Image analysis – Applications – Animal – plant – or food inspection
Reexamination Certificate
2000-08-09
2004-01-27
Mehta, Bhavesh M. (Department: 2625)
Image analysis
Applications
Animal, plant, or food inspection
C702S002000, C356S402000, C348S089000
Reexamination Certificate
active
06683970
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The invention relates to a method of diagnosing nutrition of crop by obtaining crop information represented by nitrogen content, etc. of the crop from reflection light of the crop growing in a field. The invention also relates to a method of compensating the amount of reflection light obtained individually by a plurality of image elements.
(2) Description of the Related Art
A first conventional method for obtaining crop information such as a nitrogen content rate of a crop, a leaf color value, a nitrogen absorption amount, a plant height, a dry matter weight, etc., is one in which the amount of reflection light from the reference plate and the crop in the field is obtained by image-taking, by a light receiving means such as a digital camera, the reference plate which is coated with barium sulfate, etc. and the unit field (or a part of it) in which the crop grows, the reflectance of the crop is obtained from the amount of the light reflected from the reference plate and the crop, and the nitrogen content rate (amount of nitrogen absorption, a value of leaf color, a plant height, a dry matter weight) is obtained from the reflectance obtained and the relation formula predetermined for obtaining the nitrogen content rate (amount of nitrogen absorption, a value of leaf color, a plant height, a dry matter weight) from the reflectance, and the growth diagnosis has been conducted by comparing with a standard nitrogen content rate of that time period based on the number of growth days versus the nitrogen amount curve. However, the amount of reflection light of the crop to be obtained from the field is subject to change by weather. Also, even when the weather is compensated by the reference plate, it is necessary that each of the measuring direction, wind, and planting density be in the same condition as that applied when the predetermined relation formula was prepared for obtaining the nitrogen content rate from the reflectance. When the condition is different, the compensation is necessary accordingly, so that it cannot be said that all has been compensated only by obtaining the reflectance by the reference plate as reference. Actually, the measurement has been conducted under the limitation by the solar height, measuring direction, planting density or kind.
As for a second conventional method for obtaining crop information, there is an apparatus in which the light with a wavelength having relation to the crop information subject to increase or decrease depending on the growth of the crop, for example, the light ranging from a visible light region to a near infrared region is irradiated on a leaf blade of the crop and, based on the amount of the received light obtained with respect to the light with the wavelength having relation to the crop information and on the nitrogen amount related formula predetermined for calculating from the amount of light received, for example, a leaf blade nitrogen content, the leaf blade nitrogen content is measured. This apparatus is used to measure a number of leaf blades of the crop in the field and has enabled to obtain the leaf blade nitrogen content with a high precision. However, in order to grasp the crop information accurately for the overall field, a minute measurement extending to the overall field was indispensable, which is complicated and troublesome.
In the case where, as in the nutrition diagnosis of the crop leaf conducted according to the first conventional method, the so-called “remote sensing” is conducted and a comparatively large extent of field is subjected, the observation is made from quite far away so that there has occurred no large difference in areas of object corresponding to one image element of the camera. Therefore, there has occurred no difference in respective image elements in the resolution of the camera, either. On the other hand, in the “remote sensing” conducted quite close to the object, there occurs no large difference in areas of the object corresponding to one image element so that the measurement can be made in similar degree as above.
The first method described above is one in which, although the measurement is simple, the crop information to be obtained from the field is influenced by factors such as a measuring location and a planting density and, because of constraint in the measuring time and location, the method cannot be regarded as accurate. Also, when the camera is directed to the field and takes an image, the amount of reflection light obtained in each image-taking element of the camera has required compensation by a depression angle or field angle with respect to the field or a location such as this side or an opposite side in a large field. The distance between the camera and the field as the object varies for each image element, and the image-taking area obtained for each image element varies for respective distances. Further, the reflection angle differs by the depression angle and has an influence to the amount of reflection light. The second method, having no restraint in the measurement and having a high precision, is more advantageous than the first method. However, the problems in the second method are that the measurement has to be made for each leaf blade, thus requiring a large number of points to be measured and a long time accordingly.
The conventional remote sensing is conducted under the restrained condition that no large difference occurs in the area of the object for each image element. This is done for the reason of facilitating the subsequent compensation. However, because of the above restraint, a large scale observation means is required in order to enable taking an image of a large area and, if an image is taken extremely closely, the area of measurement becomes very small and it necessitates the measurements a plurality of times.
An object of the present invention is that, when obtaining the crop information by measuring the amount of reflection light, even though the camera is placed on the ground, compensation can be made so that no large error occurs, and a method of diagnosing nutrition of the crop provided is simple in the measurement of the crop information and enhances the measurement precision.
SUMMARY OF THE INVENTION
As a first method according to the present invention, the method of diagnosing nutrition of a crop in a field is arranged wherein: a camera equipped with a plurality of image elements is located in a predetermined central depression angle with respect to a field; an amount of reflection light of a crop leaf is obtained for each image element by image-taking the field; an image-taken area is obtained for each unit image element by an area function constituted by a conversion variable including a ground clearance of the camera, an image element depression angle, the number of image elements and a field angle; an area compensation is made of the amount of reflection light for each image element; a depression angle compensation is made of the amount of reflection light by the depression angle coefficient predetermined for compensating differences of amounts of reflection light correspondingly with image element depression angles; an amount of light incident on the crop leaf is measured; reflectance is obtained from the amount of the reflection light compensated and the measured amount of incident light; and crop information in a predetermined area based on the reflectance and a first crop related formula predetermined for obtaining the crop information is obtained and made first crop information. The first crop information is stored. By irradiating crop in the same area, an amount of at least either of transmission light or reflection light which is subject to increase and decrease depending on growth of the crop and which has a wavelength having relation to the crop information is measured, and crop information from the amount of light and a second crop related formula predetermined from the amount of light for obtaining crop information is obtained and stored as second crop information. The nutritious
Hosaka Yukio
Maruyama Hideharu
Nakamura Nobuhiko
Satake Satoru
Carter Aaron
Mehta Bhavesh M.
Satake Corporation
LandOfFree
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