Patent Description:
Agricultural seeds are often processed before planting. For example, some seeds undergo a sorting or categorization process in which characteristics of individual seeds are identified and the seeds are sorted into groups according to the characteristics. In other processes, seeds are, for example, pelletized, coated, etc. To achieve optimal results, the granular materials are fully processed in each processing step. For example, seeds must be thoroughly polished during a polishing step or else they can become entangled with one another, making subsequent processing steps such as singulation and sorting less effective. Incomplete processing of seeds can also adversely affect seed sowing operations.

Beakawi Al-Hashemi et al. reviews study of angle of repose for granular material and powders to understand micro- and macro-behavior thereof in applications. Methods of measurement are not standardized or consistent. Some experiments are recorded with a fast camera [<NPL>]. Soheili Ahmad et al. describe an image-based experimental test stand solution for study of the repose angle of corn seeds in rotating drums in slumping and rolling modes for the purpose of evaluating the influence of drum properties (drum size, diameter, filling, etc) and flow regimes in processing seeds in rotating drums equipment. Experimental study is conducted by imaging seeds in different rotating drums, wherein front of drums is fixed with a transparent plate [<NPL>].

Cited art does not teach or suggest using angle of repose as a parameter for controlling seed processing.

Embodiments can be gathered from the dependent claims.

In one aspect, a method of processing seeds comprises processing seeds in a processing step. An angle of repose of at least a portion of the processed seeds is determined. Whether the processed seeds have been sufficiently processed in the processing step is determined based on the determined angle of repose.

In another aspect, a system for determining an angle of repose of processed seeds comprises a receptacle defining a cavity and an opening in communication with the cavity for receiving the processed seeds therethrough. The receptacle has a support wall configured for supporting the processed seeds in the cavity in a pile. An image sensor faces the receptacle and is configured to capture an image of the pile of processed seeds received in the cavity. An image processor is operatively connected to the image sensor to receive the captured image from the image sensor. The image processor is configured to evaluate the image to determine an angle of inclination of the pile based on the image.

In another aspect, a measurement device for measuring an angle of repose of granular material comprises a receptacle comprising a front wall, a rear wall, and a support wall extending between the front and rear walls. The receptacle has an interior between the front and rear walls. The receptacle is configured to receive granular material in the interior such that the granular material is supported on the support wall. The front wall of the receptacle is at least somewhat transparent. A plate is pivotably mounted on the front wall for rotation about an axis with respect to the receptacle through a range of motion. The plate overlaps at least a portion of the front wall along at least a portion of the range of motion. The plate is at least somewhat transparent such that the interior of the receptacle is visible through the plate and the front wall when the plate overlaps the front wall. The plate has a perimeter edge margin and protractor scale markings spaced apart along at least a segment of the perimeter edge margin. The plate further comprises at least one indicator line. An indicator arm is pivotably mounted on the front wall for rotation about the axis with respect to the receptacle independently of the plate. The indicator arm extends radially outward from the axis.

Other features will be in part apparent and in part pointed out hereinafter.

The present disclosure pertains to evaluation systems for determining an angle of repose of granular material used in a seed processing system, as well as certain seed processing systems that include or can be used in combination with the evaluation system. Referring to <FIG>, one embodiment of a seed sorting system (broadly, a seed processing system) is generally indicated at reference number <NUM>. As will be explained in further detail below, the seed sorting system <NUM> is one example of a seed processing system with which an evaluation system <NUM> configured to measure an angle of repose of granular material can be used. In general, the system <NUM> includes components that are used to conduct a seed sorting process, but other systems or components configured to conduct other seed processes can be used in other embodiments. In <FIG>, the components of the seed sorting system are schematically illustrated as being components of a single inline process. It will be appreciated, however, that in one or more embodiments, one or more of the components are operated as discrete processes separate from the other components in the seed sorting system <NUM>. A controller <NUM> (e.g., one or more processors and one or more suitable memory modules) is programmed to operate one or more aspects of the system <NUM>.

As explained below, the illustrated seed sorting system <NUM> includes the evaluation system <NUM>, which is generally configured for evaluating the progress of one or more process steps by measuring an angle of repose of granular material being processed. In the illustrated embodiment the evaluation system <NUM> is configured to determine the angle of repose of agricultural seeds (e.g., tomato seeds, pepper seeds, etc.) to evaluate the progress of a polishing process conducted by a seed polisher <NUM>, but in other embodiments the evaluation system could be used to evaluate the progress of other processing steps and/or to determine the angle of repose of other granular materials (e.g., powder seed treatment materials, pelletizing materials, etc.). In one or more embodiments, the seed polisher <NUM> is a standalone device apart from the seed sorting system <NUM> or other seed processing system. It is also understood that, in one or more embodiments, the evaluation system <NUM> is a standalone device apart from the seed sorting system <NUM> or other seed processing system.

