MXPA01004115A - Machine-readable security document and method of preparing the same - Google Patents

Abstract

A security document and its method of preparation are provided wherein a security image area on the face of the document is designated. The security image area comprises a two-dimensional array of security image blocks. Security image elements and the complementary security image elements in respective security image blocks are arranged such that the security image element and the complementary security image element portions occupy respective first and second percentages of each of the security image blocks to define respective characteristic relative occupation values (CROVs) for each security image block.

Description

SAFETY DOCUMENT LEGIBLE IN MACHINE AND * -f- METHOD FOR PREPARATION DESCRIPTION OF THE INVENTION The present invention relates to security documents that include a security image composed of individual security image elements and complementary security image elements. When you try to duplicate or reduce a document in which a security image is present, at least part of the security image elements change their appearance in the proposed duplicate document, or are altered with respect to some other physical characteristic in the duplicate document or reproduced proposed. He change in appearance, or the altered physical characteristic of the elements is used to provide an indication that attempts have been made to duplicate the document. For example, security image elements can be designed so that, in the case of duplication attempted, For example, by photocopying, the security image elements or the complementary security image elements are altered while the others remain substantially the same. The elements are distributed so that the duplication attempt results in the formation of an obvious warning image clearly on the face of the document. Specifically, when an attempt is made to copy the document, the word "NULL" may appear in the duplicate document. In addition, the security image elements and the complementary security image elements are distributed so that the presence of the security image and the security image elements are not easily apparent in the original. Examples of security documents of this type are illustrated in U.S. Patent Nos. 4,579,370, 5,149,140, 5,197,765, 5,340,159. Another example of a security document is illustrated in U.S. Patent Number 4,175,774, which describes a security document using small dots and larger dots. Small dots can not be reproduced by a copier. Another example of a security document is illustrated in U.S. Patent Nos. 5,340,159 which has elements small enough so that they are not reproduced by a color copier in a particular setting. Accordingly, the prior art described above provides a means by which a person who has the responsibility to review security documents can identify documents that are unauthorized copies of the original security document. However, the conventional security images described above are not specifically designed so that they are easily verifiable by an electronic document reader, for example an optical image-forming device. Accordingly, there is a need for a security document, a method for preparing a security document and a security document processing system wherein the security document is specially designed to provide a reliable indication of authenticity to an electronic device. of authentication, without compromising the ability of the document to provide an indication of authenticity recognizable by humans. This need is met by the present invention wherein a security document includes complementary security image element and security image element arranged to perform the double function of providing an indication of authenticity, reliable, recognizable by both humans and humans. that can be readable by a machine. The above reference to a conventional security document type is not intended to limit the scope of the application of the present invention to a specific type of security document. Rather, for the purposes of defining and describing the present invention, it should be understood that the security image elements and the complementary security image elements according to the present invention are any printed elements that function to provide an indication that an attempt has been made to duplicate or reproduce an original security document. The duplication or reproduction attempt may be by conventional methods of the state of the art of photocopying (analog, digital, color, black and white, etc.), printing methods (inkjet, laser, etcetera), publication methods, et cetera. In accordance with one embodiment of the present invention, there is provided a method for preparing a security document wherein a security image area is designated on the face of the document. The security image area comprises a two-dimensional array of security image block and each of the security image blocks is occupied by a set of security image elements and a set of complementary security image elements. The security image elements occupy a portion of the security image of each of the security image blocks and the complementary security image elements occupy a portion of complementary security image elements of each of the image blocks of the security image. security. The security image elements and the complementary security image elements in the respective security image blocks are distributed so that the portion of the security image element and the portion of the complementary security element occupy a first and second respective percentages of each of the security image blocks to define respective characteristic relative occupation values for each security image block. The respective characteristic relative occupation values are substantially equivalent among a plurality of security image blocks. A target characteristic relative occupation value is established. The respective security element portions and the respective complementary security image element portions are set so that the respective security image element portions occupy a first percentage of a selected security image block and the security element portions thereof. respective complementary security image occupy a second percentage of the selected security image block. A relative value of the first and second occupancy percentages is determined and compared with a target characteristic relative occupation value. At least one of the complementary security image element portion and the security image element portion is adjusted, if the comparison indicates a significant disparity between the first and second occupancy percentages and the objective characteristic relative occupation value, so that the relative value of the first and second occupancy percentages correspond substantially to the objective characteristic relative occupation value. Finally, a security image document is generated that includes the two-dimensional arrangement of security image blocks. Each of the security image blocks is occupied by the security image elements and the complementary security image elements. - ß - The step of adjusting at least a portion of complementary security image elements and the security image element portion may comprise changing the stroke width of the portion of the security image element or changing the dimensions of the security image elements. respective security image blocks. The security image element portion preferably comprises the security image elements and unprinted portions that separate the security image elements. Similarly, the complementary security image element portion preferably comprises complementary security image elements and unprinted portions that separate the complementary security image elements. The security image elements can be any conventional geometric shape suitable for the construction of a security image, which is selected from a group consisting of circles, lines, dots, squares, ovals, triangles and groups thereof, in various combinations You can also use other forms such as star letters, words and logos. The security image area may include a camouflage image superimposed on the portion of the security image element and the complementary security image element portion, in, where the camouflage image comprises camouflage image elements that are selected from a group consisting of printed elements and non-printed elements. The relative value of the first and second occupancy percentages can be determined by a mathematical comparison that is selected from the group consisting of a relation, a product, a difference, a sum and combinations thereof. The relative value of the first and second occupation percentages can be compared with the objective characteristic relative occupation value by a mathematical comparison that is selected from the group consisting of a relation, a product, a difference, a sum and combinations thereof. According to another embodiment of the present invention, there is provided a method for preparing a security document wherein the designated security image area comprises a two-dimensional array of security image blocks and each of the security image blocks defines an array of pixels of image blocks. The respective security image element portions and the complementary security image element portions are set to occupy a first and second pixel portions of a selected security image block pixel array. An indication of the number of pixels in the first pixel portion relative to the number of pixels in the second pixel portion is generated and compared to the objective characteristic relative occupation value. At least one of the portion of complementary security image elements and the security image element portion is adjusted, if the comparison indicates a significant disparity between the relative pixel number indication and the target characteristic relative occupancy value of so that the indication of the relative pixel number corresponds substantially to the objective characteristic relative occupation value. According to still another embodiment of the present invention, there is provided a method for preparing a security document, wherein at least one of the plurality of security image blocks defines a first security image, and at least one of the plurality of security image blocks defines a second security image so that the first security image is dimensionally different from the second security image. The respective characteristic occupation values of the first security image and the second security image are substantially equivalent. A value is established of objective characteristic relative occupation for the first security image and the second security image. The portions of the respective security image element and the complementary security image element portions are set within the first security image and the second security image so as to occupy a first and a second percentages of each of the first and second security images. security image blocks. A relative value of the first and second occupation percentages is determined and compared with the objective characteristic relative occupation value. At least one portion of complementary security image element and the security image element portion are adjusted, if the comparison indicates a significant disparity between the first and second occupation percentages and the objective characteristic relative occupation value, so that the relative value of the first and second occupancy percentages correspond substantially with the objective characteristic relative occupation value. In accordance with another embodiment of the present invention, a security document is provided comprising a document face and a security image area defined on the face of the document. At least one of the plurality of security image blocks defines a first security image and at least one of the plurality of security image blocks defines a second security image so that the first security image is dimensionally different of the security image. The respective characteristic relative occupation values of the first security image and the second security image are substantially equivalent. The tone of the security image elements and the tone of the complementary security image elements may vary through the security image area. The security image area includes a camouflage image superimposed on the security image element portion and the complementary security image element portion. According to yet another embodiment of the present invention, a security document is provided comprising a document face and a security image area on the face of the document. At least one of the plurality of security image blocks defines a first security image and at least one of the plurality of security image blocks defines a second security image so that the first security image is visually distinct of the second security image. The relative characteristic relative occupation values of the first security image and the second security image are substantially equivalent. The first security image and the second security image may occupy image blocks of substantially the same size or of different sizes. The adjacent image blocks of the security image block array may share at least one mutual limit and respective security image element portions of the adjacent image blocks may touch the mutual boundary. In addition, each of the security image blocks can be defined by an image block boundary that has multiple sides and respective security image element portions of each of the security image blocks can touch each of the Multiple sides of the image block limit.

