recognition rate of individual grains is 95% for HRS and Durum wheat, 94% for wheat, 89% for rye, 79% for oats, and the grain shape It is said that the accuracy of recognition of individual grains decreases as the point becomes narrower or the number of grains in contact with each other in the length direction.

  Shashidhar et al. (1997) developed a computer algorithm that draws an ellipse that most closely approximates the shape of the grain using the Ellipse Fitting method and recognizes each ellipse as a grain. Then, Visen et al. (2001) used the ellipse fitting method developed by Shashidhar et al. To recognize grains that are in contact with each other as being in contact with each other, and then contacted ellipses. An algorithm has been developed that recognizes individual grains by comparing and analyzing the curvature change of the outer shell to find and separate contact points. As a result of experiments on wheat, wheat, rye and oats, an average success rate of 98.6% was obtained.

  However, according to this algorithm, if the change in curvature at the contact point is not clear, or if the boundary surface is irregular and the contact surface is not clear, the individual grains are separated from the images of the grains in contact with each other. Sometimes it is said that the identification accuracy is inferior. In addition, these methods have high applicability to grains with similar shapes, but different types of grains or cracked grains with different shapes are mixed in, or the shape in which the grains are in contact is not good. It is said that the accuracy of separating and recognizing individual grains becomes low when the rules are complicated.

The object of the present invention has been devised to solve the above-mentioned conventional problems, and in order to obtain high judgment accuracy in a short time in evaluating the appearance quality of white rice and brown rice, Alternatively, instead of supplying brown rice one by one, dozens of white rice or brown rice is supplied together, and the white rice or brown rice is stored in a single image and the appearance quality of each grain is analyzed by computer image processing. It is to provide a be that way.

When the rice is processed into brown rice or rice, the brown rice includes completely brown rice, belly white brown rice, colored brown rice, cracked brown rice, cracked brown rice, etc. The rice includes full rice, belly white rice, colored rice, cracked rice, cracked rice, etc. Is included. The higher the percentage of complete rice or complete brown rice, the better the quality. Accordingly, in the present invention, when a sample of white rice or brown rice is supplied, the computer system automatically determines the appearance quality of the sample and displays the number and composition ratio. the Unlike existing systems to determine supplying one grain, be continuously supplied dozens of samples, it is possible to determine the quality of each respective sample grain, white rice and brown rice An object is to provide a method for measuring appearance quality.

That is, the present onset Ming, process and to take a polished rice or brown rice was placed on the sample stage by a camera; data corresponding to the RGB or YUV model original image milled rice or brown rice that has been taken by front Symbol camera by a frame grabber Storing in the form; and binarizing the stored image;
A process of creating a contour two-dimensional image by distance transforming the binarized image to the shortest distance (Distance Transform); and converting the two-dimensional image into three dimensions and extracting a boundary line through a watershed transform Separating the white rice or brown rice in contact with the boundary line, and labeling each white rice or brown rice; analyzing each white rice or brown rice labeled in the above step A process of determining the ratio and number of one or more of rice, powdered rice, waste rice, cracked rice, colored rice, or completely brown rice, powdered brown rice, waste rice, cracked brown rice, colored brown rice This is a method for measuring the appearance quality of white rice and brown rice .

  In addition, according to the method for measuring the appearance quality of white rice and brown rice according to the present invention, the step of binarizing the stored image can actively calculate a threshold value of concentration for distinguishing white rice or brown rice from the background. In addition, the Otsu algorithm is used.

White rice and appearance quality measurement Sadakata method of brown rice of the present invention therefore, by determining the mechanical reference, as well as saving labor and time required when determining visually, ensuring the objectivity of judgment There is an effect that can be.

