Abstract:
A portable color measuring device is provided that includes a hand-holdable housing. The color measuring device is configured to receive an independently operable processing device that is mounted to the housing. The independently operable processing device is a portable general purpose computer that executes software applications to control the operation of the color measuring device and process color data. The color measuring device measures the color properties of a sample by illuminating the sample with a light source. The measured properties are processed and/or analyzed by the independently operable processing device and results are displayed to a user. Software applications reside on the independently operable processing device allowing software upgrades or modifications to be easily performed. New applications can be downloaded to the processing device or the processing device can be interchanged with a different processing device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/180,822 filed Feb. 7, 2000. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates to the spectral analysis arts. It finds particular application to a portable color measuring device that is configured to receive and function with an independently operable processing device. It will be appreciated that the present invention will also find application to color measuring devices such as spectrophotometers, colorimeters, tristimulus colorimeters, single and multiple beam spectrophotometers, Gonio spectrophotometers and the like, and light emission type measuring devices.  
         BACKGROUND OF THE INVENTION  
         [0003]    Color measuring devices, such as spectrophotometers, are instruments used to determine the color of an object under test. They typically include a source of light that illuminates the object and a photodetector that detects and measures light signals reflected from the object. Then, signal processing circuitry connected to the photodetector computes curves or numerical values indicative of color. The general principles of construction and use of these instruments are well known and understood by those skilled in the art.  
           [0004]    One known type of spectrophotometer uses an integrating sphere in which the light reflected from the object is integrated to obtain an average reading of the color over an exposed surface area of the object. Known integrating spheres can provide readings which represent “total” reflections or “diffuse-only” reflections. The total reflections include all reflections from the exposed object, including specular reflections from the surface and diffuse reflections from particles in the body of the object. A “diffuse-only” or specular-excluded measurement is obtained by excluding specular light that is reflected from the surface of the sample at an angle equal to the incident angle. This reflected light is referred to as the specular component. Exclusion of the specular component eliminates the light contribution due to gloss, and the color values obtained from a specular-excluded reading are independent of the glossiness of the surface of the object under test.  
           [0005]    Typical bench-top or portable color measuring instruments include custom designed processing components such as a simple eight-bit processing unit and small amounts of memory. Most of the data processing function is performed by a remote personal computer that receives the measurement data from the spectrophotometer. Furthermore, the display is typically small and uses complicated menus and endless keystroke sequences to input and select data and request functions. Updating the device software requires a user to ship the entire spectrophotometer to the manufacturer. Overall, the device lacks flexibility and has limited processing power.  
           [0006]    The present invention provides a new and unique color measuring device that cures the above problems and others.  
         SUMMARY OF THE INVENTION  
         [0007]    In accordance with the present invention, a color measuring device for measuring color properties of an object is provided. The color measuring device includes a light source that transmits light onto the object. A sensor senses the light reflected from the object and generates electrical signals corresponding to the sensed light. The light source and the sensor are contained within a portable housing. The housing includes a mounting portion configured for mounting a portable independently operable computing device. An interface is configured to electrically connect a portable independently operable computing device to the portable housing and to communicate the electrical signals from the sensor to a portable independently operable computing device once mounted to the mounting portion and connected to the interface.  
           [0008]    In accordance with a more limited aspect of the present invention, the color measuring device includes a portable independently operable computing device mounted to the portable housing and connected to the interface.  
           [0009]    One advantage of the present invention is that a color measuring device can be produced in less time since custom made processing components and user interface and display are eliminated by configuring the color measuring device to mount an independently operatble computing device. With the present invention, the cost of manufacturing a color measuring device is also reduced.  
