Abstract:
A measuring device has a sensor for registering at least one parameter selected from the group consisting of at least one ingredient, at least one property, and both, of a material being investigated by the sensor, the sensor including at least one illumination source which directs at least one light beam toward the material to be investigated, at least one reference object for calibrating the measuring device, and an illumination source configured so that a portion of a light beam from the illumination source is redirected toward the reference object.

Description:
CROSS-REFERENCE TO A RELATED APPLICATION 
   The invention described and claimed hereinbelow is also described in German Patent Application DE 10 2006 035 906.2 filed on Jul. 31, 2006. This German Patent Application, whose subject matter is incorporated here by reference, provides the basis for a claim of priority of invention under 35 U.S.C. 119(a)-(d). 
   BACKGROUND OF THE INVENTION 
   The present invention relates to a measuring device with a sensor for detecting at least one ingredient and/or at least one property of a material being investigated by the sensor. 
   Publication DE 10 2004 021 448.4 makes known a spectrometric reflectance measuring head with internal recalibration. The housing of the measuring head contains two standards, preferably a black standard and a white standard for internal recalibration, which can be selectively swiveled into the beam path of the reflectance measuring head. After the spectrometer registers the measured data from both standards, the control and evaluation unit recalibrates the reflectance measuring head. In addition, at least two external standards can be provided to calibrate the reflectance measuring head before start-up of the measuring device or at certain time intervals. The at least two external standards are located in the beam path of the illumination source in place of the object to be measured. 
   The disadvantage of this known reflectance measuring head is that the standards used to calibrate the measuring device must be swiveled into the region of the beam path. This requires a swivel mechanism having a complex design, and the detection of crop material flow must be interrupted during the calibration procedure. 
   Publication EP 1 053 463 B1 makes known a combine harvester with a system for determining components of an agricultural crop material. The system includes a light source that illuminates the agricultural crop material, and a receiver for receiving the light energy reflected by the crop material. To calibrate the system, a motor is used to swivel a standard in front of the receiver, and a reference measurement is carried out. This system also has the disadvantage that a swivel mechanism with a complex design is required, and the detection of crop material must be interrupted during the calibration procedure. 
   SUMMARY OF THE INVENTION 
   The object of the present invention, therefore, is to avoid the disadvantages of the related art and, in particular, to provide a simple and, therefore, cost-favorable measuring device with which the material to be investigated and the reference object do not have to be switched back and forth. 
   In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in a measuring device, comprising a sensor for registering at least one parameter selected from the group consisting of at least one ingredient, at least one property, and both, of a material being investigated by said sensor, said sensor including at least one illumination source which directs at least one light beam toward the material to be investigated; at least one reference object for calibrating the measuring device; and an illumination source configured so that a portion of a light beam from said illumination source is redirected toward said reference object. 
   Given that a portion of the light beam from the illumination source is redirected to the reference object, there is no need for a mechanism that replaces the material to be investigated with the reference object, and the measurement of crop material flow takes place nearly continually, since there is no need to interrupt it for the swiveling procedure. 
   In a first inventive embodiment of the measuring device, a portion of the light beam from the illumination source is redirected by at least one reflector, thereby resulting in a simple, cost-favorable measuring device. 
   In a further inventive embodiment of the measuring device, the light beam from the illumination source is redirected by at least one prism, thereby also resulting in a cost-favorable measuring device with a simple design. 
   In a third inventive embodiment of the measuring device, a portion of the light beam from the illumination source is redirected such that it is guided by an optical waveguide, thereby allowing the reference object to be positioned anywhere with respect to the illumination source, without requiring a complex design. 
   Given that the material under investigation and/or the reference object reflect the light beam from the illumination source, and the light diffusely reflected by the material and/or the reference object is collected by at least one optical waveguide, and the optical waveguide guides the diffusely reflected light to a spectrometer, it is possible to position the spectrometer anywhere on the harvesting machine. In addition, further optical waveguides associated with further measuring devices on the harvesting machine can be connected with the spectrometer. 
   Given that the reference object includes a black standard and a white standard, the fluctuating light intensity of the illumination source and the change in sensitivity of the measuring device can be taken into account in the calibration, thereby preventing measured values from becoming corrupted. 
