Method and apparatus for optimizing and storing contone images for subsequent half-toning and merging with text

Claims

What is claimed is:

1. An image processing system comprising:

digitizing means for digitizing a photographic image to provide digital signals representing the densities corresponding to different locations of said photographic image;

processing means for computing the mean and the standard deviation of the distribution of densities represented by said digital signals;

means for developing a table in response to said mean and standard deviation and user-specified values, said table establishing a correspondence between densities represented by said digital signals and shifted densities, said shifted densities being optimized for a particular half-tone printing process;

means for mapping said densities represented by said digital signals into said optimized shifted densities;

means for displaying an image represented by said shifted-density digital signals;

mass storage means, coupled to said mapping means, for storing said optimized shifted densities representing the enhanced contone image and for subsequently retrieving said optimized shifted densities for half-tone rendering; and

means operatively coupled to said mass storage means for converting said retrieved optimized shifted densities to a half-tone representation and for rendering a half-tone image from said half-tone representation using said particular half-tone printing process.

2. A processing system as in claim 1 wherein said digitizing means includes:

means for electronically defining a rectangular crop area having first and second dimensions, said crop area delimiting an area of said image; and

means connected to said defining means for adjusting the size of said rectangular area and for constraining the image sample rate in the first dimension within the delimited image crop area to be equal to the image sample rate in the second dimension within said delimited image crop area.

3. An image processing system as in claim 1 wherein:

said system further includes:

means for specifying the following information: (a) image dimensions, (b) samples per inch, (c) mesh, and (d) gray level, and

said mass storage means includes means for storing said mapped densities with said specified information; and

said converting and rendering means comprises an electronic typesetter including:

means for reading said stored information from said mass storage means, and

means for directly converting said mapped densities to said half-tone representation in response to said read specified information

4. A system for printing images comprising:

video source means for producing video signals representing an image;

digitizing means for converting said video signals into digital signals encoding a contone representation of said image, said digital signals representing the densities of different locations of said image;

means for statistically analyzing the image density distribution represented by said digital signals;

means for shifting the densities represented by said digital signals in response to said statistical distribution and at least one density value optimized for a particular half-tone printing process;

mass storage means coupled to said shifting means for storing said shifted density digital signals in an image database and for subsequently retrieving said shifted density digital signals from said image database so as to permit half-tone rendering of the image represented by said shifted densities;

means operatively coupled to said mass storage means for converting said shifted density digital signals into a half-tone representation of said image; and

means for printing dots of ink onto a print medium in response to said half-tone representation,

wherein the size of said ink dots is optimized for said particular half-tone printing process in accordance with the results of said statistical analysis and is directly related to said optimized density value.

5. A method of printing text and images comprising:

(I) front end processing including the following steps (a)-(d):

(a) providing an image;

(b) providing text corresponding to said image;

(c) converting said image to a digital graphic, including the steps of:

(i) electronically defining a crop area corresponding to an area of said image,

(ii) converting the portion of said image within said crop area to digital signals representing the density distribution of said image portion, and

(iii) statistically analyzing said digital signals and shifting the density distribution represented by said digital signals in response to said statistical analysis, including the step of optimizing said shifting for a particular half-tone printing process; and

(d) storing said shifted density digital signals in an image database for later retrieval; and

(II) subsequent rendering processing including the following steps (e)-(g):

(e) retrieving said stored shifted density digital signals from said image database;

(f) electronically merging said text with said stored shifted density digital signals; and

(g) printing said merged text and graphic represented by said stored shifted density digital signals using said particular half-tone printing process.

6. A method as in claim 5 wherein said analyzing and shifting step comprises:

determining the mean density represented by said digital signals,

shifting said mean density to a user-specified midtone value empirically optimized for said particular half-tone printing process; and

shifting the other densities represented by said signals in accordance with said midtone value.

7. A method as in claim 6 wherein said analyzing and shifting step further comprises:

(x) determining the standard deviation of the distribution of densities represented by said digital signals;

(y) shifting the densities between said mean density and a preset maximum density in accordance with a normal statistical distribution; and

(z) shifting the densities between said mean density and a preset minimum density in accordance with said normal statistical distribution.

