Egg measurement method

Abstract

When an egg (10) of an unknown size transported by a conveyor is imaged from directly above by a camera (25) and a real size is determined from the size of an image of the egg, a reference surface (20) is set, the distance from the reference surface to the camera is a predetermined value (H), and a plurality of eggs having different sizes and a known maximum minor axis radius (r) are placed on the reference surface and imaged in advance, thereby determining the real size of the egg. The relationship between the actual length of the maximum minor axis radius and the length on the photograph is determined, and the relationship between the ratio of the length on the photograph to the actual length and the height h from the reference plane is determined. When the conveyor is a bar conveyor, the depth h of the lower portion of the egg between the bars (40) is corrected.

Description

Technical Field

[0001] The present invention relates to an egg measuring method for measuring the size of an egg. Background Art

[0002] The quality of eggs produced in a chicken-raising facility serves as a basis for determining whether the chicken-raising environment and feed conditions are appropriate, whether the chickens are in good health, etc., and can therefore serve as information that helps manage the raised chickens.

[0003] On the other hand, at a grading and packaging center (hereinafter referred to as a "GP center"), the quality of all eggs shipped from chicken farming facilities is measured, and the eggs are classified according to the quality as described below, and each classification is packaged and packed.

[0004] LL: 70g or more, less than 76g

[0005] L: 64g or more, less than 70g

[0006] M: 58g or more, less than 64g

[0007] MS: 52g or more, less than 58g

[0008] S: 46g or more, less than 52g

[0009] SS: 40g or more, less than 46g

[0010] In large chicken farming facilities, chickens of the same age (chickens hatched on the same day) are generally raised in one chicken house. Although there are more or less individual differences, chickens of the same age basically lay eggs of the same quality. Therefore, in the GP center, when measuring the quality of eggs in each chicken house, since the quality of the eggs is basically the same, the eggs are only concentrated in the channel for packaging eggs of a certain size, which will cause the channel for packaging eggs of other sizes to become empty, and the processing efficiency will be reduced.

[0011] In order to efficiently process eggs at the GP center, it is desirable to collect eggs of various sizes and evenly mix them as processing objects. Therefore, eggs laid in multiple chicken houses are usually mixed for processing at the GP center. As a result, the quality of eggs measured at the GP center cannot be information that helps manage chickens in chicken farming facilities.

[0012] In addition, even if the eggs measured by the GP center correspond to the chicken farms at the source of the output, it takes several days from egg laying to the feedback of the quality measurement results to the chicken farms. Chicken farms have a need to know the short-term causal relationship between egg quality and chicken feeding and management conditions, such as whether the feeding conditions of the previous day have an impact on the quality of eggs produced on that day.

[0013] For these reasons, in chicken farms, it is desirable to measure the quality of eggs produced in each facility independently in addition to the measurement at the GP center. Since a large number of eggs are produced every day in large chicken farms, it is desirable to measure them by automated processing without manpower.

[0014] As an automated measurement, the applicant has conceived of measuring the size of eggs being transported by a conveyor, and believes that if the size can be accurately measured, the mass can also be estimated. Summary of the invention

[0015] Problems to be solved by the invention

[0016] Therefore, in view of the above-mentioned circumstances, an object of the present invention is to provide an egg measuring method capable of accurately measuring the size of eggs conveyed by a conveyor.

[0017] Means of solving problems

[0018] In order to solve the above problems, the egg measuring method according to the present invention is as follows:

[0019] "A method for obtaining the true size of an egg by photographing an egg of unknown size being transported by a conveyor from above with a camera, measuring the size of an image of the egg extracted from the photograph,

[0020] The rotation center axis when the three-dimensional shape of the egg is regarded as a rotating body is taken as the major axis, and the radius with the longest length among the radii of the countless cross-sectional circles orthogonal to the major axis is taken as the maximum minor axis radius.

[0021] Set the reference plane at a specified distance from the camera.

[0022] A plurality of eggs of different sizes but with known maximum minor axis radius, or a sphere with known radius, are placed on a reference plane and photographed in advance, thereby obtaining a first relational expression as the relationship between the real length of the maximum minor axis radius and the maximum minor axis radius on the photograph, and a second relational expression indicating the change in the ratio of the length on the photograph to the real length due to the height from the reference plane is obtained from the first relational expression,

[0023] Based on the first relation and the second relation, the size of the egg image is converted into a real size.

