Patent Grant
7721204
1. Field of Invention
This invention relates to image processing as a function of the image viewing client device.
2. Description of Related Art
A user typically likes to view a document on a handheld wireless device before deciding to print, facsimile or e-mail the document. A handheld wireless device, such as, for example, a personal digital assistant (PDA), a cellular phone or a miniaturized computing device, has relatively little screen surface area for viewing documents, as well as little memory for storing the document or the applications for all the document formats a user can conceivably access and view.
Current solutions either restrict the document types that can be viewed on handheld client devices, e.g., web pages with graphics interchange format (GIEF) files, show only the ASCII text of the document, provide viewers for a small set of document types, or do not provide viewers at all. In these current solutions, the documents can exist on the handheld client device, a server, e.g., mail server, or any document file/management system in their environment. Generally, documents that do not reside on the handheld client device are typically too large to quickly and/or efficiently transmit over today's wireless networks.
A large portion of the information present in typical documents may be “best” retrieved by using the document image, i.e.: the visual representation, rather than the ASCII representation of the information. This approach is obvious for scanned data, where no ASCII representation is available unless OCR has been additionally performed. However, using the document image to retrieve information in the document may also extend to spreadsheets, where the spatial organization is important; letterheads for telephone numbers, dates, and other contact data; and PowerPoint presentation slides, where almost all information is spatially organized; and the like. Any graphic, table, picture or drawing has an important spatial organization, which can be seen from the two pages 11 and 12 of an example patent document 10 in
Generally, the document has to be represented on a small screen of the handheld client device, such as, for example, 96×40, 160×160 or 240×320 pixels. Here, the exact number of pixels is of lower importance, what is important that the physical and pixel-wise dimensions of the display are smaller than the dimensions commonly used on workstations and the like. One approach is to scale the document page image to the client device screen, and, on zooming, scale the appropriate document image regions to the screen. When displaying images on a small screen of a handheld wireless device, an obvious trade-off has to be made between image quality and transmission speed.
This invention provides methods and systems that replace the image scaling approach above with client dependent image processing that is a function of at least one or more of a client device parameter, data transmission capability, document type and/or format, and user input.
This invention provides methods and systems that create image views of documents that can be used for document identification and data retrieval on handheld client devices.
In various exemplary embodiments, this invention provides methods and systems that actively modify processing parameters of an image as a function of the image viewing client.
In various exemplary embodiments, this invention provides methods and systems that dynamically control and/or direct document image processing based on client device display capabilities, image formats supported by the client device, network bandwidth, document file format, document content, user hints and the like.
These and other features and advantages of this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments of the systems and methods according to this invention.
Various exemplary embodiments of the systems and methods of this invention will be described in detail, with reference to the following figures, wherein:
Various exemplary embodiments of systems and methods according to this invention relate to client dependent image processing for browser-based image document viewer for handheld client devices.
The server 110 processes image data of a document based on one or more of client-based parameters, transmission network capability, document type and user input requests. The server 110 then compresses the processed data, and transmits the compressed data to the client 120 by way of the network 130.
In various exemplary embodiments, the server 110 receives requests from the client 120 for processing image data and transmitting processed image data back to the client 120. In various exemplary embodiments, the server 110 processes the image data based on a selection of parameters prestored at the server 110 regarding the capabilities or requirements of the client 120 and the network 130. In various other exemplary embodiments, the server 110 processes the image data based on the selection of parameters detected from the client 120, the network 130, or a combination thereof.
In various exemplary embodiments, the server 110 processes the image data based on client device/handset display capabilities, image formats supported by the client device/handset, network bandwidth, document file format, document content, user hints and the like. In various other exemplary embodiments, the server 110 receives the selection of parameters sent from the client 120, based on various user inputs.
As part of the client-dependent image processing operations, the server 110 also compresses the processed image data before transmitting the image data to client 120. In various exemplary embodiments, the server 110 compresses the processed image data using custom color maps, as described in detail in U.S. patent application Ser. No. 10/901,333, now U.S. Pat. No. 7,539,341, entitled “System and Methods for Processing Image Data Prior to Compression”, which is incorporated herein by reference in its entirety.
The server 110 is generally associated with a computer, as described in greater detail below in connection with
In various exemplary embodiments, the client 120 is a mobile device, such as a laptop computer, a personal data assistant (PDA), a cellular phone, an electronic computing graphics tablet-like device or other handheld computing device and the like.