8. A method as in claim 4 wherein said merging step (f) includes introducing said digital graphic without substantial further processing and without scaling into a combined data stream comprising digital signals representing said text and further digital signals representing graphics.

9. A method as in claim 8 wherein:

said converting step includes specifying a screen mesh value, image height value, image width value, and image sampling rate value; and

said introducing step includes introducing said values specified by said specifying step.

10. A method as in claim 9 wherein said specifying step includes specifying a common image sampling rate value for both first and second dimensions of a two-dimensional image.

11. A method of printing text and images comprising:

front end processing including the following steps (a)-(d):

(a) providing an image;

(b) providing text corresponding to said image;

(c) converting said image to a digital graphic, including the steps of:

(i) electronically defining a crop area corresponding to an area of said image,

(ii) converting the portion of said image within said crop area to digital signals representing the density distribution of said image portion, and

(iii) statistically analyzing said digital signals and shifting the density distribution represented by said digital signals in response to said statistical analysis, including the step of optimizing said shifting for a particular half-tone printing process; and

(d) storing said shifted density digital signals in an image database for later retrieval; and

(II) subsequent rendering processing including the following steps (e)-(g):

(e) retrieving said stored shifted density digital signals from said image database;

(f) electronically merging said text with said stored shifted density digital signals; and

(g) printing said merged text and graphic represented by said stored shifted density digital signals using said particular half-tone printing process,

wherein said analyzing and shifting step comprises:

determining the mean density represented by said digital signals,

shifting said mean density to a user-specified midtone value empirically optimized for said particular half-tone printing process,

shifting the other densities represented by said signals in accordance with said midtone value,

(x) determining the standard deviation of the distribution of densities represented by said digital signals,

(y) shifting the densities between said mean density and a preset maximum density in accordance with a normal statistical distribution, and

(z) shifting the densities between said mean density and a preset minimum density in accordance with said normal statistical distribution,

wherein:

said shifting step (y) includes mapping all densities greater than a 95th percentile density value determined in accordance with said standard deviation into the same maximum density value; and

said shifting step (z) includes mapping all densities less than a 5th percentile density value determined in accordance with said standard deviation into the same minimum density value.

12. A system for printing text and images comprising:

means for providing an image;

means for providing text corresponding to said image;

means for converting said image to a digital graphic, including:

means for electronically defining a crop area corresponding to an area of said image,

meams for converting the portion of said image within said crop area to digital signals representing the density distribution of said image portion, and

means for statistically analyzing said digital signals and shifting the density distribution represented by said digital signals in response to said statistical analysis, said shifting means including means for optimizing said shifted density distribution for a particular half-tone printing process;

storing means coupled to said analyzing means for storing said shifted density digital signals in an image database and for subsequently retrieving said stored digital signals from said image database;

means connected to said storing means for electronically merging said text with said digital graphic represented by said retrieved shifted density digital signals; and

means connected to said merging means for printing said merged text and graphic using said particular half-tone printing process.

13. A system as in claim 12 wherein said analyzing and shifting means comprises:

means for determining the mean density represented by said digital signals,

means for setting said mean density to a user-specified midtone value optimized for said particular half-tone printing process; and

means for shifting the other densities represented by said signals in accordance with said midtone value.

14. a system as in claim 13 wherein said analyzing and shifting means further comprises:

means for determining the standard deviation of the distribution of densities represented by said digital signals;

first shifting means for shifting the densities between said mean density and a certain maximum density in accordance with a normal statistical distribution; and

second shifting means for shifting the densities between said means density and a certain minimum density in accordance with said normal statistical distribution.

15. A system as in claim 11 wherein said merging means includes means for introducing said digital graphic without substantial further processing and without scaling into a combined data stream comprising digital signals representing said text and further digital signals representing graphics.

16. A system as in claim 15 wherein:

said converting means includes means for specifying a screen mesh value, image height value, image width value, and image sampling rate value; and

said introducing means includes means for introducing said values specified by said specifying means.