[0024] Extracting the image of the egg from the photograph and measuring the size of the egg in the photograph can be performed by image analysis.

[0025] If the size of the egg is different, the distance from the camera photographing the egg directly above to the egg will change. For example, a large egg will be photographed larger. That is, although the purpose is to find the real size of the egg from the image of the egg in the photo, there is a problem that if the real size of the egg is different, the relationship between the size of the egg image and the real size will change.

[0026] Therefore, in the present invention, a plurality of eggs with different sizes but known maximum minor axis radius or a sphere with known radius are placed on a reference plane in advance and photographed, thereby obtaining a relational expression. The reason why the maximum minor axis radius is focused on is that when the egg located on the reference plane is photographed from directly above, the outline of the egg at the height equal to the maximum minor axis radius from the reference plane is the outline of the egg in the photo. This is a unique relationship when an egg with a stable posture with its major axis in the horizontal direction is taken as a photographing object when placed somewhere. The reason why a sphere with a known radius can be used to replace an egg with a known size is that when the central axis of rotation when the three-dimensional shape of the egg is regarded as a rotating body is used as the major axis, the cross section orthogonal to the major axis is a circle. The radius of the sphere can be regarded as the maximum minor axis radius of an egg with a known size.

[0027] As a relational expression, a first relational expression is obtained as the relation between the real length of the maximum minor axis radius and the maximum minor axis radius on the photograph, and a second relational expression is further obtained from the first relational expression to express the change in the ratio of the length on the photograph to the real length due to the height from the reference surface. When these relational expressions are obtained, it is only necessary to measure the maximum minor axis radius for each of the actual egg and the egg image, so the operation of obtaining the relational expressions is simple.

[0028] According to the present invention, by using the first and second relationship equations, as will be described in detail later, the problem of the distance from the camera changing due to the size of the egg can be solved, and the size of the captured egg image can be converted into the real length of the egg.

[0029] The egg measuring method according to the present invention may further include the following structures in addition to the above structures:

[0030] "The conveyor is a conveyor that uses the reference surface as the transport surface.

[0031] When the contour in the egg image is the contour of the egg placed on the reference surface at a height h from the reference surface,

[0032] Using the relationship of height h as the true length of the maximum minor axis radius,

[0033] The actual length of the maximum minor axis radius obtained from the first equation is used as the height from the reference plane in the second equation, and the size on the photo is converted into the actual length.

[0034] In this structure, an egg of unknown size carried on a conveyor can be regarded as an egg placed on a reference surface. Therefore, by using the true length of the maximum minor axis radius obtained by using the first relational expression based on the maximum minor axis radius on the image as the height from the reference surface and using the second relational expression, the length other than the maximum minor axis radius in the photo can be converted into the true length.

[0035] The egg measuring method according to the present invention may replace the above structure with the following:

[0036] "The conveyor is a rod type conveyor that holds the eggs between rods for transport.

[0037] When the outline in the egg image is the outline at a height h from the reference plane in the egg held between the rods, the interval between the rods is 2d, the true length of the maximum minor axis radius is r, and the reference plane is made to coincide with the imaginary plane formed by connecting the upper end lines of the rods,

[0038] Use h=(r 2 -d 2 ) 1 / 2 The third relationship expressing the relationship between the size of the egg image and the actual size of the egg is obtained from the second relationship.

[0039] The third relationship is used to determine the true size of the egg whose major axis coincides with the axial direction of the rod."

[0040] This configuration is a method for measuring eggs when the conveyor for conveying eggs is a rod conveyor. When conveyed by a rod conveyor, the eggs are in a posture where the lower part is embedded between the rods. The depth of the embedded between the rods varies depending on the size of the egg and the angle between the long axis of the egg and the axial direction of the rod. Therefore, the second relational expression cannot be used directly, which is a problem.

[0041] In this configuration, when the long axis of the egg is aligned with the axial direction of the rod, it can be considered that h = (r 2 -d 2 ) 1 / 2 The relationship (2d: the distance between the rods, r: the true length of the maximum minor axis radius) holds. By making the height h in the second relationship (r 2 -d 2 ) 1 / 2 , you can convert the size on the photo into the real size.