Further, when determining the appearance quality of milled rice and brown rice according to rice and appearance quality measurement Sadakata method of brown rice of the present invention, unlike existing systems to determine by supplying milled rice or brown rice by grain, Even if several tens of white rice or brown rice is continuously supplied, the quality of each white rice or brown rice grain can be determined. Furthermore, since a device that supplies white rice or brown rice one by one is no longer necessary, the product price of the measuring device can be dramatically reduced, and it can be distinguished in real time while supplying dozens of rice grains or brown rice grains. Therefore, the determination time can be shortened.

Figure 1 is a block diagram schematically indicate to the device to be used in rice and appearance quality measuring method of the brown rice according to the present invention. FIG. 2 is an actual photograph showing a prototype of an apparatus used in the method for measuring the appearance quality of white rice and brown rice according to the present invention. FIG. 3 is a flowchart illustrating an image processing process according to the present invention. FIG. 4 is a graph showing a density histogram of a digital image according to the present invention. FIG. 5 is a flow chart showing the separation process of the contacting sample. FIG. 6 is a diagram illustrating a process of binarizing without using the Otsu algorithm. FIG. 7 is a diagram illustrating a process of binarizing using the Otsu algorithm. FIG. 8 is a diagram illustrating a distance conversion process. FIG. 9 is a diagram showing a process of searching for a boundary line of a sample that is in contact. FIG. 10 is a diagram showing a map line formation process by boundary separation between samples in contact with each other. FIG. 11 is a drawing showing an image of broken rice. FIG. 12 is a drawing showing images of colored rice and powdery rice. FIG. 13 is a drawing showing an image of complete rice. FIG. 14 is a diagram illustrating a process of searching for a crack. FIG. 15 is a view showing the analysis result of broken rice. FIG. 16 is a drawing showing the results of analysis of powdery rice. FIG. 17 is a drawing showing the analysis results of colored rice. FIG. 18 is a drawing showing the analysis results of complete rice.

Hereinafter, with reference to the accompanying drawings according to the present invention will be described in detail rice and appearance quality measurement Sadakata method brown rice.

FIG. 1 is a configuration diagram schematically showing an apparatus used in the method for measuring the appearance quality of white rice and brown rice according to the present invention. FIG. 2 is an actual photograph of a prototype used in the method for measuring the appearance quality of white rice and brown rice according to the present invention. FIG. 3 is a flowchart showing the image processing process of the present invention. FIG. 4 is a graph showing a density histogram of a digital image according to the present invention. FIG. 5 is a flow chart showing the process of separating the contacting rice. FIG. 6 is a diagram showing a process of binarizing without using the Otsu algorithm. FIG. 7 is a diagram showing a process of binarizing using the Otsu algorithm. FIG. 8 is a diagram illustrating a distance conversion process. FIG. 9 is a diagram showing a process of searching for a border line of the contacting rice, and FIG. 10 is a diagram showing a map line forming process by boundary separation of the contacting rice.

The apparatus used in the method for measuring the appearance quality of white rice and brown rice according to the present invention is a transparent or semi-transparent material, a sample stage 30 on which a white rice or brown rice sample is placed on the upper surface; installed at the bottom of the sample stage 30; A rotating disk 50 for rotating the sample stage 30; a supply cylinder 40 which is installed on the upper part of the sample stage 30 and supplies white rice or brown rice to the sample stage 30; and the sample stage 30 provided inside the supply cylinder 40 A rotating roll 41 for adjusting the amount of white rice or brown rice supplied to 30; upper and lower lights 21 and a lower part, which are installed on the upper and lower sides of the sample stage 30, respectively, apart from the sample stage 30 and illuminate the white rice or brown rice Illumination 22; CCD camera 20 installed on the upper side from the sample stage 30 and photographing white rice or brown rice on the sample stage 30; photographed by the camera 20 using an image processing program A computer that processes the image and determines the appearance quality. A frame grabber 11 provided inside the computer 10 for controlling the camera 20; white rice or brown rice from the supply cylinder 40 in response to a signal relating to the operating state of the camera 20 from the frame grabber 11; A speed adjuster 60 for controlling the supply speed and the rotational speed of the rotating disk 50; and a discharge separating plate 51 for separating white rice or brown rice that has been photographed by the camera 20 installed on the upper surface of the sample table 30; It includes a collecting cylinder 52 that is provided at the lower part of the sample stage 30 and collects white rice or brown rice separated by the discharge separation plate 51, and a support stage 70 that supports these devices.