17. A system as in claim 16 wherein said specifying means includes means for specifying a common image sampling rate value for both first and second dimensions of a two-dimensional image.

18. A system for printing text and images comprising:

means for providing an image;

means for providing text corresponding to said image;

means for converting said image to a digital graphic, including:

means for electronically defining a crop area corresponding to an area of said image,

means for converting the portion of said image within said crop area to digital signals representing the density distribution of said image portion, and

means for statistically analyzing said digital signals and shifting the density distribution represented by said digital signals in response to said statistical analysis, said shifting means including means for optimizing said shifted density distribution for a particular half-tone printing process;

storing means coupled to said analyzing means for storing said shifted density digital signals in an image database and for subsequently retrieving said stored digital signals from said image database;

means connected to said storing means for electronically merging said text with said digital graphic represented by said retrieved shifted density digital signals; and

means connected to said merging means for printing said merged text and graphic using said particular half-tone printing process,

wherein said analyzing and shifting means comprises:

means for determining the mean density represented by said digital signals,

means for setting said mean density to a user-specified midtone value optimized for said particular half-tone printing process,

means for shifting the other densities represented by said signals in accordance with said midtone value,

means for determining the standard deviation of the distribution of densities represented by said digital signals,

first shifting means for shifting the densities between said mean density and a certain maximum density in accordance with a normal statistical distribution; and

second shifting means for shifting the densities between said mean density and a certain minimum density in accordance with said normal statistical distribution,

wherein:

said first shifting means includes means for mapping all densities greater than a 95th percentile density valve determined in accordance with said standard deviation into the same maximum density valve; and

said second shifting means includes means for mapping all densities less than a 5th percentile density value determined in accordance with said standard deviation into the same minimum density value.

19. A process for producing a printed article comprising the following steps:

(a) digitizing an image to thereby provide a contone data set representing said image;

(b) enhancing said contone data set to provide an enhanced contone data set;

(c) storing said enhanced contone data set within an image database, including the step of associating said stored data set with a unique designator;

(d) repeating said steps (a)-(c) to provide said image database of stored enhanced contone data sets having designators associated therewith;

(e) providing a plurality of blocks of textual information and associated designators;

(f) retrieving and merging said stored enhanced contone data sets with said blocks of textual information, including the step of matching designators corresponding to said blocks of textual information with designators associated with said stored data sets;

(g) converting said merged textual information blocks and data sets into half-tone representations; and

(h) rendering said half-tone representations on printing media,

wherein at least one of said converting step (g) and said rendering step (h) includes the step of affecting print quality in response to a print quality factor, and said enhancing step (b) includes the step of optimizing said enhanced contone data set beforehand in response to said print quality factor, and

wherein said affecting step includes the step of increasing the size of half-tone dots beyond nominal half-tone dot sizes, and said optimizing step includes the step of shifting pixel levels within said enhanced contone data set so as to compensate for said half-tone dot size increase.

20. A process as in claim 19 wherein:

said designators comprise real estate multiple listing numbers; and

said process includes the preliminary step of photographing images of real estate properties.

21. A process for preparing multiple listing service books including the following steps:

photographing an image of a real estate property offered for sale;

inputting textual information relating to said real estate property into a multiple listing service data processing system;

assigning a multiple listing number to said real estate property;

digitizing said photographed image to thereby provide a contone data set representing said image;

enhancing said contone data set to provide an enhanced contone data set;

inputting said assigned multiple listing number;

storing said enhanced contone data set in association with said inputted multiple listing number;

obtaining said inputted textual information and associated multiple listing number from said multiple listing service data processing system;

retrieving said stored enhanced contone data set in response to said multiple listing number;

merging said stored enhanced contone data set with said obtained textual information and converting said merged data set and textual information into half-tone representations; and

rendering said half-tone representations on printing media, wherein at least one of said converting step and said rendering step includes the step of affecting print quality in response to a print quality factor, and said enhancing step includes the step of optimizing said enhanced contone data set beforehand in response to said print quality factor by shifting pixel levels within said enhanced contone data set so as to compensate for half-tone dot size increase.

