Patent Publication Number: US-11647691-B2

Title: Close loop control of an illumination source based on sample heating

Description:
FIELD OF THE DESCRIPTION 
     The present description relates to agricultural sensors. More specifically, the present description relates to controlling an agricultural sensor on an agricultural mobile machine. 
     BACKGROUND 
     There are many different types of agricultural machines, including agricultural harvesters. There are also many different types of agricultural harvesters. Some such harvesters include combine harvesters, self-propelled forage harvesters, sugarcane harvesters, cotton harvesters, among others. 
     Harvested, crops are sometimes sampled to determine whether they have various different characteristics. For instance, in one example, a crop sample is illuminated and is analyzed for constituents with a spectrometer or other light sampling device. 
     Different proteins, oils, and other substances absorb certain light spectra. Therefore, by performing spectral analysis based on notches in the reflected radiation, the system can identify the levels of those constituent elements. High starch corn, for instance, may be more valuable for ethanol production than lower starch corn. High protein wheat may be more valuable for certain things than lower protein wheat, etc. 
     The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. 
     SUMMARY 
     Crop is routed past a sample window on an agricultural harvester. Light is impinged on the crop from an illumination source and reflected radiation is directed to a spectrometer. The output of the spectrometer is indicative of various constituents in the harvested crop. The illumination source is controlled based on the temperature proximate the crop sample. 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a block diagram of one example of a portion of an agricultural harvester with a crop sampling system. 
         FIG.  2    is a block diagram showing one example of an illumination controller, in more detail. 
         FIG.  3    is a flow diagram illustrating one example of the operation of the illumination controller. 
         FIG.  4    is a graph showing temperature vs. time. 
         FIG.  5    is a graph showing the illumination source control signal vs. time. 
         FIG.  6    is a partial pictorial, partial schematic illustration of a self propelled forage harvester. 
         FIG.  7    is a partial pictorial, partial schematic illustration of a combine harvester. 
         FIG.  8    is a block diagram showing one example of a computing environment that can be deployed on the harvesters to implement the crop sampling system discussed in previous figures. 
     
    
    
     DETAILED DESCRIPTION 
     As discussed above, some harvested crop is sampled for constituent elements. Some sampling systems are deployed on agricultural harvesters so the crop is sampled during the harvesting operation. For instance, some agricultural harvesters sample crop for various constituents using a spectrometer or other light sampling device. In such machines, an illumination source emits light onto the crop sample through a lens or sampling window. Radiation is reflected off of the crop sample onto a spectroscopy chip, a MEMS interferometer or other spectral analysis sensor. In order to obtain consistent constituent measurements, the intensity of the radiation emitted by the illumination source is held relatively constant during sampling. However, when the ambient temperature in the area of the sample analysis operation varies over a relatively wide range, then the temperature increase caused by the intensity of the radiation emitted by the illumination source can also vary. This can compromise the overall success in making consistent constituent measurements. 
     In addition, if the illumination source is activated, at full power, the crop sample proximate the sample window can get hot, especially if the crop sample is captured and held in place for a significant duration, in order to take the measurement. This problem can be exacerbated when the ambient temperature increases. 
     This problem could be addressed by periodically switching off the illumination source to ensure that the crop sample cools down sufficiently. However, this increases the sample time because, in order for there to be consistent sampling measurements, the intensity of the illumination source must be relatively consistent. If it is turned off and allowed to cool down too far, this increases the time needed for the illumination source to power back up to the desired intensity. Thus, simply turning off the illumination source periodically (with an off period sufficient to guarantee that the sample temperature will cool down enough in all weather) reduces the efficiency of the overall sampling process. For instance, when the ambient temperature is relatively cool, it may be that the illumination source needs to only be turned off a very short time, whereas when the ambient temperature is relatively hot, this may mean that the illumination source should be turned off for a longer period of time. Therefore, if a uniform or periodic cycling of the illumination source is used, then the system is not optimized for ambient temperature. Sub-optimization of the sampling system can lead to less granular (and thus less precise) sample results. 
     By sampling at the highest rate possible, the samples are attributed to a smaller area of the field. This means that the crop from the field is sampled with higher frequency, and the samples are thus more precise in reflecting the characteristics of the crop, itself, than if the samples are taken less frequently. 
     The present description thus proceeds with respect to a system that uses a temperature sensor on the sampling window, past which the crop sample travels. The temperature sensor provides a temperature signal, indicative of the temperature of the crop sampling window (or another area proximate the crop sample), to an illumination controller that controls the illumination source so that it is on (or active) until the temperature of the sampling window reaches a threshold temperature value. The illumination controller then turns off the illumination source until the temperature of the sampling window reaches a second threshold temperature, which is lower than the first threshold temperature. It then turns the illumination source back on so that additional samples can be taken. In this way, the illumination source is controlled based on a desired sample rate and based on the temperature of the sampling window so that samples can be taken at a high frequency, regardless of the ambient temperature, while still inhibiting crop overheating. 