           [0010]    Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    The following is a brief description of each drawing used to describe the present invention, and thus, are being presented for illustrative purposes only and should not be limitative of the scope of the present invention, wherein:  
         [0012]    [0012]FIG. 1A is a transparent side view of a color measuring device in accordance with the present invention;  
         [0013]    [0013]FIG. 1B is a transparent front view of FIG. 1A;  
         [0014]    [0014]FIG. 2A illustrates a independently operable processing device connected to a data interface in accordance with the present invention;  
         [0015]    [0015]FIG. 2B is a side view of FIG. 2A;  
         [0016]    [0016]FIG. 3A is an alternative configuration of the present invention; and  
         [0017]    [0017]FIG. 3B is a transparent side view of FIG. 3A.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]    With reference to FIGS. 1A and 1B, a side view and a front view, respectively, illustrate components of an exemplary color measuring device  10  in accordance with the present invention. For purposes of explanation, the color measuring device  10  is illustrated as a portable hand-held spectrophotometer. The spectrophotometer includes a housing  15  that is sized such that it may be hand-held by a user. Fingergrips  20  may be formed on the exterior of the housing  15  to accommodate a user&#39;s fingers. To measure color properties of an object, the housing includes a sample aperture  25  formed through an exterior wall against which an object under test is placed.  
         [0019]    The color measurement components of the color measuring device  10  are well known in the art. They include, for example, an integrating sphere  30  that is hollow and has an inner surface that is highly reflective. A light source  35  is mounted to the sphere to provide light within the sphere and diffusely illuminate the object under test through the sample aperture  25 . Light reflected from the object under test is directed to a data collection means, for example, a light measuring sensor  40  such as a photodiode array or other photodetector devices as is known in the art. The light sensor generates color data signals representative of the light reflected from the object under test. It will be appreciated, as is known in the art, that the color data signals may be processed according to the functions of the color measuring device. For example, the color data signals may be communicated as raw electronic impulses, may be converted to reflectance data that, for example, corresponds to the amount of reflection wavelength by wavelength for the measured light, or may be converted into Lab or XYZ terms.  
         [0020]    Other components of the color measuring device  10 , as is known in the art, include a charger printed circuit board  50 , a flash capacitor  55 , a connector  60  for external power and communications cable (e.g. RS232), and a removable battery  65 . Other components (not shown) include a serial port for external communication of data.  
         [0021]    With further reference to FIG. 1A, the housing  15  includes a mounting surface  100  to which an independently operable processing device  105  (hereinafter “IOPD”) can be mounted and attached. The mounting surface  100  forms part of the housing or can be pivotally attached or hinged to the housing  15  such that the IOPD can be selectively positioned at different angles relative to the housing once it is mounted. The IOPD  105  is a stand-alone general purpose computing device such as, for example, a personal digital assistant (hereinafter “PDA”) made by 3Com® or any other portable computing devices available and known in the art. These include, for example, Palm® OS devices, Windows® CE devices, portable personal computers, pocket computers and the like. The IOPD  105  includes, for example, a microprocessor, memory, data storage, a display, communication components and/or other components as is known in the art that form an stand-alone computing device. The display presents a graphical user interface that displays information to a user and allows a user to easily input data. The display includes a touch activated screen, button control or a combination of both.  
         [0022]    With reference to FIGS. 1B, 2A and  2 B, the color measuring device  10  includes an interface  110  that electrically and physically connects to the IOPD  105  to establish communication therebetween and directly connect the IOPD  105  to the color measuring device. It will be appreciated that depending on the configuration of the IOPD  105 , a different configuration for the interface  110  is needed in order to directly connect with the interface port of the IOPD  105  as is known in the art. Also shown in FIG. 2A is an exemplary display  115  and function keys  120  for selecting and inputting data by the user. With the interface  110 , the IOPD  105  can be easily disconnected and removed by pulling it out by hand. Alternately, the IOPD can be embedded in the color measuring device  10  which, although removable, would not be easily disconnected by hand.  
         [0023]    The IOPD  105  includes application software that allows it to communicate and operate the functions of the color measuring device  10 . Once the remote processing device  105  is connected to the interface  110 , the device becomes an autonomous portable color measuring device. The IOPD  105  provides data storage for the color measuring device and performs colorimetric calculations from measurements taken by the color measuring device. Of course, other types of processing and data analysis can be performed as is known in the art. For example, measurement of absolute color represented in various colorimetric formats (CIE, etc.); the measurement of relative color represented in various colorimetric formats; color matching by using one or more databases of pre-measured colors and color searching and comparison analysis algorithms as is known in the art; graphic display of colorimetric values for various color standards; and color quality control functions such as acceptance of an unknown color sample to a known reference sample. The data is then displayed to the user in a variety of formats including numerical and/or graphical outputs on the display  115 .  