In general, a hopper <NUM> imparts seeds to the polisher <NUM>, and the polisher is configured to polish the seeds. In one or more embodiments, the polished seeds are conveyed to a singulator <NUM> of the seed sorting system <NUM> after polishing. Suitably, the polisher <NUM> can de-awn, de-beard, remove seed hairs from, remove debris from, or scarify the seeds. Those skilled in the art will appreciate that polishing can disentangle the seeds or otherwise facilitate the later separation or singulation of the seeds using the singulator <NUM>. Polishing can be used for other things besides preparing seeds for singulation in other embodiments. As described below, the evaluation system <NUM> in the illustrated embodiment is configured to receive a sampling of seeds from the polisher <NUM> to evaluate whether the seeds are sufficiently polished for effective singulation by the singulator.

After the seeds are polished, the polished seeds can be fed to the singulator <NUM>. In the illustrated embodiment, the singulator <NUM> singulates the polished seeds and conveys the singulated seeds to an imaging and analysis assembly <NUM> used in combination with a seed sorting assembly <NUM>. Suitably, the singulator <NUM> is configured to arrange the seeds in manner that enables the imaging and analysis assembly <NUM> to individually image and analyze the seeds. In one embodiment, the singulator <NUM> comprises one or more vibratory feeders (not shown) that impart vibratory energy to the polished seeds to transport the seeds single-file along vibratory channels and thereby arrange the seeds in single-seed rows in the channels. In one or more embodiments, the vibratory energy also spaces the seeds from one another within each row. Thus, the singulator <NUM> conveys the individually spaced seeds in each row to the imaging and analysis assembly <NUM> for individually imaging and analyzing the seeds.

Any suitable imaging and analysis assembly can be used to acquire images of individual seeds and analyze the images to group individual seeds into one or more categories according to one or more identified characteristics based on the images. In the illustrated embodiment, the imaging and analysis system <NUM> includes a conveyor <NUM> for conveying the singulated seeds through the imaging and analysis system and a plurality of imaging devices 30A-30N and <NUM> mounted above and below the conveyor for capturing images of the singulated seeds. In certain embodiments, one or more of the imaging devices 30A-30N, <NUM> can have different imaging modalities. For example, one or more of the imaging devices 30A-30N, <NUM> can be configured to capture 2D images, 3D images, x-ray images, hyperspectral images, infrared images, ultrasonic images, etc. The imaging devices 30A-30N, <NUM> are configured to transmit the captured images for each seed to the controller <NUM>, which analyzes the images and categorizes the individual seeds into one or more groups based on one or more characteristics such as size, shape, color, texture, embryo size, morphology, endosperm content, internal free space, etc. For example, in one embodiment, the controller <NUM> categorizes the seeds into one of two groups, defective and non-defective (e.g., defective seeds may be identified as diseased, discolored, or mechanically damaged seeds). The controller <NUM> transmits control signals to the sorting assembly <NUM> that direct the sorting assembly to physically sort the seeds into the categorized groups determined by the controller. For example, the controller <NUM> directs the sorting system <NUM> to arrange the seeds at different locations according to their determined group.

Referring to <FIG>, one embodiment an evaluation system <NUM> that is configured to determine an angle of repose of seeds (e.g., a batch of seeds or a sample from a batch of seeds or a sample from a continuous processing of seeds) from the polisher <NUM> will now be described in greater detail. Although the illustrated evaluation system <NUM> is configured to receive seeds after a polishing step of the seed sorting process <NUM>, it will be understood that the evaluation system <NUM> could also be used to evaluate samples of granular material during other process steps of the illustrated seed sorting process or another seed process. As explained below, the illustrated evaluation system <NUM> is generally configured to determine the angle of repose of the seeds from the polisher to evaluate whether the seeds have been sufficiently polished to allow for effective singulation.

The evaluation system <NUM> includes a base <NUM> and a receptacle <NUM> mounted on the base for rotation with respect to the base about a generally horizontal axis of rotation A (<FIG>). The receptacle <NUM> defines a cavity <NUM> for receiving a pile P of granular material (e.g., polished seeds). In addition, the receptacle <NUM> defines an opening <NUM> in communication with the cavity <NUM>. Seeds or other granular material are placed into the cavity <NUM> through the opening <NUM>. In the illustrated embodiment, the cavity <NUM> has a generally circular cross-sectional shape in a plane perpendicular to the axis of rotation A and has a generally uniform depth along the axis of rotation. An embodiment could be created without including a generally circular cross-section, such as an oval or other shape where the movement of the seeds along the surface can be calculated (see, for example, the square shaped cavity <NUM> in <FIG>). The receptacle <NUM> includes a front wall <NUM>, a rear wall <NUM> spaced apart from the front wall along the axis of rotation A, and a support wall <NUM> extending between the front and rear walls along the axis of rotation. In certain embodiments, the internal surface of the support wall <NUM> has a rough surface texture. The front and rear walls <NUM>, <NUM> are joined to the support wall <NUM> to define the generally cylindrical cavity <NUM>. In the illustrated embodiment, each of the front and rear walls <NUM>, <NUM> comprises a transparent, generally circular disc formed from, for example, acrylic material. In the illustrated embodiment, the support wall <NUM> has an annular shape (e.g., a circular arc shape) and extends between the perimeter edge margins of the front and rear walls <NUM>, <NUM> to support the pile P of granular material received in the cavity <NUM>. In other embodiments, the support wall can have other arcuate shapes or non-arcuate shapes. In the illustrated embodiment, the support wall <NUM> comprises opaque material (e.g., plastic). The illustrated support wall <NUM> defines the opening <NUM> leading into the cavity <NUM>. A door (not shown) may be coupled to the support wall <NUM>, such as by a hinge or other fastener, to allow selective covering and uncovering of the openings <NUM>. It should be noted that the door does not need to be directly fastened, and may be placed over an opening, or there also may a removeable front or rear. In certain embodiments, the annular support wall <NUM> extends at least about <NUM>° (e.g., at least about <NUM>°) of the arc of a circle. As explained below, the annular support wall <NUM> facilitates supporting a pile P of granular material in the cavity <NUM> at a plurality of positions of the receptacle <NUM> that are angularly spaced about the axis of rotation.