22. A method of printing real estate advertising listings for multiple real estate properties, said printed listings including images of real estate properties and text associated with said real estate properties, said method including the following steps:

(a) capturing, in a digital data form, an image of a real estate property;

(b) optimizing said digital data for a particular printing process to provide optimized digital data such that the image can be printed at high quality in response to said optimized digital data using said particular printing process without the necessity for significant further print image quality related post-processing, said optimizing step including the following steps:

deriving and statistically analyzing a density distribution for at least a portion of said image in response to said captured digital data, and

shifting the density of the captured digital data in response to said statistical analysis so as to provide digital data optimized for said particular printing process;

(c) storing said optimized digital data in an electronic library of real estate property image data so optimized;

(d) providing text in electronic form; (e) retrieving optimized image data from said library in response to said provided text, and electronically merging said retrieved image data with said text; and

(f) printing said advertising listings in response to said merged text and image data using said particular printing process.

23. A method as in claim 22 wherein:

said storing step includes the step of assigning an identification to each of said images;

said providing step (d) includes the step of specifying image identifications associated with provided text; and

said retrieving step selects and retrieves image data in response to said image identifications associated with said text.

24. A method as in claim 22 wherein said steps (d)-(f) are subsequently repeated with different provided text, and said merging step selects only a subset of the image data in said image library.

25. A method as in claim 22 wherein said optimizing step includes the step of displaying said image, and adjusting said digital data in a manner which degrades the displayed image but optimized the digital data for rendering using said particular printing process.

26. A method as in claim 22 wherein said digital data comprises continuous tone data, and said particular printing process renders said image using half-tone rendering.

27. A method as in claim 22 wherein said image data in said electronic library is optimized for said particular printing process on an image-by-image basis.

28. A method as in claim 22 wherein said printing step includes generating print masters of said text and images using a conventional electronic typesetter by applying a conversion process common to image data corresponding to each of several images.

CROSS REFERENCE TO RELATED APPLICATION

This application is related to copending commonly assigned application serial number 757,959 filed Sep. 17, 1991 in the name of Bijnagte entitled "APPARATUS AND METHOD FOR COMMUNICATING TEXTUAL AND IMAGE INFORMATION BETWEEN A HOST COMPUTER AND A REMOTE DISPLAY TERMINAL."

FIELD OF THE INVENTION

This invention generally relates to digitization of images. The invention more particularly relates to digitizing photographic images, merging the resulting digital image information with text information, and printing the merged image and text information. Still more particularly, the present invention relates to preparing and printing "multiple listing service" real estate listing booklets and similar printed matter (e.g., advertisements, magazine copy, etc.) using data processing techniques to generate and integrate digitized images with digital text information.

The process of producing real estate "multiple listing service" ("MLS") "books" has always been a labor-intensive and expensive process. Such books contain listings of all real estate properties listed for sale in a given geographical area by member real estate brokers, and are used by real estate agents to locate properties that fit the needs of their clients. Such books reflect the properties currently on the market, and must therefore be printed relatively often (e.g., once a week in many areas).

A large percentage of the listings in one such book are generally identical to the listings in the previous version of that book (since properties are typically listed for sale in the book until they are sold). In addition, new listings may have to be inserted between older listings--requiring the entire book to be reorganized and repaginated for each printing. For these and other reasons, automated typesetter/word processing workstations have been used for many years to compose, format (and reorganize and edit) the text appearing on the pages of real estate listing books.

While textual information in real estate listing books provides a lot of information to a prospective buyer about a particular property, real estate agents have long known that the efficiency of their sales efforts increases dramatically if they can show the buyer photographs of the properties in addition to the text. Buyers often have strong preferences for certain architectural styles and property outward appearances. Allowing a buyer to pre-screen properties by viewing photographs printed in the listing book (or using the computerized PHOTOTRIEVE system available from Moore Data Management Services Division) saves the buyer and the real estate agent countless hours of travelling to and inspecting properties that could be eliminated from consideration by simply viewing photographs of the property.

