Abstract:
An optical system for measuring an irregularly shaped object includes a dimensioning station having a base, a first wall extending from the base, and a second wall extending from the base. A collimated light is passed from each of first and second collimated light sources arranged generally parallel to the base, illuminating the first and second walls and defining first and second shadows, respectively. A camera is arranged to obtain image data representing each of the first and second shadows. The system is configured to collect the image data for determining at least one dimension of an object from each of the first and second shadows. Each of the first and second collimated light sources may be a light with a collimating lens arranged between the light and the respective wall. The light source may be an LED and the collimating lens may be a collimating Fresnel lens.

Description:
BACKGROUND OF THE INVENTION 
     The transportation of objects, such as packages, luggage, boxes and other goods from one place to another by a common carrier, or the like, is an expensive operation. As can be easily understood, the object&#39;s dimensions and/or volume may be as important, or more so, than the weight of the object. For example, many modes of transportation have a weight limit that will never be met or exceeded if objects of relatively low density are being transported. In other words, the object&#39;s dimensions and/or volume may be more of a limiting factor in terms of the number of transported items, than weight. For many years, however, the weight of an object has been nearly the sole means for assessing the cost of shipping an object. Given the high cost of fuel and the limited amount of space for objects, carriers now want to be able to more accurately include the dimensions and/or volume into the amount charged for such a shipment. 
     Obtaining an object&#39;s dimensions and/or volume is not typically fast, easy, or without error. This fact is a primary reason why many shippers have failed to incorporate the object&#39;s dimensions and/or volume into any fee calculations. For example, when the object is a simple box shape, a person may use a tape measure to obtain dimensions for the box&#39;s height, width and depth. The usefulness of the tape measure or other physical measuring device is not typically an accurate means for measuring objects having a complex shape such as a pyramid, any shape with rounded corners, a shape with projections occurring along a side surfaces, etc. Of course, in a laboratory setting, a technician could have an object&#39;s volume measured by submerging the object into a liquid and measuring the volume of the displaced liquid. This method would, of course, be incompatible with most objects sent via a common carrier on a daily basis, and would not provide the objects linear dimensions, which may be more important than the object&#39;s volume. 
     As a result of these challenges, carriers have taken an approach of roughly approximating an overall box size or envelope that encompasses the object having a complex shape. Other carriers have adopted the use of a template enclosure, which is used to determine merely whether an object is oversized (i.e., will not fit within the template). These approaches are, however, merely rough approximations. 
     Carriers attempting to increase profits must have a way to quickly obtain an object&#39;s dimensions and/or volume regardless of whether the object is of a complex shape. Knowing the approximate dimensions and/or volume of an object allows the carrier to more efficiently fill containers and more appropriately charge consumers for the space required by their object. Further, the process of obtaining such measurements can not add additional time to the overall process flow in such a manner that eliminates the gains achieved by the accurate measurements. In light of the foregoing, it should be easy to see that accurate and fast measurements of an object to be shipped may allow a carrier to remain profitable during times of increased energy costs, increased labor costs, and constant consumer pressure to reduce costs. 
     SUMMARY OF THE INVENTION 
     The present invention helps a carrier to obtain an object&#39;s dimensions and/or volume in a fast and efficient manner. Due to the relative speed and accuracy of the present invention, common carriers can now more easily determine accurate charges for shipping an object, and more accurately apportion the true cost of shipping a particular object. 
     In accordance with one embodiment of the present invention, an optical system is provided for measuring an irregularly shaped object. The system includes a dimensioning station having a base and a first wall extending from the base. The system further includes a first collimated light source. A first collimated light passes from the first collimated light source generally parallel to the base, illuminating the first wall, and defining a shadow. The system further includes a camera arranged to obtain image data representing the shadow. The system is configured to collect the image data for determining at least one dimension of an object. Preferably, the first wall extends perpendicular to the base. 
     In accordance with one embodiment of the present invention, the system further includes a second wall extending from the base. Preferably, the second wall extends perpendicular to the base. Preferably, the second wall extends perpendicular to the first wall. 