  The upper illumination 21 has higher illuminance than the lower illumination 22. The camera 20 is provided so as to be movable in the vertical direction while adjusting the lens to change the focal length. The frame grabber 11 adjusts the lens of the camera 20 according to the brightness of the upper illumination 21 and the lower illumination 22, and controls the rotating roll 41 inside the supply cylinder 40 to adjust the supply amount of white rice or brown rice. . Further, the computer 10 may be one or more of perfect rice, powdered rice, waste rice, cracked rice, colored rice or completely brown rice, powdery brown rice, waste rice, cracked brown rice, colored brown rice, and immature brown rice. The appearance quality of the whole white rice and brown rice is automatically determined.

  The process in which the computer 10 determines the appearance quality of white rice and brown rice is as follows.

  A sample of white rice or brown rice placed on the sample stage 30 is photographed with a camera. An original image of the sample taken by the camera 20 is stored by the frame grabber 11 in a data format corresponding to the RGB or YUV model. Evolve the stored image. The transformed image is distance transformed to the shortest distance (Distance Transform) to create a contour two-dimensional image. The two-dimensional image is three-dimensionalized and a boundary line is extracted through a watershed transform. Samples that are in contact with each other based on the boundary line are separated, each sample is labeled, each labeled sample is analyzed, and complete rice, powdery rice, waste rice, cracked rice, The ratio and number of one or more of colored rice or completely brown rice, powdery brown rice, waste rice, cracked brown rice, colored brown rice, and immature brown rice are determined.

  In order to binarize the stored image, it is preferable to use the Otsu algorithm so that a concentration threshold value for distinguishing between the sample and the background can be actively calculated.

Hereinafter, embodying the general structure of the, described experimental example of the milled rice and appearance products position measuring method of the brown rice of the present invention.

1. Experimental materials As the rice used in the experiment, the rice processed in the general grain processing plant (produced in 2002) is visually inspected at the processing site to produce complete grains (Sound kernel), broken rice (Broken kernel), and powdered grains (Chalky) kernel) and colored kernels. The standard of rice grade classification is based on the standard announced by the Ministry of Agriculture and Forestry of Korea. Complete grains, rice appearance properties on the inner although has a rice is not cracked, 3/4 or more forms of even rice cracked complete grains having an average length, powdery substance grains, Heat loss grains and damage grains were excluded, and the average length of each grain was calculated by measuring 15 or more complete grains. Kuzumai, of the Korean Industrial Standard KS A 5101 standard sieve, in what remains on the Furutte sieve with a net sieve size 1.7mm call, was cracked in less than 3/4 of the full grain average length grain. The powdery grains were grains having a powdery state with 1/2 or more of the volume. The colored grains were damaged grains, heat loss grains, and the like, and grains colored 1/4 or more of the grain length.

2. Appearance quality judgment device An appearance quality judgment device having an illumination device, an image processing device, and a rice supply / discharge device was manufactured to measure the appearance quality of rice. The configuration of the apparatus will be described with reference to FIG. 1 and FIG.

A. Illumination device An incandescent lamp with 12W capacity is installed as the upper illumination 21 on the top of the sample stage 30 on which the rice to be analyzed is placed, and two fluorescent lamps with 4W capacity are installed as the lower illumination 22 at the lower part of the sample stage 30. did. The rice was illuminated with a lighting device. At this time, in order to adjust the light quantity of the lower illumination 22 irradiated from the lower part of the sample stage 30, the sample stage 30 was made of a white translucent acrylic plate. Here, the sample stage 30 is preferably transparent or translucent, and if the illumination brightness at the time of measurement changes, an error may occur in the measurement result, so the illumination brightness is measured before the measurement. If it is different from the reference value, the lens of the camera 20 is adjusted to adjust the brightness to the reference value.