According to still another embodiment of the present invention, there is provided a security document processing system comprising a document issuing station and at least one document receiving station. The document receiving station includes a security document reader placed to read the respective characteristic occupation values of the security document. Accordingly, an object of the present invention is to provide a security document that includes security image elements and complementary security image elements distributed in a manner that performs the dual function of providing an indication of reliable authenticity, recognizable to humans and readable in machine. Other objects of the present invention will be apparent in light of the description of the description of the invention embodied herein. The following detailed description of the preferred embodiments of the present invention can be better understood when read in conjunction with the following drawings, wherein similar structures are indicated with similar reference numerals, and in which: Figure 1 is a schematic illustration of a security document according to the present invention; Figure 2 is a schematic illustration of a security image block according to the present invention; Figures 3 and 4 are schematic illustrations of a security image element portion and a complementary security image element portion of the present invention, respectively; Figures 5 and 6 are schematic illustrations of alternative security image areas according to the present invention; and Figure 7 is a flow chart illustrating a method for preparing a security document in accordance with the present invention. To describe and define the present invention, it should be understood that a security document is a document that includes a feature or feature designed or distributed to avoid successful duplication or unauthorized reproduction of the document, typically by providing an indication that the document has been duplicated or reproduced in itself. The indication of an attempt of duplication or reproduction may be such that it is evident to the naked eye or that it is evident through the use of an optical scanner, special observation optical equipment, physical elements of special detection, and so on.