In the prior art, photographs are added to listing book copy by printing the composed textual information (in which space is reserved for photographs) and using conventional paste-up techniques to physically adhere actual photographs of the properties to the copy. The copy with photographs added is then processed using conventional photo lithography and printing techniques. Needless to say, this overall process is extremely tedious and labor-intensive, and has other disadvantages as well.

For example, the organization, order and pagination of the written copy typically changes each time a new version of the listing book is composed (because new listings are typically inserted between older listings and some listings are typically deleted). Consequently, the hard copy of the previous book must be discarded. It is, however, cost prohibitive (and an organizational nightmare) to photographically print new photographs for all of the listings in the new version. Copy artists must therefore remove photographs from the old copy and paste them onto the new copy at the proper positions. Mistakes can easily be made mismatching photographs and listings during the paste-up process (even though each photo is usually labelled on the back with a listing number and/or other designation)--causing the book to be printed with text information describing one property and a photo of an entirely different property. The photographs are sometimes also torn or damaged during removal and subsequent paste-up--requiring the darkroom to reprint photos on a rush basis (assuming the proper negatives can be located).

Another very significant problem with the paste-up techniques used in the prior art relates to the image quality and consistency in the printed product. Photographs of different properties are generally shot by different people (with disparate levels of experience as photographers) using different equipment and film. Consequently, the photographs of the various properties often have too much or too little contrast, may be under-exposed or overexposed, and may be poorly composed and framed. Since washed out or contrasty photos (and poorly framed photos) of properties in the listing book may cause agents and prospective buyers to overlook properties they might otherwise be interested in, it is important for all photographs to be of acceptable quality. Moreover, image quality consistency is an extremely desirable goal, since it improves the overall appearance and "readability" of the listing book. In the past, desired quality and consistency of the images printed in the listing book was obtained only through use of expensive and time-consuming photograph processing services involving custom cropping and printing techniques.

The present invention solves many or all of these problems by converting photographed (or videotaped) images to digital graphics at the "front end" of the publishing process. This image conversion ("capture") process includes cropping, contrast adjustment using statistical techniques, and generation of control information needed later in the process. A library of digital graphics and associated information is maintained. Graphics selected from this library and a conventional "multiple listing service" text database are then merged during a text composition process to provide a stream of digital data including all of the information (text as well as embedded graphics) to be printed in the listing book. Because all image operations (e.g., sizing, cropping, and even digital image quality enhancement) are performed when the images are captured, no time consuming post processing steps are required. That is, image capture is performed in a single step, and once an image is captured it can be used "as is" without further review, modification or post processing.

These and other features and advantages of the invention will be better understood by studying the following detailed description of presently preferred exemplary embodiments in conjunction with the appended sheets of drawings of which:

FIG. 1 is a schematic block diagram of an exemplary graphics capture system in accordance with the present invention;

FIG. 2 is a overall flow chart of steps performed in accordance with the presently preferred exemplary embodiment of the present invention;

FIG. 3 is a flow chart of the "build MLS listing database" block shown in FIG. 2;

FIG. 4 is a flow chart of the "obtain new graphics" block shown in FIG. 2;

FIG. 5 is a flow chart of the "build graphics database" block shown in FIG. 2;

FIG. 6 is a more detailed chart of exemplary program control steps performing the "capture image" block shown in FIG. 4;

FIGS. 7A and 7B are schematic diagrams of data structures used by the system shown in FIG. 1;

FIG. 8 is a detailed flow chart of the "adjust crop window" shown in FIG. 6;

FIGS. 9A and 9B schematically illustrate the mapping of input pixels to output dots in accordance with the crop window established by the steps shown in FIG. 8;

FIG. 10 is a flow chart of the "process image" block shown in FIG. 6;

FIG. 11 is a flow chart of the "adjust line configuration" block shown in FIG. 6; and

FIG. 12 is a flow chart of the "save image" block shown in FIG. 6.