         [0024]    Due to the independent functionality of the IOPD  105 , it can be replaced and interchanged with a different IOPD from another color measuring device. In doing so, the color measuring device is re-characterized with the preferences existing in the different IOPD. In this manner, a user can simply remove their preprogrammed IOPD  105  from a first color measuring device and connect it to a second color measuring device so that the second color measuring device operates in the same manner as the first color measuring device.  
         [0025]    Other configurations are possible with the IOPD  105  and color measuring device  10  combination rather than being a self-contained color measuring device. For example, the color measuring device  10  can be connected to a remote computer which performs colorimetric functions without using the IOPD  105  (which can be connected or not). The IOPD  105  can be removed and connected to a computer via connections of various types, for example, RS-232, universal serial bus, wireless connection, intranet, infrared communications, and global networks. Once connected, color data can be transmitted in various formats for different color processing applications. In another configuration, the remote processing device  105 , while connected to the color measuring device  10 , can transmit information in various formats as stated above to the internet, a remote network or computer by direct connection or by wireless communication as is know in the art. For wireless communication, the IOPD  105  includes a signal transmitter and receiver and associated circuitry as is known in the art.  
         [0026]    The IOPD  105  includes an industry standard operating system and user interface. This results in less training and easier operation of the color measuring device for users familiar with the standard operating system and interface. Using the standard operating system of the IOPD, software development is made easier and faster as well as hardware development. Upgrading the processing system of the color measuring device  10  is performed simply by replacing the IOPD  105  with a newer model and loading the color measuring device application software on it.  
         [0027]    Another configuration includes connecting the color measuring device with an interface to a personal computer. Then the color measuring device can be transparent to the system while the remote processing device  105  and the personal computer directly exchange color information. Another configuration includes detaching the IOPD from the color measuring device and directly connecting it to a personal computer. Color data is then exchanged therebetween. Upgrades to the color measuring device software application on the IOPD can be performed by downloading a new version of the software from an internet site, from a remote computer, or by using other downloading or software installation techniques as is known in the art. The software application can also be “tied” to a particular color measuring device, for example at the time of registration, which prevents unauthorized copying.  
         [0028]    The present invention has many applications to measure color attributes, perform color matching, color analysis, color verification, and other calculations. Exemplary applications include measuring textiles, inks, plastics, powdered substances, liquid substances, metals, paints, metallic paints, cosmetics, food stuffs, wood stuffs, and paper. Of course, one of ordinary skill in the art will appreciate that the present invention can be used for other applications and can be programmed to perform other desired functions associated to color measuring and analysis. Although the above examples have been described using an integrating sphere, other types of spectrophotometers and/or color measuring devices can be used. For example, spectrophotometers commonly referred to as 0/45 or 45/0 sensor based instruments, other sphere based spectrophotometers, Gonio spectrophotometers, colorimeters or densitometers.  
         [0029]    With reference to FIGS. 3A and 3B, the present invention is shown having an alternative configuration. FIG. 3A shows a transparent top view of the color measuring device  10  and FIG. 3B shows a transparent side view showing the inner components. In this configuration, the color measuring device generally is positioned horizontal to the object being measured which would be positioned against the sample aperture  25 . This type of configuration is suited for the print and ink industries. Also shown on the housing  15  is a cover  200  which can be snapped-on or hinged to the housing  15 . The cover  200  secures the IOPD  105  to the housing and serves to protect it. The cover  200  includes a window such that a user can view the processing device  105  therethrough. Of course, the cover  200  can be used with the color measuring device configuration described above. Also shown is a power supply  210  and a stapler foot-type targeting device  215  that helps a user align a test sample with the aperture  25 . The targeting device  215  is hinged to the housing  15  at  220  for movement.  
         [0030]    The invention has been described with reference to the preferred embodiment. Obviously, modifications and alterations will occur to others upon a reading and understanding of this specification. It is intended to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalence thereof.