In addition, the indication may be such that it is evident through more than one of these means. For example, when an attempt is made to duplicate a document with a photocopier, the word "NULL" may appear in the duplicate document, when viewed with the naked eye. In addition, some of the image elements can be altered in the duplicate document so that the alteration is apparent with the help of special scanning, observation or physical detection elements. The security document of the present invention and its method of preparation are illustrated in detail herein, with reference to Figures 1 to 7, wherein a similar structure is indicated with similar reference numerals. A security document 10 is prepared in accordance with the present invention by designating a security image area 12 on the face 11 of the document 10, see Figure 7, step 100. Figure 1 illustrates the typical placement of the image area 12 of Security on the face of the security document. However, it is contemplated by the present invention that the security image area 12 may be distributed to occupy the entire face 11 of the document 10 or only a specific portion of the face 11 of the document 10. Preferably, the image area 12 of Security occupies at least the portions of the face 11 dedicated to the security data 13, for example, the drawer, the drawee, the quantity, the authorized signature, and so on. The security image area 12 comprises a two-dimensional arrangement of component security image blocks 14 which collectively form a total security image 15, see Figures 2, 5 and 6. Figure 2 schematically illustrates a single security image block 14. Figures 5 and 6 schematically illustrate two distributions of the security image blocks 14 within the security image area 12. It is contemplated by the present invention that, although the security document 10 illustrated in the Figures of the present invention is presented in the form of a substantially uniform "NULL" ink pantograph, the present application is also applicable to variable tone security documents. or graduated mesh and other types of security documents. In Figures 2, 5 and 6, the boundaries of the blocks 14 are indicated to the security image with dashed lines which typically are not printed on the face 11 of the document 10. Each of the security image blocks 14 is occupied by a set of security image elements 16 and a set of complementary security image elements 18. In Figure 2, the security image elements 16 form the individual letters of the word "NULL" while the complementary security image elements 18 form the background of the word. As will be appreciated by those practicing the present invention, the size of the security image elements 16 in the illustrated embodiment is selected so that they are easily reproduced by a photocopier, while the size of the complementary security image elements 18 it is selected so that, when photocopied, the background image is significantly degraded and the letters of the word "NULL" become easily apparent to an incidental observer. As will be further appreciated by those who practice the present invention in practice, the actual sizes, spacing and shape of the security image elements 16 and the complementary security image elements 18 are not illustrated in Figure 2. instead of this, the actual sizes, the spacing and the shapes of the image elements 16, 18 are left to the selection of a particular technician made in light of the teachings set forth herein and of the teachings of the prior art mentioned above incorporated herein by reference. According to one embodiment of the present invention, the security image elements 16 comprise relatively small points spaced at a frequency of 51 dots per cm (130 dots per inch) and the complementary security image elements 18 comprise relatively large dots separated at a frequency of 25 dots per cm (65 dots per inch). The specific sizes of the points are selected to create a total uniform document tone. To describe and define the present invention, it is stated that the security image elements 16 occupy a portion 20 of security image element of each of the security image blocks 14, see Figures 2 and 3. Similarly , the complementary security image elements 18 occupy a portion 22 of complementary security image element of each of the security image blocks 14, see Figures 2 and 4. The security image elements 16 and the elements 18 of complementary security image in the respective security image blocks 14 are distributed so that the security image element portion 20 and the complementary security image element portion 22 occupy a first and second respective percentages of each of the security image blocks 14 for defining respective characteristic occupation values (CROV) for each security image block 14. The respective CROVs are substantially constant between the security image blocks 14. It is contemplated by the present invention that the CROVs of all safety image blocks 14 need not be precisely controlled for some applications of the present invention. As will be appreciated by those who practice the present invention, the shape and stroke width of the particular characters defining the security image element portion 20 and the complementary safety image element portion 22 of each of the security image blocks 14 is subject to alteration of according to the preferences and particular needs of those who practice the present invention. The security image elements 16 and the complementary security image elements 18 together define the CROV for each security image block 14. Specifically, when the security image elements 16 occupy a first percentage of the security image block 14 (the security image element portion 20), and when the complementary security image elements 18 occupy a second percentage of the security block 14. of security image (the portion 22 of complementary security image element), a relative value of the first and second occupation percentages can be calculated to determine the CROV of the security image block 14. The CROV can be a ratio, a difference, product, sum or any other quantitative mathematical comparison of: (i) the security image element portion 20 and the complementary security image element portion 22, (ii) the portion 20 of the security image element and the security image block 14, or (iii) the complementary