The network 130 transmits data, requests or other information between the server 110 and the client 120. In various exemplary embodiments, the network 130 is a wired network. In various other exemplary embodiments, the network 130 is a wireless network. In various other exemplary embodiments, the network 130 includes both wired and wireless networks. In various exemplary embodiments, the network 130 includes the Internet. A user may view processed data on a web page displayed on the client 120. In various other exemplary embodiments, the network 130 includes a wireless cellular phone network or any other existing or yet to be invented communication network. A user may view the processed data displayed on a cellular phone at the client 120.
It will be noted that the following discussion does not discuss in detail all the client-dependent image processing operations that may be performed, or that are possible, according to various exemplary embodiments of systems and methods of this invention. The image processing operations/effects that are discussed below are well known in the art and are relatively straight forward. For example, if the client only supports GIF image formats, only those files will be created. Other image processing operations/effects, such as, for example, crop windows, image orientation, and the like, may also be practiced according to various exemplary embodiments of the systems and methods of this invention.
As shown in
Next, in step S130, the server processes the document data. The document data may be processed based on one or more of client device/handset display capabilities, image formats supported by the client device/handset, network bandwidth, document file format, document content, user hints and the like.
Following the processing of the document data, at step S140, the client-dependent processed data is transmitted to the client device for display on the client device. Then, operation of the method continues to step S150 where the operation stops. It should be noted that all standard methods of anticipating user requests can be performed on the server, based on configuration, load, etc., thereby reducing the latency for subsequent requests without altering the spirit of the invention.
As shown in
Next, at step S1320, the ‘RIPed’ data is subsequently scaled to the desired zoom settings. For example, in various exemplary embodiments, the data may be scaled to one of the current prototype mDoc version 4 zoom settings, e.g., 2, 4, 8 and 16 reduction, using a density preserving reduction (filter & down sampling) leading to 5 raw images at the 5 different resolutions. The raw images may not yet adhere to the client color and bit-depth requirements.
Following data scaling, operation of the method continues to step S1330 where client-dependent image filtering is performed. At high reduction levels, the page content can only be “guessed” by the user. Twelve point text, for example, would be rendered at single pixel height for most letters. In various exemplary embodiments of the methods and systems according to this invention, the image sharpness is strongly increased for higher reduction factors, well above any limit that would be used for normal image viewing. However, increasing the sharpness at high reduction factors gives the user the perception of “text” without making the text readable. For the exemplary prototype mDoc application, speed is an important consideration as it directly influences user latency. As a speed/quality compromise, in one exemplary embodiment, a 5 element filter was chosen where four ring values are constant (“−1”) and the center value is varied. Smaller center values yield stronger enhancement. Other techniques known in the art or later developed may also be used to perform client dependent filtering operations.
After image sharpening, at step S1340, enhancement TRCs are used to further increase the contrast of the data. The TRCs are a function of reduction factors (stronger enhancement for higher reductions) and of document applications. In this case, presentation slides and scanned data undergoes an essential symmetric contrast enhancement. Text documents and spreadsheets undergo a non-symmetric enhancement leading to a strong visual darkening. This is based on the likelihood that different color and foreground/background schemes are used in the different document types.
At step S1350, a data compression operation is performed. As part of the data compression operation, data compression parameters may be varied based on transmission bandwidth and client storage capabilities, as well as other factors. In the binary case, no variation can be obtained at this step directly, but rather a different enhancement can be performed. For color clients, a choice exists between JPEG and GIF compressions, since both are normally supported in the browser. In JPEG compression, the Q-table/Q-Factor can be used to change compression ratios. For the “GIF compression” (better in the GIF format encapsulated compression method), the compression efficiency may be modified by the initial color mapping. For the discussion presented below, a dynamic color mapping between “222” (8 colors) and “794” (252 colors) is assumed, as described in detail in U.S. patent application Ser. No. 10/901,333, entitled “Systems and Methods For Processing Image Data Prior To Compression”, which is incorporated herein by reference in its entirety.
Following data compression, the method continues to step S1360 where a client dependent data formatting operation is performed. Following formatting of the data, the client dependent processed document/image is transmitted to the client device, step S140.
Table 1 is an exemplary embodiment of an image processing table showing the different image processing aspects as a function of reduction (zoom setting) and application. In Table 1, TRC name 64 L indicates a TRC that is non-symmetric (“L”eft) and that maps all pixel values below 64 to “black”. A TRC name 32 indicates a symmetric TRC that maps all values below 32 to black and all values above 223 to white. The rest of the range is a linear mapping between black and white. The term “reduce” refers to a filtered subsampling, preferably maintaining image density attributes.
