Abstract:
The present invention discloses a system and method for providing an automated imaging system comprising an illumination source, a phosphorescent imaging target, and an optical imaging sensor for receiving luminance information emitted from the phosphorescent imaging target.

Description:
BACKGROUND  
         [0001]    Improvements in robotic technologies has increased the level of automation in many industries. From the automobile industry to the semiconductor manufacturing industry, robotic technology has automated many of the repetitive tasks formerly performed by humans. A benefit of the mechanical automation is the precision achievable by computer-controlled automated systems. For automated alignment or operational robotic systems, the programming of such robots is typically extensive, with much of the physical processing of the automated systems tied to the precise locations and measurements of the automated system and the objects on which it operates.  
           [0002]    In order to maintain precision, an automated alignment system is usually either (a) locked into a rigid positional frame of reference or (b) capable of “seeing” the objects and adjusting its positioning and processing to the objects&#39; orientation. Because maintaining a rigid frame of reference as a sole imaging or alignment method typically requires considerable effort, “sight”-automated systems, which typically have a combination of a fixed frame of reference and sighting means, are generally more reliable and economical to employ.  
           [0003]    One successful method for building a “sight”-automated system has been to provide an automated system, such as an autochanger for large-scale computer storage, with an illumination source and optical sensing components. Imaging targets are typically affixed to the objects to provide a reflection point for the illumination source and image sensors of the system. The imaging targets are normally white in order to maximize the contrast between the background equipment and the target. As the illumination source shines or radiates over the white imaging target, optical sensors pick up the change in the reflected light based on the large contrast between the target and the background. In some applications, the imaging targets may also include bar codes, thereby providing an intelligence to the optical sensing.  
           [0004]    Still other applications may take advantage of a combination of both plain imaging targets and bar codes. Such systems use the plain imaging target to align with the object. The optical sensors are then generally able to read the bar code to determine whether the object is the correct target object. Furthermore, the bar codes may provide an initial reference to the automated system that indicates a general area of the system to which the automated sensor must generally move.  
           [0005]    For example, multiple tapes of electronic information may be stored in magazines cataloged by bar code and stacked in racks or shelves. Each shelving unit generally has an imaging target used by the automated system to pinpoint different locations on the shelf. In such systems, a single illumination source and optical sensor is used to lock onto both the imaging target and the bar codes. This combination generally simplifies the design of the automated system and reduces operating costs. However, problems generally arise as the illumination source is positioned farther from the imaging target. Because only a single illumination source and optical sensor are used to image both elements, it may be positioned in such a manner to image one element more easily than the other or in such a manner to read both elements with the same, but non-optimal, difficulty. In typical embodiments, the illumination source and optical sensors are normally positioned to provide accurate reading of each individual tape&#39;s bar code. Thus, the greater distance between the illumination source and the general imaging target may sometimes cause failed or inaccurate detection by the optical sensing device. This problem could be alleviated by manufacturing a dual illumination source and optical sensor, or by increasing the size and intensity of the illumination source and/or the size and sensitivity of the optical sensor. However, both of these options add cost and complexity to the automated systems.  
           [0006]    Furthermore, the white imaging targets frequently fail to provide adequate return radiation to register on the optical sensor. This failure may be caused by a background material that is glossy or shiny, creating a reflection comparable to the white imaging target. The failure to may also be caused by the particular shape of the object at the point on which the imaging target is affixed. If the object&#39;s facing is curved or angles away from the illumination source, the optical sensor may not register sufficient light reflection or contrast from the imaging target.  
         SUMMARY OF THE INVENTION  
         [0007]    Because of the problems found in the current systems, it would be advantageous to have an imaging target capable of providing a high degree of return radiation. The present invention is directed to a system and method for providing an automated imaging system comprising an illumination source, a phosphorescent imaging target, and an optical imaging sensor for receiving luminance information emitted from the phosphorescent imaging target.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0008]    [0008]FIG. 1A is a block diagram illustrating a prior art autochanger;  
         [0009]    [0009]FIG. 1B is a detailed block diagram illustrating the picking mechanism and the imaging system of the autochanger of FIG. 1A used with the colored imaging targets;  
         [0010]    [0010]FIG. 2A is a close-up diagram of a phosphorescent imaging target configured according to a preferred embodiment of the present invention;  
         [0011]    [0011]FIG. 2B is a close-up diagram of a prior art colored imaging target;  
         [0012]    [0012]FIG. 3 is a block diagram illustrating an autochanger configured according to a preferred embodiment of the present invention; and  
         [0013]    [0013]FIG. 4 is a block diagram illustrating an auto-mechanical alignment system configured according to a preferred embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION  
       [0014]    [0014]FIG. 1A illustrates a prior art autochanger typically used for mass computer storage of memory tapes and/or optical disks. Autochanger  10  comprises mechanical picker  100  which travels in a ‘U’-shaped path on track  101 . The storage media units are housed in shelves  102 , which may be stacked one on top of the other, or may be housed in single story units. As mechanical picker  100  selects the desired storage media units, the media units are placed into drives  103  to provide access to the data stored thereon. Mechanical picker  100  retrieves storage media units from shelves  102  at many possible positions, such as positions  100  and  100 ″. The retrieved media units would then typically be placed into one of drives  103  at several possible positions, such as position  100 ′. With the setup illustrated in autochanger  10 , mechanical picker  100  moves across track  101  to pick the targeted storage units and then insert them into drives  103 , or to retrieve the units from drives  103  and return them to their designated positions in shelves  102 .  