B. Image processing device The image processing device is a color CCD camera 20 (LG Honeywell, GC-450NA-G), frame grabber 11 (WDM method, using BT878chip, self-made) and PC10 (Pentium IV 2.0G, DDR-RAM 512MB). Configured. The image processing apparatus used for the inspection takes an image of the supplied rice using the CCD camera 20 and the frame grabber 11 provided in the PC 10, and analyzes the taken image with the image processing program of the PC 10. I saved it.

  The CCD camera 20 was moved up and down so that the height could be adjusted, and a lens with a focal length of 6 mm and a brightness of F1.2 was attached. If the size of the rice grain image changes due to the position of the camera 20 or the lens change, an error occurs in the measurement result. Therefore, the size of the coin was measured before the measurement, and if it was different from the reference size, the position of the camera 20 and the lens were adjusted to match the size with the reference value.

  The frame grabber 11 has no RAM recognition limit compared to Windows (registered trademark) 98 (depending on the specifications of the main board, but recently recognizes up to about 4 GB of DDR-RAM) Windows (registered trademark) 2000 and Windows (Registered trademark) A self-made one using a WDM (Windows (registered trademark) Driver Model) type BT878 chip (chip) was used so that it could be used in the OS of XP. That is, a normal frame grabber can recognize only up to 128 MB even when using an OS of Windows (registered trademark) 98 and using RAM of 128 MB or more. = 921600 Bytes) image data takes a long time to process.

It is also possible to shoot with the VFW (Video For Window) method that uses the shooting function of a general inexpensive TV card, but it takes time to shoot an image with a resolution of 640 x 480 that is suitable for research use. It takes more. Therefore, a driver limited to the VxD method must be provided. When the driver is not a VxD system, it is possible to shoot at a resolution of 320 × 240 and lower. If you need a 320 × 240 or better resolution, because it must know the API of the card manufacturing company, it is possible to actually use impossible. The image processing program of the PC 10 was created using the Visual C ++ language by the MFC (Microsoft foundation Class Library) method.

C. Rice supply and discharge device The rice supply device for supplying samples continuously is a rice supply cylinder 40 for discharging rice by a fixed amount by a rotating roll 41, and a rotation for transferring the supplied sample to the lower side of the camera 20. A disc 50, a discharge separation plate 51 for separating the sample after photographing, and a collecting cylinder 52 for collecting the sample were constituted. At this time, if the rice moves while the camera 20 captures an image, an accurate image cannot be captured. Therefore, the rice supply was stopped while taking the image, and it was supplied again after the image was taken. That is, the frame grabber 11 is configured to detect the operating state of the camera 20 and open and close the power supply relay at intervals of 0.001 seconds. For this purpose, the operation of the motor for driving the rotating roll 41 of the rice supply cylinder 40 and the rotating disk 50 for transferring the rice was controlled. In order to adjust the amount of rice supplied, the speed controller 60 is used to manually adjust the rotation speed of the motor that drives the rotary roll 41 and the transfer rotary disk 50 of the rice supply cylinder 40. I made it. In this case, the lower illumination 22, the speed controller 60, and the collecting cylinder 52 were mounted on the support base 70.

3. Image processing Image processing is the most basic processing for digital images, and includes removal of noise contained in the image, extraction of features of the image, and filtering operations for performing various basic operations. . Image processing techniques can be classified into various forms depending on the application object. In the present invention, image processing is performed according to the procedure shown in FIG. 3, and each rice grain is separated and identified from an image of rice supplied one by one, and necessary information is extracted.