security image element portion 22 and the security image block 14. In accordance with one aspect of the present invention, the security document 10 is prepared by constructing each security image block 14 from a plurality of individual pixels arranged in an array arranged so that each image block 14 defines an array of pixel of image block. The place where each image block 14 defines an image block pixel array, each security image element portion 20 can be said to occupy a first pixel portion of a selected security image block pixel array. , as opposed to a first percentage of a selected security image block 14. Similarly, each complementary security image element portion 22 can be said to occupy a second pixel portion of the selected security image block pixel array, as opposed to a second percentage of a secure image block 14. selected. In addition, an indication of the number of pixels in the first pixel portion can be generated relative to the number of pixels in the second pixel portion as an alternative for determining the relative value of the first and second occupancy percentages, as described above. The AdobeMR Photoshop ™ programs, available from Adobe Systems Incorporated, San Jose, California, are an example of graphical software packages that allow a designer to conveniently divide an image area or a block into pixels and separate the pixels into a first group of pixels. pixels representing printed material and a second group of pixels representing printed material. In the same way that the security image area 12 should be designed to prepare the security document 10 of the present invention, the objective characteristic relative occupation value (target CROV) should also be set, see Figure 7, step 102. Typically the target CROV is established or selected to meet the requirements of the particular electronic authentication device to be used to validate the security document 10 because the security document 10 is preferably designed to allow electronic authentication or validation by an electronic device imager programmed to recognize the CROV or one or more security image blocks 14 with the security document 10. Figures 2 to 4 illustrate the target CROV according to one embodiment of the present invention, wherein a significant portion of the security image block 14 is occupied by the security image element portion 20. The security image element portions 20 are set, that is, the size and shape of the security image element portions 20 are selected to occupy a first percentage of the respective security image blocks 14, see Figure 7, step 104. Similarly, the complementary security image element portions 22 are set to occupy a second percentage of the respective security image blocks 14, see Figure 7, step 106. In this way , a first percentage of each of the security image blocks 14 will be occupied by a portion 20 of security image element consisting of security image elements 16, and a second percentage of each of the image blocks 14 of the security image. security will be occupied by a portion 22 of complementary security image element consisting of complementary security image elements 18. As will be appreciated by those who practice the present invention, these occupancy percentages may correspond to any of numerous specific mathematical quantities. The description of the present invention constituted herein refers mainly to the percentage of the area of a security image area 12 occupied by the general boundaries of the letters forming the "NULL" image as illustrated in Figures 2 and 3. In Figures 2 and 3, the security image element portion 20 comprises the security image elements 16 and the non-printed portions separate the security image elements 16. The complementary security image element portion 22 comprises the complementary security image elements 18 and the portions of reprints separate the complementary security image elements 18. It is contemplated by the present invention, however, that occupancy percentages may be the respective sums of the separate areas occupied by the individual security image elements 16 and the elements 18 complementary security images within the security image area 12. It is also contemplated by the present invention that the security image elements 16 may be selected from a group consisting of circles, lines, squares, ovals, triangles, dots and groups thereof, in various combinations. Other shapes can also be used, such as star letters, words and logos. Then the relative values of the first and second occupation percentages are determined, ie the respective CROVs are compared with the target CROV, see figure 7, s 108 and 110. When this comparison indicates a significant disparity between the first and second occupancy percentages, i.e., the respective CROVs and the target CROV, either or both of the complementary security image element portion 22 and the security image element portion 20 are adjusted to substantially eliminate the disparity, see FIG. 7, s 112 and 114. The adjustment can be carried out, for example, by changing the stroke width of the security image element portion 20, the dimensions of the respective security image blocks 14, or the dimensions totals of the security image element portions 20 relative to the security image block 14. For example, if you set a target CROV to 0.4, indicating that 40% of the security image area will be occupied by the portion 20 of the security image element, and if the relative values of the first and second occupancy percentages in each block 14 security image indicate that only 30% of. each safety image block 14 is occupied by the security image element portion 20, then the respective areas occupied by the image elements 16 are security and the complementary security image elements 18 are altered so that the relative value of the first and second occupancy percentages correspond substantially with the target CROV. If the relative value of the occupation percentages is a relation and the objective relative occupation value is also a relation, the relative value of the first and second occupancy percentages can be said to correspond substantially with the target CROV when the two values are equal , within an acceptable margin of error. The acceptable margin of error depends mainly on the operational preferences of those who practice the present