[0042] In addition, eggs conveyed on a rod conveyor are usually in various orientations. By rotating the rods about their respective axes in at least a portion of the conveying path of the rod conveyor, the orientation of the eggs can be adjusted so that the long axis coincides with the axial direction of the rods. This is because the eggs change to a stable posture in which they are embedded deepest between the rods as they rotate along with the rotation of the rods. Therefore, if the rods are rotated about their axes in at least a portion of the conveying path of the rod conveyor at a position upstream of the location where the camera is used to take pictures, the eggs can be photographed after the orientation is adjusted to coincide. Therefore, the present invention can be applied to almost all the eggs being conveyed.

[0043] Secondly, the egg measuring method according to the present invention may also be:

[0044] "A method for obtaining the true size of an egg by photographing an egg of unknown size being transported by a conveyor from above with a camera, measuring the size of an image of the egg extracted from the photograph,

[0045] The conveyor is a rod type conveyor that holds and transports eggs between rods.

[0046] The long axis is the central axis of rotation when the three-dimensional shape of the egg is regarded as a rotating body.

[0047] A plurality of eggs or egg-shaped substitutes of known and different sizes are held between the rods in advance so that their long axes form different angles with the axial direction of the rods, and photographed, thereby creating a table that correlates the sizes on the photographs with the actual sizes and angles.

[0048] Measure the size of the egg image and the angle between the long axis in the photograph and the axial direction of the rod, and from this, find the actual size of the egg from the table.

[0049] This structure is a method for measuring eggs when the conveyor for transporting eggs is a rod-type conveyor and the orientation of the eggs is in various orientations. As described above, in addition to the size of the egg, the depth of embedding between the rods also varies depending on the orientation of the egg. When the angle between the long axis of the egg and the axial direction of the rod is close to a right angle, the embedding depth becomes smaller, and the larger the egg, the greater the degree of reduction. On the other hand, if the angle between the long axis of the egg and the axial direction of the rod becomes smaller, the embedding depth becomes larger, and the smaller the egg, the greater the degree of increase.

[0050] Therefore, in the present method, a plurality of eggs of known and different sizes are held between rods in various orientations in advance, and a table is prepared to associate the size on the photo with the real size and angle. The size focused on when making the table can be the maximum minor axis radius, or the major axis diameter to be described later, and a table can be prepared for each of the two. Since the ratio of the size on the photo to the real size can also be known from the table, if the real length of the size focused on when making the table is known, the other sizes on the photo can be converted into real sizes using this ratio. In addition, substitutes such as egg-shaped models can also be used to replace the plurality of eggs of known and different sizes.

[0051] Effects of the Invention

[0052] As described above, according to the present invention, it is possible to provide an egg measuring method for accurately measuring the size of eggs conveyed by a conveyor. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 (a) is an explanatory diagram of a photograph of an egg placed on a reference surface. Figure 1 (b) is a diagram showing a photograph.

[0054] Figure 2 This is a schematic diagram for explaining a method of calculating the volume of an egg.

[0055] Figure 3 This diagram explains how the distance from the camera changes depending on the size of the egg.

[0056] Figure 4 (a) is a graph illustrating the first relational expression, Figure 4 (b) is a graph illustrating the second relational expression.

[0057] Figure 5 This is a diagram for explaining the method of obtaining the first relationship.

[0058] Figure 6 (a) and Figure 6 (b) is a diagram showing eggs transported by a rod conveyor.

[0059] Figure 7 (a)~ Figure 7 (c) is a diagram for explaining that the depth between the embedding rods varies depending on the size of the egg.

[0060] Figure 8 (a) and Figure 8 (b) is an explanatory diagram of a method for determining the height h from a reference surface of an egg held between rods.

[0061] Fig. 9(a) is a graph showing the relationship between the maximum minor axis radius (true length) of an egg held between rods and the height h from a reference plane. Fig. 9 (b) is a graph illustrating the third relational expression.

[0062] Fig.10 This is a graph showing the effect of the difference in the angle between the long axis of the egg and the axial direction of the rod on the measurement of the size.

[0063] Fig.11 (a) is the first table, Fig.11 (b) is the second table.