A. Image Capture The original rice image captured by the color CCD camera 20 was stored in memory by the frame grabber 11 in a data format corresponding to the 640 × 480 pixel YUV2 model. The YUV2 model data was converted to RGB24 model data and stored in a buffer. Normally, color images are displayed with RGB components, but the reason for displaying them in YUV format is that if the images are displayed with luminance and color difference components, memory can be used more efficiently than RGB, and processing can be performed at a higher speed. Because it can be done. The reason why the memory can be used efficiently in the YUV format is that color difference components are not given to each pixel, but one color difference component is given for every four pixels. That is, in the case of the 4: 1: 1 YUV format, four pixels constituting the image are bundled, the luminance (Y) is sampled, and the average value of the four pixels is taken as the color difference (U, V). . Therefore, since there are 4 luminances and 1 color difference (U, V) for each pixel, 6 samples are obtained in total. Therefore, the memory can be reduced to 1/2 compared to the RGB case where there are 3 samples for 4 pixels and 12 samples in total. If it is 4: 2: 2 instead of 4: 1, 1: 1, it becomes a YUV2 model.

B. This is a technique for expressing a digital image with only two values, black 0 and white 255, in order to extract specific information by separating the background and the analysis object from the captured image. When separating the background and the characteristics of the object to be analyzed, a lightness threshold is set. By setting the value below the threshold to 0 and the value above the threshold to 1, the object can be easily identified. The threshold setting may be determined by the user's judgment, or a technique for determining the dynamic threshold may be used. In the appearance quality determination device, since several tens of rice are supplied together and one image is taken, the brightness of the image changes depending on the number of supplied rice.

Therefore, if a fixed threshold is used, an error occurs in binarization. Therefore, the dynamic threshold is determined using the Otsu method. The Otsu method is an algorithm proposed by Otsu in 1979, and is one of the algorithms that have been referred to so far, and automatically finds a threshold value from a histogram of a dynamic image. An outline of the Otsu method is as follows. When an image having a gray level (Grey level) from 0 to L-1 represents a distribution like the histogram in FIG. 2, assuming that an arbitrary gray level between 0 and L-1 is k, k is As a reference, it can be divided into a left region from 0 to k points and a right region from k + 1 to L-1. At this time, the k value is determined as the point at which the variance (σ ² B (k)) between the two regions is maximized.

  Here, k is an arbitrary threshold, μT is an average value of the histogram, ω (k) is a zero-order cumulative moment, μ (k) is a first-order cumulative moment, p (i) is a normal probability density function of the histogram, n ( i) is the number of pixels at gray level i, and N is the total number of pixels.

  This method is not based on changes in the histogram due to external factors such as lighting and noise, but actively according to a histogram that changes when the amount of rice to be measured changes and the brightness of the rice grains changes. Can be detected.

C. Boundary separation of adjacent rice In digital images, even if the rice is separated from the background, a large number of rice is in contact with each other, so in order to extract information on individual rice grains, All must be separated and recognized. To find and separate the borders of rice that touch each other, a watershed algorithm was applied as shown in FIG. First, using a 3 × 3 Euclidean mask, a contoured image is created by distance transforming the binarized image to the shortest distance from the outline.

  In order to perform a watershed transform, a 2D image was converted to 3D. Discriminate the ridgeline of rice that touches from the three-dimensional image, create an additional image, combine this with the binarized original image, attach the boundary line at the part where the rice touches, and touch The rice grains are separated and images of each rice grain are extracted.

  Next, unnecessary images such as an image where the edge of the image was frayed and destroyed, or a small dust and a foreign substance larger than ordinary rice were removed (Edge off). For the selected rice grain image, each rice grain was labeled with an identification number for independent classification.

D. Appearance quality judgment of rice In order to use it as a standard sample for judging the appearance quality of rice, the rice was visually classified into complete rice, waste rice, colored rice, powdery rice, and cracked rice. These standard samples, taking an image using the rice appearance quality judging device, and extracts the image data used for appearance quality determination. In the present invention, the major axis length, shortened length, width, area, perimeter length, red (Red), green (Blue), blue (Blue), blue-green ( Cyan), reddish purple (Magenta), yellow (Yellow), black (Black), hue (Hue Value), saturation (Saturation), density (Intensity) average and standard deviation image data was extracted and used .