EXEMPLARY GRAPHICS CAPTURE SYSTEM

FIG. 1 is a schematic block diagram of a presently preferred exemplary graphics capture system 50 in accordance with the present invention. System 50 includes a microcomputer 52 and associated keyboard 54, a mass storage device 56, a graphics monitor 58, a source of video 60 (and optional associated live video monitor 62), and a text monitor 64.

Video source 60 provides video signals representing images to be captured. In the preferred embodiment, video source 60 actually comprises two alternate sources selectable under software control: a video tape recorder capable of playing back videotaped footage of real estate properties; and a video camera mounted on a copy stand for producing video of photographic prints placed on the copy stand. Optional live video monitor 62 is not really necessary, but may be helpful for locating/editing video taped footage.

The output of video source 60 is applied to the input of an AT&T Targa 8 video digitizer board internal to microcomputer 52 (which in the preferred embodiment is a Zenith 241 PC/AT personal computer with color graphics). CRT monitor 58 in the preferred embodiment is a Sony KV-1311 monitor which is connected to the monitor/display output of the internal video digitizer. Additional text monitor 64 is connected to the main monitor output of microcomputer 52--thus permitting simultaneous display of information stored in the display buffer of microcomputer 52 (on monitor 64) and graphics information stored in the on-board frame buffer of the internal video digitizer (on monitor 58). Video provided by video source 60 is processed by the AT&T video digitizer internal to microcomputer 52, and the processed video is displayed on monitor 58. In the preferred embodiment, the video digitizer permits two modes of display: "live video" (i.e., the "live" output of video source 60) can be displayed on monitor 58; or alternatively, digitized video stored in the digitizer frame buffer can be displayed on the monitor.

Digitized image and other information may be written from the frame buffer of the internal digitizer onto magnetic tape loaded on mass storage device 56. Mass storage device 56 in the preferred embodiment is a STORAGETEK tape drive connected to microcomputer 52 via an Innovative Data Technology ("IDT") tape controller.

Microcomputer 52 includes an internal hard disk drive which stores various software used to capture, process and store digitized images. Various conventional software packages are used for utility operations in the preferred embodiment (e.g., Blaise C Tools for text screen displays, Blaise C Tools II for clock and interrupt routines, AT&T libraries for Targa 8 video digitizer graphics routines, and Innovated Data Technology routines for control of mass storage device 56). These various utility routines are called and controlled by a custom-designed menu driven software interface which performs substantial image processing functions in addition to providing sophisticated control of the various parts of system 50. The user interfaces with and controls the system 50 and associated program control software via text monitor 64 and keyboard 54.

The software interface provides, for example, a "main menu" which provides user control for various digitizing and other functions, including:

the storage of images (begin tape, capture photos, and end tape);

input parameters (e.g., negative/positive image rendering, and camera/VCR selection);

output image parameters (e.g., height, width, screen mesh, number of gray levels);

image processing parameters (e.g., maximum black value, minimum white value, ideal mid-gray value, threshold for black to white transition for line art);

image identification parameters (e.g., format of picture identification, repetitive portion of ID, database ID); and

storage of parameters (e.g., database name, permanent storage).

OVERALL DEVELOPMENT AND PRINTING OF GRAPHICS & TEXT

FIG. 2 is an overall schematic flowchart of the steps performed by the preferred embodiment in accordance with the present invention for building a real estate MLS listing textual database, building a corresponding graphics database, and electronically merging the two databases to provide copy for typesetting and printing of an MLS listing "book."

New textual MLS listings of real estate properties which are to be listed for sale are obtained in the form of a "transaction list" from a main-frame computer which maintains a current MLS database (block 72). This MLS database is maintained by real estate brokers and agents (who add, change and delete listings "on-line") and thus is always up-to-date. A current MLS listing database is built in the preferred embodiment from the transaction list and from an archive ("shadow") of the last MLS listing database (block 74). Meanwhile, images are obtained from the listing agent for each newly listed property (block 76)--either in the form of video tape footage of