US3626161A

US3626161A - Method of producing a character or pattern original for use in quantizing a character or pattern and obtaining digital data therefrom by photoelectrical scanning

Info

Publication number: US3626161A
Application number: US774767A
Authority: US
Inventors: Roman Koll
Original assignee: HELL RUDOLF DR ING KG
Current assignee: Dr-Ing Rudolf Hell Kg; HELL RUDOLF DR ING KG
Priority date: 1967-11-29
Filing date: 1968-11-12
Publication date: 1971-12-07
Anticipated expiration: 1988-12-07
Also published as: GB1250213A; FR1599061A

Abstract

Method of producing a character or pattern original for use in the quantization and production of digital data corresponding thereto, by photoelectrical scanning, in which the initial pattern or character representation is initially adapted to a registered lined grid by so disposing a transparent sheet carrying the pattern or character representation with respect to the grid that as many as possible vertical and horizontal straightedge lines of the character or pattern coincide with the corresponding raster lines, and as many as possible curvilinear edge lines thereof touch raster lines, and eliminating deviations still existing between edge and raster lines by removing the part of the character extending beyond the raster line or filling in the raster field in which it extends, making such selection on the basis of which would result in the smallest possible change in shape of the character or pattern.

Description

United States Patent METHOD OF PRODUCING A CHARACTER 0R PATTERN ORIGINAL FOR USE IN QUANTIZING A CHARACTER OR PATTERN AND OBTAINING DIGITAL DATA THEREFROM BY PHOTOELECTRICAL SCANNING 6 Claims, 1 Drawing Fig.

U.S. Cl 235/6l.l2 N, 340/1463 A Int. Cl G06k 19/00 Field of Search 235/61.12,

Primary Examiner-Maynard R. Wilbur Assistant ExaminerThomas .I. Sloyan Attorney-Hill, Sherman, Meroni, Gross & Simpson ABSTRACT: Method of producing a character or pattern original for use in the quantization and production of digital data corresponding thereto, by photoelectrical scanning, in which the initial pattern or character representation is initially adapted to a registered lined grid by so disposing a transparent sheet carrying the pattern or character representation with respect to the grid that as many as possible vertical and horizontal straightedge lines of the character or pattern coincide with the corresponding raster lines, and as many as possible curvilinear edge lines thereof touch raster lines, and eliminating deviations still existing between edge and raster lines by removing the part of the character extending beyond the raster line or filling in the raster field in which it extends, making such selection on the basis of which would result in the smallest possible change in shape of the character or pattern.

PATENTEUUEB nan "3626161 INVENTOR 190mg? 0// ATTYS.

METHOD OF PRODUCING A CHARACTER OR PATTERN ORIGINAL FOR USE IN QUANTIZING A CHARACTER OR PATTERN AND OBTAINING DIGITAL DATA TI-IEREF ROM BY PHOTOELECTRICAL SCANNING BACKGROUND OF THE INVENTION The invention is directed to a method for producing a character or pattern original which is to be photoelectrically scanned for the purpose of quantizing the character or pattern represented thereby and obtaining digital data therefrom.

A quantization and digitalization of a character or pattern is necessary, in particular, for the purpose of controlling highspeed phototype setters which utilize raster techniques. In the operation of high-speed phototype setters of this type each character to be set is formed on the screen of a cathode ray tube by suitable control of the electron beam thereof, as a plurality of closely adjacent vertical picture lines and the luminous image thus produced is simultaneously projected on a photosensitive layer. The control information necessary for this purpose is stored as digital data, for example, in a ring core matrix and is recalled according to a prescribed setting program from which it is ultimately reconverted into analog values.

In order to obtain such digital data, for feeding into such a storage device, representing the character pattern, it is already known to photoelectrically scan a graphic original provided with a raster line grid on which such character or pattern is copied in considerably enlarged form, counting each of the occupied and empty raster fields or areas per se, i.e., the dark and light raster fields, as ascertained, during successive scanning travel thereover, and to record the actual result of such counting in digital form. In the past the character or pattern original was produced in the obvious manner, i.e., drawing the character or pattern by hand, employing ink or other suitable material, in the raster line grid of the original sheet. This method, however, not only is tedious and laborious, but more important it is extraordinarily time consuming, particularly where it is desired to produce complete alphabets of a plurality of different types of script, each containing about one hundred characters.

SUMMARY OF THE INVENTION The invention is directed to a method whereby the production of such originals may be effected considerably more simply and quickly. This is accomplished by applying the initial character or pattern representation, form which the final original is to be derived, to a separate transparent or translucent film, and securing the film, with the surface carrying the applied character or pattern uppermost, in such a position on the original carrier that as many as possible of the vertical and horizontal straightedge lines of the character or pattern representation coincide with corresponding raster lines and as many as possible of its curvilinear edge lines touch raster lines, and thereafter eliminating deviations still existing between edge lines and raster lines by filling in the spaces or removing the part of the character or pattern representation projecting beyond the raster line, making such selection on the basis of which would result in the smallest possible change in shape of the character or pattern. The final original thus results in effect, from conforming edge portions of the character or pattern representation to the raster grid in such a manner that the vertical and horizontal straightedge lines thereof coincide with corresponding raster lines and that any curvilinear edge lines are so disposed that a raster line is tangent thereto.