Referring to <FIG>, a driver <NUM> is supported on the base <NUM> and is operatively connected to the receptacle <NUM> to selectively drive rotation of the receptacle about the axis of rotation A with respect to the base <NUM>. In certain embodiments, the driver <NUM> can comprise a motor, such as a servo motor and/or a stepper motor. It is understood that in other embodiments, other types of drivers could be used or the receptacle could be rotated or tilted manually. Referring to <FIG>, a controller <NUM> (e.g., one or more processors and one or more suitable memory modules and or one or more amplifiers) is operatively connected to the driver <NUM> to control rotation of the receptacle <NUM> about the axis A. As explained below, the controller <NUM> is configured to actuate the driver <NUM> to synchronize rotation of the receptacle <NUM> with activation of an imaging system, generally indicated at <NUM>.

As will be explained in further detail below, the imaging system <NUM> is configured to determine the orientation of the top of the pile P of seeds in the receptacle <NUM>. By rotating the receptacle <NUM>, the pile P can be rearranged so that at least a portion of the top of the pile is oriented at the angle of repose for the granular material. When the pile P of granular material is received in the cavity <NUM>, rotation of the receptacle <NUM> about the axis of rotation in either direction can cause an angle of inclination of the pile to change until the pile is at the angle of repose of the granular material, at which time additional rotation will cause the pile to slump or slide (<FIG> show one example of the change on slope caused by rotation of the receptacle <NUM>). When the slope of the pile P begins to stay about the same with further rotation of the receptacle, the top of the pile is oriented at about the angle of repose of the granular material. Thus, as explained below, the driver <NUM> is configured to drive rotation of receptacle <NUM> about the axis of rotation A to a plurality of angular positions to identify the angle of repose of granular material received in the cavity <NUM>. It is understood that the driver <NUM> can incrementally rotate the receptacle <NUM> to each of the plurality of angular positions or continuously rotate the receptacle so that the receptacle passes through the positions as it rotates. In one or more embodiments, the receptacle incrementally rotates <NUM> at least <NUM>° about the axis of rotation A before completing the determination of the angle of repose. In certain embodiments, the angle of repose is determined based on rotation about the axis of rotation A of less than <NUM>°.

Referring to <FIG>, the imaging system <NUM> includes a camera <NUM> (broadly, an image sensor) and a backlight <NUM> (broadly, a light source). The camera <NUM> is mounted on the base <NUM> in operative alignment with the receptacle <NUM> to capture images of the receptacle. In one or more embodiments, the camera <NUM> and the receptacle <NUM> are aligned at spaced apart positions along the axis of rotation A. Suitably, the camera <NUM> is oriented horizontally, pointed in a direction substantially parallel to the axis of rotation A. The camera <NUM> and the receptacle <NUM> are oriented relative to one another so that the front wall <NUM> of the receptacle faces the camera. Because the front wall <NUM> is transparent, the camera <NUM> can capture images of the pile P of granular material supported in the cavity <NUM> inside the receptacle <NUM>. The backlight <NUM> is positioned behind the rear wall <NUM> of the receptacle <NUM> for illuminating the cavity <NUM> through the transparent rear wall. In the illustrated embodiment, the backlight <NUM> has an illumination surface facing the back wall <NUM> that is larger than the receptacle <NUM> and is positioned to illuminate substantially the entire cavity <NUM> from behind. This backlighting arrangement enables the camera <NUM> to produce images (broadly, image data) having a high degree of contrast (e.g., as shown in <FIG>) between portions of the cavity <NUM> that are filled with granular material (filled space) and portions of the cavity that are free of granular material (non-filled space). In the illustrated embodiment, the backlight <NUM> has an illumination hole <NUM> in which the backlight does not illuminate the receptacle <NUM>. The illumination hole <NUM> is spaced apart above the pile P of granular material received in the cavity <NUM> in images captured by the camera <NUM>. In the captured images, the hole <NUM> also contrasts with non-filled space in the sampling cavity. Although the illustrated embodiment uses a camera as an image sensor, other embodiments can use other types of image sensors to capture images of the sampled granular material received in the receptacle. Likewise, while the illustrated embodiment uses a backlight, other embodiments can use other types of light sources to illuminate the cavity.