         [0015]    [0015]FIG. 1B provides a more detailed illustration of mechanical picker  100  and shelving unit  102  of autochanger  10 , from FIG. 1A. In the prior art embodiment shown, the auto-changing system uses both a positional imaging target, target  110 , and an informational imaging target, bar codes  1025 . Shelf  102  is shown with a capacity for holding storage media units, three of which,  1021 - 1023 , are filled with storage media units, and two of which,  1020  and  1024 , are empty. Target  110  is affixed to shelf  102  to provide mechanical picker means for calculating its relative position in front of shelf  102 .  
         [0016]    It should be noted that while shelf  102  is shown here with a five tape capacity, the present invention is not limited to such types of storage shelves. Alternative embodiments of the present invention may preferably operate with any number of different automated systems including other large-scale storage systems with varying storage capacities.  
         [0017]    Mechanical picker  100  includes illumination source  1001 , which typically comprise light emitting diodes (LEDs) or the like, to shine light onto target  110  and/or bar codes  1025 . Optical sensor  1002 , which comprises lens  1002 - 1  and optical sensor array  1002 - 2 , receives reflected light from any of target  110  and/or bar codes  1025 . Optical sensor array  1002 - 2  may comprise charge coupled devices (CCDs), contact image sensors (CISs), or other known optical imaging sensors. Optical sensor  1002  acts as a bar code reader to read the information from bar codes  1025 . It also reads target  110  to determine machine picker  100 &#39;s relative position at shelf  102 .  
         [0018]    In the prior art system depicted in FIG. 1B, target  110  is a right triangle. The locations of each tape or media unit in shelf  102  are generally known to be a certain distance from the apex of the triangle of target  110 . Thus, if the position of the apex is known, mechanical picker  100  is typically capable of locating any tape or storage unit in shelf  102 , simply by performing measured movements. The location process begins by performing vertical scans of the triangle to obtain its changes in height from one point to the next. After at least two such scans, the slope can be calculated using the known changes in triangle height. The system then uses the slope to predict and find the position of the triangle apex of target  110 .  
         [0019]    As shown in FIG. 1B, target  110  is typically placed at the edge of the range of optical sensor  1002 . Lens  1002 - 1  has a limited field of vision, shown by periphery  1003 . The light reflected into periphery  1003  generally is focused onto optical sensor array  1002 - 2  for detection. Illumination from illumination source  1001  begins to fade at the edges of periphery  1003 . Using the colored targets of target  110  and bar codes  1025 , the fading illumination at the edge of periphery  1003  generally causes little light to reflect back from target  110 . Furthermore, the typical angle of incidence of light hitting target  110  also contributes to the diminished level of light typically reflected into periphery  1003 . With a low amount of reflected light re-entering periphery  1003 , system  10  often has a difficult time determining whether the reflected light is from target  110  or from the background shelf  102 .  
         [0020]    [0020]FIG. 2A is a detailed illustration of a phosphorescent imaging target according to a preferred embodiment of the present invention. Phosphorescent target  20  is preferably affixed to object  21 , which may be an item such as shelf  102  of FIGS. 1A or  1 B. As phosphorescent target  20  is illuminated with light photons  200 , the phosphor material of phosphorescent target  20  absorbs some of the light energy, which, in turn, preferably excites atoms  201  within phosphorescent target  20 . As a result of the phosphorescence of the material, some of the light energy radiated at phosphorescent target  20  is preferably re-radiated out of phosphorescent target  20 . The re-radiated photonic illumination  202 , thus, preferably creates a temporary illumination source out of phosphorescent target  20 .  
         [0021]    In contrast, FIG. 2B illustrates an example prior art colored imaging target. The colored target is typically white to maximize contrast against the background. White target  22  is affixed to object  21 , which may be an item such as shelf  102  of FIGS. 1A or  1 B. In contrast to phosphorescent target  20  (FIG. 2A), as white target  22  is illuminated with light photons  200 , some of the light energy is absorbed into white target  22 . However, without the ability to have its atoms  204  excited to the same level as the phosphorescent material of the present invention, light is merely reflected or redirected from white target  22  in dispersive light patterns  203 . While re-radiated photonic illumination  202  of phosphorescent target  20  (FIG. 2A) provides relatively strong, relatively coherent re-radiated light energy, dispersive light patterns  203  (FIG. 2B) provide a much weaker aggregate of reflected light. Because of the phosphorescent attributes of phosphorescent target  20 , a strong return signal is beneficially produced, thus, making it easier for an optical sensor to register the re-radiated light.  