Preferably the transparent or translucent film with the applied material forming the character or pattern representation may take the form of a photographic diapositive (transparency).

If an example of the character or pattern is available, for example, in the form of printers type, the photographic diapositive may be produced by photomechanically enlarging a print thereof.

In the practice of the invention the production of the original may be further simplified by severing the film at suitable locations on the character or pattern and each individual piece adapted per se to the corresponding raster lines, mutually displacing the pieces by an amount necessary for the adaptation, and if this is accomplished by separation of the pieces, subsequently filling in any space left as a result thereof. In the event the character or pattern representation contains edge lines converging at acute angles, far too great a filling or rounding of the acute angle may occur in the reproduced character or pattern due to the efiective operational diameter of the scanning beam. Advantageously, this may be avoided by so widening the acute angle formed by the edge lines that the divergence includes the surface area of at least a whole raster field.

BRIEF DESCRIPTION OF THE DRAWING In the drawing there is illustrated by way of example, a character original for a single letter of the alphabet, namely a lower case d, produced according to the method of the invention.

DETAILED DESCRIPTION Referring to the drawing, the character d" is carried on the upper face of a transparent sheet or film 2, which is secured to the original sheet 1, provided with a raster line grid, with the character being so disposed on the original sheet that each vertical and horizontal edge line coincides exactly with a corresponding vertical or horizontal raster line.

Curvilinear edge lines are so disposed that respective vertical or horizontal raster lines form in each case the tangent to a curvilinear edge line.

Following initial application of the film 2 on the original sheet 1, the film is shifted with respect to the original sheet to dispose one of the vertical and one of the horizontal edge lines in coincidence with corresponding raster lines. Following securement of the film to the original sheet, and upon ascertaining that the other straight edge lines fall between two raster lines, such edge lines are adapted to the raster line lying closest thereto, namely by scraping away the layer of material forming the character or by filling the surface between edge line and raster line, as may be necessary or desirable.

Preliminary adaptation may also be achieved by cutting the film into individual pieces, as indicated by the dashed and dotted lines 3 and 4, and suitable mutually displacing the respective pieces whereby the desired edge alignment may be accomplished. In this operation, the respective pieces may be moved either to overlap one another or separated from one another and obviously in the latter case the resulting gap must be subsequently filled.

Where the character or pattern representation contains edge lines which converge at acute angles, as present in the illustrated example and indicated at 5 and 6, the acute angle formed thereby may be broadened to the corresponding dimension of a raster field, as a raster field having more than half its area occupied would, during scanning, be considered and treated as being completely covered, whereby such angle would appear to be completely filled or rounded when reproduced from a recording of the character.

Suitable symbols such as the blocks 7 of varying sizes appearing at the left edge of the original represent coded information pertaining to the type of script, height and width of the character as well as control signals for use in connection with the storage operations and are so disposed that they will be scanned prior to the scanning of the character. Thus, assuming that the scanning beam vertically traverses the original from left to right, the first elements to be scanned will be the code symbols.

It will be appreciated from the above that use of the present method enables the efficient and rapid production of character or pattern originals in connection with photoelectrical scanning operations, in which individual operations including manual drawing etc. is limited solely to adaptation procedures by means of which the configuration of the character or pattern representation is conformed to the raster grid lines, completely eliminating the necessity of laboriously producing the entire character.

Having thus described my invention it will be obvious that various immaterial modifications may be made in the same without departing from the spirit of my invention.

lclaim:

l. A character or pattern original which is to be photoelectrically scanned for the purpose of quantizing such a character or pattern and for obtaining digital data therefrom, in which the original carrier has a raster line grid, comprising a film, the light transmission characteristics through which is sufficient to enable viewing of the grid therethrough, and the upper surface of which carries a representation of the character or pattern involved, said film being secured to the original carrier with such character or pattern representation being of a size and so disposed on the original carrier that all vertical and horizontal straight edge lines if any of such character or pattern representation coincide with corresponding raster lines and its characteristic curvilinear insert as a result of conformation of edge lines if any touch raster lines tangentially the character or pattern thereto by a corresponding shifting of respective edge lines, retaining curvilinear configuration of any such curvilinear edge lines said original carrier having disposed thereon coded information in scannable form relating to the type, height and width of the character as well as coded control signals for use in the storage of the digital data to be obtained, said coded information being so located with respect to the advanced direction of the intended scanning that it will be scanned prior to scanning of such character or pattern representation.

