Patent Description:
In the agricultural industry, and more specifically in the seed breeding industry, it is important for scientists to be able to analyze seeds with high throughput. By this it is meant that the analysis of the seeds preferably occurs not only quickly, but also reliably and with high total volume. Historically, seeds are sorted by size using mechanical equipment containing screens with holes corresponding to predetermined sizes. Seed sorting is also conducted using image analysis of the seeds to detect certain appearance characteristics of the seeds. However, prior image analysis seed sorting systems are limited in their ability to detect the size, shape, and appearance of the seeds.

<CIT> teaches a non-invasive solution for classifying objects contained in seed lots, that can be used for sorting of seeds randomly placed on a conveyor. <CIT> suggests using pneumatic sorting in a generic manner but does not provide further information on how to implement a pneumatic sorting for high-speed seed sorting.

The seed sorting system for sorting seeds generally comprises a seed transfer station configured to move seeds through the system. An imaging assembly comprises a 2D camera configured to acquire 2D images of the seeds as the seeds move through the system and a 3D camera configured to acquire 3D images of the seeds as the seeds move through the system. A sorting assembly is configured to sort the seeds into separate bins based on the acquired 2D and 3D images of the seeds.

In another aspect, a method of sorting seeds using the seed sorting system generally comprises moving seeds through the system using a seed transfer station. Acquiring, using a 2D camera, 2D images of the seeds as the seeds move through the system via the seed transfer station. Acquiring, using a 3D camera, 3D images of the seeds as the seeds move through the system via the seed transfer station. Analyzing the 2D and 3D images to determine a parameter of each of the seeds. Sorting, using a sorting assembly, the seeds based on determined parameters of the seeds.

Referring to <FIG>, a seed sorting system is indicated generally at <NUM>. The system is configured to receive, analyze, and sort a plurality of seeds into selected categories for later processing, assessment, or analysis. The system <NUM> comprises a load and transfer assembly <NUM> configured to receive and deliver the seeds through the system, an imaging and analysis assembly <NUM> for collecting image data of the seeds as they are delivered through the system by the load and transfer assembly, and a sorting assembly <NUM> configured to sort the seeds into selected categories based on the image data collected for the seeds by the imaging and analysis assembly. A controller <NUM> (e.g., a processor and suitable memory) is programmed to operate the system <NUM>. The imaging and analysis assembly <NUM> acquires <NUM>-dimensional image data and incorporates optimized image analysis algorithms for providing rapid and highly accurate size and shape measurements of the seeds. The sorting assembly <NUM> is configured to sort the seeds into two or more selected categories so that the seeds can be more precisely categorized for later processing, assessment, or analysis. The imaging and analysis assembly <NUM> and the sorting assembly <NUM> allow the system to provide high throughput measurement of the seeds to meet real time seed sorting requirements. As such, the system <NUM> can be implemented into an existing seed processing system and quickly and seamlessly provide a seed sorting function.

Referring to <FIG> and <FIG>, the load and transfer assembly <NUM> comprises a hopper (broadly, a seed loading station) <NUM> including an inlet <NUM> for receiving the seeds into the hopper and an outlet <NUM> for dispensing the seeds from the hopper, and a conveyor <NUM> (broadly, a seed transfer station) at the outlet of the hopper. In the illustrated embodiment, the conveyor <NUM> comprises a belt <NUM> defining a flat horizontal conveyor transport surface. The conveyor <NUM> provides a flat surface for the seeds to rest as they are delivered through the system <NUM>. As a result, the system <NUM> is able to better control the travel of each seed through the system and therefore better track the position of the seeds as they move on the conveyor <NUM> because the seeds will remain in a substantially fixed orientation and position on the conveyor. In one embodiment, a high precision encoder (not shown) is incorporated into the system <NUM> to track the position of the seeds on the conveyor <NUM>. As will be explained in greater detail below, the flat surface allows for more accurate measurements to be acquired by the imaging and analysis assembly <NUM>. Moreover, the projectile motion of the seeds as they are expelled off an end of the conveyor <NUM> provides a predictable flight pattern of each seed which can be used to sort the seeds as will be explained in greater detail below.