       FIG.  1    shows one example of an agricultural harvester  100 . Harvester  100  illustratively includes propulsion system  102 , steering system  104 , a variety of different harvesting functionality  106  (which will vary based on the type of harvester), operator interface mechanisms  108 , communication system  110 , geographic position system  111 , computing system  112 , and a spectrometer device or spectroscopy device, or interferometer (or other spectral analysis sensor)  114 , sources of illumination  116  and  118 , a crop sample  120  that travels past a sample window element  122  that defines a sample window, and it can include a wide variety of other items  124 . Computing system  112 , itself, can include one or more processors  126 , data store  128  (which can include a sample rate  130  sample results  131  and other items  132 ), crop sampling system  134 , and other items  136 . Crop sampling system  134  can include closed loop lamp control system  138  (which can itself include sample trigger generator  140 , illumination driver component  142 , illumination controller  144  and other items  146 ), sample processing system  148  and other items  150 .  FIG.  1    also shows that agricultural harvester  100  can be operated by an operator  152  and can be connected one or more remote systems  154  over a network  156 . Network  156  can thus be a wide area network, a local area network, a near field communication network, a cellular communication network, or any of a wide variety of other networks or combinations of networks. Remote systems  154  can be systems in remote server environments, (e.g., cloud-based systems), farm manager systems, vendor systems, or other remote systems. Before describing the overall operation of agricultural harvester  100  in controlling illumination sources  116  and  118 , a brief description of some of the items in harvester  100 , and their operation, will first be provided. 
     Propulsion system  102  propels a set of ground-engaging elements (such as wheels or tracks) on agricultural harvester  100  to move it. Steering system  104  can be controlled by operator  152 , or automatically, to steer agricultural harvester  100 . Other harvesting functionality can be any of a wide variety of different types of functionality, such as header functionality, crop accelerator, separator, and cleaning mechanisms, when the harvester is a combine harvester. It can include silage generation functionality where the harvester is a forage harvester. It can include billet generation functionality when the harvester is a sugarcane harvester and bale generation functionality when the harvester is a cotton harvester. These are examples only and other harvesting functionality can be used based upon the type of harvester. 
     Operator interface mechanisms  108  can include a wide variety of different mechanisms that operator  152  can interact with in order to control agricultural harvester  100 . Therefore, they can include steering wheels, pedals, levers, linkages, joysticks, buttons, a microphone and speaker (where speech recognition and synthesis are provided), a user actuatable display which can be actuated using a point and click device, using touch gestures, or otherwise, or a wide variety of other user interface mechanisms. 
     Communication system  110  can be used to enable communication among the various items of agricultural harvester  100  and also communication between harvester  100  and remote systems  104 . Therefore, communication system  110  can include a controller area network (CAN) communication system, a cellular communication system, a wide area network communication system, a local area network communication system, or any of a wide variety of other systems or combination of systems. Geographic position system  111  can include a global navigation receiver for receiving GNSS signals, a dead reckoning system, or any of a wide variety of other positioning systems that generate a position signal indicative of a geographic position or location of agricultural harvester  100 . 
     Crop sampling system  134  illustratively handles crop sampling so that as a crop sample  120  moves adjacent sampling window element  122 , illumination sources  116  and  118  can be activated, or turned on, to illuminate crop sample  120  through window element  122 . Element  122  can be glass, polymer, or other material that allows the radiation to pass through. Radiation  160  thus impinges on the crop sample  120  through window element  122 . Radiation  162  is reflected off of the crop sample  120 , and travels through window element  122  and impinges on sensor  114 . Sensor  114  generates an output  164 , which is provided to sample processing system  148 . Sample processing system  148  identifies constituent elements in the crop sample  120 , based upon a spectral analysis of the reflected radiation  162 . Sample processing system  148  can also provide an output to closed loop lamp control system  138  which controls the illumination sources  116  and  118 . 
     Window element  122  illustratively has a temperature sensor  166  disposed thereon. Temperature sensor  166  can be any of a wide variety of different temperature sensors that senses the temperature of sample window element  122  and provides an output signal, indicative of that temperature, to illumination controller  144 . Illumination controller  144  thus generates a signal to illumination driver component  142  indicating whether the illumination sources  116  and  118  should be turned on or off based upon the temperature generated by temperature sensor  166 . Illumination driver component  142  can then provide an output signal to drive illumination sources  116  and  118  to turn them on and off based upon the output from illumination controller  144 . Illumination controller  144  may also detect a desired sample rate  130  (which can be stored in data store  128  or elsewhere) to determine how often to sample the grain as it passes window element  122 . The sample rate  130  may indicate that the grain is to be sampled once per second, once every three seconds, as often as possible, etc. Thus, based upon the temperature of the sample window element  122  and the desired sample rate  130 , illumination controller  144  generates an output to illumination driver component  142  indicating that illumination driver component  142  should turn on or off the illumination sources  116  and  118 . 
     Under certain circumstances, especially when the harvesting operation is beginning, it may take a threshold amount of time for illumination sources  116  and  118  to reach a sufficient power output that the samples taken will be consistent. Therefore, illumination driver component  142  can provide an output to sample trigger generator  140  to indicate that the illumination sources  116  and  118  have been on long enough to reach a sufficient power to provide consistent sampling results. At that point, sample trigger generator  140  can generate an output to sensor  114  indicating that a sample should be taken, based upon the radiation  162  impinging thereon, and an output  164  can be provided from spectrometer chip  114  to sample processing system  148  for analysis. 
     Sample processing system  148  can generate an output to store the sample results  131  in data store  128  so they can be displayed to operator  152  over an operator interface mechanism  108 . The sample results  131  can also be sent to remote systems  154 , or elsewhere, using communication system  110 . 