The controller <NUM> is operatively connected to the camera <NUM> to synchronize image capture with rotation of the receptacle <NUM> to a plurality of angularly spaced apart positions. The controller <NUM> is configured to direct the driver <NUM> to incrementally rotate the receptacle <NUM> to a plurality of positions that are angularly spaced apart about the axis of rotation A. At each incremental position, the controller <NUM> directs the camera <NUM> to capture an image of the backlit receptacle <NUM>. As explained below, an image processor <NUM> is configured to analyze the images to determine the angle of repose of the material an orientation or an angle of inclination of the pile P of granular material received in the cavity <NUM>. The controller <NUM> can be configured to direct the evaluation system <NUM> to capture images of the receptacle <NUM> at a plurality of positions that are angularly offset from a reference position, for example, in which the cavity receives the sample of granular material. It should be noted that the receptacle <NUM> does not need to be stopped to capture the images.

Suitably, the controller <NUM> is configured to direct the evaluation system <NUM> to capture images at a range of angularly offset positions that is suitable for determining an angle of repose of granular material received in the cavity <NUM>. For example, a range of angular positions suitable for determining the angle of repose can include a plurality of angular positions at which the pile P is oriented generally at the angle of repose of the granular material. Rotating the receptacle <NUM> in only one of first and second rotational directions R1, R2 (<FIG>) will cause the angle of inclination of the pile P to change significantly until it reaches the angle of repose for the granular material, at which time the pile begins to collapse (e.g., slide or slump) and the angle of inclination of the pile generally remains constant with some variations due to the collapsing of the pile. In one embodiment, the controller <NUM> ensures an adequate range of angular positions by capturing images of the receptacle <NUM> at predetermined angular positions for each sample of granular material it receives (e.g., a predetermined range of angular positions of at least <NUM>° or less than <NUM>°). In other embodiments, the controller <NUM> is configured to determine the range of positions based on feedback from the image processor <NUM>. For example, the controller <NUM> can determine the range of receptacle positions required to accurately measure the angle of repose of the granular material by determining when the angle of inclination of the pile P is substantially constant for n incremental positional adjustments in the same rotation direction R1, R2, where n is greater than or equal to <NUM>. It will be understood that an image system could continuously image the pile as the receptacle is driven in continuous rotation.

In one embodiment, the controller <NUM> is configured to direct the driver <NUM> to rotate the receptacle <NUM> in both rotational directions. For example, the controller <NUM> first directs the driver <NUM> rotate the receptacle <NUM> in the first rotational direction R1 to a first set of angularly spaced positions and then directs the driver to rotate the receptacle in the second rotational direction R2 to a second set of rotational positions. Suitably, each of the first and second sets of positions covers a sufficiently large angular range to allow separate angle of repose measurements to be determined based on the image data for the respective set of positions. For example, in a first set of angular positions, the angle of repose would be determined based on the pile P sloping from right to left as shown in <FIG> and in the second set of angular positions the angle of repose would be determined based on the pile sloping from left to right as shown in <FIG>. In one embodiment, the image processor <NUM> is configured to determine the angle of repose by averaging the absolute values of the angle of repose measurements determined from images of the first and second sets of positions. Averaging the angle of repose measurement can account for measurement errors induced by misalignment between the camera <NUM> and true horizontal.

The image processor <NUM> is operatively connected to the camera <NUM> to receive the captured images from the camera and is configured to determine an angle of inclination of the pile P of granular material received in the cavity <NUM> based on the images. Referring to <FIG>, in one embodiment, the image processor <NUM> is configured to process each image from the camera <NUM> to produce one or more processed images 140A, 140B. In the illustrated embodiment, the image processor <NUM> is configured to binarize and invert the raw image (examples of raw images are shown in <FIG>) to produce a binarized and inverted image 140A by mapping light areas of the image to dark and dark areas of the image to light. In the binarized and inverted image 140A shown in <FIG>, the filled space occupied by the pile P of granular material is rendered substantially in white and the non-filled space is rendered substantially in black. The image processor <NUM> is further configured to extract a region of interest ROI from the inverted image 140A to produce an extracted image 140B (<FIG>). The extracted image 140B excludes the end portions of the pile P, which may not be consistent with the middle portion included in the region of interest ROI. In the illustrated embodiment, the region of interest ROI also excludes the hole <NUM> of the backlight and the irregularities from the inner edge of the support wall <NUM>.