The conveyor <NUM> may be a high-speed conveyor capable of operating at speeds of up to about <NUM>,<NUM>/s (<NUM> in/sec) and above. For example, the conveyor <NUM> can be operated at up to about <NUM>,<NUM>/s (<NUM> in/sec). Depending on the size of the outlet <NUM> of the hopper <NUM>, the conveyor <NUM> can deliver the seeds through the system <NUM> at a rate of about <NUM> to <NUM> seeds/sec. However, other seed rates are envisioned. For example feed rates of up to <NUM> seeds/second are envisioned. Feed rates of higher than <NUM> seeds/second are also envisioned. In one embodiment, the conveyor <NUM> is blue. The color blue has been found to provide a desired background contrast for obtaining clear images of the seeds. For example, the blue background has been found to provide a desired contract with the yellow color of the seeds. However, the conveyor can be other colors without departing from the scope of the disclosure.

Referring to <FIG>, the imaging and analysis assembly <NUM> comprises an imaging assembly including a 2D line scan RBG camera (broadly, a 2D camera) <NUM> and a 3D line laser profiler (broadly, a 3D camera) <NUM> mounted above the conveyor <NUM> for acquiring image data of the seeds to measure the size and shape of the seeds in three dimensions. The imaging and analysis assembly <NUM> also includes a processor and memory for processing (i.e., analyzing) the image data, although in other embodiments the controller <NUM> may be used for such processing. The imaging and analysis assembly <NUM> can obtain length, width, and thickness (or roundness) dimensions for the seeds. Additionally, a light source <NUM> (<FIG>) may be mounted above the conveyor <NUM> for illuminating the fields of view of the cameras <NUM>, <NUM> to assist in producing clear and bright images. In one embodiment, the 2D camera <NUM> is mounted above the conveyor <NUM> in a substantially vertically orientation such that a focal axis of the 2D camera extends perpendicular to a horizontal plane of the conveyor, and the 3D camera <NUM> is mounted above the conveyor at an angle skewed from vertical such that a focal axis of the 3D camera extends at a non-orthogonal angle to the plane of the conveyor. With the 2D camera <NUM> pointed directly downward, the major and minor axes of the 2D camera image are interpreted as length and width dimensions, respectively. Therefore, as the seeds pass through the focal window of the 2D camera <NUM>, length and width dimensions of each seed are recorded. The pixels of the 2D camera <NUM> may be calibrated for true x-y dimensions. It is envisioned that the 2D camera <NUM> could be oriented such that the major and minor axes define width and length dimensions, respectively, without departing from the scope of the disclosure. In one embodiment, the shortest and longest axes define the width and length dimensions. This axis interpretation assumes that the seed is lying on its side such that the length of the seeds extends along the conveyor surface. However, it the seed is standing upright, the system automatically adjusts to ensure the height, width, and thickness measurements are recorded correctly.

The 3D camera <NUM> uses a laser triangulation technique to projects a line laser to create a line profile of the seed's surface. The 3D camera <NUM> measures the line profile to determine displacement which is represented by an image of the seed showing varying pixel intensities. A thickness dimension of the seeds is obtained through the pixel intensity of the 3D image produced by the 3D camera <NUM>. For example, a maximum pixel intensity can be interpreted as a marker of seed thickness. Thus, as the seeds pass through the focal window of the 3D camera <NUM>, a thickness of each seed is recorded as the maximum pixel intensity detected by the 3D camera for each seed. To acquire an accurate thickness measurement, it may be necessary to calibrate the image intensity of the 3D camera <NUM> based on the distance the 3D camera is spaced from the surface of the conveyor <NUM>. Using the length and width dimensions acquired from the 2D camera <NUM> and the thickness dimensions acquired from the 3D camera <NUM>, the system <NUM> can obtain volume estimates for each seed. In another embodiment, more sophisticated image processing may be used to estimate volume from a detailed contour map of the top half of each seed. For a known or estimated weight of the seed, the volume data can be used to estimate seed density. One example of a suitable 2D camera is the CV-L107CL model by JAI. One example of a suitable 3D camera is the DS1101R model by Cognex. In another embodiment, a different 3D measurement technique such as Time-of-Flight cameras, Stereo Imaging, Light field technique, and others can be used in place of or together with the laser profiler to get the 3D measurements of the seed.