invention. It is contemplated by the present invention that the relative value of the first and second occupancy percentages can be compared to the target CROV through a mathematical comparison that is selected from a group consisting of a relation, a product, a difference, a sum and combinations thereof. To complete the procedure, the security document 10 is generated. That is, the security document 10 is printed on a laser printer or other suitable printer for the production of security documents including security image elements 16 and security elements 18 of complementary security, see Figure 7, s116. Preferably, the security image area 12 also includes a camouflage image superimposed on the secure image element portion 20 and the image element portion 22 is complementary security. As will be appreciated by those who practice the present invention, particularly in light of the teachings of the prior art, the camouflage image may comprise printed or non-printed image elements and must be distributed on the surface of the document so as not to alter the respective CROVs of each image block 14. security. In addition, the tone of the image elements 16 is secured, the complementary security image elements 18 and the camouflage image may vary together through the security image area 12, as described in U.S. Pat. 5,340,159. The security image block distributions of FIGS. 5 and 6 include a plurality of security image blocks 14. A first set of security image blocks 14 define first security images 24 respective components, a second set of security image blocks 14 define second security images 26 respective components, and the additional sets of image blocks are security additional security images 30, 32, 34, 36, 38, 40 define additional components. As clearly illustrated in Figure 5 and 6, the first component of the security image 24 is dimensionally and visually different from the second security image component 26 and each additional image component 30, 32, 34, 36, 38, 40 of security. Specifically, the first security image component 24 comprises the relatively large single word "NULL", the second security image component 26 comprises 4 relatively small words "NULL", and the additional components of security images 30, 32, 34 , 36, 38 and 40 comprises combinations of the selected portions of the first and second components of the security images 24, 26. To describe and define the present invention, it is noted that the dimensionally distinct images are images that define different physical dimensions relative to one another, and that the visually distinct images are images that define different visual appearances relative to each other. In Figure 5, the first security image component 24 and the second security image component 26 occupy image blocks of substantially the same size and contain either one to four complete images of the term "NULL". In contrast, with reference to Figure 6, although the first component of the security image 24, the second component of the security image 26 and the additional components of the security images 30, 32, 34 and 36 occupy image blocks substantially of the same size, the additional component of the security images 38 and 40 occupy image blocks of a different size compared to the first and second components of the security images 24, 26. In addition, the additional component of security images 30, 32, 34, 36, 38 and 40 contains partial versions of the term "NULL". Despite these important differences between the security image components, the respective CROVs of each security image component, including the first security image component 24, the second security image component 26, and the additional image components 30 , 32, 34, 36, 38 and 40 of security are substantially equivalent. In this manner, an electronic device set to read the CROV of a portion of a security document in accordance with the present invention, and which includes various components of security images, will generate substantially the same detected CROV regardless of which portion of the security document. security is read, scanned or imaged by the electronic device, insofar as the portion read, scanned or imaged is of an appropriate size. Preferably, the portion read, scanned or from which an image is formed is equivalent to the size of at least one block. To further improve reliability in an electronic validation, it is preferable to ensure that each component of security images 24, 26, 30, 32, 34, 36, 38 and 40 substantially or completely fill its security image block 14. For example, with reference to Figure 5, since all the adjacent image blocks 14 share at least one mutual boundary, for example, discontinuous line 43 between adjacent blocks 42 and 44, it is preferable to set image element portions 20. of respective security of the adjacent image blocks 14 so that the respective security image element portions 20 of the adjacent image blocks touch the mutual boundary. Stated more specifically, the adjacent image blocks 14 of the array of security image blocks share a plurality of mutual boundaries, for example discontinuous lines 43 and 45 between adjacent blocks 42, 44 and 46, and the element portions 20 of FIG. respective security images of the adjacent image blocks touch the mutual boundaries. Referring now to Figure 2, each of the security image blocks 14 are defined by an image block boundary having multiple sides 14A, 14B, 14C and 14D, and the respective security image element portions 20. from each of the security image blocks 14 touch each of the multiple sides 14A, 14B, 14C and 14D of the image block boundary. In a particular embodiment of the present invention, the means provided for establishing an electronic validation of the security document 10 is an explorer that is also capable of reading and storing transaction data printed or encoded on the face of document 10. Typically, once that the document 10 is validated, the transaction data is separated from the data used to allow electronic validation of the document 10 and is placed in a long-term data memory for further processing. The data used to allow electronic validation can be discarded after carrying out the final validation stage. Having described the invention in detail and with reference to the preferred embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims.