         [0022]    [0022]FIG. 3 is a detailed illustration showing components of an autochanger configured according to a preferred embodiment of the present invention. Similar to the autochanger depicted in FIG. 1B, the autochanger of FIG. 3 comprises shelf  102  with storage columns  1020 - 1024  and mechanical picker  100 . However, the imaging targets of the autochanger according to this preferred embodiment of the present invention incorporate phosphorescent triangle  300  and phosphorescent bar codes  3000 . Using the phosphorescent characteristics of triangle  300  and bar codes  3000 , optical sensor  302  may preferably be comprised of less sensitive, smaller, and, thus, less expensive components. Optical sensor  302  would preferably comprise modified lens  3020  and modified sensor array  3021 . Similarly, modified illumination source  301  may preferably be smaller or may preferably comprise a light source of smaller intensity.  
         [0023]    In operation, as mechanical picker  100  performs its initial vertical scans of triangle  300 , the stronger re-radiated photonic illumination emitted from triangle  300  is more easily registered by modified sensor array  3021  through periphery  1003 . Because the surrounding background material does not fluoresce, modified sensor array  3021  may preferably differentiate the strong luminance information re-radiated from triangle  300  from the less-intense reflected light from the background material of shelf  102 , even with a smaller, modified illumination source  301  and less-sensitive optical sensor  302 .  
         [0024]    Operating in this manner, optical sensor  302  would preferably be capable of not only reading bar codes  3000 , but may also preferably be capable of detecting the presence of any given tapes, on which bar codes  3000  may be disposed. Thus, as mechanical picker  100  is directed to a tape located in shelf  1021 , the luminance information reflected from bar code  3000  on the tape signals the presence of the tape in shelf  1021 . Additionally, as mechanical picker  100  is directed to a location of another particular tape, for example shelf  1024 , the lack of luminance information reflected from one of bar codes  3000  would preferably indicate that the desired tape is not resident in the designated location of shelf  1024 .  
         [0025]    Optical sensor  302  would also preferably be capable of reading bar codes  3000  more easily because of their phosphorescent material. However, it should be noted that bar codes  3000  are not required to be constructed with phosphorescent material. It should also be noted that phosphorescent imaging targets may be used with any number of different automated systems. Systems such as robotic welders, automated conveyor systems, and/or automated counters may also benefit from a preferred embodiment of the present invention.  
         [0026]    It should also be noted that while FIG. 3 illustrates an autochanger utilizing the right triangle for determining the mechanical pickers positional relationship to the storage shelve, the present invention is not limited to automated systems which employ such methods of positional orientation determination. Many different means, including additional bar codes may be used along with alternative embodiments of the present invention.  
         [0027]    [0027]FIG. 4 illustrates an auto-mechanical optical alignment system. Unlike the autochangers of FIGS. 1A, 1B, and  3 , auto-alignment system  40  of FIG. 4 moves the targeted object over the imaging equipment. Object  41  is held on maneuvering arm  42  with bracket  422 . Object  41  includes phosphorescent imaging targets  43  located in known positions. Maneuvering arm  42  moves object  41  across stationary optical sensor  45 . Optical sensor  45  comprises lens  46  and optical array  47 . Illumination sources  44  provide the seed light energy for phosphorescent imaging targets  43 . As object  41  passes over optical sensor  45 , light energy from illumination sources  44  passes through window  48 . The light energy is absorbed by phosphorescent imaging targets  43  and re-radiated out from each target as object  41  continues over the sensing area. Controller unit  49  receives the luminance information from optical array  47  through memory  490 . Memory  490  supplies the luminance information to processor  491  in order to calculate object  41 &#39;s positional orientation.  
         [0028]    One application of auto-alignment system  40  could be to provide laser etching of a pre-milled putter head. As a block of solid metal, such as titanium, aluminum, and/or steel passes over optical sensor  45 , phosphorescent imaging targets  43  preferably provide controller unit  49  with luminance information to calculate object  41 &#39;s positional orientation. Controller unit  49  then preferably controls maneuvering arm  42  to position object  41  in the appropriate orientation over an etching laser (not shown). Once correctly positioned, the etching laser would preferably etch a design or name onto the pre-milled block of metal.  
         [0029]    It should be noted that alternative embodiments of the present invention may also be used in a variety of automated systems. For example, and not by way of limitation, simple counters may preferably use the phosphorescent imaging targets of the present invention to count the number of objects passed over the optical sensors. Referring to FIG. 4, as object  41  is moved over optical sensor  45  the light energy re-radiated from imaging targets  43  is preferably detected and received by processor  491  as re-radiated photonic illumination from optical array  47  through memory  490 . In response to the received re-radiated photonic illumination, processor  491  may preferably increment a counter for detecting the number of objects that have passed over optical sensor  45 . Such an alternative embodiment will, therefore, be capable of keeping track of the number of objects processed through the system.