     In accordance with one embodiment of the present invention, the system further includes a second collimated light source, a second collimated light passing from a second collimated light source generally parallel to the base, illuminating the second wall, and defining a second shadow. Preferably, the second collimated light is generally perpendicular to the first collimated light. 
     In accordance with one embodiment of the present invention, the system further includes a third collimated light source, a third collimated light passing from the third collimated light source generally perpendicular to the base, illuminating the base, and defining a third shadow. Preferably, the third collimated light is generally perpendicular to at least one of the first collimated light and the second collimated light. 
     In accordance with one embodiment of the present invention, the first collimated light source is a first light and a first collimating lens arranged between the first light and the first wall. Preferably, the first collimating lens is a collimating Fresnel lens. In accordance with one embodiment, the first light is an LED. In accordance with another embodiment, the first light is a laser diode. 
     In accordance with one embodiment of the present invention, the second collimated light source is a second light and a second collimating lens arranged between the second light and the second wall. Preferably, the second collimating lens is a collimating Fresnel lens. In accordance with one embodiment, the second light is an LED. In accordance with another embodiment, the second light is a laser diode. 
     In accordance with one embodiment of the present invention, the object is resting on the base. A size of a shadow formed on one of the first wall and the second wall represents at least one of a height, width and depth of the object. A size of a shadow formed on another one of the first wall and the second wall represents at least one of a height, width and depth of the object. In accordance with one embodiment, at least one dimension of the object is greater than 4 inches. In accordance with another embodiment, at least one dimension of the object is greater than 6 inches. In accordance with another embodiment, at least one dimension of the object is greater than 12 inches. 
     In accordance with one embodiment of the present invention, a method is provided for measuring an irregularly shaped object. The method includes providing a dimensioning station including a base and a first wall extending from the base, illuminating the first wall with a first collimated light arranged generally parallel to the base, and placing an object to be measured on the base. The method further includes measuring a size attribute of a first shadow formed on the first wall by the first collimated light and the object to be measured. Preferably, the size attribute of the first shadow is measured using a camera arranged to have a view of the first wall. Preferably, the first collimated light is created using a light source and a collimating lens. Preferably, the collimating lens is a Fresnel lens. In accordance with one embodiment, the light source is a LED. In accordance with another embodiment, the light source is a laser diode. 
     In accordance with one embodiment of the present invention, the method further includes providing a second wall extending from the base, illuminating the second wall with a second collimated light arranged generally parallel to the base, and measuring a size attribute of a second shadow formed on the second wall by the second collimated light and the object to be measured. Preferably, the size attribute of the second shadow is measured using a camera arranged to have a view of the first wall and the second wall. Preferably, the second collimated light is created using a light source and a collimating lens. Preferably, the collimating lens is a Fresnel lens. In accordance with one embodiment, the light source is a LED. In accordance with another embodiment, the light source is a laser diode. 