Claims (24)

1. A method for preparing a security document comprising the steps of: designating a security image area on the face of the document, wherein the security image area comprises a two-dimensional arrangement of security image blocks, each of which Security image blocks is occupied by a set of security image elements and a set of complementary security image elements, the security image elements occupy a portion of security image element of each of the image blocks of security, the complementary security image elements occupy a portion of complementary security image element of each of the security image blocks, the security image elements and the complementary security image elements in the image blocks of respective security define respective characteristics in relation to occupation values for each block of image of security, wherein the respective characteristic relative occupation values for each security image block correspond to the percentages of each of the security image blocks occupied by the security image element portion and the image element portion of the security image portion. complementary security, and wherein the respective characteristic relative occupation values are substantially equivalent among a plurality of security image blocks; establish an objective characteristic relative occupation value for the security document; setting respective security image element portions and complementary security image element portions for the respective security image blocks of the two-dimensional arrangement of security image blocks so that the respective security image element portions and the portions of complementary security image elements occupy the respective first and second percentages of the respective security image blocks; determine a relative value of the first and second occupancy percentages; compare the relative value of the first and second occupancy percentages with the objective characteristic relative occupation value; adjusting at least one of the complementary security image element portion and the security image element portion, wherein the comparison indicates a reference between the first and second occupancy percentages and the objective characteristic relative occupation value, of so that the relative value of the first and second occupancy percentages correspond substantially to the objective characteristic relative occupation value; generate a security document that includes the two-dimensional arrangement of the security image blocks.

