Patent Abstract:
A method of providing a super-resolution image is disclosed. The method uses a processor to perform the following steps of acquiring a captured low-resolution image of a scene and resizing the low-resolution image to provide a high-resolution image. The method further includes computing local edge parameters including local edge orientations and local edge centers of gravity from the high-resolution image, selecting edge pixels in the high-resolution image responsive to the local edge parameters, and modifying the high-resolution image in response to the selected edge pixels to provide a super-resolution image.

Full Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a method for producing a super-resolution image from a low-resolution image of a scene. 
       BACKGROUND OF THE INVENTION 
       [0002]    It is well-known that to produce a low-resolution image from a high-resolution, the high-resolution is first blurred (low-pass filtered) and then subsampled to a lower resolution. It is frequently desirable to invert this process to produce a high-resolution image from a low-resolution image. However, even if the blurring and subsampling operations used to produce the low-resolution image are completely known, they are generally not invertible in a mathematical sense. The most common approximation to this inversion process is to begin by increasing the resolution of the low-resolution image using bicubic, bilinear, or some other linear interpolation process. The result of the interpolation operation is then sharpened in some standard way, such as with unsharp masking. The main problem with this approach is that the linear interpolation operation cannot restore the high-frequency spatial detail discarded by the original subsampling process. As a result, the sharpening operation can only operate on the spatial frequency detail that survived the original subsampling process. Super-resolution processing attempts to address this liability by added new high-frequency spatial detail that is consistent with the existing low-frequency spatial detail to produce a super-resolution image that, in a visual sense, more closely approximates the original high-resolution image. U.S. Pat. No. 7,215,831 to Altunbasak, et al., is an example of one class of super-resolution methods that take a number of low-resolution images that differ from each other by subpixel shifts and combine them into a single high-resolution image. The problem with this approach is that the multiple versions of the low-resolution image are generally not available unless special efforts are made at the time of image capture. A second problem with this approach is the requirement to store and process several low-resolution images which incurs large demands of computation resources. U.S. Pat. No. 7,218,796 to Bishop, et al., is an example of another class of super-resolution methods that use a dictionary of low-resolution regions and their corresponding high-resolution regions to construct a high-resolution image using a dictionary look up process. The problem with this approach is that the dictionary needs to be large and constructed from an appropriate training set of image in order to produce acceptable quality high-resolution images. If the dictionary has too few entries, there may not be enough variety in the spatial information to produce a good quality high-resolution image. If the low-resolution image is too dissimilar to the images in the training set used to create the dictionary, the quality of the resulting high-resolution image may also be insufficient. The solution of having a large dictionary, however, brings with it the significant problems of storing and searching such a large database of information. U.S. Patent Application Publication No. 2010/0061638 to Tanaka is an example a third class of super-resolution methods that examines each pixel neighborhood within the low-resolution image and produces corresponding high-resolution pixel neighborhoods based on combining only similar pixels within the low-resolution pixel neighborhood to produce the corresponding high-resolution pixel neighborhood. The problem with this approach is that while it uses nonlinear processing to produce results superior to linear interpolation methods, it is still limited to the spatial frequency detail present in the low-resolution image. No new high-frequency detail is added in a true super-resolution manner. 
       SUMMARY OF THE INVENTION 
       [0003]    In accordance with the present invention there is provided a method of providing a super-resolution image, comprising using a processor to perform the following: 
         [0004]    (a) acquiring a captured low-resolution image of a scene; 
         [0005]    (b) resizing the low-resolution image to provide a high-resolution image; 
         [0006]    (c) computing local edge parameters including local edge orientations and local edge centers of gravity from the high-resolution image; 
         [0007]    (d) selecting edge pixels in the high-resolution image responsive to the local edge parameters; and 
         [0008]    (e) modifying the high-resolution image in response to the selected edge pixels to provide a super-resolution image. 
         [0009]    This invention has the advantage that the super-resolution image is produced without the need of several different captured low-resolution images of the scene or a dictionary of low-resolution to high-resolution image regions that needs to be created, stored, and searched. As a result, the computational requirements of the present invention are significantly reduced and the processing time considerably shortened over the prior art. 
         [0010]    It has the additional advantage of being able to produce super-resolution improvement for multiple spatial frequencies throughout the spatial frequency spectrum without substantial increase in computation resources or processing time. 
         [0011]    This and other aspects, objects, features, and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and appended claims, and by reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a high-level diagram showing the components of a digital camera system; 
           [0013]      FIG. 2  is a flow diagram depicting typical image processing operations used to process digital images in a digital camera; 
           [0014]      FIG. 3  is a block diagram of the preferred embodiment of the present invention; 
           [0015]      FIG. 4  is a block diagram showing a detailed view of the super-resolution sharpening block for a preferred embodiment of the present invention; 
           [0016]      FIG. 5  is a block diagram showing a detailed view of the sharpen luminance block for a preferred embodiment of the present invention; 
           [0017]      FIG. 6  is a block diagram showing a detailed view of the sharpen high-pass image block for a preferred embodiment of the present invention; 
           [0018]      FIG. 7  is a block diagram showing a detailed view of the adaptive sharpening block for a preferred embodiment of the present invention; 
           [0019]      FIG. 8  is a block diagram showing a detailed view of the sharpen edge pixels block for a preferred embodiment of the present invention; 
           [0020]      FIG. 9  is a block diagram showing a detailed view of the adjust sharpness gain block for an alternate embodiment of the present invention; 
           [0021]      FIG. 10  is a diagram of a support region used in a preferred embodiment of the present invention; 
           [0022]      FIG. 11  is a block diagram of an alternate embodiment of the present invention; 
           [0023]      FIG. 12  is a block diagram of an alternate embodiment of the present invention; and 
           [0024]      FIG. 13  is a block diagram of an alternate embodiment of the present invention. 
       