       FIG.  2    is a block diagram showing one example of illumination controller  144 , in more detail.  FIG.  2    shows that illumination controller  144  receives a desired sample rate  130 . It also receives the temperature sensor signal  180  from temperature sensor  166 . It generates an output signal  182  to turn on and off illumination sources  116  and  118 , based upon the desired sample rate  130  and the temperature of sample window  122 , reflected by temperature sensor signal  180 . 
     In the example shown in  FIG.  2   , illumination controller  144 , itself, illustratively includes signal conditioning component  184 , lamp on/off controller  186 , and it can include other items  188 . Signal conditioning component  184  can include functionality such as filtering functionality which smooths the temperature sensor signal  180 . It can also include amplification functionality, normalization or linearization functionality, among other signal conditioning functionality. Lamp on/off controller  186  generates on/off signals  182  (which are provided to illumination driver component  184  for generating the actual illumination drive signals) based upon the desired sample rate  130 . In doing so, controller  186  ensures that the temperature of the sample window element  122 , sensed by temperature sensor  166 , does not exceed a threshold temperature value but also ensures that the illumination sources  116  and  118  do not cool down too much so as to undesirably slow down the sample rate. Thus, controller  186  attempts to control illumination sources  116  and  118  so that the desired sample rate  130  can be achieved, while still not overheating the crop sample  120  (by overheating the sample window element  122 ). 
       FIG.  3    is a flow diagram illustrating one example of the operation of illumination controller  144 , in more detail. It is assumed that, at some point, agricultural harvester  100  will begin operating so that samples are to be taken by crop sampling system  134 . Thus, at some point, lamp on/off controller  186  generates a lamp on signal  182  and provides it to illumination driver component  142 , which generates an output signal to turn on the lamps. This is indicated by block  190  in the flow diagram of  FIG.  3   . It is also assumed that illumination sources  116  and  118  (the lamps) are to be turned on for some period during which the output illumination level ramps up to full power, or to a threshold power that is sufficient to take an accurate spectral sample. Sample trigger generator  140  (based on an output from driver component  142  or controller  144  indicating that the lamps have been turned on) determines whether the lamp output is at the measurement threshold level so that an accurate measurement can be taken. This is indicated by block  192  in the flow diagram of  FIG.  3   . 
     Once the lamps  116 - 118  are at the measurement threshold output level, then sample trigger generator  140  generates a sample trigger and provides it to sensor  114 . This triggers sensor  114  to take a measurement or sample based upon the reflected radiation  162 , corresponding to the crop sample  120 . Generating a sample trigger output to sensor device  114  is indicated by block  194  in the flow diagram of  FIG.  3   , and taking a sample using sensor  114  is indicated by block  196 . 
     The sample from sensor  114  is provided to sample processing system  148  which performs a spectral analysis on the output to identify various constituent elements in crop sample  120 . The results can be provided from system  148  to data store  128  as sample results  131 . Performing spectral analysis is indicated by block  198  in the flow diagram of  FIG.  3   . Storing the sample results is indicated by block  200 . The sample can be taken and processed in other ways as well, and this is indicated by block  202 . 
     During the sampling, temperature sensor  166  senses the temperature of sample window element (or lens)  122  and provides the temperature sensor signal  180  back to signal conditioning component  184  in illumination controller  144 . Detecting the lens (or sample window element) temperature is indicated by block  204  in the flow diagram of  FIG.  3   . Lamp on/off controller  186  compares the temperature of element  122  to a threshold temperature to determine whether lamp on/off controller  186  should turn off lamps  116  and  118  so that element  122  can cool down. This is indicated by block  206 . If, at block  206 , it is determined that the temperature of sample window element  122  has not yet reached the turn off threshold, then processing reverts to block  194  where sample trigger generator  140  can generate a trigger signal and provide it to sensor  114  to continue to take samples, at the desired sample rate. 
     However, if at block  206  lamp on/off controller  186  determines that the sample window element  122  has reached the turn off temperature threshold, then lamp on/off controller  186  generates an output signal so that illumination driver component  142  turns off lamps  116  and  118 . Turning off the lamps is indicated by block  208  in the flow diagram of  FIG.  3   . 
     Unless the harvesting operation is complete, as indicated by block  210  in the flow diagram of  FIG.  3   , lamp on/off controller  186  continues to detect the sample window element temperature to determine whether it has dropped sufficiently so that the lamps can be turned back on and so that sample trigger generator  140  can trigger more samples to be taken by sensor  114 . Detecting the sample window temperature is indicated by block  212  and determining whether it has dropped sufficiently to reach a turn-on threshold temperature is indicated by block  214 . If not, lamp on/off controller  186  simply waits for the temperature to drop further, and processing reverts to block  212 . 
     However, once the temperature of sample window element  122  has dropped to the turn on threshold temperature, then lamp on/off controller  186  again generates an output signal  182  to illumination driver component  184  to turn the lamps back on. This is indicated by block  216 . With the lamps back on, processing reverts to block  194  where sample trigger generator  140  can again continue to generate sample triggers so that sensor  114  can take more samples. 