2. A method for preparing a security document, as described in claim 1, wherein the step of adjusting at least one portion of complementary security image element and the security image element portion comprises changing a width of career of the security image element portion.

3. A method for preparing a security document, as described in claim 1, wherein the step of adjusting at least one portion of complementary security image element and the security image element portion comprises changing the dimensions of the security elements. respective security image blocks.

4. A method for preparing a security document, as described in claim 1, wherein the security image element portion comprises security image elements and unprinted portions that separate the security image elements.

5. A method for preparing a security document, as described in claim 1, wherein the complementary security image element portion comprises complementary security image elements and unprinted portions that separate the complementary security image elements.

6. A method for preparing a security document, as described in claim 1, wherein the security image elements are selected from the group consisting of circles, lines, squares, ovals, triangles, dots and groups thereof, in various combinations.

7. A method for preparing a security document, as described in claim 1, wherein the relative value of the first and second occupation percentages is determined by: generating an indication of the number of pixels of the first pixel portion in relation to the number of pixels of the second portion of pixels; compare the indication of relative pixel number with the objective characteristic relative occupation value.

8. A security document, comprising a document face and a security image area defined on the face of the document, wherein: The security image area comprises a plurality of security image blocks; each of the security image blocks is occupied by a set of security image elements and a set of complementary security image elements; the security image elements occupy a portion of the security image element of each of the security image blocks; the complementary security image elements occupy a portion of complementary security image element of each of the security image blocks; the security image elements and the complementary security image elements in the respective security image blocks are distributed so that the security image element portion and the complementary security image element portion occupy a first and second security element. respective percentages of each of the security image blocks to define respective characteristic relative occupation values for each security image block; at least one of the plurality of security image blocks defines a first security image and at least one of the plurality of security image blocks defines a second security image so that the first security image is dimensionally different of the second security image; and the respective characteristic occupation values of the first security image of the second security image are substantially equivalent.

9. The security document, as described in claim 8, wherein the tone of the security image elements and the tone of the complementary security image elements vary together through the security image area.

10. A security document, comprising: a document face; and a security image area on the face of the document, wherein the security image area comprises a two-dimensional array of security image blocks, each of the security image blocks is occupied by a set of security elements. security image and a set of complementary security image elements, the security image elements occupy a portion of security image element of each of the security image blocks, the complementary security image elements occupy a portion of complementary security image element of each of the security image blocks, the security image elements and the complementary security image elements in the respective security image blocks are distributed so that the element portion of safety image and the complementary safety image element portion occupy a first and second respective percentages In each of the security image blocks to define the respective relative characteristic occupation values for each security image block, at least one of the plurality of security image blocks defines a first image and at least one of the plurality of security image block defines a second security image so that the first security image is visually different from the second security image, and the respective characteristic occupation values of the first security image and the second security image. Security image are substantially equivalent.

11. The security document, as described in claim 10, wherein the first security image and the second security image occupy image blocks of substantially the same size.

12. The security document, as described in claim 11, wherein the adjacent image blocks of the security image array share at least one mutual boundary, and wherein the respective security image element portions of the security blocks correspond to each other. adjacent images touch at least one mutual limit.

13. The security document, as described in claim 12, wherein each of the security image blocks are defined by an image block boundary having multiple sides, and wherein the respective security image element portions. of each of the image blocks is security touches each of the multiple sides of the image block limit.

14. The security document, as described in claim 11, wherein the adjacent image blocks of the security image array share a plurality of mutual boundaries, and wherein the respective security image element portions of the image blocks Adjacent ones touch the mutual boundaries.

15. The security document, as described in claim 14, wherein each of the security image blocks are defined by an image block boundary having multiple sides, and wherein the respective security image element portions. of each of the security image blocks touch each of the multiple sides of the image block boundary.

16. The security document, as described in claim 11, wherein each of the security image blocks is defined by an image block boundary having multiple sides, and wherein the respective security image element portions. of each of the image blocks touch each of the multiple sides of the image block boundary.

17. The security document, as described in claim 10, wherein the first security image and the second security image occupy blocks of substantially different sizes.