Referring to <FIG>, <FIG>, and <FIG>, the sorting assembly <NUM> comprises a plurality of high speed air valve banks <NUM> and a plurality of sorting bins <NUM> located at an end of the conveyor <NUM> for sorting the seeds into at least two different categories based on the measurements obtained by the imaging and analysis assembly <NUM>. Each valve bank <NUM> includes multiple air valves <NUM> in fluid communication with an air compressor <NUM> for producing burst of air directed at the seeds as they are expelled from the conveyor <NUM>. The air is used to redirect the flight of the seeds so that the seeds land in a selected sorting bin <NUM> corresponding to the characteristics of the seeds identified by the imaging and analysis assembly <NUM>. As previously mentioned, the seeds are tracked by a high precision encoder (not shown). Thus, the system <NUM> can monitor the path of the seeds and predict when and where the seeds will be expelled from the conveyor <NUM>. Therefore, the system <NUM> can predict the location and flight of each seed as it leaves the conveyor <NUM>. This information is used by the controller <NUM> to instruct the operation of the valves <NUM> in the valve banks <NUM>. In one embodiment, each valve bank <NUM> includes thirty two (<NUM>) air valves <NUM>. However, a different number or air valves is envisioned without departing from the scope of the disclosure. The array of valves <NUM> is provided in an adequate number and arrangement to locate the valves in position to accommodate the random placement of the seeds on the conveyor.

In the illustrated embodiment, there are two (<NUM>) valve banks <NUM> selectively positioned for sorting the seeds into three (<NUM>) sorting bins <NUM>. A first sorting bin 42a is located closest to the conveyor <NUM>, a second sorting bin 42b is located next to the first sorting bin and located farther from the conveyor than the first sorting bin, and a third sorting bin 42c is located next to the second sorting bin and spaced farther from the conveyor than the second sorting bin. Thus, the second sorting bin 42b is located between the first and third sorting bins 42a, 42c. A first valve bank 40a is disposed generally over the first sorting bin 42a and directed downward such that the bursts of air from the valves <NUM> in the first valve bank create a downward diverting force along a substantially vertical axis. This downward diverting force can redirect the path of a seed as it leaves the conveyor <NUM> so that the seed falls into the first sorting bin <NUM>. A second valve bank 40b is disposed in the second sorting bin 42b and directed upward at an angle toward the third sorting bin 42c. Therefore, the bursts of air produced by the valves in the second valve bank 40b create an upward diverting force along an angled axis so that seeds leaving the conveyor <NUM> can be diverted away from the second sorting bin 42b and into the third sorting bin 42c. Thus, if a seed is not redirected by either of the valve banks 40a, 40b, the seed will land in the second valve bin 42b as a result of the natural trajectory of the seed leaving the conveyor <NUM>. It will be understood that the conveyor <NUM> can be operated and/or the sorting bins <NUM> can be positioned so that the natural flight of the seeds will land the seeds in either the first or third sorting bin 42a, 42c.

In the illustrated embodiment, the second valve bank 40b is angled at a <NUM> degree angle. However, the second valve bank 40b could be oriented at a different angle without departing from the scope of the disclosure. Also, it will be understood that the valve banks 40a, 40b could be located in different positions to redirect the seeds along different paths. For example, in one embodiment, a natural trajectory of the seeds may cause them to fall into the first sorting bin 42a. In this instance, a valve bank may be located in the first sorting bin to redirect the seeds into the second sorting bin. Moreover, additional valve banks could be used for sorting the seeds into more than three bins. In this embodiment, each valve bank would direct the seeds into a specific bin. For example, a first valve bank would direct the seeds into the first sorting bin 42a, a second valve bank would be positioned to direct the seeds into the second sorting bin 42b, and a third valve bank would be positioned to direct the seeds into the third sorting bin 42c. The seeds natural trajectory would carry them to a fourth sorting bin (not shown) when not disturbed by air from any of the valves.