    
    
       [0025]    It is to be understood that the attached drawings are for purposes of illustrating the concepts of the invention and may not be to scale. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    In the following description, a preferred embodiment of the present invention will be described in terms that would ordinarily be implemented as a software program. Those skilled in the art will readily recognize that the equivalent of such software can also be constructed in hardware. Because image manipulation algorithms and systems are well known, the present description will be directed in particular to algorithms and systems forming part of, or cooperating more directly with, the system and method in accordance with the present invention. Other aspects of such algorithms and systems, and hardware or software for producing and otherwise processing the image signals involved therewith, not specifically shown or described herein, can be selected from such systems, algorithms, components and elements known in the art. Given the system as described according to the invention in the following materials, software not specifically shown, suggested or described herein that is useful for implementation of the invention is conventional and within the ordinary skill in such arts. 
         [0027]    Still further, as used herein, a computer program for performing the method of the present invention can be stored in a computer readable storage medium, which can include, for example; magnetic storage media such as a magnetic disk (such as a hard drive or a floppy disk) or magnetic tape; optical storage media such as an optical disc, optical tape, or machine readable bar code; solid state electronic storage devices such as random access memory (RAM), or read only memory (ROM); or any other physical device or medium employed to store a computer program having instructions for controlling one or more computers to practice the method according to the present invention. 
         [0028]    The invention is inclusive of combinations of the embodiments described herein. References to “a particular embodiment” and the like refer to features that are present in at least one embodiment of the invention. Separate references to “an embodiment” or “particular embodiments” or the like do not necessarily refer to the same embodiment or embodiments; however, such embodiments are not mutually exclusive, unless so indicated or as are readily apparent to one of skill in the art. The use of singular or plural in referring to the “method” or “methods” and the like is not limiting. It should be noted that, unless otherwise explicitly noted or required by context, the word “or” is used in this disclosure in a non-exclusive sense. 
         [0029]    Because digital cameras employing imaging devices and related circuitry for signal capture and processing, and display are well known, the present description will be directed in particular to elements forming part of, or cooperating more directly with, the method and apparatus in accordance with the present invention. Elements not specifically shown or described herein are selected from those known in the art. Certain aspects of the embodiments to be described are provided in software. Given the system as shown and described according to the invention in the following materials, software not specifically shown, described or suggested herein that is useful for implementation of the invention is conventional and within the ordinary skill in such arts. 
         [0030]    The following description of a digital camera will be familiar to one skilled in the art. It will be obvious that there are many variations of this embodiment that are possible and are selected to reduce the cost, add features or improve the performance of the camera. 
         [0031]      FIG. 1  depicts a block diagram of a digital photography system, including a digital camera  10  in accordance with the present invention. Preferably, the digital camera  10  is a portable battery operated device, small enough to be easily handheld by a user when capturing and reviewing images. The digital camera  10  produces digital images that are stored as digital image files using image memory  30 . The phrase “digital image” or “digital image file”, as used herein, refers to any digital image file, such as a digital still image or a digital video file. 
         [0032]    In some embodiments, the digital camera  10  captures both motion video images and still images. The digital camera  10  can also include other functions, including, but not limited to, the functions of a digital music player (e.g. an MP3 player), a mobile telephone, a GPS receiver, or a programmable digital assistant (PDA). 
         [0033]    The digital camera  10  includes a lens  4  having an adjustable aperture and adjustable shutter  6 . In a preferred embodiment, the lens  4  is a zoom lens and is controlled by zoom and focus motor drives  8 . The lens  4  focuses light from a scene (not shown) onto an image sensor  14 , for example, a single-chip color CCD or CMOS image sensor. The lens  4  is one type optical system for forming an image of the scene on the image sensor  14 . In other embodiments, the optical system can use a fixed focal length lens with either variable or fixed focus. 
         [0034]    The output of the image sensor  14  is converted to digital form by Analog Signal Processor (ASP) and Analog-to-Digital (A/D) converter  16 , and temporarily stored in buffer memory  18 . The image data stored in buffer memory  18  is subsequently manipulated by a processor  20 , using embedded software programs (e.g. firmware) stored in firmware memory  28 . In some embodiments, the software program is permanently stored in firmware memory  28  using a read only memory (ROM). In other embodiments, the firmware memory  28  can be modified by using, for example, Flash EPROM memory. In such embodiments, an external device can update the software programs stored in firmware memory  28  using a wired interface  38  or a wireless modem  50 . In such embodiments, the firmware memory  28  can also be used to store image sensor calibration data, user setting selections and other data which must be preserved when the camera is turned off. In some embodiments, the processor  20  includes a program memory (not shown), and the software programs stored in the firmware memory  28  are copied into the program memory before being executed by the processor  20 . 
         [0035]    It will be understood that the functions of processor  20  can be provided using a single programmable processor or by using multiple programmable processors, including one or more digital signal processor (DSP) devices. Alternatively, the processor  20  can be provided by custom circuitry (e.g., by one or more custom integrated circuits (ICs) designed specifically for use in digital cameras), or by a combination of programmable processor(s) and custom circuits. It will be understood that connectors between the processor  20  from some or all of the various components shown in  FIG. 1  can be made using a common data bus. For example, in some embodiments the connection between the processor  20 , the buffer memory  18 , the image memory  30 , and the firmware memory  28  can be made using a common data bus. 