18. The security document, as described in claim 17, wherein the adjacent image blocks of different size of the arrangement of security image blocks share at least one mutual limit, and wherein the portions of the security image element respective of the adjacent image blocks touch at least one mutual limit.

19. The security document, as described in claim 18, wherein each of the security image blocks with different size are defined by an image block boundary having multiple sides, and wherein the image element portions of respective security of each of the security image blocks with different size touches each of the multiple sides of the image block boundary.

20. The security document, as described in claim 17, wherein the adjacent image blocks of different size of the array of security image blocks share a plurality of mutual boundaries, and wherein the respective security image element portions. of the adjacent image blocks touch the mutual boundaries.

21. The security document as claimed in claim 20, wherein each of the security image blocks of different size are defined by an image block boundary having multiple sides, and wherein the image element portions of The respective security of each of the security image blocks of different size touch each of the multiple sides of the image block boundary.

22. The security document, as described in claim 17, wherein each of the security image blocks of different size are defined by an image block boundary having multiple sides, and wherein the image element portions of respective security of each of the security image blocks of different size touch each of the multiple sides of the image block boundary.

23. The security document, as described in claim 10, wherein the security image area includes a camouflage image superimposed on the security image element portion and the complementary security element portion, wherein the image of Camouflage comprises camouflage image elements that are selected from the group consisting of printed elements and non-printed elements.

24. A method for processing a security document in a security document processing system comprising a document issuing station and at least one document receiving station that includes a security document reader placed to read printed data in a document of security, wherein the security document comprises a document face and a security image area defined on the face of the document, the security image area comprising a plurality of security image blocks, each of the image blocks of security is occupied by a set of security image elements and a set of complementary security image elements, the security image elements occupy a portion of security image element of each of the security image blocks, the complementary security image elements occupy a portion of complementary security image element of ac gives one of the security image blocks, the security image elements and the complementary security image elements in the respective security image blocks are positioned so that the security image element portion and the element portion of complementary security images occupy a first and second respective percentages of each of the security image blocks to define respective characteristic relative occupation values for each security image block, at least one of the plurality of image blocks of security defines a first security image and at least one of the plurality of security image blocks defines a second security image so that the first security image is dimensionally different from the second security image, and occupancy values relative respective characteristics of the first security image and the second security image. ad are substantially equivalent, and wherein the method of processing the security document comprises the steps of: establishing an objective characteristic relative occupation value; establishing respective safety image element portions and complementary safety image element portions so that the respective safety image element portions and complementary safety image element portions occupy a first and second percentages of the image block security selected; determine a relative value of first and second occupancy percentages; compare the relative value of the first and second occupancy percentages with the objective characteristic relative occupation value; adjusting at least one portion of complementary security image element and the security image element portion, wherein the comparison indicates a significant difference between the first and second occupancy percentages and the objective characteristic relative occupation value, so that the relative value of the first and second occupancy percentages correspond substantially to the objective characteristic relative occupation value; generating a security document including the two-dimensional array of security image blocks, wherein each of the security image blocks is occupied by the security image elements and the complementary security image elements; and placing the security document in relation to the security document reader so that the respective characteristic relative occupation values are determined. SUMMARY A security document and its preparation method are provided where a security image area is designated on the face of the document. The security image area comprises a two-dimensional array of security image blocks. The security image elements and the complementary security image elements in the respective security image blocks are distributed so that the security image element and the complementary security image element portions occupy respective first and second percentages of each of the security image blocks to define respective characteristic relative occupation values (CROV) for each security image block. The respective CROVs are substantially equivalent among a plurality of security image blocks. A target CROV is established. The respective security image element portions and the respective complementary security image element portions are set so that the respective security image element portions occupy a first percentage of a selected security image block and the portions of respective complementary security image element occupy a second percentage of the selected security image block. A relative value of first and second occupancy percentages is determined and compared with the target CROV. At least one portion of complementary security image element and the security image element portion is adjusted, if the comparison indicates a significant disparity between the first and second occupancy percentage and the target CROV, so that the relative value of the first and second occupancy percentages correspond substantially with the target CROV. Finally, a security document is generated that includes a two-dimensional arrangement of security image blocks, wherein each of the security image blocks is occupied by the security image elements and the complementary security image elements.