       FIGS.  4  and  5    are graphs illustrating how the temperature sensor signal  180  varies relative to the lamp on/off signal  182 .  FIG.  4    graphs the temperature indicated by the temperature sensor signal  180  versus time.  FIG.  4    shows that the temperature sensor signal can be compared against a turn on threshold and a turn off threshold. The turn off threshold is a temperature at which sample window element  122  is becoming too hot so the lamps  116  and  118  should be turned off, allowing element  122  to cool down. The turn on threshold is a temperature at which sample window element  122  is sufficiently cool so that the lamps  116  and  118  can be turned back on. It will be noted that, in one example, the turn on threshold is still high enough so that once lamps  116  and  118  are turned on, they are at a sufficient power level so that sensor  114  can take consistent samples. More specifically, when the lamps  116  and  118  are cold (e.g., near ambient temperature) it may take some time for them to heat up sufficiently (once they are turned on) so that the spectral results will be consistent. In one example, the turn on threshold is set high enough so that once the lamps are turned on (after they have cooled down from the turn off threshold) the amount of time needed to take consistent spectral results is a very short time, or is zero. Thus, the sampling rate will not suffer simply because the lamps  116  and  118  are intermittently turned off to allow the sample window element temperature to cool down. 
       FIG.  5    shows that at time t 0 , the lamps  116  and  118  are turned on, as indicated by the on/off signal  182 . When this happens, the temperature of sample window element  122  will eventually reach the turn on threshold and continue to ramp upwardly. Once the temperature of sample window element  122  reaches the turn off threshold, at time t 1 , then lamp on/off controller  186  generates the on/off signal  182  to turn off the lamps  116  and  118 . During the time from t 0  to t 1 , sample trigger generator  140  can trigger sensor  114  to take samples based on the desired sample rate  130 . Once the lamps  116  and  118  are turned off, this causes the temperature signal  180  of the sample window  122  to begin to fall until it again reaches the turn on threshold at time t 2 . At that point, lamp on/off controller  186  then turns the lamps on again and the temperature signal  180  begins to rise until it reaches the turn off threshold at time t 3  when the lamps are turned off and the temperature again begins to fall until it reaches the turn on threshold at time t 4 . This type of operation illustratively continues, with samples enabled when lamps  116  and  118  are on, until the harvesting operation is complete. 
     It can thus be seen that the present description describes a system which controls the illumination sources  116  and  118  based on the temperature of the sampling window element  122 , instead of simply periodically. This ensures that the sample rate can be as high as possible, while still not overheating the crop samples. 
     A number of more specific examples of agricultural harvester  100  will now be provided. These are examples only. 
       FIG.  6    is a partial pictorial, partial sectional view an example in which agricultural harvester  100  is a forage harvester  300 . Forage harvester  300  illustratively includes a mainframe  302  that is supported by ground engaging elements, such as front wheels  304  and rear wheels  306 . The wheels  304 ,  306  can be driven by an engine (or other power source) through a transmission. They can be driven by individual motors (such as individual hydraulic motors) or in other ways. 
       FIG.  6    shows that, in the example illustrated, forage harvester  300  includes operator compartment  350 . Operator compartment  350  has a plurality of different operator interface mechanisms  108  that can include such things as pedals, a steering wheel, user interface display devices, touch sensitive display screens, a microphone and speech recognition components, speech synthesis components, joysticks, levers, buttons, as well as a wide variety of other mechanical, optical, haptic or audio interface mechanisms. During operation, the machine moves in the direction generally indicated by arrow  352 . 
     A header  308  is mounted on the forward part of forage harvester  300  and includes a cutter that cuts or severs the crop being harvested, as it is engaged by header  308 . The crop is passed to upper and lower feed rolls  310  and  312 , respectively, which move the harvested material to chopper  314 . In the example shown in  FIG.  6   , chopper  314  is a rotatable drum with a set of knives mounted on its periphery, which rotates generally in the direction indicated by arrow  316 . Chopper  314  chops the harvested material received through rollers  310 - 312 , into pieces, and feeds it to a kernel processing unit which includes kernel processing rollers  318  and  320 . The kernel processing rollers  318  and  320  are separated by a gap and are driven by one or more different motors which can drive the rollers at different rotational speeds. Therefore, as the chopped, harvested material is fed between rollers  318  and  320 , the rollers crush and grind the material (including the kernels) into fragments. 
     In one example, at least one of the rollers  318  and  320  is mounted for movement under control of actuator  322 . Actuator  322  can be an electric motor, a hydraulic actuator, or any other actuator which drives movement of at least one of the rollers relative to the other, to change the size of the gap between rollers  318  and  320  (the kernel processing gap). When the gap size is reduced, this can cause the kernels to be broken into smaller fragments. When the gap size is increased, this can cause the kernels to be broken into larger fragments, or (if the gap is large enough) even to remain unbroken. The kernel processing rollers  318  and  320  can have surfaces that are relatively cylindrical, or the surfaces of each roller can have fingers or knives which protrude therefrom, and which cooperate with fingers or knives of the opposite kernel processing roller, in an interdigitated fashion, as the rollers turn. These and other arrangements or configurations are contemplated herein. 
     The processed crop is then transferred by rollers  318 - 320  to conveyor  324 . Conveyor  324  can be a fan, or auger, or other conveyor that conveys the harvested and processed material upwardly generally in the direction indicated by arrow  326  through chute  328 . The crop exits chute  328  through spout  330 . 