         [0036]    The processed images are then stored using the image memory  30 . It is understood that the image memory  30  can be any form of memory known to those skilled in the art including, but not limited to, a removable Flash memory card, internal Flash memory chips, magnetic memory, or optical memory. In some embodiments, the image memory  30  can include both internal Flash memory chips and a standard interface to a removable Flash memory card, such as a Secure Digital (SD) card. Alternatively, a different memory card format can be used, such as a micro SD card, Compact Flash (CF) card, MultiMedia Card (MMC), xD card or Memory Stick. 
         [0037]    The image sensor  14  is controlled by the timing generator  12 , which produces various clocking signals to select rows and pixels and synchronizes the operation of the ASP and A/D converter  16 . The image sensor  14  can have, for example, 12.4 megapixels (4088×3040 pixels) in order to provide a still image file of approximately 4000×3000 pixels. To provide a color image, the image sensor  14  is generally overlaid with a color filter array, which provides an image sensor  14  having an array of pixels that include different colored pixels. The different color pixels can be arranged in many different patterns. As one example, the different color pixels can be arranged using the well-known Bayer color filter array, as described in commonly assigned U.S. Pat. No. 3,971,065 to Bayer, the disclosure of which is incorporated herein by reference. As a second example, the different color pixels can be arranged as described in commonly assigned U.S. Patent Application Publication 2007/0024931 to Compton and Hamilton, the disclosure of which is incorporated herein by reference. These examples are not limiting, and many other color patterns can be used. 
         [0038]    It will be understood that the image sensor  14 , timing generator  12 , and ASP and A/D converter  16  can be separately fabricated integrated circuits, or they can be fabricated as a single integrated circuit as is commonly done with CMOS image sensors. In some embodiments, this single integrated circuit can perform some of the other functions shown in  FIG. 1 , including some of the functions provided by processor  20 . 
         [0039]    The image sensor  14  is effective when actuated in a first mode by timing generator  12  for providing a motion sequence of lower resolution sensor image data, which is used when capturing video images and also when previewing a still image to be captured, in order to compose the image. This preview mode sensor image data can be provided as HD resolution image data, for example, with 1280×720 pixels, or as VGA resolution image data, for example, with 640×480 pixels, or using other resolutions which have significantly columns and rows of data, compared to the resolution of the image sensor  14 . 
         [0040]    The preview mode sensor image data can be provided by combining values of adjacent pixels having the same color, or by eliminating some of the pixels values, or by combining some color pixels values while eliminating other color pixel values. The preview mode image data can be processed as described in commonly assigned U.S. Pat. No. 6,292,218 to Parulski, et al which is incorporated herein by reference. 
         [0041]    The image sensor  14  is also effective when actuated in a second mode by timing generator  12  for providing high resolution still image data. This final mode sensor image data is provided as high resolution output image data, which for scenes having a high illumination level includes all of the pixels of the image sensor, and can be, for example, a 12 megapixel final image data having 4000×3000 pixels. At lower illumination levels, the final sensor image data can be provided by “binning” some number of like-colored pixels on the image sensor, in order to increase the signal level and thus the “ISO speed” of the sensor. 
         [0042]    The zoom and focus motor drivers  8  are controlled by control signals supplied by the processor  20 , to provide the appropriate focal length setting and to focus the scene onto the image sensor  14 . The exposure level of the image sensor  14  is controlled by controlling the f/number and exposure time of an adjustable aperture and adjustable shutter  6 , the exposure period of the image sensor  14  via the timing generator  12 , and the gain (i.e., ISO speed) setting of the ASP and A/D converter  16 . The processor  20  also controls a flash  2  which can illuminate the scene. 
         [0043]    The lens  4  of the digital camera  10  can be focused in the first mode by using “through-the-lens” autofocus, as described in commonly-assigned U.S. Pat. No. 5,668,597 to Parulski et al., which is incorporated herein by reference. This is accomplished by using the zoom and focus motor drivers  8  to adjust the focus position of the lens  4  to a number of positions ranging between a near focus position to an infinity focus position, while the processor  20  determines the closest focus position which provides a peak sharpness value for a central portion of the image captured by the image sensor  14 . The focus distance which corresponds to the closest focus position can then be utilized for several purposes, such as automatically setting an appropriate scene mode, and can be stored as metadata in the image file, along with other lens and camera settings. 
         [0044]    The processor  20  produces menus and low resolution color images that are temporarily stored in a display memory  36  and are displayed on an image display  32 . The image display  32  is typically an active matrix color liquid crystal display (LCD), although other types of displays, such as organic light emitting diode (OLED) displays, can be used. A video interface  44  provides a video output signal from the digital camera  10  to a video display  46 , such as a flat panel HDTV display. In preview mode, or video mode, the digital image data from buffer memory  18  is manipulated by processor  20  to form a series of motion preview images that are displayed, typically as color images, on the image display  32 . In review mode, the images displayed on the image display  32  are produced using the image data from the digital image files stored in image memory  30 . 
         [0045]    The graphical user interface displayed on the image display  32  is controlled in response to user input provided by user controls  34 . The user controls  34  are used to select various camera modes, such as video capture mode, still capture mode, and review mode, and to initiate capture of still images, recording of motion images. The user controls  34  are also used to set user processing preferences, and to choose between various photography modes based on scene type and taking conditions. In some embodiments, various camera settings can be set automatically in response to analysis of preview image data, audio signals, or external signals such as GPS, weather broadcasts, or other available signals. 
         [0046]    In some embodiments, when the digital camera  10  is in a still photography mode the above-described preview mode is initiated when the user partially depresses a shutter button, which is one of the user controls  34 , and the still image capture mode is initiated when the user fully depresses the shutter button. The user controls  34  are also used to turn on the digital camera  10 , control the lens  4 , and initiate the picture taking process. User controls  34  typically include some combination of buttons, rocker switches, joysticks, or rotary dials. In some embodiments, some of the user controls  34  are provided by using a touch screen overlay on the image display  32 . In other embodiments, the user controls  34  can include a way to receive input from the user or an external device via a tethered, wireless, voice activated, visual or other interface. In other embodiments, additional status displays or images displays can be used. 