   Given that a multiplexer is installed upstream of the spectrometer—the multiplexer controlling which optical waveguide transmits the light to the spectrometer—it is possible to automatically switch between the measuring mode and calibration of the measuring device, and calibration takes place within milliseconds. 
   The fact that the spectrometer registers the measured data on the light diffusely reflected by the material under investigation and/or the reference object rules out the possibility that light reflected by the disk located between the illumination source and the crop material, for example, is also absorbed by the optical waveguides, which would result in incorrect measured data. 
   Given that the spectrometer is connected with a control and evaluation unit that calculates the content of ingredients and/or properties of the material under investigation, based on the measured data registered by the spectrometer, it is possible to analyze the material under investigation quickly and without destroying it. 
   The illumination source is advantageously designed as an infrared light source, since wavelengths in the near infrared range are optimally suited for detecting ingredients such as protein and the like in the material under investigation. 
   Advantageously, the material under investigation is a flowing stream of an agricultural product, thereby ensuring that a continual real-time measurement of a continually conveyed crop material flow can be carried out. 
   The measuring device is advantageously located on a harvesting machine, thereby enabling the analysis to be carried out while the crop material is being harvested with the harvesting machine. 
   The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a forage harvester in a side view, with an inventive measuring device. 
       FIG. 2  shows a detailed depiction of the inventive measuring device. 
       FIG. 3  shows an inventive measuring device with a reflector for redirecting the light beams. 
       FIG. 4  shows an inventive measuring device with a prism for redirecting the light beams. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  shows a side view, with a partial cross-sectional view, of an agricultural harvesting machine  2  designed as a self-propelled forage harvester  1 . A front attachment  3  is assigned to the front, which picks up crop material  4  during the working operation of forage harvester  1 , cuts it, then guides it to downstream, rotating intake and compression rollers  5 . Intake and compression rollers  5  guide crop material  4  to downstream, rotating chopper drum  6 , which fragmentizes crop material  4  in interaction with a shear bar  7 . Fragmentized crop material  4  is transferred to a post-fragmentation device  8 , which pounds the crop grains, e.g., corn, and transfers them via a conveyer chute  9  to a post-accelerator  10 . Post-accelerator  10  accelerates fragmentized crop material  4  and conveys it—via a horizontally and vertically displaceable upper discharge chute  11 —to a not-shown hauling device assigned to upper discharge chute  11 . 
   Inventive measuring device  14 —which will be described in greater detail, below—is located on upper discharge chute  11  in order to analyze crop material  4  being conveyed through the upper discharge chute. 
   It is also feasible to locate measuring device  14  on a feed channel of a baler or in the feed rake or the grain tank filling auger. 
   Measuring device  14  known per se is used to determine certain ingredients in crop material  4 . Reference is made to EP 1 053 463 with regard for a more detailed determination of the ingredients; the teaching thereof is integrated in this full written disclosure via reference. Measuring device  14  registers the portions of ingredients in crop material  4 , such as water content, or the content of raw protein or fat, and further parameters of crop material  4 , such as fiber length, fiber content, and dry matter. 
     FIG. 2  shows a detailed depiction of inventive measuring device  14  located on upper discharge chute  11 . An opening  15  is provided in upper discharge chute  11 , in the region of which measuring device  14  is located. Measuring device  14  includes a sensor  16 , which is an optical sensor that operates in the reflectance mode. 
   Sensor  16  includes an illumination source  18  designed as an infrared light source and located inside housing  17 , which emits a collimated light beam  20  downward, in the direction of upper discharge chute  11 , using a parabolic mirror  19  located above illumination source  18 . A portion of light beam  20  is collected by optical waveguides  21 , which are also located in housing  17 , and is guided toward upper discharge chute  11 . Light beams  22  emerging from the lower end of optical waveguides  21  pass through a disk  23  of housing  17  located in the region of upper discharge chute  11  and into conveyor channel  24  of upper discharge chute  11 , through which crop material  4  is conveyed. Light beams  22  are reflected diffusely by crop material  4 . Further optical waveguides  25  are located inside housing  17 , in order to collect a portion of diffusely reflected light  26 . The ends of optical waveguides  25  are located at an angle of approximately 45 degrees relative to disk  23 , to prevent light that is reflected by disk  23  from also being collected. 