     In the example shown in  FIG.  6   , chute  328  includes an image capture housing  332  disposed on the side thereof. If can be separated from the interior of chute  328  by an optically permeable barrier (or sample window element)  122 . Barrier  122  can be, for instance glass, plastic, or another barrier that permits the passage of at least certain wavelengths of light therethrough. Housing  332  illustratively includes a radiation source  116 ,  118 , a spectral analysis sensor  114 , and can also include an image capture device  340 . Radiation source  116 ,  118  illustratively illuminates the crop passing through chute  328  with radiation. Sensor  114  detects radiation that is fluoresced or otherwise transmitted from the crop, and image capture device  340  can capture an optical image of the crop. Sensor  114  can sense radiation spectra reflected by the crop and sample processing system  148  can identify constituent elements of the sampled crop. Also, based on the image and the sensed radiation, a size distribution indicative of the distribution of the size of the kernels or kernel fragments in the harvested crop passing through chute  328  can be identified. It can be passed to a control system which controls the speed differential of rollers  118  and  120 , and/or the size of the gap between rollers  318  and  320  based upon the size distribution of kernels and kernel fragments. 
     It will also be noted that, in another example, instead of having the sensors in housing  332  sense characteristics of the crop passing through chute  328 , a sample of the crop can be diverted into a separate chamber, where its motion is momentarily stopped so the image can be taken and the characteristics can be sensed. The crop can then be passed back into the chute  328  where it continues to travel toward spout  330 . These and other arrangements and configurations are contemplated herein. 
       FIG.  7    is a partial pictorial, partial schematic, illustration of a self-propelled agricultural harvester  100 , in an example where harvester  100  is a combine harvester (or combine)  400 . It will be appreciated that the present description can just as easily be applied to a cotton harvester, a sugarcane harvester, a windrower or other agricultural harvesters. It proceeds now with respect to a combine harvester by way of example only. 
     It can be seen in  FIG.  7    that combine  400  illustratively includes an operator compartment  401 , which can have a variety of different operator interface mechanisms  108 , for controlling combine  400 . Combine  400  can include a set of front end equipment that can include header  402 , and a cutter generally indicated at  404 . It can also include a feeder house  406 , a feed accelerator  408 , and a thresher generally indicated at  410 . Header  402  is pivotally coupled to a frame  403  of combine  400  along pivot axis  405 . One or more actuators  407  drive movement of header  402  about axis  405  in the direction generally indicated by arrow  409 . Thus, the vertical position of header  402  (the header height) above ground  411  over which it is traveling can be controlled by actuating actuator  407 . While not shown in  FIG.  7   , it may be that the tilt and/or roll angle of header  402  or portions of header  402  can be controlled by separate actuators. Tilt, refers to the angle at which the cutter engages the crop, the angle being defined about an axis that is traverse (e.g., orthogonal) to the direction of movement of the harvester  400 . The roll refers to the orientation of header  402  about the front-to-back longitudinal axis of combine  400 . 
     Thresher  410  illustratively includes a threshing rotor  412  and a set of concaves  414 . Further, combine  400  can include a separator  416  that includes a separator rotor. Combine  400  can include a cleaning subsystem (or cleaning shoe)  418  that, itself, can include a cleaning fan  420 , chaffer  422  and sieve  424 . The material handling subsystem in combine  400  can include (in addition to a feeder house  406  and feed accelerator  408 ) discharge beater  426 , tailings elevator  428 , clean grain elevator  430  (that moves clean grain into clean grain tank  432 ) as well as unloading auger  434  and spout  436 . Combine  400  can further include a residue subsystem  438  that can include chopper  440  and spreader  442 . Combine  400  can also have a propulsion subsystem that includes an engine that drives ground engaging wheels  444  or tracks, etc. It will be noted that combine  400  may also have more than one of any of the subsystems mentioned above (such as left and right cleaning shoes, separators, etc.). 
     In operation, and by way of overview, combine  400  illustratively moves through a field in the direction indicated by arrow  447 . As it moves, header  402  (and the associated reel) engages the crop to be harvested and gathers it toward cutter  404 . The operator illustratively sets a height setting for header  402  (and possibly a tilt and/or roll angle setting) and a control system controls actuator  407  (and possibly a tilt and/or roll actuators—not shown) to maintain header  402  at the set height above ground  411  (and at the desired tilt and/or roll angles). The control system responds to header error (e.g., the difference between the set height and measured height of header  404  above ground  411  and possibly tilt and/or roll angle error) with a responsiveness that is determined based on a set sensitivity level. If the sensitivity level is set high, the control system responds to, smaller header position errors, and attempts to reduce them more quickly than if the sensitivity is set lower. 
     Returning to the description of the operation of combine  400 , after the crop is cut by cutter  404 , it is moved through a conveyor in feeder house  406  toward feed accelerator  408 , which accelerates the crop into thresher  410 . The crop is threshed by rotor  412  rotating the crop against concaves  414 . The threshed crop is moved by a separator rotor in separator  416  where some of the residue is moved by discharge beater  426  toward the residue subsystem  438 . It can be chopped by residue chopper  440  and spread on the field by spreader  442 . In other configurations, the residue is simply chopped and dropped in a windrow, instead of being chopped and spread. 