         [0047]    The camera modes that can be selected using the user controls  34  include a “timer” mode. When the “timer” mode is selected, a short delay (e.g., 10 seconds) occurs after the user fully presses the shutter button, before the processor  20  initiates the capture of a still image. 
         [0048]    An audio codec  22  connected to the processor  20  receives an audio signal from a microphone  24  and provides an audio signal to a speaker  26 . These components can be used to record and playback an audio track, along with a video sequence or still image. If the digital camera  10  is a multi-function device such as a combination camera and mobile phone, the microphone  24  and the speaker  26  can be used for telephone conversation. 
         [0049]    In some embodiments, the speaker  26  can be used as part of the user interface, for example to provide various audible signals which indicate that a user control  34  has been depressed, or that a particular mode has been selected. In some embodiments, the microphone  24 , the audio codec  22 , and the processor  20  can be used to provide voice recognition, so that the user can provide a user input to the processor  20  by using voice commands, rather than user controls  34 . The speaker  26  can also be used to inform the user of an incoming phone call. This can be done using a standard ring tone stored in firmware memory  28 , or by using a custom ring-tone downloaded from a wireless network  58  and stored in the image memory  30 . In addition, a vibration device (not shown) can be used to provide a silent (e.g., non audible) notification of an incoming phone call. 
         [0050]    The processor  20  also provides additional processing of the image data from the image sensor  14 , in order to produce rendered sRGB image data which is compressed and stored within a “finished” image file, such as a well-known Exif-JPEG image file, in the image memory  30 . 
         [0051]    The digital camera  10  can be connected via the wired interface  38  to an interface/recharger  48 , which is connected to a computer  40 , which can be a desktop computer or portable computer located in a home or office. The wired interface  38  can conform to, for example, the well-known USB 2.0 interface specification. The interface/recharger  48  can provide power via the wired interface  38  to a set of rechargeable batteries (not shown) in the digital camera  10 . 
         [0052]    The digital camera  10  can include the wireless modem  50 , which interfaces over a radio frequency band  52  with a wireless network  58 . The wireless modem  50  can use various wireless interface protocols, such as the well-known Bluetooth wireless interface or the well-known 802.11 wireless interface. The computer  40  can upload images via the Internet  70  to a photo service provider  72 , such as the Kodak Gallery. Other devices (not shown) can access the images stored by the photo service provider  72 . 
         [0053]    In alternative embodiments, the wireless modem  50  communicates over a radio frequency (e.g. wireless) link with a mobile phone network (not shown), such as a 3GSM network, which connects with the Internet  70  in order to upload digital image files from the digital camera  10 . These digital image files can be provided to the computer  40  or the photo service provider  72 . 
         [0054]      FIG. 2  is a flow diagram depicting image processing operations that can be performed by the processor  20  in the digital camera  10  ( FIG. 1 ) in order to process color sensor data  100  from the image sensor  14  output by the ASP and A/D converter  16 . In some embodiments, the processing parameters used by the processor  20  to manipulate the color sensor data  100  for a particular digital image are determined by various photography mode settings  175 , which are typically associated with photography modes that can be selected via the user controls  34 , which enable the user to adjust various camera settings  185  in response to menus displayed on the image display  32 . 
         [0055]    The color sensor data  100  which has been digitally converted by the ASP and A/D converter  16  is manipulated by a white balance step  95 . In some embodiments, this processing can be performed using the methods described in commonly-assigned U.S. Pat. No. 7,542,077 to Miki, the disclosure of which is herein incorporated by reference. The white balance can be adjusted in response to a white balance setting  90 , which can be manually set by a user, or which can be automatically set by the digital camera  10 . 
         [0056]    The color image data is then manipulated by a noise reduction step  105  in order to reduce noise from the image sensor  14 . In some embodiments, this processing can be performed using the methods described in commonly-assigned U.S. Pat. No. 6,934,056 to Gindele et al, the disclosure of which is herein incorporated by reference. The level of noise reduction can be adjusted in response to an ISO setting  110 , so that more filtering is performed at higher ISO exposure index setting. 
         [0057]    The color image data is then manipulated by a demosaicking step  115 , in order to provide red, green and blue (RGB) image data values at each pixel location. Algorithms for performing the demosaicking step  115  are commonly known as color filter array (CFA) interpolation algorithms or “deBayering” algorithms. In one embodiment of the present invention, the demosaicking step  115  can use the luminance CFA interpolation method described in commonly-assigned U.S. Pat. No. 5,652,621 to Adams et al., the disclosure of which is incorporated herein by reference. The demosaicking step  115  can also use the chrominance CFA interpolation method described in commonly-assigned U.S. Pat. No. 4,642,678 to Cok, the disclosure of which is herein incorporated by reference. 
         [0058]    In some embodiments, the user can select between different pixel resolution modes, so that the digital camera  10  can produce a smaller size image file. Multiple pixel resolutions can be provided as described in commonly-assigned U.S. Pat. No. 5,493,335 to Parulski et al., the disclosure of which is herein incorporated by reference. In some embodiments, a resolution mode setting  120  can be selected by the user to be full size (e.g. 3,000×2,000 pixels), medium size (e.g. 1,500×1000 pixels) or small size (750×500 pixels). 
         [0059]    The color image data is color corrected in color correction step  125 . In some embodiments, the color correction is provided using a 3×3 linear space color correction matrix, as described in commonly-assigned U.S. Pat. No. 5,189,511 to Parulski, et al., the disclosure of which is incorporated herein by reference. In some embodiments, different user-selectable color modes can be provided by storing different color matrix coefficients in firmware memory  28  of the digital camera  10 . For example, four different color modes can be provided, so that the color mode setting  130  is used to select one of the following color correction matrices: 
       Setting 1 (Normal Color Reproduction) 
       [0060]    
       