[0064] Fig.12 This is an illustration of the three-dimensional shape of an egg as a solid of rotation. DETAILED DESCRIPTION

[0065] The specific embodiment of the present invention will be described below with reference to the drawings. The egg measuring method of this embodiment is to photograph the egg 10 conveyed by the conveyor from above using the camera 25 and to obtain the real size of the egg 10 based on the photograph 30 .

[0066] First, consider the following situation: Figure 1 As shown in FIG. 2A , an egg 10 placed on a reference plane 20 at a distance H from the camera 25 is photographed from directly above using a camera 25 with an optical axis Z in a vertical direction. Figure 1 As shown in (b), a photograph 30 (still image) including an image 10d of an egg is obtained. Fig.12 As shown, the three-dimensional shape of the egg 10 is regarded as a rotating body, and the central axis of rotation is called the "major axis L". Among the lines connecting two points on the contour of the cross section of the egg 10 cut by the plane containing the major axis L, the length of the line connecting the two points P1 and P2 with the longest length is called the "major axis diameter LD". The radii of the countless cross-sectional circles orthogonal to the major axis L are collectively called "minor axis radii SRn", and the largest radius among the minor axis radii SRn is called the "maximum minor axis radius SRn". max ”.

[0067] The outline of the egg photo 10d taken by the camera 25 from directly above can be regarded as the outline at the height where the outer shape of the egg 10 when cut in a horizontal plane becomes the largest, and this is called the "maximum outline". For the actual egg 10, if the height from the reference plane 20 to the maximum outline is h, then the height h is the maximum minor axis radius SR max This is a relationship that is specific to the case where the egg 10, which has the most stable posture with its long axis L in the horizontal direction, is taken as the imaging object.

[0068] h=SR max

[0069] In order to distinguish the major axis diameter, minor axis radius and maximum minor axis radius in the egg image 10d extracted from the photograph 30 from these dimensions in the actual egg 10, they are respectively referred to as follows:

[0070] Long axis diameter LD′

[0071] Minor axis radius SR′n

[0072] Maximum minor axis radius SR′ max

[0073] If the major axis diameter LD′, the minor axis radius SR′n, and the maximum minor axis radius SR′ can be measured for the egg image 10d, max , and converted into the major axis diameter LD as the actual length, the minor axis radius SRn, the maximum minor axis radius SR max , the volume of the egg 10 can be calculated. Figure 2 As shown, the volume of the egg 10 can be calculated by dividing the egg 10 at a certain interval ΔL in the direction of the long axis L and approximating the three-dimensional shape of the egg 10 to a stack of disks with a thickness ΔL and a radius SRn (single-dot chain line in the figure). Alternatively, the volume of the egg 10 can be calculated by finding a formula representing the short axis radius SRn and integrating the area of ​​the circle with the radius SRn in the direction of the long axis L by the length of the long axis diameter LD.

[0074] Since the density of the egg 10 is not greatly affected by the size of the egg 10 and is basically constant, the density is measured for a sufficient number of eggs in advance and the average value is obtained. If the density is multiplied by the volume of the egg 10, the mass of the egg 10 can be estimated.

[0075] That is, if the size of the egg image 10 d can be converted into the real size of the egg 10 , the volume and mass of the egg 10 can be calculated.

[0076] However, if Figure 3 As schematically shown in FIG. 1 , this becomes a problem because the height h from the reference plane 20 to the maximum contour varies depending on the size of the egg 10. In other words, the distance Hc from the camera 25 to the maximum contour varies depending on the size of the egg 10. For example, a large egg is photographed larger. Therefore, the relationship between the length of the egg image 10d and the actual length of the egg 10 varies depending on the size of the egg 10.

[0077] Therefore, it is previously studied how the relationship between the length of the egg image 10d and the true length changes with respect to the height h from the reference plane. maxA plurality of eggs 10 are placed on the reference plane 20 and photographed under the same photographing conditions. The maximum minor axis radius is considered because, as mentioned above, the height h from the reference plane 20 to the maximum contour is equal to the maximum minor axis radius SR. max There is a characteristic relationship in the eggs.

[0078] Thus, we obtain Figure 4 (a) is the linear equation shown in Figure 1. This is the first linear equation. If the linear equation is y = ax + b, then "x" is the maximum minor axis radius SR as the true length. max ", and is the "height h". From the first relationship, we can find "coefficient k = x / y". Coefficient k is the ratio of the length on the photo 30 to the actual length. Figure 4 As shown in (b), the relationship between the coefficient k and the height h is also a linear equation. This is referred to as the second relationship.