As can be observed from Table 1, different image processing settings are used for different document types and zoom levels. The exemplary values given in Table 1 are currently used in an exemplary mDoc viewer demo produced by the inventors. For binary clients, such as for example, WAP phoned, processing stops at the level of Table 1, with only the file format conversion to WBMP being done after the image processing. For color capable clients, some additional steps, which are well known in the art, may be added.
The reference image shown on the right of
The client dependent image processing controls discussed above show a clear image quality improvement compared to standard, fixed processing. The processing overhead on a standard personal computer is small compared to the standard transmission times over the wireless network, and generally can be ignored. One possible exception to this may be the speed of the sharpness filter, leading to its omission for the largest images (full zoom).
As shown in
In various exemplary embodiments, the data processing system 800 is implemented on a programmable general purpose computer. However, the data processing system 800 can also be implemented on a special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit elements, an ASIC or other integrated circuits, a digital signal processor (DSP), a hard wired electronic or logic circuit, such as a discrete element circuit, a programmable logic device such as a PLD, PLA, FPGA or PAL, or the like. In general, any device capable of implementing a finite state machine that is in turn capable of implementing the flowchart shown in
The input/output interface 820 interacts with the outside of the data processing system 800. In various exemplary embodiments, the input/output interface 820 may receive input from the outside, such as a network, via one or more links 810. The input/output interface 820 may output data for subsequent delivery or transmission via the one or more links 810 to a client device (shown in
The one or more links 810 may be direct connections, or may be implemented using a connection device such as a modem, a local area network, a wide area network, an intranet, the Internet, and any other distributed processing network, or any other known or later-developed connection device.
As shown in
The memory 840 may also store any data and/or program necessary for implementing the functions of the data processing system 800. The memory 840 can be implemented using any appropriate combination of alterable, volatile, or non-volatile memory or non-alterable or fixed memory. The alterable memory, whether volatile or non-volatile, can be implemented using any one or more of static or dynamic RAM, a floppy disk and a disk drive, a writable or rewritable optical disk and disk drive, a hard drive, flash memory or the like. Similarly, the non-alterable or fixed memory can be implemented using any one or more of ROM, PROM, EPROM, EEPROM, an optical ROM disk, such as a CD-ROM or a DVD-ROM disk and disk drive or the like.
In the exemplary embodiments of the data processing system 800 shown in
The raster image processing circuit, routine or application 850, under the control of controller 830, converts a document requested by the client to a raster image on the server using well known raster image processing (RIP) techniques.
The document data scaling circuit, routine or application 860, under the control of controller 830, scales the ‘RIPed’ data to the desired zoom settings. For example, in various exemplary embodiments, the data may be scaled to one of the current prototype mDoc version 4 zoom settings, e.g., 2, 4, 8 and 16 reduction, using a density preserving reduction (filter & down sampling) leading to 5 raw images at the 5 different resolutions.
The client dependent image filtering circuit, routine or application 870, under the control of controller 830, performs client-dependent image filtering of the scaled data. In various exemplary embodiments of the methods and systems according to this invention, the image sharpness is strongly increased for higher reduction factors, well above any limit that would be used for normal image viewing.
The client-dependent image enhancement circuit, routine or application 880, under the control of controller 830, uses enhancement TRCs to further increase the contrast of the data.
Following image enhancement, the data compression circuit, routine or application 890, under the control of the controller 830, compresses the processed data. In various exemplary embodiments, the data compression circuit, routine or application 890 compresses the processed image data using tonal reproduction curves (TRC) to suppress backgrounds and to further enhance the perception of detail and optionally and/or custom color maps, as described in detail in U.S. patent application Ser. No. 10/901,333, now U.S. Pat. No. 7,539,341 entitled “System and Methods For Processing Image Data Prior to Compression”, which is incorporated herein by reference in its entirety.
The client dependent data formatting circuit, routine or application 895, under the control of controller 830, finally formats the data prior to transmitting the data over the network to the client device. In various exemplary embodiments, the client dependent data formatting circuit, routine or application 895 formats the data based on one or more client dependent image processing table(s) 842. As discussed above, tables 842 store different image processing settings that are used for different document types, zoom levels, and the like.
While particular embodiments have been described, alternatives, modifications, variations and improvements may be implemented within the spirit and scope of the invention.
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