Referring to <FIG>, after extracting the region of interest ROI of the binarized and inverted image, the image processor <NUM> is configured to fit a line FL through pixels that define the top of the pile P. Referring to <FIG>, to determine the fitted line FL, the image processor <NUM> identifies the pixels PX representing the top of the pile P. In one or more embodiments, the image processor <NUM> calculates a least square fit based on the pixels PX to determine the fitted line FL. It will be understood that other methods of fitting a line to the pixels may be used in one or more embodiments. In certain embodiments, the image processor <NUM> can be configured to determine how well the fitted line FL represents the pixels PX by calculating a statistical R<NUM> for the pixels and the fitted line. As will be appreciated, the statistical R<NUM> provides a percentage that indicates how well the response variable (in this case, the pixels PX) are explained by the linear model (in this case, the fitted line FL). When the statistical R<NUM> is close to <NUM>, the image processor <NUM> may determine that the fitted line FL provides a good representation of the pixels representing the top of the pile P. When the statistical R<NUM> value is significantly less than <NUM>, the image processor <NUM> may determine that the fitted line FL is a poor or unreliable representation of the pixels representing the top of the pile P.

Referring to <FIG> and <FIG>, after the fitted line FL representing the top of the pile P is determined, the image processor <NUM> is configured to determine an angle α of the fitted line with respect to the reference line RL. In the illustrated embodiment, the reference line RL is known to be horizontal. When the reference line RL is horizontal, the angle α between the fitted line FL and the reference line is a measurement of the "angle of inclination" of the top of the pile P. It will be appreciated, however, that the reference line RL can be a line that is not horizontal in certain embodiments. When the reference line RL is not horizontal, angle of inclination can be calculated by determining an offset angle between the reference line and true horizontal.

The determined angles of inclination α for the images at the angularly spaced positions of the receptacle <NUM> are evaluated to determine the angle of repose for the granular material. <FIG> shows a graph of data points D, wherein for each data point, an angular position of the receptacle <NUM> is plotted on the x-axis and the determined angle of inclination α for the pile P at the respective angular position of the receptacle is plotted on the y-axis. In particular, <FIG> includes data points D corresponding to the pile P as shown in the angular positions of the receptacle <NUM> shown in <FIG>. As explained above, the range of angular positions of the receptacle <NUM> that are used or required to determine the angle of repose can vary and can be greater than or equal to <NUM>° or less than <NUM>° in various embodiments. As can be seen in <FIG>, the pile P initially is inclined in the right to left direction (<FIG>) and is rotated until the pile inclines in the left to right direction (<FIG>). This change in orientation of the pile P is represented as a zero crossing on the graph of <FIG>. That is, when the top of the pile P is generally horizontal (broadly, parallel to the reference line RL), the image processor <NUM> determines that the angle of inclination α is zero; when the top of the pile inclines from left to right with respect to the reference line, the image processor determines that the angle of inclination is negative; and when the top of the pile inclines from right to left with respect to the reference line, the image processor determines that the angle of inclination is positive.

As the data points D are plotted, the image processor <NUM> is configured to determine a connecting line CL that connects the data points. In addition, the illustrated image processor is configured to determine a smoothed line SL through the data points D based on a moving average of a plurality of (e.g., three) data points. The system is configured to determine the slope of the smoothed line SL. As explained above, when the seed pile S begins to slide or slump and the angle of inclination α stops increasing in absolute value with the incremental rotation of the receptacle <NUM>, the top of the pile P is oriented at about the angle of repose AOR for the granular material. To determine when the angle of inclination α is no longer increasing, the image processor <NUM> is configured to determine when the slope of the smoothed line SL falls below a threshold value. After the slope of the smoothed line SL is determined to have fallen below the threshold value, the image processor <NUM> is configured to begin collecting a set SD of a predetermined number of data points D for use in determining the angle of repose AOR. The image processor is configured to calculate the angle of repose AOR as the average of the angles of inclination α of the data points D in the set SD. Another method to find the images that contain the angle of inclination of interest is to start rotating the receptacle and wait some time while taking images until one is sure that the seed pile is slumping. The images taken in such a way only contain the angle of inclination which can be used to determine the angle of repose.

Referring again to <FIG>, <FIG>, one embodiment of a method of using the evaluation system <NUM> with the seed sorting system <NUM> will now be briefly described, with the understanding that the evaluation system can also be used independently or with another seed processing system in other embodiments. Initially, seeds are loaded into the seed polisher <NUM>. The polisher <NUM> then begins the process of polishing the seeds. Periodically, the seeds being polished are sampled from the polisher and placed into the cavity <NUM> of the receptacle <NUM> in the evaluation system <NUM>. In one embodiment, the controller <NUM> can direct the polisher <NUM> to automatically dispense samples of the seeds into the receptacle <NUM>, for example, at predetermined intervals. In another embodiment, the technician manually samples seeds from the polisher <NUM> and places them in the receptacle <NUM>. In yet another embodiment, an entire batch of polished seeds may be added to the receptacle <NUM>, either by automation or manually. In still another embodiment, the evaluation system is integrated into the polisher to receive the seeds as they are being polished.