     In accordance with one embodiment of the present invention, the method further includes illuminating the base with a third collimated light arranged generally perpendicular to the base, and measuring a size attribute of a third shadow formed on the base by the third collimated light and the object to be measured. Preferably, the size attribute of the third shadow is measured using a camera arranged to have a view of the first wall, the second wall and the base. Preferably, the third collimated light is created using a light source and a collimating lens. Preferably, the collimating lens is a Fresnel lens. In accordance with one embodiment, the light source is a LED. In accordance with another embodiment, the light source is a laser diode. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a further understanding of the nature and objects of the invention, references should be made to the following detailed description of a preferred mode of practicing the invention, read in connection with the accompanying drawings in which: 
         FIG. 1  is a side view representation of a dimensioning station system arranged in accordance with an embodiment of the present invention; 
         FIG. 2  is a front view representation of the dimensioning station system shown in  FIG. 1 ; 
         FIG. 3  is a side view representation of a dimensioning station system arranged in accordance with an embodiment of the present invention; 
         FIG. 4  is a front view representation of the dimensioning station system shown in  FIG. 3 ; 
         FIG. 5  is a upper perspective view of a dimensioning station system arranged in accordance with an embodiment of the present invention; and 
         FIG. 6  is a flow chart representing a dimensioning process applicable to the dimensioning station systems shown in  FIGS. 1 ,  3 , and  5 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring first to  FIGS. 1 and 2 , which represent a dimensioning station system arranged in accordance with one embodiment of the present invention, an object  10  creates a shadow area  20  ( FIG. 1 ),  25  ( FIG. 2 ) on a wall  30  when a light source  40  is arranged to direct a light  50  toward the wall  30 . The light  50  reaches the wall  30  in a lighted area  60 , while a transition area  70  is formed at the intersection between the shadow area  20  and the lighted area  60 . A camera  80  can be used to determine the location of the shadow area  20  and/or the transition area  70  and thus be able to determine a height  110  of the shadow area  20  above a base  90  on which the object  10  is resting. In particular, as shown in  FIG. 2 , the transition area  70  is a relative profile of the object  10  such that an actual height  100  ( FIG. 1 ) and an actual width  120  ( FIG. 2 ) of the object  10  can be estimated. The actual process of the determining the height  110  and width  120  of the shadow area  20  and  25 , respectfully, from an image will be discussed in further detail below. Of current concern, is that the transition area  70  may not closely represent the actual height  100  and actual width  120  of the object  10 . 
     As can be seen in  FIGS. 1 and 2 , the nature of the light  50  passing from the light source  40  is that it will create the transition area  70  with an error relating directly to the length  130  of the object  10 . In general, the larger the length  130  is in relation to the wall  30 , the larger the errors will be in measuring the actual height  100  and the actual width  120  by measuring the dimensions of the transition area  70 . Further, when the object  10  is irregularly shaped, as it is shown in  FIG. 1 , a projection  15  off of the object can cause additional problems when trying to accurately measure the dimensions of the object  10 . The amount of error induced by the projection  15  relates directly to where the projection is positioned along the length  130  of the object. As can be understood from  FIG. 1 , if the projection were located further from the wall  30 , the height  100  of the shadow  20  would be taller. Conversely, if the projection  15  were located closer to the wall  30 , the height  100  of the shadow  20  would be shorter. The same is true when measuring width  120 . 
     Referring now to  FIGS. 3 and 4 , a collimating lens  160  is placed between the wall  30  and a light source  150  such that a collimated light  140  passes generally parallel to the base  90 . The light source is located at a focal point for the collimating lens  160  to create the collimated light  140 . Before furthering the discussion relating to the present embodiment, it must be understood that the term “generally” is used along with the term parallel because true collimated light is a theoretical goal, especially in a practical sense. In other words, there are many factors that nearly prohibit the possibility of perfect collimated light, which could be truly parallel to the base  90 . 
     For example, assuming that there is a perfect collimating lens, the light source would need to be an impossibly small, point, light source. A light source having any size, albeit a small size, will create columns of light having as least some conical shape, which relates directly to size of the light source. Further, while many forms of collimating lenses, such as Fresnel lenses, mirrored lenses, etc, are quite good, these lenses are not perfect in terms of distortion added to the collimated light. In view of the forgoing, the term “generally” is defined and should be understood to include these small amounts of conical shape and distortion that are inherent to practical designs for providing collimated light. 
     The collimated light  140  present in the embodiment of  FIGS. 3 and 4  allows for a shadow  20  and transition area  70  that more directly relate to the actual height  100  of the object  10 . As shown in  FIG. 4 , the transition area  70  follows closely the actual height  100  ( FIG. 3 ) and actual width  120  profile of the object  10 . Further, because the collimated light  140  is generally perpendicular to the base  90 , the transition area  70  will continue to closely follow the height and width profile of the object  10 , regardless of the length  130  of the object  10 . Because the length  130 , or other dimensions, of the object  10  no longer adversely affect the relationship between the transition area  70  and the height and width profile of the object  10 , the object  10  can be of a larger size, such as over 4 inches, 6 inches, 12 inches, etc. Even though the object  10  is shown nearly against the wall  30  in the figures, it may be beneficial to place the object a greater distance away from the wall so that the shadow  20  is more easily identified separate from the object  10 . 