         
           
             
               
                 
                   
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                             1.80 
                           
                           
                             
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       Setting 2 (Saturated Color Reproduction) 
       [0061]    
       
         
           
             
               
                 
                   
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       Setting 3 (De-Saturated Color Reproduction) 
       [0062]    
       
         
           
             
               
                 
                   
                     
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       Setting 4 (Monochrome) 
       [0063]    
       
         
           
             
               
                 
                   
                     
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                             0.10 
                           
                         
                         
                           
                             0.30 
                           
                           
                             0.60 
                           
                           
                             0.10 
                           
                         
                       
                       ] 
                     
                   
                    
                   
                     [ 
                     
                       
                         
                           
                             R 
                             in 
                           
                         
                       
                       
                         
                           
                             G 
                             in 
                           
                         
                       
                       
                         
                           
                             B 
                             in 
                           
                         
                       
                     
                     ] 
                   
                 
               
               
                 
                   ( 
                   4 
                   ) 
                 
               
             
           
         
       
     
         [0064]    In other embodiments, a three-dimensional lookup table can be used to perform the color correction step  125 . 
         [0065]    The color image data is also manipulated by a tone scale correction step  135 . In some embodiments, the tone scale correction step  135  can be performed using a one-dimensional look-up table as described in U.S. Pat. No. 5,189,511, cited earlier. In some embodiments, a plurality of tone scale correction look-up tables is stored in the firmware memory  28  in the digital camera  10 . These can include look-up tables which provide a “normal” tone scale correction curve, a “high contrast” tone scale correction curve, and a “low contrast” tone scale correction curve. A user selected contrast setting  140  is used by the processor  20  to determine which of the tone scale correction look-up tables to use when performing the tone scale correction step  135 . 
         [0066]    The color image data is also manipulated by an image sharpening step  145 . In some embodiments, this can be provided using the methods described in commonly-assigned U.S. Pat. No. 6,192,162 to Hamilton, et al., the disclosure of which is incorporated herein by reference. In some embodiments, the user can select between various sharpening settings, including a “normal sharpness” setting, a “high sharpness” setting, and a “low sharpness” setting. In this example, the processor  20  uses one of three different edge boost multiplier values, for example 2.0 for “high sharpness”, 1.0 for “normal sharpness”, and 0.5 for “low sharpness” levels, responsive to a sharpening setting  150  selected by the user of the digital camera  10 . 
         [0067]    The color image data is also manipulated by an image compression step  155 . In some embodiments, the image compression step  155  can be provided using the methods described in commonly-assigned U.S. Pat. No. 4,774,574 to Daly et al., the disclosure of which is incorporated herein by reference. In some embodiments, the user can select between various compression settings. This can be implemented by storing a plurality of quantization tables, for example, three different tables, in the firmware memory  28  of the digital camera  10 . These tables provide different quality levels and average file sizes for the compressed digital image file  180  to be stored in the image memory  30  of the digital camera  10 . A user selected compression mode setting  160  is used by the processor  20  to select the particular quantization table to be used for the image compression step  155  for a particular image. 
         [0068]    The compressed color image data is stored in the digital image file  180  using a file formatting step  165 . The digital image file  180  can include various metadata  170 . Metadata  170  is any type of information that relates to the digital image, such as the model of the camera that captured the image, the size of the image, the date and time the image was captured, and various camera settings, such as the lens focal length, the exposure time and f-number of the lens, and whether or not the camera flash fired. In a preferred embodiment, all of this metadata  170  is stored using standardized tags within the well-known Exif-JPEG still image file format. In a preferred embodiment of the present invention, the metadata  170  includes information about various camera settings  185 , including the photography mode settings  175 . 
         [0069]    The present invention will now be described with reference to  FIG. 3 .  FIG. 3  is a flowchart of a top view of the preferred embodiment. A bicubic interpolation block  302  produces a high-resolution image  304  from a low-resolution image  300  which is read from the digital image file  180  ( FIG. 2 ). The bicubic interpolation block  302  is a standard operation well-known to those skilled in the art. In an alternate embodiment of the present invention bilinear interpolation is used in place of bicubic interpolation. A super-resolution sharpening block  306 , to be described below, produces a super-resolution image  308  from the high-resolution image  304 . 
         [0070]      FIG. 4  is a detailed description of the super-resolution sharpening block  306  ( FIG. 3 ) for the preferred embodiment. A convert to YCC block  400  produces a YCC image  402  from the high-resolution image  304  ( FIG. 3 ). The convert to YCC block  400  uses the following transform create luminance (Y) and chrominance (C 1  and C 2 ) pixel values from red (R), green (G), and blue (B) pixel values. 
         [0000]    
       
         
           
             
               ( 
               
                 
                   
                     Y 
                   
                 
                 
                   
                     
                       C 
                       1 
                     
                   
                 
                 
                   
                     
                       C 
                       2 
                     
                   
                 
               
               ) 
             
             = 
             
               
                 1 
                 4 
               
                
               
                 ( 
                 
                   
                     
                       1 
                     
                     
                       2 
                     
                     
                       1 
                     
                   
                   
                     
                       
                         - 
                         1 
                       
                     
                     
                       2 
                     
                     
                       
                         - 
                         1 
                       
                     
                   
                   
                     
                       2 
                     
                     
                       0 
                     
                     
                       
                         - 
                         2 
                       
                     
                   
                 
                 ) 
               
                
               
                 ( 
                 
                   
                     
                       R 
                     
                   
                   
                     
                       G 
                     
                   
                   
                     
                       B 
                     
                   
                 
                 ) 
               
             
           
         
       
     
         [0071]    A sharpen luminance block  404 , to be described below, produces a sharpened YCC image  406  from the YCC image  402 . A convert to RGB block  408  produces the super-resolution image  308  ( FIG. 3 ) from the sharpened YCC image  406 . The following transform is used by the convert to RGB block  408  to produce RGB pixel values from YCC pixel values. 
         [0000]    
       
         
           
             
               ( 
               
                 
                   
                     R 
                   
                 
                 
                   
                     G 
                   
                 
                 
                   
                     B 
                   
                 
               
               ) 
             
             = 
             
               
                 ( 
                 
                   
                     
                       1 
                     
                     
                       
                         - 
                         1 
                       
                     
                     
                       
                         - 
                         1 
                       
                     
                   
                   
                     
                       1 
                     
                     
                       1 
                     
                     
                       0 
                     
                   
                   
                     
                       1 
                     
                     
                       
                         - 
                         1 
                       
                     
                     
                       1 
                     
                   
                 
                 ) 
               
                
               
                 ( 
                 
                   
                     
                       Y 
                     
                   
                   
                     
                       
                         C 
                         1 
                       
                     
                   
                   
                     
                       
                         C 
                         2 
                       
                     
                   
                 
                 ) 
               
             
           
         
       
     
         [0072]    It will be apparent to those skilled in the art that other transforms can be used to convert to YCC and to convert to RGB. 
         [0073]      FIG. 5  is a detailed description of the sharpen luminance block  404  ( FIG. 4 ) for the preferred embodiment. A compute high-pass and low-pass images block  500  produces a low-pass image  504  and a high-pass image  502  from the YCC image  402  ( FIG. 4 ). The compute high-pass and low-pass images block  500  convolves the following high-pass filter (h) with the luminance channel of the YCC image  402  ( FIG. 4 ) to produce the high-pass image  502 . 
         [0000]    
       
         
           
             h 
             = 
             
               
                 1 
                 374 
               
                
               
                 ( 
                 
                   
                     
                       
                         - 
                         1 
                       
                     
                     
                       
                         - 
                         3 
                       
                     
                     
                       
                         - 
                         4 
                       
                     
                     
                       
                         - 
                         4 
                       
                     
                     
                       
                         - 
                         4 
                       
                     
                     
                       
                         - 
                         3 
                       
                     
                     
                       
                         - 
                         1 
                       
                     
                   
                   
                     
                       
                         - 
                         3 
                       
                     
                     
                       3 
                     
                     
                       3 
                     
                     
                       4 
                     
                     
                       3 
                     
                     
                       3 
                     
                     
                       
                         - 
                         3 
                       
                     
                   
                   
                     
                       
                         - 
                         4 
                       
                     
                     
                       3 
                     
                     
                       2 
                     
                     
                       3 
                     
                     
                       2 
                     
                     
                       3 
                     
                     
                       
                         - 
                         4 
                       
                     
                   
                   
                     
                       
                         - 
                         4 
                       
                     
                     
                       4 
                     
                     
                       3 
                     
                     
                       4 
                     
                     
                       3 
                     
                     
                       4 
                     
                     
                       
                         - 
                         4 
                       
                     
                   
                   
                     
                       
                         - 
                         4 
                       
                     
                     
                       3 
                     
                     
                       2 
                     
                     
                       3 
                     
                     
                       2 
                     
                     
                       3 
                     
                     
                       
                         - 
                         4 
                       
                     
                   
                   
                     
                       
                         - 
                         3 
                       
                     
                     
                       3 
                     
                     
                       3 
                     
                     
                       4 
                     
                     
                       3 
                     
                     
                       3 
                     
                     
                       