The evaluation system <NUM> is configured to determine an angle of repose of the seeds in the receptacle <NUM>. With the backlight <NUM> illuminating the cavity <NUM> and its contents, the controller <NUM> directs the driver <NUM> to rotate the receptacle <NUM> incrementally through a range of angularly spaced positions and at each position synchronously directs the camera <NUM> to capture an image of the receptacle. In one embodiment, the controller <NUM> directs the driver <NUM> to rotate the receptacle <NUM> from the reference position in which it receives the seeds in a first direction R1 to a first set of positions and then directs the driver to rotate the receptacle in a second direction R2 to a second set of positions. For each captured image, the image processor <NUM> inverts and binarizes the image and extracts the region of interest ROI. The image processor <NUM> determines the pixels PX defining the top of the pile in the region of interest ROI and fits a line FL to the pixels (see <FIG>). In certain embodiments, the image processor <NUM> evaluates the quality of the representation of the fitted line by calculating a statistical R<NUM> comparing the fitted line and the pixels PX. For each image, the image processor <NUM> calculates the angle α of the fitted line with respect to the reference line RL. Suitably, a horizontal reference line RL is used such that the angle α represents the angle of inclination of the pile P.

Referring to <FIG>, using the data points D representing the determined angle of inclination α for each angular position of the receptacle <NUM> as it is rotated in the first direction R1, the image processor <NUM> calculates a first smoothed line SL. The image processor <NUM> determines when the slope of the first smoothed line SL falls below a threshold and then determines a first measurement of the angle of repose AOR as the absolute value of an average of the determined angles of inclination α for a subset SD of the data points D at angular positons after the slope has fallen below the threshold. Then, using the points D representing the determined angle α for each angular position of the receptacle <NUM> as it is rotated in the second direction R2, the image processor <NUM> calculates a second smoothed line SL. The image processor <NUM> determines when the slope of the second smoothed line SL falls below a threshold and then determines a second measurement of the angle of repose AOR as the absolute value of an average of the determined angles of inclination α for a subset SD of the data points S at angular positions after the slope has fallen below the threshold. In one or more embodiments, the image processor <NUM> calculates an average of the first and second angle of repose measurements to determine a final angle of repose measurement for the seeds.

It has been found that the angle of repose of seeds can be a useful signal of whether the seeds have been sufficiently polished for effective singulation. Ineffectively polished seeds can tend to clump together more than effectively polished seeds. This can cause ineffective singulation, which may require manual intervention or restarting of a seed sorting process. But, in addition to adversely affecting singulation, the entanglement of poorly polished seeds causes the seeds to have a different angle of repose than effectively polished seeds. For a given type of seed (e.g., tomato seed, pepper seed, etc.) a suitable threshold angle of repose can be empirically derived through experimentation and used by the sorting system <NUM> to determine whether the seeds are ready for singulation. For example, in one embodiment the sorting system controller <NUM> is operatively connected to the evaluation system controller <NUM> to receive an indication of the determined angle of repose. The controller <NUM> can be configured to compare the determined angle of repose to an empirically derived threshold angle of repose to determine if the seeds are sufficiently polished before singulation or whether additional polishing should occur before singulation. In another embodiment, the determined angle of repose can be used in other ways (e.g., be considered by a human user) to evaluate whether the seeds have been sufficiently polished for singulation. If the seeds are determined to be sufficiently polished, the controller <NUM> or the user directs the polisher <NUM> to convey the seeds to the singulator <NUM>. If the seeds are not determined to be sufficiently polished, the controller <NUM> or the user directs the polisher <NUM> to continue polishing until the evaluation system <NUM> is used to determine the angle of repose of another sample. This process is repeated until the determined angle of repose indicates that polishing is complete (e.g., reaches a predetermined threshold value), at which point the controller <NUM> or the user causes the polished seeds to be moved to the singulator <NUM>.

In one embodiment, the singulator <NUM> singulates the seeds as described above and conveys the singulated seeds to the imaging and analysis system <NUM>. The imaging and analysis system <NUM> images the individual seeds and categorizes them according to predefined characteristics. As the conveyor <NUM> conveys the individual seeds to the sorting device <NUM>, the controller <NUM> transmits control instructions to the sorting device that direct the sorting device to physically group each seed by its determined category.

Although in the illustrated embodiment the evaluation system <NUM> is used to evaluate seeds being processed by the polisher <NUM>, in other embodiments the evaluation system could be used before the seeds are processed or to evaluate the progress of other processing steps. For illustration purposes, evaluation system <NUM> can be used to measure an angle of repose of samples of seeds being singulated by the singulator. Properly singulated seeds have a different angle of repose than more poorly singulated seeds. Thus, a measure of whether the seeds are properly singulating could be made during singulation by sampling the seeds during the singulation process and measuring the angle of repose of the samples.