     The collimated light  140  in the present embodiment is created by passing light from the light source  150 , such as an LED, a laser, a laser diode, an arc lamp, an incandescent lamp, a halogen lamp, etc. placed at the focal point of the collimating lens, through the collimating lens  160 . The Fresnel lens is chosen as the collimating lens  160  for this embodiment because of its small thickness and because of cost. An example of the type of Fresnel lens that may be used is the “magnifying sheet,” item number 931974, which may be purchased from Staples®. It should be understood that any of the known collimating lenses (e.g. plastic lenses or mirrors) may function well in place of the collimating Fresnel lens represented in this embodiment. 
     Before proceeding, it should be understood that the embodiments disclosed in  FIGS. 1-4  measure dimensions in a single measurement plane of the object  10 . For example, dimensions along two axes, such as height and width, height and length, length and width, etc., may be measured in each measurement plane. However, it is very unlikely that two axes may be measured in the single measurement plane of the embodiment shown in  FIGS. 1 and 2 , because the light source  40  would need to be located at the center of the object  10 , which is not the case, as represented in  FIG. 2 . The use of the collimated light  140  in the embodiment of  FIGS. 3 and 4  makes it possible to measure dimensions along two axes in the plane of measurement, even if the light source  150  is not located at the center of the object  10 . 
     For at least the forgoing reasons, only a profile (i.e. the transition area  70 ) of the height  110  and width  120  of the shadow  20  in the single measurement plane are determined in the embodiment represented in  FIGS. 3 and 4 . To determine a profile relative to the length  130  or other base dimensions of the object, additional light sources  40  ( FIG. 1 ),  150  ( FIGS. 3 and 5 ),  250  ( FIG. 5 ), and  350  ( FIG. 5 ) may be used. In other words, to obtain these other dimensions, additional measurement planes could be incorporated in the same manner as the first measurement plane in  FIGS. 1-4 . 
     It should also be understood that the term “base” (i.e., base  90 ) does not specifically define a surface perpendicular to gravity. For example, the term “base” can be interchanged with one “wall” when/if the embodiment shown in  FIG. 3  is arranged 90 degrees clockwise from the arrangement currently shown. In other words, while the term “base” is used instead of a “wall” to add clarity for the reader, the “base” may be thought of as a “wall” separate from, and preferably perpendicular to, the first wall  30  ( FIGS. 1-5 ), and/or the second wall  230  ( FIG. 5 ). 
     As few as one measurement plane may be beneficial in some applications, while two or three measurement planes may be beneficial in others. Additionally, a single measurement plane system could be employed with a rotary table (not shown) to obtain dimensions from another axis by rotating the object  10  in 90 degree increments. An embodiment with more than one measurement plane is represented in  FIG. 5 , which is discussed below. 
     Referring now to  FIG. 5 , three collimating light sources, represented solely by light sources  150 ,  250 ,  350  can be used to obtain additional dimensional characteristics of the object. Please note that corresponding collimating lenses are not represented in  FIG. 5  for the sake of clarity. They would, however, be located between the light source  150 ,  250 ,  350  and respective walls/base  30 ,  230 ,  90  in the manner represented in  FIG. 3 . Further, while each of light sources  150  and  250  produce collimated light generally parallel for the base  90 , light source  350  is to produce collimated light generally perpendicular to the base for similar reasons. It should be understood that function of each collimating light source  150 ,  250 ,  350  will be similar in form and function to the singular axis of measurement example described above in relation to  FIGS. 3 and 4 . 
