GB2430504A

GB2430504A - Position encoding pattern with markings which contrast with background content

Info

Publication number: GB2430504A
Application number: GB0518792A
Authority: GB
Inventors: Maurizio Pilu
Original assignee: Hewlett Packard Development Co LP
Current assignee: Hewlett Packard Development Co LP
Priority date: 2005-09-15
Filing date: 2005-09-15
Publication date: 2007-03-28
Also published as: GB0518792D0

Abstract

To enable a data encoding pattern 401 to be distinguished from the content to be applied to a product the content to be applied to a product is analysed and colour of the markings 401, 402, 403 of the pattern is selected to be optically detectable when applied in areas overlaying the content. The markings 402 may be formed from two separate colours where they overlap a portion of the content or entirely from a contrasting colour where they are contained within the edges of portion of the content. The pattern can be used as part of a digital pen (300, figure 3) and paper (100, figure 1) system and printed using standard inks.

Description

DATA ENCODING PATTERN, SYSTEM AND METHOD

FIELD OF THE INVENTION

The present invention relates to a data encoding pattern, and more specifically, but not exclusively, to an optically detectable pattern for use with a digital pen and paper system.

BACKGROUND

Many digital pen and paper systems have been proposed. One that is in use is the Anoto system, which can be implemented using a device such as the Logitech 102 pen, available from Logitech of 6505 Kaiser Drive, Fremont, Calif. 94555, USA.

Generally, using such technology, the pen senses a position determining pattern that has been printed onto a page and an evaluation of the pen's position, and movements, is made using data collected by the pen.

WO 03/046708 discloses a system of this kind. In the known Anoto type arrangements, the pen is connected by a Universal Serial Bus (USB) cable or wirelessly to a processing device such as a mobile telephone or a personal computer. The processing device receives data from the pen and can identify the document which has been marked by the pen.

This can result in the processing device determining information about how the document should be handled. This information may identify an application, perhaps stored on the processing device or held remotely, which enables the information from the pen to be processed.

In order for systems such as those described above to function correctly, a position encoding pattern printed on the digital paper must be discernable from other content such as text or images for example. A typical solution is to print the encoding pattern and the content using different inks. For example, the data encoding pattern can be printed using infra-red or ultraviolet ink which can only be sensed using a suitable sensor, and which is not affected by over printing with another IR transparent ink which is detectable in the visible region of the spectrum. This enables the detector to detect the pattern using light at a wavelength that is absorbed or reflected by the pattern but not the content, or by the content and not the pattern.

US20050063000 (Silverbrook) describes a printer for printing an interface onto a surface using a complementary ink set.

However, this requires the use of two different inks, which can add to the complexity of the printing process.

Furthermore, the large number of users with standard printers requires a more generic solution. For example, the space of existing installed printers requires a solution which does not necessitate a printer to be modified.

SUMMARY OF THE PRESENT INVENTION

According to a first aspect of the present invention there is provided a method of applying a data encoding pattern to a product, the method comprising analysing a content to be applied to the product, on the basis of the analysis, determining a marking colour for at least a portion of a marking of the pattern such that the marking colour is optically detectable with respect to the content.

According to a second aspect of the present invention there is provided a method of applying a data encoding pattern to a product, the method comprising analysing a content to be applied to the product, adapting a parameter of at least a marking of said pattern on the basis of the analysis, and applying the content and the or each adapted marking to the product.

According to a third aspect of the present invention there is provided a printing device operable to apply a position identifying pattern to a product, the device further operable to analyse a content to be applied to the product, and on the basis of the analysis, determine a marking colour for at least a portion of a marking of the pattern to be applied, such that the marking colour is optically detectable with respect to the content.

According to a fourth aspect of the present invention there is provided a computer program product for use with a computing device, said computer program product comprising, a computer useable medium having computer executable program code embodied thereon, wherein said product is operable, in association with said device, to effect application of a data encoding pattern to a product, by, analysing a content to be applied to the product, and on the basis of the analysis, determine a marking colour for at least a portion of a marking of the pattern such that the marking colour is optically detectable with respect to the content.

According to a fifth aspect of the present invention there is provided a computer program, comprising machine readable instructions, wherein said program is arranged, in association with said machine, to apply a data encoding pattern to a product, by, analysing a content to be applied to the product, adapting a parameter of at least a marking of said pattern on the basis of the analysis, and applying the content and the or each adapted marking to the product.