3. Rice Appearance Quality Judgment Algorithm A. Image binarization and correction of rice brightness change When separating rice and background from a digital image, a threshold T = 165 is applied to two images with different brightness, as shown in Figure 4. Since the brightness changes when it is binarized, the rice and the background are not clearly separated, so the threshold must be changed according to the change in brightness. This is a phenomenon that occurs when the intensity histogram changes due to changes in the brightness of each rice depending on the amount of rice supplied.

  In order to prevent this, a computer program that actively calculates the threshold of concentration for distinguishing rice and background was created using the Otsu algorithm. FIG. 7 shows threshold values calculated for two images with different brightness and binarized results using the Otsu algorithm. By using the Otsu algorithm, it is possible to actively calculate a concentration threshold for distinguishing rice from the background. Compared to Fig. 6 which shows the result of binarization without using the Otsu algorithm, we can confirm that the performance of binarization has been improved.

B. Boundary separation of rice in contact Even if the rice is separated from the background in the digital image, a large number of rice is in contact with each other. Therefore, in order to extract information on individual rice grains, it is necessary to separate and recognize all the rice in contact. A distance transform and a watershed transform algorithm were applied to find and separate the borders of the touching rice. FIG. 8 shows the process of distance conversion. A distance map (Distance map) having contour lines as shown in FIG. 8 (d) was created from the binarized image as shown in FIG. 8 (b).

  When rice grains overlap each other, a boundary line is extracted as shown in FIG. 9 (a) by branch point transformation from an image of a distance map as shown in FIG. 8 (d) in order to separate the boundaries. This is called basin division, and there are division using distance conversion, division using inclination, and division using marker control. In the present invention, basin segmentation by distance conversion is used. If the image of the valley ridge obtained in this way is inverted (Inverse) and then joined with a binary image (And), the borderline of the rice that is in contact is recognized apart. FIG. 9 is a diagram showing the process of finding the borderline of the rice in contact.

  The accuracy of finding the valley ridge is also greatly influenced by the distance of the distance map. In other words, if the distance between the distance maps is too large, it becomes difficult to detect the basin ridgeline. When the distance between the distance maps is too small, as shown in FIG. 10 (b), a normal rice image is separated into several parts.

Here, in order to analyze each rice grain, as shown in FIG. 9 (d), it is called labeling to give a name by dividing the rice grain independently. For this purpose, it is determined whether the pixels are separated from each other or are in contact with each other, and different names are assigned to the separated pixels, and the same name is assigned to the pixels in contact.
In the present invention, a recursive component labeling algorithm is used.

C. Appearance quality judgment of rice The number is given to the rice by labeling and the area of each rice is calculated, but whether or not it is waste rice was determined based on the area of the rice. In general, the area of rice is the same as the total number of pixels occupied by the rice image. Therefore, the number of pixels of rice becomes the area of rice, and in the present invention, when the number of pixels of the rice image is 1,000 or less, it is determined as waste rice. FIG. 11 is a diagram illustrating an image of waste rice taken by the rice appearance quality determination device according to the present embodiment.

  Powdered rice and colored rice were judged by comparing the color information of the rice image. First, powdery rice was classified as powdery rice when Red value> Blue value and Red value> Yellow value in RGB color coordinates. However, some of the complete rice may be identified as powdered rice. Therefore, when the green value-Black value> 6,000 among the powdery rice, it was classified as complete rice. On the other hand, colored rice was classified as colored rice if Red value> Blue value but Red value <Yellow value or the number of colored pixels was 30 or more. However, some powdery rice may be identified as colored rice. Therefore, when the Yellow value-Red value was 5000 or more among the colored rice and (the number of colored pixels) X3 <(the number of white pixels), it was classified as powdery rice.

  FIG. 12 is a diagram showing images of powdery rice and colored rice taken by the rice appearance quality determination device of the present invention. Rice that was not cracked rice, colored rice or cracked rice was determined as complete rice. Also, among the complete rice, cracked rice was judged as cracked rice.