     Grain falls to cleaning shoe (or cleaning subsystem)  418 . Chaffer  422  separates some of the larger material from the grain, and sieve  424  separates some of the finer material from the clean grain. Clean grain falls to an auger which moves the grain to an inlet end of clean grain elevator  430 , which moves the clean grain upward and deposits it in clean grain tank  432 . Residue can be removed from the cleaning shoe  418  by airflow generated by cleaning fan  420 . Cleaning fan  420  directs air along an airflow path upwardly through the sieves and chaffers and the airflow carries residue rearwardly in combine  400  toward the residue handling subsystem  438 . 
     Tailings can be moved by tailings elevator  428  back to thresher  410  where they can be re-threshed. Alternatively, the tailings can also be passed to a separate re-threshing mechanism (also using a tailings elevator or another transport mechanism) where they can be re-threshed as well. 
       FIG.  7    also shows that window element  122  can be situated anywhere along the travel path of the harvested crop where a sample is to be taken. In one example, the window element  122  can be disposed on a wall proximate the auger that moves grain to the lower end of the clean grain elevator  430 . Illumination sources  116  and  118  and sensor  114  can be positioned appropriately to illuminate a grain sample as it moves along the sample window element  122 . In another example, a grain sample can be momentarily captured in a measurement chamber to take a measurement with sensor  114  and then re-introduced into the grain pathway for continued processing. 
     In yet another example, illustrated in  FIG.  7   , window element  122  can be disposed at the upper end of the clean grain elevator  430 , along with illumination sources  116 ,  118  and sensor  114 . It will be noted that these items can be located elsewhere along the grain travel path in harvester  400  as well. Also, crop sampling system  134  can be located closely proximate sensor  114  or elsewhere on harvester  400 . 
       FIG.  7    also shows that, in one example, combine  400  can include ground speed sensor  447 , one or more separator loss sensors  448 , a clean grain camera  450 , a forward looking image capture mechanism  451  (e.g., a stereo or mono camera), and one or more cleaning shoe loss sensors  452 . Ground speed sensor  446  illustratively senses the travel speed of combine  400  over the ground. This can be done by sensing the speed of rotation of the wheels, the drive shaft, the axel, or other components. The travel speed can also be sensed by a positioning system, such as a global positioning system (GPS), a dead reckoning system, a LORAN system, or a wide variety of other systems or sensors that provide an indication of travel speed. 
     Cleaning shoe loss sensors  452  illustratively provide an output signal indicative of the quantity of grain loss by both the right and left sides of the cleaning shoe  418 . In one example, sensors  452  are strike sensors which count grain strikes per unit of time (or per unit of distance traveled) to provide an indication of the cleaning shoe grain loss. The strike sensors for the right and left sides of the cleaning shoe can provide individual signals, or a combined or aggregated signal. It will be noted that sensors  452  can comprise only a single sensor as well, instead of separate sensors for each shoe. 
     Separator loss sensor  448  provides a signal indicative of grain loss in the left and right separators. The sensors associated with the left and right separators can provide separate grain loss signals or a combined or aggregate signal. This can be done using a wide variety of different types of sensors as well. It will be noted that separator loss sensors  448  may also comprise only a single sensor, instead of separate left and right sensors. 
     It will also be appreciated that sensor and measurement mechanisms (in addition to the sensors already described) can include other sensors on combine  400  as well. For instance, they can include a header height sensor that senses a height of header  402  above ground  411 . They can include a residue setting sensor that is configured to sense whether machine  400  is configured to chop the residue, drop a windrow, etc. They can include cleaning shoe fan speed sensors that can be configured proximate fan  420  to sense the speed of the fan. They can include a threshing clearance sensor that senses clearance between the rotor  412  and concaves  414 . They can include a threshing rotor speed sensor that senses a rotor speed of rotor  412 . They can include a chaffer clearance sensor that senses the size of openings in chaffer  422 . They can include a sieve clearance sensor that senses the size of openings in sieve  424 . They can include a material other than grain (MOG) moisture sensor that can be configured to sense the moisture level of the material other than grain that is passing through combine  400 . They can include machine setting sensors that are configured to sense the various configurable settings on combine  400 . They can also include a machine orientation sensor that can be any of a wide variety of different types of sensors that sense the orientation of combine  400 . Crop property sensors can sense a variety of different types of crop properties, such as crop type, crop moisture, and other crop properties. They can also be configured to sense characteristics of the crop as they are being processed by combine  400 . For instance, they can sense grain feed rate, as it travels through the feeder house  406 , clean grain elevator  430  or elsewhere in the harvester  400 . They can sense mass flow rate of grain through elevator  430  or through other portions of the harvester  400 , or provide other output signals indicative of other sensed variables. These are examples only. 
     The present discussion has mentioned processors and servers. In one embodiment, the processors and servers include computer processors with associated memory and timing circuitry, not separately shown. They are functional parts of the systems or devices to which they belong and are activated by, and facilitate the functionality of the other components or items in those systems. 
     Also, a number of user interface displays have been discussed. They can take a wide variety of different forms and can have a wide variety of different user actuatable input mechanisms disposed thereon. For instance, the user actuatable input mechanisms can be text boxes, check boxes, icons, links, drop-down menus, search boxes, etc. They can also be actuated in a wide variety of different ways. For instance, they can be actuated using a point and click device (such as a track ball or mouse). They can be actuated using hardware buttons, switches, a joystick or keyboard, thumb switches or thumb pads, etc. They can also be actuated using a virtual keyboard or other virtual actuators. In addition, where the screen on which they are displayed is a touch sensitive screen, they can be actuated using touch gestures. Also, where the device that displays them has speech recognition components, they can be actuated using speech commands. 