2. A method of producing a character or pattern original which is to be photoelectrically scanned for the purpose of quantizing the same and for obtaining digital data therefrom, in which the original character is provided with a raster line grid, comprising the steps of applying a representation of the character or pattern to a film, the light transmission characteristics through which is sufficient to enable viewing of a grid therethrough, arranging such film with the surface carrying the character or pattern representation uppermost in such position in respect to the original carrier that as many as possible of the vertical and horizontal straight edge lines of the character or pattern representation, if any, coincide with corresponding raster lines, and as many as possible vertical and horizontal raster lines at least approach tangency to corresponding curvilinear edge lines, if any, of the character or pattern, and thereafter eliminating deviations in such coincidence which still exist between raster lines and such straight edge lines, as a result of such a straight edge falling between two adjacent raster lines, by shifting such edge line to thereby make it coincide with one of said adjacent raster lines by a filling in of the next adjacent corresponding raster line, or removing the part of the character or pattern projecting beyond the adjacent preceding corresponding raster line, and eliminating deviations in tangency which still exist between such a curvilinear edge line as a result of such a curvilinear edge line as a result of such a curvilinear edge line falling between two adjacent corresponding raster lines by shifting each such a curvilinear edge line, while retaining curvilinear configuration thereof, to thereby make a selected one of said two adjacent raster lines tangent to such curvilinear edge line, by a correspondent filling of raster grid spaces, to the next adjacent corresponding raster line or by correspondent removal of portions of the character or pattern representation projecting beyond the adjacent preceding corresponding raster line, making the selection of removal or filling on the basis of which would result in the smallest possible change in the initial shape of the character or pattern.

3, A method according to claim 2 comprising forming a photographic diapositive as the film carrying the character or pattern representation 4. A method according to claim 2, comprising the additional steps of dividing the film at predetermined places on such character or pattern representation and shifting the respective pieces as required to individually adapt the respective pieces to the raster line, with the pieces being mutually displaced by an amount necessary for adaptation and filling any spaces resulting therefrom.

5. A method according to claim 4 comprising the further step of removing part of the character or pattern representation at an acute angle formed by acutely converging edge lines to the area of at least a whole raster grid space.

6. A method according to claim 2, comprising the further step of applying to the original coded information in scannable form relating to the type, height and width of the character as well as coded control signals for use in the storage of the digital data to be obtained, so positioning said coded information on the original with respect to the advanced direction of the intended scanning that scanning of such coded information will precede the scanning of the character or pattern carried thereby.

Claims

1. A character or pattern original which is to be photoelectrically scanned for the purpose of quantizing such a character or pattern and for obtaining digital data therefrom, in which the original carrier has a raster line grid, comprising a film, the light transmission characteristics through which is sufficient to enable viewing of the grid therethrough, and the upper surface of which carries a representation of the character or pattern involved, said film being secured to the original carrier with such character or pattern representation being of a size and so disposed on the original carrier that all vertical and horizontal straight edge lines if any of such character or pattern representation coincide with corresponding raster lines and its characteristic curvilinear as a result of conformation of edge lines if any touch raster lines tangentially the character or pattern thereto by a corresponding shifting of respective edge lines, retaining curvilinear configuration of any such curvilinear edge lines said original carrier having disposed thereon coded information in scannable form relating to the type, height and width of the character as well as coded control signals for use in the storage of the digital data to be obtained, said coded information being so located with respect to the advanced direction of the intended scanning that it will be scanned prior to scanning of such character or pattern representation.

2. A method of producing a character or pattern original which is to be photoelectrically scanned for the purpose of quantizing the same and for obtaining digital data therefrom, in which the original character is provided with a raster line grid, comprising the steps of applying a representation of the character or pattern to a film, the light transmission characteristics through which is sufficient to enable viewing of a grid therethrough, arranging such film with the surface carrying the character or pattern representation uppermoSt in such position in respect to the original carrier that as many as possible of the vertical and horizontal straight edge lines of the character or pattern representation, if any, coincide with corresponding raster lines, and as many as possible vertical and horizontal raster lines at least approach tangency to corresponding curvilinear edge lines, if any, of the character or pattern, and thereafter eliminating deviations in such coincidence which still exist between raster lines and such straight edge lines, as a result of such a straight edge falling between two adjacent raster lines, by shifting such edge line to thereby make it coincide with one of said adjacent raster lines by a filling in of the next adjacent corresponding raster line, or removing the part of the character or pattern projecting beyond the adjacent preceding corresponding raster line, and eliminating deviations in tangency which still exist between such a curvilinear edge line as a result of such a curvilinear edge line falling between two adjacent corresponding raster lines by shifting each such a curvilinear edge line, while retaining curvilinear configuration thereof, to thereby make a selected one of said two adjacent raster lines tangent to such curvilinear edge line, by a correspondent filling of raster grid spaces, to the next adjacent corresponding raster line or by correspondent removal of portions of the character or pattern representation projecting beyond the adjacent preceding corresponding raster line, making the selection of removal or filling on the basis of which would result in the smallest possible change in the initial shape of the character or pattern.

3. A method according to claim 2 comprising forming a photographic diapositive as the film carrying the character or pattern representation.

4. A method according to claim 2, comprising the additional steps of dividing the film at predetermined places on such character or pattern representation and shifting the respective pieces as required to individually adapt the respective pieces to the raster line, with the pieces being mutually displaced by an amount necessary for adaptation and filling any spaces resulting therefrom.