Systems and methods for witness card analysis

#The present invention is related to performance analysis of instrument controlled spraying. In particular, the present invention pertains to the use of backlit semiopaque witness cards to determine sprayed drop statistics.

#U.S. Pat. No. 7,277,570, which is incorporated herein by reference, describes image processing techniques to determine as-sprayed drop statistics for sprayed witness cards (WCs). As described therein, a wide variety of manufacturing and agricultural processes rely upon the use of instrument controlled spraying. For example, farmers and foresters typically use aircraft and/or farm equipment equipped with instrument sprayers to apply fertilizers and pesticides. Manufacturers use spray techniques to apply coatings and/or layers of a prescribed density and/thickness.

#In the case of farming and forestry, the spraying process preferably results in a prescribed amount of fertilizer or pesticide being distributed uniformly to the ground, crop or trees. A spray that distributes too little fluid to a target area may reduce the effectiveness of the fertilizer or pesticide treatment, resulting in lost crops/trees and/or reduced yield. A spray that distributes too much fluid to a target area typically increases the cost of applying the treatment and may result in additional losses due to undesired side effects and/or pollution. A spray that distributes fluid to a target area unevenly, typically results in some portions of the sprayed area receiving too little treatment and other portions of the area receiving too much treatment, resulting in both types of losses described above.

#FIG. 1 is a block diagram of a spray performance analysis system in accordance with an exemplary embodiment of the present invention.

#FIGS. 2A and 2B are schematic diagrams of stand-alone and networked computer environments, respectively, capable of supporting a spray performance analysis system in accordance with an exemplary embodiment of the present invention.

#FIG. 3 is a process flow diagram depicting the development of calibration equations used to calibrate a spray performance analysis system in accordance with an exemplary embodiment of the present invention.

#FIG. 1 is a block diagram of a spray performance analysis system 100 in accordance with an exemplary embodiment of the present invention. As shown in FIG. 1, analysis system 100 includes a WC image capture unit 102, a calibration image analysis unit 104, a WC image analysis unit 105, a calibration unit 106 and a statistics unit 108. WC image capture unit 102 captures witness card images that are submitted to either unit 104 or unit 105 depending on the type of image being processed. WC images of calibration witness cards are submitted to unit 104. WC images of as-sprayed witness cards are submitted to unit 105. The image analysis units 104 and 105 preferably include the same core image preprocessing control parameters, but are configured to perform different functions. The calibration image analysis unit 104 generates stain area information from calibrated drops of one or several stains as directed by the user. The WC image analysis unit 105 automatically identifies as many as all of the stains within a witness card image and may determine stain areas for each identified stain and physical attributes of the stain image space. Calibration unit 106, receives calibration witness card stain dimension data from calibration image analysis unit 104 and known droplet volume information to generate a calibration curve equation, or set of linear and/or non-linear equations, capable of accurately estimating a droplet dimension (e.g., droplet diameter or MMD) as a function of a determined stain dimension (e.g., stain diameter) for an identified fluid at an identified temperature upon an identified paper stock. Statistics unit 108 receives and stores one or more calibration equations generated by calibration unit 106.

#Upon receiving as-sprayed witness card stain dimension data from WC image analysis unit 105, statistics unit 108 may select a stored calibration equation, or set of equations, based upon the fluid, fluid temperature and type of witness card used to produce the as-sprayed stains. Statistics unit 108 then uses the selected calibration equation (s) to estimate spray droplet diameters (i.e., MMD values) and spray density for each as-sprayed witness card. In addition, based upon the number of droplets, spray density, and MMD values determined for each as-sprayed witness card retrieved from a known location within a sprayed target area, statistics unit 108 is capable of generating statistical data that characterizes spray performance within any or all portions of the sprayed target area.

#FIG. 2A depicts an exemplary embodiment of the present invention in which a spray performance analysis system 200 is implemented in a stand-alone configuration. As shown in FIG. 2A, such an embodiment may include a scanner 202 (or more generally, a WC image capture unit 102 including a digital camera 640 as will be discussed more fully in connection with FIG. 6), and a conventional computer processing unit 204 with conventional user input/output devices such as a display 206, keyboard 208 and mouse 210. The computer system may use any of the major platforms such as Windows, Linux, Macintosh, Unix or OS2. Further, computer processing unit 204 includes components (e.g. processor, disk storage or hard drive, etc.) having sufficient processing and storage capabilities to effectively execute spray performance analysis system processes. In such an embodiment, a user interfaces with the spray performance analysis system executing upon computer processing unit 204 via a command line or graphical user interface to process witness cards in accordance with the present invention. WC image capturing, image analysis, generation of calibration equations, and the generation of as-sprayed statistics may, accordingly, be performed from a single location.