[0079] For an egg 10 of unknown size, if the image is taken under the same shooting conditions as when the above relationship is obtained, the actual size of the egg 10 can be known from the size of the egg image 10d by using the above relationship. For example, when the maximum minor axis radius SR′ in the egg image 10d is max For a certain length, according to Figure 4 The first relation (a) gives the maximum minor axis radius SR as the true length max , we know that the height h is the same as that of . Figure 4 The second relational expression (b) shows the coefficient k when the height is h. Therefore, by multiplying the major axis diameter LD' and the minor axis radius SR' in the egg image 10d by the coefficient k, the major axis diameter LD and the minor axis radius SRn can be converted into the actual length.

[0080] In addition, the above example shows how to find Figure 4 (a) Figure 4 The relationship shown in (b) is that the maximum minor axis radius SR max It is known that a plurality of eggs are placed on a reference surface 20 for photographing. Instead of this method, as Figure 5 As shown, a sphere 51 with a known radius R and a variety of radii R may be used. If such a sphere 51 is placed on the reference surface 20 and photographed under the same photographing conditions, a relational expression similar to the first relational expression described above can be obtained based on the radius of the sphere in the photograph 30. The reason why a sphere 51 with a known radius can be used instead of an egg with a known size is that the maximum minor axis radius SR is the focus of the relational expression. max The radius R of the sphere can be considered as the maximum minor axis radius SR of an egg of known size. max .

[0081] <When the conveying plane of the conveyor is a plane (first embodiment)>

[0082] For example, if the conveyor for conveying the egg 10 is a belt conveyor, the conveying surface is considered to be a plane. When the egg 10 conveyed on the conveyor is photographed from directly above, the reference plane 20 coincides with the conveying surface. Therefore, through the above-mentioned steps, the size of the egg image 10d can be converted into the real size of the egg 10, and the volume of the egg 10 can be further calculated to estimate the mass.

[0083] <When the conveyor is a rod conveyor (second embodiment)>

[0084] Since the egg 10 is in a shape that is easy to roll, a rod conveyor is often used for conveying. The rod conveyor is a conveyor in which a plurality of rods 40 are arranged at a certain interval, and the two ends of the rods 40 are supported by a pair of endless chains. Since the egg 10 is conveyed in a state where the lower part is inserted between the rods 40, it will not roll and is conveyed in a stable posture.

[0085] When the lower portion of the egg 10 is embedded between the rods 40, the distance Hc from the camera 25 to the maximum contour becomes larger by the embedding depth compared to the case where the egg is placed on the reference surface 20. Figure 6 (a) Figure 6 (b), the orientation of the egg relative to the rod 40 is different, as shown in FIG. Figure 7 (a)~ Figure 7 (c) also varies depending on the size of the egg 10. Therefore, when the actual size of the egg 10 is obtained from the photograph 30 taken from directly above the egg 10 transported by the rod conveyor, the above method cannot be used directly. Figure 4 (a) Figure 4 (b) The first and second relationship equations are described.

[0086] When the long axis L of the egg 10 is consistent with the axial direction of the rod 40, as shown in FIG. Figure 8 (a) Figure 8 As shown in (b), when the egg 10 held between the rods 40 is viewed from the axial direction of the rods 40, the maximum minor axis radius SR max is a circle of radius r. Figure 8 (b) means that Figure 8(a) Case where a large egg 10 is held between the rods 40. As can be seen from these figures, the smaller the egg 10, the greater the depth Δh of the egg 10 embedded between the rods 40. If the reference plane 20 at a distance H from the camera 25 is an imaginary plane connecting the upper end lines of the rods 40, and the distance between the rods 40 is 2d, then between the height h from the reference plane 20 to the maximum contour and the radius r, the following relationship can be approximately established based on the Pythagorean theorem.