  An edge discrimination method was used to determine cracked rice. That is, cracked rice was identified using the fact that the brightness of the cracked portion of the rice surface is different from the brightness of the other portions. For this reason, the image of each rice grain was separated from the image taken with the camera, and one image was made for each rice grain. And after calculating the angle (orientation angle) that the major axis of rice is inclined with respect to the horizontal direction, the rice grains are rotated and arranged so that the major axis is horizontal, and using the vertical edge discriminating operator, The vertical edge component was extracted.

  However, not all of the extracted vertical edge components are cracked components, so vertical enhancement filtering was performed to thicken the vertical components. To separate the crack components, it was binarized using mean-standard deviation values. Next, thinning was performed to thin the thick crack component. Small cracks were removed to create a pure cracked image. The original image and the cracked image were combined to show cracks in the rice.

  FIG. 13 shows an image of complete rice taken by the rice appearance quality determination device of the present invention. In this case, FIG. 14 shows a process performed by an algorithm created for detecting cracks.

4). Manufacture of precision grade automatic judgment machine A. The structure of an automatic quality determining machine for rice bran quality An automatic rice quality determining machine with the configuration shown in Figs. 1 and 2 was manufactured. The rice bran quality measuring apparatus of the present invention includes a drive unit that supplies rice and captures an image, and a computer that analyzes the captured image. The drive unit is equipped with a rotating roll 41 and a rice supply cylinder 40 that supplies rice in a certain amount, and a rotating disk (Φ500mm) made of translucent acrylic that transfers the supplied rice to the lower part of the CCD camera 20 Consists of 50. A sample stage 30 was mounted on the rotating disk 50, and a 12 W capacity incandescent lamp for illuminating the rice as the upper illumination 21, and a CCD camera 20 (LG Honeywell, GC-450NA-G) were mounted.

  The CCD camera 20 is provided with a lens with a focal length of 6 mm and a brightness of F1.2 on the front surface, so that the focus and the amount of light can be adjusted. The CCD camera 20 was manufactured so that the height could be adjusted in the vertical direction. In addition, a discharge separation plate 51 and a collection cylinder 52 for discharging rice after image shooting are installed, and two fluorescent lamps for illumination with 4 W capacity are provided as the lower illumination 22 at the lower part of the rotating disk 50. It was. In order to adjust the speeds of the rotary roll 41 and the rotary disc 50 of the rice supply cylinder 40, a speed adjuster 60 was attached.

  The computer 10 used in the prototype was a Pentium (registered trademark) IV (2,0G, DDR2-RAM512M), and Windows (registered trademark) XP was used as the O / S. The operation method of the prototype is that after the rice to be measured is put into the rice supply cylinder 40, the operation switch of the rotating disk (50) is pushed, and the rice supplied at the front is supplied to the lower part of the CCD camera 20. Then, the operation of the rotating disk 50 is stopped. Then, press the brightness measurement mode on the computer monitor to check whether the brightness is within the reference range. After that, when the start button is pressed, rice is automatically analyzed while being analyzed. While being measured, rice images and analysis results are displayed on the monitor in real time. When the analysis is completed, the data is stored in a computer storage device as a text file while the result value is displayed on the monitor. The frame grabber 11 built into the computer is a WDM (Windows (registered trademark) Driver Model) BT878 chip so that it can be used with Windows (registered trademark) 2000 and Windows (registered trademark) XP operating systems. I made it myself. The image processing program was created using the Visual C ++ language with the MFC (Microsoft Foundation Class Library) method.