                         - 
                         3 
                       
                     
                   
                   
                     
                       
                         - 
                         1 
                       
                     
                     
                       
                         - 
                         3 
                       
                     
                     
                       
                         - 
                         4 
                       
                     
                     
                       
                         - 
                         4 
                       
                     
                     
                       
                         - 
                         4 
                       
                     
                     
                       
                         - 
                         3 
                       
                     
                     
                       
                         - 
                         1 
                       
                     
                   
                 
                 ) 
               
             
           
         
       
     
         [0074]    The high-pass filter is the convolution of a 5×5 low-pass filter and a 3×3 high-pass filter. It will be apparent to those skilled in the art how to construct similar high-pass filters. The high-pass image  502  is subtracted from the luminance channel of the YCC image  402  ( FIG. 4 ) to produce the low-pass image  504 . A sharpen high-pass image block  506 , to be described below, produces a sharpened high-pass image  510  from the high-pass image  502 . A combine high-pass and low-pass images block  508  adds the sharpened high-pass image  510  and the low-pass image  504  to produce the sharpened YCC image  406  ( FIG. 4 ). 
         [0075]      FIG. 6  is a detailed description of the sharpen high-pass image block  506  ( FIG. 5 ) for the preferred embodiment. A global sharpening block  600  produces a global sharpened image  602  by scaling (multiplying) the high-pass image  502  ( FIG. 5 ) by a global sharpening scaling constant. If y H  is the high-pass image  502  ( FIG. 5 ), γ G  is the global sharpening scaling constant, and y HG  is the global sharpened image  602 , then γ HG =γ G  y H . A typical value for γ G  is 1.25. An adaptive sharpening block  604 , to be described below, produces the sharpened high-pass image  510  ( FIG. 5 ) from the high-pass image  502  ( FIG. 5 ) and the global sharpened image  602 . 
         [0076]      FIG. 7  is a detailed description of the adaptive sharpening block  604  ( FIG. 6 ) for the preferred embodiment. A sharpen edge pixels block  700 , to be described below, produces sharpened edge pixels  702  from the high-pass image  502  ( FIG. 5 ) and the global sharpened image  602  ( FIG. 6 ). A compute first contrast block  704  produces a first contrast  708  from the global sharpened image  602  ( FIG. 6 ). The compute first contrast block  704  defines a support region as shown in  FIG. 10  for each pixel location within the global sharpened image  602  ( FIG. 6 ). In  FIG. 10  the first contrast  708  for P 13  is computed by finding the maximum global sharpened image  602  ( FIG. 6 ) pixel value and the minimum global sharpened image  602  ( FIG. 6 ) pixel value for all the pixel values, P 1  through P 25 , within the support region. If y HGmax  is the maximum global sharpened image  602  ( FIG. 6 ) pixel value and y HGmin  is the minimum global sharpened image  602  ( FIG. 6 ) pixel value, then the first contrast  708  c 1  is (y HGmax −y HGmin )/(y HGmax +y HGmin ). A compute second contrast block  706  produces a second contrast  710  from the sharpened edge pixels  702 . The compute second contrast block  706  performs a similar computation to the compute first contrast block  704 , using a support region as shown in  FIG. 10 . If y HA  is the sharpened edge pixels  702 , then y HAmax  is the maximum sharpened edge pixels  702  pixel value and y HAmin  is the minimum sharpened edge pixels  702  pixel value. The second contrast  710  c 2  is (y HAmax −y HAmin )/(y HAmax +y HAmin ). An adjust sharpness gain block  712 , to be described below, produces the sharpened high-pass image  510  ( FIG. 5 ) from the first contrast  708 , the second contrast  710 , and the sharpened edge pixels  702 . 
         [0077]      FIG. 8  is a detailed description of the sharpen edge pixels block  700  ( FIG. 7 ) for the preferred embodiment. A compute edge parameters block  800  produces local edge parameters  802  from the high-pass image  502  ( FIG. 5 ). The compute edge parameters block  800  defines a support region, as depicted in  FIG. 10 , around each pixel in the high-pass image  502  ( FIG. 5 ). Using the values within the support region, a horizontal edge value, u, and a vertical edge value, v, are computed as follows. 
         [0000]    
       
      
       u=+P 
       2 
       +P 
       6 
       +P 
       7 
       +P 
       11 
       +P 
       12 
       +P 
       16 
       +P 
       17 
       +P 
       21 
       +P 
       22 
       −P 
       4 
       −P 
       5 
       −P 
       9 
       −P 
       10 
       −P 
       14 
       −P 
       15 
       −P 
       19 
       −P 
       20 
       −P 
       24 
       −P 
       25  
      
     
         [0000]    
       
      
       v=P 
       1 
       +P 
       2 
       +P 
       3 
       +P 
       4 
       +P 
       5 
       +P 
       6 
       +P 
       7 
       +P 
       8 
       +P 
       9 
       +P 
       10 
       −P 
       16 
       −P 
       17 
       −P 
       18 
       −P 
       19 
       −P 
       20 
       −P 
       21 
       −P 
       22 
       −P 
       23 
       −P 
       24 
       −P 
       25  
      
     
         [0078]    The magnitude of the edge for the support region, r, is √{square root over (u 2 +v 2 )}. The orientation or angle of the edge for the support region, θ, is the value that produces the maximum value of u sin θ+v cos θ. In the preferred embodiment, the possible values of θ are restricted to 0, π/4, π/2, 3π/4, π, 5π/4, 3π/2, and 7π/4. Finally, the center of gravity values, x c  and y c  are computed for the support region. 
         [0000]    
       
         
           
             
               x 
               c 
             
             = 
             
               
                 
                   - 
                   2 
                 
                  
                 
                   ( 
                   
                     
                       P 
                       1 
                     
                     + 
                     
                       P 
                       6 
                     
                     + 
                     
                       P 
                       11 
                     
                     + 
                     
                       P 
                       16 
                     
                     + 
                     
                       P 
                       21 
                     
                   
                   ) 
                 
               
               - 
               
                 ( 
                 
                   
                     P 
                     2 
                   
                   + 
                   
                     P 
                     7 
                   
                   + 
                   
                     P 
                     12 
                   
                   + 
                   
                     P 
                     17 
                   
                   + 
                   
                     P 
                     22 
                   
                 
                 ) 
               