BRIEF DESCRIPTION OF THE FIGURES

For a better understanding of the present invention, and to further highlight the ways in which it may be brought into effect, embodiments will now be described, by way of example only, with reference to the following drawings in which:- Figure 1 is a schematic representation of a product comprising a data encoding pattern and content; Figure 2 is schematic representation of a portion of an exemplary data encoding pattern; Figure 3 is a schematic representation of a detector for use with the product of figure 1; and Figure 4 is a schematic representation of a format for markings of a data encoding pattern when applied over content to a product.

It should be emphasised that the term "comprises/comprising" when used in this specification specifies the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

DETAILED DESCRIPTION

Referring to figure 1, a document 100 for use in a digital pen and paper system comprises a carrier 102 in the form of a single sheet of paper 104 with position identifying markings 106 printed on some parts of it to form areas 107 of a position identifying pattern 108. Also printed on the paper 104 are further markings 109 which are clearly visible to a human user of the form, and which make up the content of the document 100. The content 109 will obviously depend entirely on the intended use of the document. The content, format or use of the document described with reference to figure 1 is not intended to be limiting.

In this case an example of a very simple questionnaire document is shown. The content comprises a number of boxes 110, 112 which can be pre-printed with user specific information such as the user's name 114 and a document identification number 116. The content further comprises a number of check boxes 118 any one of which can be marked by a user, and two larger boxes 120, 121 in which the user can write comments, as well as some printed text and images.

The form content also comprises a send box 122 which can be checked by the user when they have completed the questionnaire. When ticked or marked, this can initiate a document completion process by which pen stroke data and typographical information on the form such as the headings or labels 124 for the various boxes 110, 112, 118, 120 is forwarded for processing for example.

A position identifying pattern 108 can be printed onto the parts of the form which the user is expected to write on or mark, within the check boxes 118, the comments boxes 120, 121 and the send box 122 for example, or over the entire page.

Referring to figure 2, an exemplary position identifying pattern 108 is made up of a number of markings 130. The arrangement of the markings defines an imaginary pattern space, and only a small part of the pattern space need be taken up by the pattern on the document 100. By allocating a known area of the pattern space to the document 100, for example by means of a co-ordinate reference, the document and any position on the patterned parts of it can be identified from the pattern printed on it. It will be appreciated that many position identifying patterns can be used. Some examples of suitable patterns are described in WO 00/73983, WO 01/26033 and Wa 01/71643 for example.

Referring to figure 3, a digital pen 300 comprises a writing stylus 310, and a camera 312. The camera 312 is arranged to image an area adjacent to the tip 311 of the pen stylus 310.

A processor 318 processes images from the camera 312. A pressure sensor 320 detects when the stylus 310 is in contact with the document 100 and triggers operation of the camera 312. Whenever the pen is being used on a patterned area of the document 100, the processor 318 can therefore determine from the pattern 108 the position of the stylus of the pen whenever it is in contact with the document 100.

From this it can determine the position and shape of any marks made on the patterned areas of the document 100. This information is stored in a memory 322 in the pen as it is being used.

The pen is provided with an output port which can comprise at least one electrical contact that connects to corresponding contacts on a base station (not shown) Alternatively, the pen and base station can communicate wirelessly using an infra-red or radio frequency communications link such as Wi-Fi or Bluetooth for example.

Other alternatives are possible.

Although reference is made herein to a digital pen comprising a camera this is not intended to be limiting, as it will be appreciated that all which is required in order to effectively image a pattern is an image capturing device.

Such a device can be incorporated into a number of products, not just a pen. For example, an image capture device can be incorporated into a mobile station such as a mobile telephone or pager, or in a personal digital assistant for example. Other alternatives are possible.

According to an embodiment, a position encoding pattern 108 can be printed onto a carrier in addition to other content such as text and/or pictures/drawings for example. The pattern, and more specifically the markings of the pattern are printed in such a way to ensure that it is detectable with respect to any other content on the page. According to an embodiment a marking of pattern 108 can be printed so that the marking changes colour over the edges of content, or responds to colour changes in the content. Any portion of a marking which overlays content can be colour adjusted to ensure detectability.

Figure 4 is a schematic representation of some text (content) and markings for a position identifying pattern 108. The text is magnified in order to illustrate a way in which markings and content can be printed onto a product such as a carrier. A marking 401 is not printed over any content (which, in this case is the word "Text"), and so it can take a standard form, such as a dot, or other suitable shape, perhaps composed of a number of sub-markings for example. Marking 402 of the pattern overlaps with some of the content, and is therefore advantageously adapted in order to effect a change of colour over the edge of the content and for the portion of the marking which overlays the content in question as depicted in figure 4. The outline of marking 402 is therefore preserved. More specifically, the change in colour of marking 402 preserves contrast between the marking and the content.