Referring to <FIG>, seeds are first placed in the hopper <NUM> in preparation of being transported by the conveyor <NUM> through the system <NUM>. As the seeds leave the outlet <NUM> of the hopper <NUM>, the conveyor carries the seeds into view of the 2D camera <NUM> and 3D camera <NUM>. Because the seeds travel along the flat, blue conveyor <NUM>, clear image data are acquired. Additionally, the seeds remain in a known location and fixed orientation which allows each seed to be tracked with a high level of accuracy by the precision encoder. The seeds first pass under the focal view of the 2D camera <NUM>. The 2D camera <NUM> acquires a <NUM>-dimensional image of each seed which is processed by the controller <NUM> to produce length and width data for each seed. In one embodiment, the value associated with a maximum length and width measurements are recorded as the length and width values for the seed. <FIG> shows a representative image acquired by the 2D camera <NUM>. An encoder reading is also recorded as the seed is imaged by the 2D camera <NUM> to track the position of the seed on the conveyor <NUM>.

The seeds continue to travel along the conveyor <NUM> until the seeds pass under the focal view of the 3D camera. The 3D camera <NUM> acquires a <NUM>-dimensional image of each seed which is processed by the controller <NUM> to produce thickness data for each seed. <FIG> shows a representative image acquired by the 3D camera <NUM>. Using the 3D image, the controller <NUM> produces the surface profile shown in <FIG>. The different colors of the surface profile indicate thickness. In the illustrated embodiment, the thickness increases from blue to red. Analysis of the surface profile provides a thickness measurement for a given seed. In one embodiment, the value associated with the thickest region is recorded as the thickness value for the seed. An encoder reading is also recorded as the seed is imaged by the 3D camera <NUM> to track the position of the seed on the conveyor <NUM>. It will be understood that the analysis of the surface profile can also provide information regarding seed volume and mechanical seed damage.

Based on the length and width data from the 2D camera <NUM>, and the thickness data from the 3D camera <NUM>, the controller <NUM> can identify and categorize each seed according to its size. For example, predetermined size categories may be stored in the controller <NUM>. The size categories may be based on dimension thresholds for each of the length, width, and thickness data. Based on these thresholds, at least two categories can be defined. Each sorting bin <NUM> is representative of a category. Thus, in the illustrated embodiment, three categories are defined. As each seed is analyzed the seed is associated with one of the categories. For example, a seed having one or more dimensions that exceed a threshold valve are categorized into a first category, and seeds having one or more dimensions that are within a threshold valve are categorized into a second category. Multiple threshold values may be established to further categorize the seeds into more than two categories. Once the seed reaches the end of the conveyor <NUM>, the valve banks <NUM> are operated by the controller <NUM> to divert the seed into the bin <NUM> associated with its designated category.

Claim 1:
A seed sorting system for sorting seeds, the system comprising:
a seed transfer station configured to move seeds through the system comprising a conveyor;
an imaging assembly comprising a 2D camera configured to acquire 2D images of the seeds as the seeds move through the system and a 3D camera configured to acquire 3D images of the seeds as the seeds move through the system, the 2D and the 3D cameras being mounted above the conveyor;
a sorting assembly configured to sort the seeds into separate bins based on the acquired 2D and 3D images of the seeds; and
a controller configured to determine length and width dimensions of the seeds from the acquired 2D images and thickness dimensions of the seeds from the acquired 3D images and to control the sorting assembly to sort the seeds based on the determined length and width dimensions of the seeds from the acquired 2D images and the determined thickness dimensions of the seeds from the acquired 3D images;
wherein the sorting assembly comprises a plurality of high speed air valve banks and a plurality of sorting bins located at an end of the conveyor, the valve banks being operable by the controller to sort the seeds into the sorting bins as the seeds leave the seed transfer station, each valve bank including multiple air valves in fluid communication with an air compressor for producing burst of air directed at the seeds as they are expelled from the conveyor,
wherein the burst of air redirects the flight of the seeds so that the seeds land in a selected sorting bin corresponding to the characteristics of the seeds identified by the controller, and
wherein the multiple air valves is provided in an array with an adequate number and arrangement to locate the valves in position to accommodate a random placement of the seeds on the conveyor.