               + 
               
                 ( 
                 
                   
                     P 
                     4 
                   
                   + 
                   
                     P 
                     9 
                   
                   + 
                   
                     P 
                     14 
                   
                   + 
                   
                     P 
                     19 
                   
                   + 
                   
                     P 
                     24 
                   
                 
                 ) 
               
               + 
               
                 2 
                  
                 
                   ( 
                   
                     
                       P 
                       5 
                     
                     + 
                     
                       P 
                       10 
                     
                     + 
                     
                       P 
                       15 
                     
                     + 
                     
                       P 
                       20 
                     
                     + 
                     
                       P 
                       25 
                     
                   
                   ) 
                 
               
             
           
         
       
       
         
           
             
               y 
               c 
             
             = 
             
               
                 
                   - 
                   2 
                 
                  
                 
                   ( 
                   
                     
                       P 
                       21 
                     
                     + 
                     
                       P 
                       22 
                     
                     + 
                     
                       P 
                       23 
                     
                     + 
                     
                       P 
                       24 
                     
                     + 
                     
                       P 
                       25 
                     
                   
                   ) 
                 
               
               - 
               
                 ( 
                 
                   
                     P 
                     16 
                   
                   + 
                   
                     P 
                     17 
                   
                   + 
                   
                     P 
                     18 
                   
                   + 
                   
                     P 
                     19 
                   
                   + 
                   
                     P 
                     20 
                   
                 
                 ) 
               
               + 
               
                 ( 
                 
                   
                     P 
                     6 
                   
                   + 
                   
                     P 
                     7 
                   
                   + 
                   
                     P 
                     8 
                   
                   + 
                   
                     P 
                     9 
                   
                   + 
                   
                     P 
                     10 
                   
                 
                 ) 
               
               + 
               
                 2 
                  
                 
                   ( 
                   
                     
                       P 
                       1 
                     
                     + 
                     
                       P 
                       2 
                     
                     + 
                     
                       P 
                       3 
                     
                     + 
                     
                       P 
                       4 
                     
                     + 
                     
                       P 
                       5 
                     
                   
                   ) 
                 
               
             
           
         
       
     
         [0079]    The magnitude of the edge, r, the orientation or angle of the edge, θ, and the center of gravity values, x c  and y c , taken together of the local edge parameters  802  for a given pixel location within the high-pass image  502  ( FIG. 5 ). A scale edge pixels block  804  produces the sharpened edge pixels  702  ( FIG. 7 ) from the local edge parameters  802 , the high-pass image  502  ( FIG. 5 ), and the global sharpened image  602  ( FIG. 6 ). For each pixel location in the global sharpened image  602  ( FIG. 6 ) a support region as shown in  FIG. 10  is defined around the pixel location P 13 . If the value of the magnitude of the edge, r, associated with P 13  is less than an edge threshold value, t, then the global sharpened image  602  ( FIG. 6 ) pixel values are left unchanged for the support region. A typical value for t is 25. If the value of the magnitude of the edge, r, associated with P 13  is greater than or equal to the edge threshold value, t, then five pixels in the support region of the global sharpened image  602  ( FIG. 6 ) are replaced with corresponding high-pass image  502  ( FIG. 5 ) pixel values scaled (multiplied) by an adaptive scaling constant, γ A . A typical value of γ A  is 6. The five pixels to be scaled are selected based on the orientation or angle of the edge, θ, and the center of gravity values, x c  and y c  for the support region. Referring to  FIG. 10 , if θ=0 or 0=π, a horizontal row of pixel values with y=y c  is scaled by γ A . For example, if y c =1, then pixel values P 6 , P 7 , P 8 , P 9 , and P 10  will be scaled by γ A . If θ=7π/2 or θ=3π/2, then a vertical column of pixel values with x=x c  is scaled by γ A . For example, if x c =−1, then pixel values P 2 , P 7 , P 12 , P 17 , and P 22  will be scaled by γ A . If θ=7π/4 or θ=5π/4, then a “slash” diagonal of pixel values with x=x c  is scaled by γ A . For example, if x c =1, then pixel values P* 1 , P 22 , P 18 , P 14 , and P 10  will be scaled by γ A . Note that the value of P* 1  refers to the value P 1  from a support adjacent to the bottom edge of the support region shown in  FIG. 10 . Finally, if θ=3π/4 or θ=7π/4, then a “backslash” diagonal of pixel values with x=x c  is scaled by γ A . For example, if x c =1, then pixel values P 2 , P 8 , P 14 , P 20 , and P* 21  will be scaled by γ A . Note that the value of P* 21  refers to the value P 21  from a support adjacent to the right edge of the support region shown in  FIG. 10 . All scaled pixels overwrite the corresponding pixel values in the global sharpened image  602  ( FIG. 6 ) with the fully modified global sharpened image  602  ( FIG. 6 ) becoming the sharpened edge pixels  702  ( FIG. 7 ). 
         [0080]      FIG. 9  is a detailed description of the adjust sharpness gain block  712  ( FIG. 7 ) for the preferred embodiment. A compute contrast ratio block  900  produces a contrast ratio  902  from the first contrast  708  ( FIG. 7 ) and the second contrast  710  ( FIG. 7 ). The contrast ratio  902  c R  is computed to be c 2 /c 1  by the compute contrast ratio block  900 . A contrast ratio test block  904  tests to see if the contrast ratio  902  is greater than a contrast limit, c L , “True” in  FIG. 9 , or if it is less than or equal to the contrast limit, “False” in  FIG. 9 . A typical value for c L , is 2. In the case of a “False” result from the contrast ratio test block  904 , a no sharpening change block  906  pass the sharpened edge pixels  702  ( FIG. 7 ) unaltered to the sharpened high-pass image  510  ( FIG. 5 ). In the case of a “True” result from the contrast ratio test block  904 , a modify sharpness gain block  908  recomputes the sharpened edge pixels  702  ( FIG. 7 ) in the manner of the scale edge pixels block  804  ( FIG. 8 ) with a modified adaptive scaling constant of γ A /2, i.e., half of the adaptive scaling constant γ A . A typical value of the modified adaptive scaling constant is 3. The resulting recomputed sharpened edge pixels are passed to the sharpened high-pass image  510  ( FIG. 5 ). 
         [0081]      FIG. 11  is a flowchart of a top view of an alternate embodiment of the present invention. A super-resolution sharpening block  1102  produces a sharpened low-resolution image  1104  from a low-resolution image  1100  which is read from the digital image file  180  ( FIG. 2 ). The details of the super-resolution sharpening block  1102  are the same as for the super-resolution sharpening block  306  ( FIG. 3 ) except that the values of γ G  and γ A  are one-half the size for the super-resolution sharpening block  1102  than used in the super-resolution sharpening block  306  ( FIG. 3 ). A bicubic interpolation block  1106  produces a high-resolution image  1108  from the sharpened low-resolution image  1104 . The bicubic interpolation block is, again, a standard operation well-known to those skilled in the art. A super-resolution sharpening block  1110  produces a super-resolution image  1112  from the high-resolution image  1108 . The details of the super-resolution sharpening block  1110  are the same as for the super-resolution sharpening block  306  ( FIG. 3 ) including using the same values for γ G  and γ A . This alternate embodiment can be viewed as a two-layer pyramid process with super-resolution sharpening occurring at two different image resolutions. 
         [0082]      FIG. 12  and  FIG. 13  are flowcharts of a top view of another alternate embodiment of the present invention. In  FIG. 12 , a pyramid decomposition block  1202  produces pyramid image components  1204  from a low-resolution image  1200  which is read from the digital image file  180  ( FIG. 2 ). The pyramid decomposition block  1202  performs a Laplacian-Gaussian pyramid decomposition that is well-known to those skilled in the art. In an alternate embodiment the pyramid decomposition block  1202  performs a wavelet decomposition, also well-known to those skilled in the art. A super-resolution sharpening block  1206  produces sharpened pyramid image components  1208  from the pyramid image components  1204 . The super-resolution sharpening block  1206  performs super-resolution sharpening on each pyramid component in the manner of super-resolution sharpening block  1102  ( FIG. 11 ) and super-resolution sharpening block  1110  ( FIG. 11 ), with values of γ G  and γ A  chosen appropriately for each pyramid level of the pyramid image components  1204 . For example, for a four-level pyramid, the values of γ G  would be γ G /8, γ G /4, γ G /2, and γ G , from lowest resolution to highest resolution, with γ G =0.625. The corresponding values of γ A  would be γ A /8, γ A /4, γ A /2, and γ A , from lowest resolution to highest resolution, with γ A =3. A pyramid reconstruction block  1210  produces a sharpened low-resolution image  1212  from the sharpened pyramid image components  1208 . The pyramid reconstruction block  1210  performed the inverse operations of the pyramid decomposition block  1202  and is well-known to those skilled in the art. Turning to  FIG. 13 , a bicubic interpolation block  1300  produces a high-resolution image  1302  from the sharpened low-resolution image  1212  ( FIG. 12 ). The bicubic interpolation block is, again, a standard operation well-known to those skilled in the art. A super-resolution sharpening block  1304  produces a super-resolution image  1306  from the high-resolution image  1302 . The super-resolution sharpening block  1304  performs the same operations as the super-resolution sharpening block  306  ( FIG. 3 ). 
         [0083]    A computer program product can include one or more storage medium, for example; magnetic storage media such as magnetic disk (such as a floppy disk) or magnetic tape; optical storage media such as optical disk, optical tape, or machine readable bar code; solid-state electronic storage devices such as random access memory (RAM), or read-only memory (ROM); or any other physical device or media employed to store a computer program having instructions for controlling one or more computers to practice the method according to the present invention. 
         [0084]    The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. 
       PARTS LIST 
       [0000]    
       