     A number of data stores have also been discussed. It will be noted they can each be broken into multiple data stores. All can be local to the systems accessing them, all can be remote, or some can be local while others are remote. All of these configurations are contemplated herein. 
     Also, the figures show a number of blocks with functionality ascribed to each block. It will be noted that fewer blocks can be used so the functionality is performed by fewer components. Also, more blocks can be used with the functionality distributed among more components. 
     It will be noted that the above discussion has described a variety of different systems, components and/or logic. It will be appreciated that such systems, components and/or logic can be comprised of hardware items (such as processors and associated memory, or other processing components, some of which are described below) that perform the functions associated with those systems, components and/or logic. In addition, the systems, components and/or logic can be comprised of software that is loaded into a memory and is subsequently executed by a processor or server, or other computing component, as described below. The systems, components and/or logic can also be comprised of different combinations of hardware, software, firmware, etc., some examples of which are described below. These are only some examples of different structures that can be used to form the systems, components and/or logic described above. Other structures can be used as well. 
       FIG.  8    is one example of a computing environment in which elements of  FIG.  1   , or parts of it, (for example) can be deployed. With reference to  FIG.  8   , an example system for implementing some embodiments includes a computing device in the form of a computer  810  programmed to operate as described above. Components of computer  810  may include, but are not limited to, a processing unit  820  (which can comprise a processor or server from previous FIGS.), a system memory  830 , and a system bus  821  that couples various system components including the system memory to the processing unit  820 . The system bus  821  may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. Memory and programs described with respect to  FIG.  1    can be deployed in corresponding portions of  FIG.  8   . 
     Computer  810  typically includes a variety of computer readable media. Computer readable media can be any available media that can be accessed by computer  810  and includes both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, computer readable media may comprise computer storage media and communication media. Computer storage media is different from, and does not include, a modulated data signal or carrier wave. It includes hardware storage media including both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by computer  810 . Communication media may embody computer readable instructions, data structures, program modules or other data in a transport mechanism and includes any information delivery media. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. 
     The system memory  830  includes computer storage media in the form of volatile and/or nonvolatile memory such as read only memory (ROM)  831  and random access memory (RAM)  832 . A basic input/output system  833  (BIOS), containing the basic routines that help to transfer information between elements within computer  810 , such as during start-up, is typically stored in ROM  831 . RAM  832  typically contains data and/or program modules that are immediately accessible to and/or presently being operated on by processing unit  820 . By way of example, and not limitation,  FIG.  8    illustrates operating system  834 , application programs  835 , other program modules  836 , and program data  837 . 
     The computer  810  may also include other removable/non-removable volatile/nonvolatile computer storage media. By way of example only,  FIG.  8    illustrates a hard disk drive  841  that reads from or writes to non-removable, nonvolatile magnetic media, an optical disk drive  855 , and nonvolatile optical disk  856 . The hard disk drive  841  is typically connected to the system bus  821  through a non-removable memory interface such as interface  840 , and optical disk drive  855  are typically connected to the system bus  821  by a removable memory interface, such as interface  850 . 
     Alternatively, or in addition, the functionality described herein can be performed, at least in part, by one or more hardware logic components. For example, and without limitation, illustrative types of hardware logic components that can be used include Field-programmable Gate Arrays (FPGAs), Application-specific Integrated Circuits (e.g., ASICs), Application-specific Standard Products (e.g., ASSPs), System-on-a-chip systems (SOCs), Complex Programmable Logic Devices (CPLDs), etc. 
     The drives and their associated computer storage media discussed above and illustrated in  FIG.  8   , provide storage of computer readable instructions, data structures, program modules and other data for the computer  810 . In  FIG.  8   , for example, hard disk drive  841  is illustrated as storing operating system  844 , application programs  845 , other program modules  846 , and program data  847 . Note that these components can either be the same as or different from operating system  834 , application programs  835 , other program modules  836 , and program data  837 . 
     A user may enter commands and information into the computer  810  through input devices such as a keyboard  862 , a microphone  863 , and a pointing device  861 , such as a mouse, trackball or touch pad. Other input devices (not shown) may include a joystick, game pad, satellite dish, scanner, or the like. These and other input devices are often connected to the processing unit  820  through a user input interface  860  that is coupled to the system bus, but may be connected by other interface and bus structures. A visual display  891  or other type of display device is also connected to the system bus  821  via an interface, such as a video interface  890 . In addition to the monitor, computers may also include other peripheral output devices such as speakers  897  and printer  896 , which may be connected through an output peripheral interface  895 . 
     The computer  810  is operated in a networked environment using logical connections (such as a controller area network—CAN, local area network—LAN, or wide area network WAN) to one or more remote computers, such as a remote computer  880 . 
     When used in a LAN networking environment, the computer  810  is connected to the LAN  871  through a network interface or adapter  870 . When used in a WAN networking environment, the computer  810  typically includes a modem  872  or other means for establishing communications over the WAN  873 , such as the Internet. In a networked environment, program modules may be stored in a remote memory storage device.  FIG.  8    illustrates, for example, that remote application programs  885  can reside on remote computer  880 . 