In another embodiment, an evaluation system <NUM> is used to measure an angle of repose of samples of powders used for pelletizing seeds during a mixing process of the powders. Properly mixed powders would be expected to have a different angle of repose than more poorly mixed powders. Thus, the quality of the mixing of the powders could be evaluated by sampling the mixed powder during the mixing process and measuring the angle of repose of the samples. In still other embodiments, the evaluation system <NUM> could be used to measure the angle of repose of raw powder prior to mixing and/or pelleting as a quality check of the powder. If the angle of repose of powder known to have the desired composition is known, it can be compared to the determine angle of repose of the powder sample to evaluate whether the raw powder has the desired composition. A difference could indicate that the composition of the sampled powder deviates in some way from the desired composition.

In another embodiment, the evaluation system <NUM> is used to measure an angle of repose of samples of pelletized or coated seeds during or after a pelleting or coating process. Properly pelletized seeds would be expected to have a different angle of repose than more poorly pelletized seeds. Likewise, properly coated seeds would be expected to have a different angle of repose than more poorly coated seeds. As above, a threshold angle of repose for properly pelletized or coated seeds could be determined empirically, and the effectiveness of the pelletizing or coating of seeds during a later pelletizing process could be evaluated by sampling the later-pelletized or later-coated seeds and measuring the angle of repose of the samples.

In yet another embodiment, the evaluation system <NUM> is used to measure an angle of repose of samples of seeds during a drying process. Properly dried seeds would be expected to have a different angle of repose than more poorly dried seeds. As above, a threshold angle of repose for properly dried seeds could be determined empirically, and the effectiveness of drying of seeds during a later drying process could be evaluated by sampling the later-dried seeds and measuring the angle of repose of the samples. The evaluation system <NUM> can be used to evaluate drying based on the angle of repose of the seeds while the drying process is in progress, e.g., while the seeds are being dried in a rotating drum.

In a further example and for illustration purposes, evaluation system <NUM> can be used to measure an angle of repose of samples of seeds during a priming process. Properly primed seeds would be expected to have a different angle of repose than more poorly primed seeds. As above, a threshold angle of repose for properly primed seeds could be determined empirically, and the effectiveness of the priming of seeds during a later priming process could be evaluated by sampling the later-primed seeds and measuring the angle of repose of the samples.

In an embodiment, the evaluation system <NUM> is used to measure an angle of repose of samples of seeds (e.g., cotton seeds) during a delinting process. Properly delinted seeds would be expected to have a different angle of repose than seeds that are not properly delinted. As such, a threshold angle of repose for properly delinted seeds could be determined empirically, and the effectiveness of the delinting of seeds during a later delinting process could be evaluated by sampling the later-delinted seeds and measuring the angle of repose of the samples.

Thus, it can be seen that the evaluation system <NUM> has wide application to processes involving granular materials in the production of seeds. To provide quality assurance, the angle of repose of a granular material can be measured and compared to a known angle of repose for corresponding granular material that meets the desired quality standards for the process. Differences in angle of repose can provide an indication that the granular material is defective or requires additional processing.

Referring to <FIG>, another embodiment of an evaluation system for determining an angle of repose of granular material is generally indicated at reference number <NUM>. The evaluation system <NUM> includes a base <NUM> and a receptacle, generally indicated at <NUM>, which is fixed to the base. The receptacle <NUM> defines a cavity <NUM> and a top opening <NUM> through which the granular material passes into the cavity. In the illustrated embodiment, the cavity <NUM> is substantially rectangular. The receptacle <NUM> includes a front wall <NUM>, a rear wall <NUM>, a bottom support wall <NUM>, and first and second side walls <NUM>. The bottom support wall <NUM> is substantially flat and extends in a fixed, generally horizontal plane HP. A feed system <NUM> is configured to gradually feed the granular material into the support cavity <NUM> through opening <NUM> so that the granular material forms a pile P (<FIG>) atop the support wall <NUM>. In the illustrated embodiment, the feed system <NUM> comprises a vibratory feeder (not shown) configured to feed the seeds along a feed channel <NUM> (<FIG>) that narrows as it extends toward an outlet <NUM> (<FIG>). The outlet <NUM> is generally aligned with one side region of the cavity so that the granular material forms a pile P in a corner of the cavity and defines a top that, in substantial part, slopes in a single direction.

In use, the feed system <NUM> gradually feeds the granular material through the outlet <NUM> and it falls through the opening <NUM> into the cavity <NUM>. The gradually fed granular material slowly forms a pile P on the support wall <NUM>. A top of the pile P has an angle of inclination that increases until the angle is at about the angle of repose of the granular material. In one embodiment, the evaluation system <NUM> includes the imaging system <NUM> (not shown in <FIG>) configured to capture images of the pile P of granular material through the front wall <NUM> of the receptacle <NUM> as it grows in size. The imaging system <NUM> functions in a similar way as described with the first embodiment and the controller can control the flow of material into the cavity <NUM> based on the calculated angle of repose. In still other embodiments, a technician can monitor the piling of granular material in the receptacle <NUM> and determine when the top has reached the angle of repose (e.g., by visually determining when the angle of inclination of the top stops increasing). When the technician determines that the top of the pile P has reached the angle of repose, the technician can use an instrument such as a protractor to measure the angle of repose.