B. Rice appearance quality judgment performance As a result of arbitrarily blending rice of various forms and colors and analyzing the supplied rice using a prototype machine, the accuracy of recognizing the rice that is in contact with each other by software separation Was 98%. This accuracy was obtained when Visen et al. (2001) used the ellipse fitting method to recognize the grains that were in contact with wheat, wheat, rye, and oats as individual grains. Compared to the study result that the accuracy was 98.6% on average, it was judged to be much improved. That is, the research results of Visen et al. Show that when the curvature change at the contact point is not clear, or when individual grains are separated from the images of grains in contact with each other, the boundary surface is irregular and the contact surface is If it is not clear, the identification accuracy is lowered, and these methods can be applied to grains with similar shapes, but different kinds of grains or broken grains with different shapes, etc. This is because the accuracy of separating and recognizing individual grains decreases if the shape where the grains come into contact or the shape in contact with the grains is irregular and complicated.

  The prototype was able to judge 100% of waste rice. FIG. 15 shows the result of analyzing broken rice. FIG. 16 shows the results of analysis of 94 powdery rice and 6 waste rice. The accuracy of discrimination was 98.9% because one of the powdery rice was identified as complete rice. FIG. 17 shows the results of analysis of 95 colored rices and 5 waste rices. One of the colored rices was identified as powdery rice, and the discrimination accuracy was 98.9%. FIG. 18 shows the result of analyzing 93 perfect rices and 12 broken rices. The accuracy of discrimination was 96.8% because three of the rice were identified as powdery rice. Moreover, according to the visual discrimination of the complete grain, the number of cracked rice was 73, whereas the discrimination result by the prototype was 68, and the discrimination accuracy was 93.2%.

The time required to determine 100 rice grains was about 15 seconds. This is very short and excellent compared to the time required by the existing determination method . By using the determination method of the present invention, it is possible to provide a device that is simpler in construction than existing products and less expensive to manufacture.

According to the appearance quality measurement method of white rice and brown rice of the present invention, not only can save labor and time at the time of determination visually, so determined by the mechanical reference, ensuring the objectivity of judgment There is an effect that can be.

Further, according to the white rice and the appearance quality measuring method of the brown rice of the present invention, unlike existing systems to determine by supplying milled rice or brown rice one grain, continuously feeding dozens of milled rice or brown rice In addition, the quality of each white rice or brown rice grain can be discriminated, and a device for supplying white rice or brown rice one by one is not necessary. Since it discriminates in real time while supplying individual rice grains or brown rice grains, there is an effect that the discrimination time can be shortened.

  As mentioned above, although the preferable Example of this invention was described, this invention can be applied also to the appearance quality determination of other grains, such as wheat, wheat, oat, and rye, as well as brown rice. Further, the scope of the present invention is not limited by such specific embodiments, and those who have ordinary knowledge in the relevant field can make appropriate changes within the scope described in the claims of the present invention. It is possible.

10: Computer 11: Frame grabber 20: CCD camera 21: Upper illumination 22: Lower illumination 30: Sample stage 40: Supply cylinder 41: Rotating roll 50: Rotating disc 51: Discharge separation plate 52: Collection cylinder 60: Speed control

Claims (2)

Taking a picture of white rice or brown rice placed on a sample table with a camera;
Storing an original image of white rice or brown rice photographed by the camera in a data format corresponding to an RGB or YUV model by a frame grabber;
The process of binarizing stored images;
Creating a contoured two-dimensional image by distance transforming the binarized image to the shortest distance;
Converting the two-dimensional image into a three-dimensional image and extracting a boundary line through a watershed transform;
Separating the image of white rice or brown rice that is in contact with the boundary line, and labeling the image of each white rice or brown rice;
Analyzing the image of each white rice or brown rice labeled in the above process, complete rice, powdery rice, waste rice, cracked rice, colored rice or complete brown rice, powdery brown rice, waste rice, cracked brown rice, coloring A method for measuring the appearance quality of white rice and brown rice, comprising the step of determining the ratio and number of one or more brown rice.   The method of claim 1, wherein the step of binarizing the stored image uses an Otsu algorithm so that a threshold of concentration for distinguishing between white rice or brown rice and background can be actively calculated. The method for measuring the appearance quality of the described white rice or brown rice.