Marking 403 is located completely within some of the content, and its colour is adjusted accordingly. Marking 403 is colour adjusted to a colour which contrasts that of the content in order to allow the marking to be detected.

According to an embodiment, content to be printed to a product is analysed prior to printing in order to determine a layout and colour of markings for a position identifying pattern. The content can be analysed using a suitable processor of a computing device or printer for example, and any analysis can be carried out immediately prior to printing, on the fly (i.e. as content is being printed), or prior to printing - for example, content can be analysed remotely and results can be transmitted wirelessly or using a wired link (via the internet for example) . Other alternatives are possible.

According to an embodiment, the disposition of markings on a product is not dependent on the product content. Once content has been analysed prior to printing, a parameter of the markings for the pattern which are determined as either overlapping a portion of the content (such as 402 for example), or which are completely within a portion of the content (such as 403 for example) can be adjusted in order ensure that such markings remain optically detectable when the content and markings are printed on the product.

According to an embodiment, and as explained above, such markings can be colour adjusted, such that the adjusted marking parameter is its colour, or a portion of its colour depending on the amount by which the marking in question overlays content.

The colour to which a marking or a portion thereof is adjusted if any overlap with content occurs can depend on the colour of that content. In the example of figure 4, the content and markings are printed in black, and the background is white. Markings 402, 403 have therefore been adjusted in order to make them detectable in a black/white colour pair. It will be appreciated that the portion of 402, and 403 can be printed in a colour other than white.

All that is required is that the marking/content contrast is sufficient to ensure that a marking is detectable. This can be achieved using contrasting colour pairs for marking/content. In the example of figure 4, a black/white colour pair is used for the marking/content to ensure contrast. Other colour pairs can be used depending on the content colour. For example, red or green content can be overlaid with green or red (respectively) markings as appropriate. Other colour pairings are possible, such as red and cyan, green and magenta, or blue and yellow for example. It will be appreciated that the above pairings are complementary colour pairs. Other colour pairings can be used as desired. For example, colours from the CYMK colour space can be used. Alternatively, markings can be halftone or dithered, i.e. a marking can be composed of a cluster/group of more than one colour, to ensure contrast over the content.

According to an embodiment, a marking can be detected in a number of ways. Providing the colour of the marking and its surroundings are sufficiently contrasting to enable the marking to be optically detectable, the marking can be detected using the image capture device (camera) of a digital pen (or similar device as appropriate). More specifically, an imaged area can be processed in order to determine if there are portions of the area which correspond to markings. Alternatively, a marking can be detected on the basis of the absolute value, or function thereof, of centre-surround differences between a colour value of the marking and its surroundings. Further alternatively, a marking can be detected using a parametric model operable to model a form of a marking. Such a model, or set thereof, can be stored in a memory of the detector (pen, for example) . Advantageously, marking detection can be performed irrespective of a product orientation.

According to an embodiment, a computing device as described above which is operable to analyse content to be printed can include a memory comprising data representing a type of detector to be used in conjunction with the content to be printed by it, and/or data representing the detector (for example a digital pen) and position identifying pattern detection pipeline used by a user. The computing device or printer can be adapted to adapt printed content accordingly and on the basis of the stored data. For example, a particular detector (pen) can have a particular spectral sensitivity profile and the pattern printing device can take advantage of this fact by using its printer gamut to the full in order to maximally separate markings and content, and/or provide a maximal level of contrast between markings and content given the detector and pipeline characteristics.

Accordingly, an optically detectable position identifying pattern for use in a digital pen and paper system, for example, can be printed using standard ink (in the sense that they do not move printed data into a nonvisible part of the spectrum) and over arbitrary content. Digital-penand-paper-enables content can be created using a standard consumer printer and ink for example.