     It should also be noted that the different examples described herein can be combined in different ways. That is, parts of one or more examples can be combined with parts of one or more other examples. All of this is contemplated herein. 
     Example 1 is an agricultural mobile machine, comprising: 
     an illumination source that is actuated to illuminate a crop sample being processed by the agricultural mobile machine, through a sample window element, with electromagnetic radiation; 
     a detector that detects radiation reflected from the crop sample and generates a detector signal indicative of the reflected radiation; 
     a temperature sensor that senses a temperature of the sample window element and generates a temperature sensor signal indicative of the sensed temperature; and 
     a closed loop control system that generates an illumination source control signal to control the illumination source based on the temperature sensor signal. 
     Example 2 is the agricultural mobile machine of any or all previous examples wherein the detector comprises: 
     a near infrared radiation spectroscopy sensor. 
     Example 3 is the agricultural mobile machine of any or all previous examples wherein the closed loop control system comprises: 
     an illumination source controller configured to generate a lamp on/off signal to turn the illumination source on and off based on the temperature sensor signal. 
     Example 4 is the agricultural mobile machine of any or all previous examples wherein the closed loop control system comprises: 
     a sample trigger generator that receives a sample rate signal and generates, based on the sample rate signal, a trigger signal triggering the detector to generate the detector signal. 
     Example 5 is the agricultural mobile machine of any or all previous examples wherein the illumination source controller is configured to control the illumination source to keep the temperature of the sample window element in a predetermined temperature range. 
     Example 6 is the agricultural mobile machine of any or all previous examples wherein the illumination source controller is configured to turn the illumination source on and off to maintain the temperature of the sample window between a first threshold temperature value and a second temperature threshold value. 
     Example 7 is the agricultural mobile machine of any or all previous examples wherein the illumination controller comprises: 
     a signal conditioning component configured to filter the temperature sensor signal. 
     Example 8 is the agricultural mobile machine of any or all previous examples wherein the agricultural mobile machine comprises a combine harvester that harvests crop and moves the harvested crop through a crop passageway, the sample window being provided in the crop passageway. 
     Example 9 is the agricultural mobile machine of any or all previous examples wherein the agricultural mobile machine comprises a self-propelled forage harvester that harvests crop and moves the harvested crop through a crop passageway, the sample window being provided in the crop passageway. 
     Example 10 is the agricultural mobile machine of any or all previous examples and further comprising: 
     a geographic position sensor that senses a geographic position of the agricultural mobile machine and generates a position signal indicative of the agricultural mobile machine. 
     Example 11 is a method of controlling an agricultural mobile machine, comprising: 
     processing a harvested crop; 
     actuating an illumination source to illuminate a crop sample being processed by the agricultural mobile machine, through a sample window element, with electromagnetic radiation; 
     detecting radiation reflected from the crop sample; 
     generating a detector signal indicative of the reflected radiation; 
     sensing a temperature of the sample window element; 
     generating a temperature sensor signal indicative of the sensed temperature; and 
     generating an illumination source control signal, with a closed loop control system, to control the illumination source based on the temperature sensor signal. 
     Example 12 is the method of any or all previous examples wherein detecting radiation comprises: 
     detecting near infrared radiation with a spectroscopy sensor. 
     Example 13 is the method of any or all previous examples generating an illumination source control signal comprises: 
     generating a lamp on/off signal to turn the illumination source on and off based on the temperature sensor signal. 
     Example 14 is the method of any or all previous examples wherein detecting radiation comprises: 
     receiving a sample rate signal; and 
     generating, based on the sample rate signal, a trigger signal triggering the detector to generate the detector signal. 
     Example 15 is the method of any or all previous examples wherein generating a lamp on/off signal comprises: 
     controlling the illumination source to keep the temperature of the sample window element in a predetermined temperature range. 
     Example 16 is the method of any or all previous examples wherein controlling the illumination source comprises: 
     turning the illumination source on and off to maintain the temperature of the sample window between a first threshold temperature value and a second temperature threshold value. 
     Example 17 is an agricultural harvester, comprising: 
     harvesting functionality that harvests crop and moves the harvested crop along a crop travel path, through a crop passageway; 
     a sample window element that defines a portion of the crop passageway; 
     an illumination source that is actuated to illuminate a crop sample being processed by the agricultural harvester, through the sample window element, with electromagnetic radiation; 
     a detector that detects radiation reflected from the crop sample and generates a detector signal indicative of the reflected radiation; 
     a temperature sensor that senses a temperature proximate the crop sample and generates a temperature sensor signal indicative of the sensed temperature; and 
     a closed loop control system that generates an illumination source control signal to control the illumination source based on the temperature sensor signal. 
     Example 18 is the agricultural harvester of any or all previous examples wherein the temperature sensor is configured to sense a temperature of the sample window element. 
     Example 19 is the agricultural harvester of any or all previous examples wherein the detector comprises: 
     a near infrared radiation spectroscopy sensor. 
     Example 20 is the agricultural harvester of any or all previous examples wherein the closed loop control system comprises: 
     an illumination source controller configured to generate a lamp on/off signal to turn the illumination source on and off based on the temperature sensor signal. 
     Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.