     A single camera  80  can be used so long as it is arranged with a full view of the walls  30 ,  230  and/or the base  90 . This statement should not be interpreted as to exclude additional cameras  80 , because the dimensioning station shown in  FIG. 5  could include additional cameras  80 , as required by space constraints, clarity required, etc. It should also be understood that because there is only one camera  80  used in the present embodiment, the camera  80  can be arranged with a view of the walls  30 ,  230  and base  90  that will be used for dimensioning purposes. If there is no third light source  350  present, the camera may not need a view of the base  90 , and so on. 
     The flowchart depicted  FIG. 6  describes a process with which the camera  80  is used to obtain the dimensions and/or volume of the object  10  placed on the base  90 . The camera  80  can be provided as part of a camera assembly  82  including the camera  80 , for use in collecting a processable image, and a processing unit  84 , for use in processing the image. The processor unit  84  can be CPU based. First, an image is taken of the object  10  on the base of the dimensioning station in step  400 . The processing unit  84  then verifies a position of the camera  80  by checking the positions of known marks (not shown) on the walls  30 ,  230  and/or base  90  of the dimensioning station in step  410 . The identification of these known marks from the image occurs due to the known marks having a contrast in color, shade, or texture from the walls  30 ,  230  and the base  90  that can easily be differentiated from the background. 
     In step  420 , the processing unit  84  places the system into a calibration sequence  430  if the position of the known marks is not verified. If the position of the known marks is verified, the processing unit  84  will proceed with a dimensioning sequence  440 . 
     In the calibration sequence  430 , the processing unit  84  detects the known marks from the image taken, determines the position of the camera  80  and saves the information in preparation for dimensioning sequence  430 . If the processing unit  84  determines that the position of the camera  80  is not valid, the processing unit  84  will issue a warning that the position of the camera  80  is not valid. Once the position of the camera is determined to be acceptable, the position data relating to the positions of known marks is then saved, in step  450  for use in the dimensioning sequence  440 , which can then be started. 
     In the dimensioning sequence  440 , the processing unit  84  detects the shadow  20 . More precisely, the processing unit detects an extreme edge of the shadow that has been referred to above as the transition area  70 . Using the data saved in step  450 , the profile of the transition area  70  on each of the relevant walls  30 ,  230  and/or base  90  can then be used to determine the dimensions and/or volume of the object  10 . For example, an area of the shadows  20  identified on the first wall  30  and the second wall  230  could multiplied together to obtain a basic area of the object  10 . When the third axis (e.g. the base  90 ) is utilized, selective portions of shadows from each of the walls  30 ,  230  and the base  90  can be used to calculate the volume, understanding that some of the transition areas  70  and the corresponding shadows  20  are duplicates among the three axes. For example, the width  120  and length  130  of the object may be identified in the third axis using the base  90 . 
     Depending on the desired level of accuracy, these duplicate representative areas could be averaged or combined using a percentage of each, such that the value obtained from one axis is granted greater weight in an averaging process than the respective value obtained from another axis. Another option would be to determine a variety of different calculated volumes for the object  10  by using different combinations of the available dimensions in order to find one combination resulting in the smallest volume. The smallest calculated volume may be closest to the actual volume of the object  10 . 
     Finding the smallest calculated volume, may be accomplished more easily by defining a particular method for placing the object  10  onto the dimensioning station. For example, a user could place the largest support base of the object  10  onto the base  90 , and to then slide the second largest face against the first wall  30 . Lastly, the user could slide the object so that the third largest face of the object  10  against the third wall. Even though this method of placing the object may result in a calculated volume that is closest to the actual volume of the object  10 , it is envisaged that the object  10  will be placed randomly on the base  90 , because of the amount of time and skill required for such placement. 
     While the present invention has been particularly shown and described with reference to certain exemplary embodiments, it will be understood by one skilled in the art that various changes in detail may be effected therein without departing from the spirit and scope of the invention as defined by claims that can be supported by the written description and drawings. Further, where exemplary embodiments are described with reference to a certain number of elements it will be understood that the exemplary embodiments can be practiced utilizing either less than or more than the certain number of elements.