[0087] r 2 =h 2 +d 2

[0088] Thus, h = (r 2 -d 2 ) 1 / 2

[0089] In this formula, if the radius r (with the maximum minor axis radius SR max Substituting various values, and substituting 32 mm as the distance between the rods 40, for example, the following is obtained: Fig. 9 (a) shows the graph. If h=(r 2 -d 2 ) 1 / 2 Substitute the value of as the height h into Figure 4 In the second relation of (b), Fig. 9 As shown in (b), a linear equation representing the relationship between the length of the egg 10 held between the rods 40 in the photograph 30 and the real length is obtained. This is taken as the third relational equation. Thus, if the major axis diameter LD′, the minor axis radius SR′n, and the maximum minor axis radius SR′ are measured in the image 10d of the captured egg, max , the third relationship can be used to convert the major axis diameter LD, minor axis radius SRn, and maximum minor axis radius SR max , the volume of egg 10 can be calculated and the mass can be inferred.

[0090] When eggs are transported by a rod conveyor, the orientation of the eggs is generally various. In a conventional rod conveyor, the rod does not rotate around the axis to transport the items. In contrast, in the present embodiment, in at least a portion of the transport path of the rod conveyor, the rod is rotated around the axis to adjust the orientation of the eggs so that the long axis L of the egg is aligned with the axial direction of the rod. The eggs held between the rotating rods rotate along with the rotation of the rods. During such rotation, the eggs that were transported in a posture where the long axis L was not aligned with the axial direction of the rod also become in a posture where the long axis L is aligned with the axial direction of the rod. The reason for this is that in this posture, the eggs are deeply embedded between adjacent rods and become stable.

[0091] Therefore, at a position upstream of the location where the camera is used to take the image, the rod is rotated about its axis in at least a portion of the transport path of the rod conveyor, and the orientation of the eggs is adjusted so that the major axis L coincides with the axial direction of the rod, thereby making it possible to use the above-mentioned method of using the rod conveyor to carry out the egg feeding. Fig. 9 (a) Fig. 9 (b) The third relational expression described above can be used to determine the true size of the egg. As a method for rotating the rod about its axis, for example, a plate is provided below the conveying path of the rod conveyor so that the rod can rotate freely and contacts the rod. The rod rotates by contacting the plate as it moves.

[0092] <When the conveyor is a rod conveyor (third embodiment)>

[0093] Next, the actual size of the eggs is determined by photographing the eggs from above with a camera when the eggs are transported in various orientations by a rod conveyor without aligning the orientation of the eggs. As described above, the eggs transported by the rod conveyor are embedded between the rods, and the embedding depth varies depending on the size of the eggs. Furthermore, if the angle between the long axis of the egg and the axial direction of the rod is different, the actual size of the eggs is determined by the angle between the long axis of the egg and the axial direction of the rod. Fig.11 As shown, the depth between the embedded rods is affected, which has an impact on the length in the photo. Fig.11 This is a graph showing the values ​​(calculated values) converted from the long axis diameters in the photographs together with the actual lengths of the long axis diameters, with the long axis angles between the long axis and the axial direction of the rods being different for eggs A and B of different sizes. The calculated values ​​are values ​​calculated using the second relational expression when the eggs are placed on a reference surface without considering the depth of embedding between the rods.

[0094] As from Fig.11 As can be seen, without considering the depth of the embedded rods, the length calculated from the size on the photo becomes smaller than the actual length. The reason is that the distance from the camera increases by the amount of the embedded depth. In addition, the smaller the egg size, the greater the degree to which the calculated value is smaller than the actual length, and the smaller the angle between the long axis of the egg and the axial direction of the rod, the greater the degree to which the calculated value is smaller than the actual length.

[0095] Therefore, a plurality of eggs of known but different sizes are held between the rods in such a manner that the angle θ of the long axis L relative to the axial direction of the rod is different in the range of 0° to 90°, and photographed from directly above under the same photographing conditions. The length on the photograph is measured, as shown in FIG. Fig.11As shown in (a), a table is prepared to make the length on the photo correspond to the real length for each angle θ. This is used as the first table. Here, a table is shown in which the long axis diameter of the egg size is known and corresponds to the long axis diameter on the image, but the size of interest is not limited to the long axis diameter, and may also be the maximum short axis radius or the maximum short axis diameter (the diameter of the largest cross-sectional circle among the cross-sectional circles orthogonal to the long axis).

[0096] In addition, if Fig.11 As shown in (b), based on the first table, a table is prepared in which the ratio of the real length to the length on the photograph corresponds to the real length for each angle θ, and this is used as the second table. Fig.11 (b) illustrates a case where the ratio is the ratio of the length on the photograph to the actual length.