           2  flash 
           4  lens 
           6  adjustable aperture and adjustable shutter 
           8  zoom and focus motor drives 
           10  digital camera 
           12  timing generator 
           14  image sensor 
           16  ASP and A/D Converter 
           18  buffer memory 
           20  processor 
           22  audio codec 
           24  microphone 
           26  speaker 
           28  firmware memory 
           30  image memory 
           32  image display 
           34  user controls 
           36  display memory 
           38  wired interface 
           40  computer 
           44  video interface 
           46  video display 
           48  interface/recharger 
           50  wireless modem 
           52  radio frequency band 
           58  wireless network 
           70  Internet 
           72  photo service provider 
       
     
       PARTS LIST CONT&#39;D 
       [0000]    
       
           90  white balance setting 
           95  white balance step 
           100  color sensor data 
           105  noise reduction step 
           110  ISO setting 
           115  demosaicking step 
           120  resolution mode setting 
           125  color correction step 
           130  color mode setting 
           135  tone scale correction step 
           140  contrast setting 
           145  image sharpening step 
           150  sharpening setting 
           155  image compression step 
           160  compression mode setting 
           165  file formatting step 
           170  metadata 
           175  photography mode settings 
           180  digital image file 
           185  camera settings 
           300  low-resolution image 
           302  bicubic interpolation block 
           304  high-resolution image 
           306  super-resolution sharpening block 
           308  super-resolution image 
           400  convert to YCC block 
           402  YCC image 
           404  sharpen luminance block 
       
     
       PARTS LIST CONT&#39;D 
       [0000]    
       
           406  sharpened YCC image
         408  convert to RGB block   
     
           500  compute high-pass and low-pass images block 
           502  high-pass image
         504  low-pass image   
     
           506  sharpen high-pass image block 
           508  combine high-pass and low-pass images block 
           510  sharpened high-pass image 
           600  global sharpening block 
           602  global sharpened image 
           604  adaptive sharpening block 
           700  sharpen edge pixels block 
           702  sharpened edge pixels 
           704  compute first contrast block 
           706  compute second contrast block 
           708  first contrast 
           710  second contrast 
           712  adjust sharpness gain block 
           800  compute edge parameters block 
           802  local edge parameters 
           804  scale edge pixels block 
           900  compute contrast ratio block 
           902  contrast ratio 
           904  contrast ratio test block 
           906  no sharpening change block 
           908  modify sharpness gain block 
           1100  low-resolution image 
       
     
       PARTS LIST CONT&#39;D 
       [0000]    
       
           1102  super-resolution sharpening block 
           1104  sharpened low-resolution image 
           1106  bicubic interpolation block 
           1108  high-resolution image 
           1110  super-resolution sharpening block 
           1112  super-resolution image 
           1200  low-resolution image 
           1202  pyramid decomposition block 
           1204  pyramid image components 
           1206  super-resolution sharpening block 
           1208  sharpened pyramid image components 
           1210  pyramid reconstruction block 
           1212  sharpened low-resolution image 
           1300  bicubic interpolation block 
           1302  high-resolution image 
           1304  super-resolution sharpening block 
           1306  super-resolution image

Technology Classification (CPC): 6