Referring to <FIG>, another device for measuring the angle of repose of granular material used in a seed process is generally indicated at reference number <NUM>. The measurement device <NUM> includes a receptacle <NUM> that is similar in shape and arrangement to the receptacle <NUM> of the evaluation system <NUM> described above. Like the receptacle <NUM>, the receptacle <NUM> includes a front wall <NUM>, a rear wall <NUM>, and a support wall <NUM> that define a generally circular cavity <NUM> having an open top end. The internal surface of the support wall <NUM> has a rough surface texture. Unlike the receptacle <NUM>, the rear wall <NUM> of the receptacle <NUM> is substantially opaque. The measuring device <NUM> further includes a transparent plate <NUM> that is pivotably mounted on the front wall. The transparent plate includes a plurality of parallel indicator lines <NUM> and protractor scale markings <NUM> along a segment of a perimeter edge margin thereof. The protractor scale markings <NUM> have a fixed angular position with respect to the indicator lines <NUM> such that the <NUM>° position on the protractor scale markings is oriented substantially parallel to the indicator lines and the <NUM>° position on the protractor scale markings is oriented substantially perpendicular to the indicator lines. An indicator arm <NUM> is also pivotably mounted on the front wall <NUM> of the receptacle <NUM> to pivot relative to the receptacle independently of the plate <NUM>.

In use, seeds or other granular material is placed into the receptacle <NUM> and the receptacle is rolled along a horizontal surface (or other surface of known inclination). As the receptacle <NUM> rolls, the indicator arm <NUM> pivots relative to the receptacle to remain in a downwardly oriented position. When the pile of seeds or other granular material in the receptacle <NUM> begins to slump or slide, the user pivots the plate <NUM> so that the indicator lines <NUM> are oriented substantially parallel to the top of the pile. The user then determines an indicated angle to which the downwardly oriented indicator arm <NUM> is pointing on the protractor scale markings <NUM>. The angle of inclination of the seed pile (or angle of repose when the seed pile has slumped) is calculated as <NUM>° minus the indicated angle. Referring to <FIG> and <FIG>, another embodiment of a system for measuring the angle of repose of granular material such as seeds is generally indicated at reference number <NUM>. The system <NUM> includes a base <NUM> and a receptacle <NUM> (<FIG>) mounted on the base for rotation with respect to the base about a generally horizontal axis of rotation. The receptacle <NUM> can have any of the features of the receptacle <NUM> discussed above. In the illustrated embodiment, the base <NUM> comprises an enclosure <NUM> that encloses a driver (not shown) operatively coupled to the receptacle for rotating about a generally horizontal axis of rotation with respect to the base. A controller (not shown) is configured to actuate the driver <NUM> to synchronize rotation of the receptacle <NUM> with activation of an imaging system <NUM> to determine the angle of repose as explained above. As shown in <FIG>, the illustrated imaging system <NUM> includes a camera <NUM> that is mounted on the enclosure <NUM> opposite the receptacle <NUM> to capture images and/or video of the receptacle as it rotates. In one or more embodiments, the camera <NUM> is aimed generally parallel to the axis of rotation of the receptacle <NUM>. In the illustrated embodiment, the imaging system <NUM> further comprises a display <NUM> that is configured to display the unprocessed or processed images that are captured by the camera <NUM>. Suitably, user can navigate a user interface displayed on the display <NUM> to select images to view. In one or more embodiments, the system <NUM> includes a measurement processor (not shown) configured to automatically determine the angle of repose of granular material in the receptacle <NUM> in accordance with any of the methods discussed above. The user can view the determined angle of repose on the display in one or more embodiments.

When introducing elements of the present invention or the embodiment(s) thereof, the articles "a", "an", "the" and "said" are intended to mean that there are one or more of the elements.

Claim 1:
A method of processing seeds, the method comprising:
(a) processing seeds in a processing step, wherein processing the seeds comprises at least one of polishing, pelletizing, coating, drying and delinting;
(b) determining an angle of repose of at least a portion of the processed seeds; and
(c) determining whether the processed seeds have been sufficiently processed in the processing step based on the determined angle of repose;
wherein step (b) comprises forming a pile of the at least a portion of the processed seeds in a receptacle (<NUM>, <NUM>, <NUM>, <NUM>);
wherein step (b) further comprises rotating the receptacle (<NUM>, <NUM>, <NUM>, <NUM>) about a generally horizontal axis to a plurality of positions that are angularly offset about the generally horizontal axis to cause a top of the pile to become inclined;
further comprising one of (i) singulating the processed seeds if the processed seeds are determined to be sufficiently processed in step (c) or (ii) repeating steps (a)-(c) if the processed seeds are not determined to be sufficiently processed in step (c).