   Optical waveguides  25  guide diffusely reflected light  26  via a multiplexer  27 —which will be described in greater detail below—to a spectrometer  28 . Spectrometer  28  registers—in a wavelength-specific manner—the spectrum of reflected light  26  and, therefore, the reflectivity of illuminated crop material  4 . 
   Spectrometer  28  is connected with a control and evaluation unit  29 , which calculates—based on signals provided by spectrometer  28 , as described in greater detail in EP 1053 463 B1 mentioned above—the contents of crop material  4  in terms of certain ingredients, such as water, starch, organic substances, non-organic substances, raw protein, oil, and the like . . . . The calculated values are transmitted to a fieldwork computer  30  that maps the values in a location-dependent manner. The values are also displayed in a display unit  31 . 
   A reference object  34  that includes a black standard  32  and a white standard  33  is located inside housing  17 ; reference object  34  is used to calibrate measuring device  14  using a reference signal. 
   According to the present invention, in order to carry out a reference measurement, a portion of light beam  20  from illumination source  18  is redirected to reference object. 
   In the exemplary embodiment shown, the redirection takes place via curved optical waveguides  35 ,  36 , each of which includes a first end, which points toward illumination source  18 , and a second end, which points toward white standard  33  or black standard  32 . Optical waveguides  35 ,  36  absorb a portion of light beam  20  from illumination source  18  and guide the collected light to standards  32 ,  33 . 
   The light diffusely reflected by white standard or black standard is separated via first optical waveguide  36 , and it is collected by a further optical waveguide  37  and sent to multiplexer  27 . 
   Multiplexer  27  controls whether the light reflected by crop material  4 —which is transmitted via optical waveguides  21  to multiplexer  27 —or the light reflected by white standard  33 —which is transmitted via optical waveguide  35  to multiplexer  27 —or the light reflected by black standard  32 —which is transmitted by optical waveguide  36  to multiplexer  27 —is forwarded to spectrometer  28 . 
   Before measuring device  14  is calibrated, multiplexer  27  forwards, in succession, the light reflected by white standard  33  and guided by optical waveguide  35 , and the light reflected by black standard  32  and guided by optical waveguide  36  to spectrometer  28 . 
   Spectrometer  28  forwards the measured data on standards  32 ,  33  to control and evaluation unit  29 , which calibrates measuring device  14  using these measured data. 
   When determining the ingredients in a crop material  4 , multiplexer  27  only forwards the light reflected by crop material  4 —which is transmitted via optical waveguides  21  to multiplexer  27 —to spectrometer  28 . 
   The determination of the ingredients in crop material  4  must be halted in order to calibrate measuring device  14 ; in so doing, calibration is carried out within milliseconds and the ingredients in crop material  4  that is flowing past do not change substantially within this short period of time. 
   A further inventive measuring device  14  is possible, with which—in contrast to the design described above—the light reflected by white standard  33  and guided by optical waveguides  35 , and the light reflected by black standard  32  and guided by optical waveguides  36  is directed to a first spectrometer, and the light reflected by crop material  4  is directed to a second spectrometer. This design has the advantage, in particular, that the investigation of crop material  4  can also be carried out permanently during the calibration measurements, since the light reflected by standards  32 ,  33 , and the light reflected by crop material  4  can be evaluated independently of each other in separate spectrometers. 
     FIG. 3  shows an inventive measuring device  14 , with which a portion of light beams  21  from illumination source  18  directed at crop material  4  strikes reflector  40  positioned at an angle relative to light beams  21  and is redirected by reflector  40  to reference object  34 . 
   With inventive measuring device  14  shown in  FIG. 4 , a portion of light beams  21  from illumination source  18  directed at crop material  4  strikes a prism  41  and is redirected by prism  41  to reference object  34 . 
   It is within the scope of the ability of one skilled in the art to modify the exemplary embodiments described in a manner not presented, or to use them in other machines to achieve the effects described, without leaving the framework of the invention. 
   It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the type described above. 
   While the invention has been illustrated and described as embodied in a measuring device for ingredient detection, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. 
   Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.