[0097] Furthermore, when these tables are prepared, an egg of unknown size is photographed from above under the same photographic conditions, with the same conditions such as the interval between the rods and the like and being carried by the rod conveyor. By image analysis, an image of the egg is extracted from the obtained photograph, and an image of the rod is extracted. When the shapes of eggs of different sizes are regarded as similar shapes, if the size of the egg image is measured, and the angle θ of the major axis L in the photograph relative to the axial direction of the rod is measured, the real size of the egg can be obtained by using the first table and the second table. For example, when the major axis diameter LD' in the photograph is 57.4 mm and θ is 30°, the first table shows that the actual major axis diameter LD of the egg is 58.0 mm. Furthermore, from the second table, when the actual major axis diameter LD is 58.0 mm and θ is 30°, the ratio of the length on the photograph to the real length is 0.99. Therefore, if the length of other parts on the photograph, such as the minor axis radius SR'n, is divided by this ratio, the corresponding real length can be obtained, and the volume of the egg can be calculated and the mass can be estimated.

[0098] The present invention has been described above by taking preferred embodiments as examples; however, the present invention is not limited to the above embodiments, and various improvements and design changes are possible without departing from the gist of the present invention.

[0099] For example, in the above embodiment, the real length and the length on the photo are compared and explained in the same unit (millimeter), but the length on the image can also be measured in pixels. Even if the unit is pixels, the above processing steps and the method of obtaining the relationship are the same.

Claims

1. A method for measuring eggs, characterized in that: The camera is used to take a picture of an egg of unknown size being transported by a conveyor from directly above, and the size of the egg image extracted from the picture is measured to find the true size of the egg. The rotation center axis when the three-dimensional shape of the egg is regarded as a rotating body is taken as the major axis, and the radius with the longest length among the radii of the countless cross-sectional circles orthogonal to the major axis is taken as the maximum minor axis radius. Set the reference plane at a specified distance from the camera. A plurality of eggs of different sizes but with known maximum minor axis radius, or a sphere with known radius, are placed on a reference plane and photographed in advance, thereby obtaining a first relational expression as the relationship between the real length of the maximum minor axis radius and the maximum minor axis radius on the photograph, and a second relational expression indicating the change in the ratio of the length on the photograph to the real length due to the height from the reference plane is obtained from the first relational expression, Based on the first relational expression and the second relational expression, the size of the egg image is converted into a real size.

2. The egg measuring method according to claim 1, wherein: The conveyor is a conveyor that uses the reference surface as the transport surface. When the contour in the egg image is the contour of the egg placed on the reference surface at a height h from the reference surface, Using the relationship of height h as the true length of the maximum minor axis radius, The actual length of the maximum minor axis radius obtained from the first relational expression is used as the height from the reference plane in the second relational expression, and the size on the photograph is converted into the actual length.

3. The egg measuring method according to claim 1, wherein: The conveyor is a rod type conveyor that holds the eggs between rods for transportation. When the outline in the egg image is the outline at a height h from the reference plane in the egg held between the rods, the interval between the rods is 2d, the true length of the maximum minor axis radius is r, and the reference plane is made to coincide with the imaginary plane formed by connecting the upper end lines of the rods, Use h=(r 2 -d 2 ) 1 / 2 The third relationship expressing the relationship between the size of the egg image and the actual size of the egg is obtained from the second relationship. The third relationship is used to calculate the actual size of the egg whose long axis is consistent with the axial direction of the rod.

4. A method for measuring eggs, comprising: photographing an egg of unknown size being conveyed by a conveyor from above with a camera, measuring the size of an image of the egg extracted from the photograph, and obtaining the true size of the egg. The conveyor is a rod type conveyor that holds and transports eggs between rods. The long axis is the central axis of rotation when the three-dimensional shape of the egg is regarded as a rotating body. A plurality of eggs or egg-shaped substitutes of known and different sizes are held between the rods in advance so that their long axes form different angles with the axial direction of the rods, and photographed, thereby creating a table that correlates the sizes on the photographs with the actual sizes and angles. The size of the egg image and the angle between the long axis and the axial direction of the rod in the photograph were measured, and the actual size of the egg was calculated from the table.

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