Claims

CLAIMS: 1. A method of applying a data encoding pattern to a product, the

method comprising: analysing a content to be applied to the product; and on the basis of the analysis, determining a marking colour for at least a portion of a marking of the pattern such that the marking colour is optically detectable with respect to the content.
2. A method as claimed in claim 1, wherein analysing a content of the product comprises determining a colour of at least a portion of the content.
3. A method as claimed in claim 2, wherein the marking colour is selected to contrast with the content colour.
4. A method as claimed in any preceding claim, further comprising: determining if at least a portion of a marking for the pattern overlays a portion of the content; and on the basis of the determination, adjusting the colour of the marking portion which overlays the content.
5. A method as claimed in any of claims 2 to 4, wherein the marking colour and the content colour are optically distinguishable.
6. A method as claimed in claim 5, wherein the marking colour and the content colour form a colour pair comprising any two colours from either of the RGB or CYMK colour spaces.
7. A method as claimed in any preceding claim, wherein analysing product content further comprises: determining edge data for the content representing edges of the content; and on the basis of the edge data, determining a disposition for markings such that said markings do not fall within a desired boundary around said edges.
8. A method as claimed in claim 7, wherein the edge data relates to edges of background content to be applied to the product.
9. A method as claimed in any preceding claim, wherein the data encoding pattern is used to determine changes in position of a detector, which detector is used in conjunction with the product.
10. A method as claimed in claim 9, wherein the detector is a digital pen comprising an image capturing device, the pen operable to apply a marking to the product.
11. A method as claimed in any preceding claim, wherein the marking colour is selected in order to provide a level of contrast between it and a colour of the surrounding content sufficient to enable the marking to be optically detectable.
12. A method as claimed in claim 11, wherein the marking is optically detectable when it can be imaged and distinguished by a suitable image capture device.
13. A method as claimed in claim 11 or 12, wherein the level of contrast is determined on the basis of a colour of content surrounding a marking in question.
14. A method as claimed in any preceding claim, further comprising: detecting a marking using a detector; and on the basis of the detection determining if a change in position of the detector has occurred.
15. A method as claimed in claim 14, wherein the marking is detected using an absolute value, or function thereof, of centre-surround differences of a colour value of the marking and the content surrounding the marking.
16. A method as claimed in claim 14, wherein the marking is detected using a parametric model, the model operable to model the marker form.
17. A method as claimed in claim 15 or 16, wherein detecting a marking is independent of an orientation of said product.
18. A method as claimed in any preceding claim, further comprising: applying said data encoding pattern and said content to the product.
19. A method of applying a data encoding pattern to a product, the method comprising: analysing a content to be applied to the product; adapting a parameter of at least a marking of said pattern on the basis of the analysis; and applying the content and the or each adapted marking to the product.
20. A method as claimed in claim 19, wherein a marking parameter comprises at least on of a marking colour, and a disposition of a marking with respect to said content.
21. A method as claimed in any preceding claim, wherein the product is a carrier.
22. A method as claimed in any preceding claim, wherein applying the pattern comprises printing the pattern to the product.
23. A printer for applying a position identifying pattern to a product in accordance with the method as claimed in any preceding claim.
24. A printing device operable to apply a position identifying pattern to a product, the device further operable to: analyse a content to be applied to the product; and on the basis of the analysis, determine a marking colour for at least a portion of a marking of the pattern to be applied, such that the marking colour is optically detectable with respect to the content.
25. A device as claimed in claim 24, wherein analysing a content to be applied comprises: determining a colour for a portion of said content; and on the basis of the determination, selecting a marking colour for at least a portion of a marking to be applied within said portion of said content.
26. A device as claimed in claim 25, wherein a selected marking colour contrasts sufficiently with said content colour in order to enable the marking to be optically distinguishable from the content colour.
27. A device as claimed in any of claims 24 to 26, further comprising a memory operable to store data relating to a detector for use with said product, wherein the device is operable to use the data in order to determine a marking colour.
28. A device as claimed in any claims 24 to 26, further comprising a memory operable to store data relating to a parameter of a detector for use with said product, wherein the device is operable to use the data in order to adapt at least a portion of a marking colour to be printed.
29. A device as claimed in claim 27 or 28, wherein the device is operable to use the data in association with the determined content colour.
A device as claimed in any of claims 27 to 29, wherein the detector is a digital pen comprising an image capture device.
31. A logic circuit programmed to operate in accordance with the method as claimed in any of claims 1 to 22.
32. A computer program product for use with a computing device, said computer program product comprising: a computer useable medium having computer executable program code embodied thereon, wherein said product is operable, in association with said device, to effect application of a data encoding pattern to a product, by: analysing a content to be applied to the product; and on the basis of the analysis, determine a marking colour for at least a portion of a marking of the pattern such that the marking colour is optically detectable with respect to the content.
33. A product as claimed in claim 32, wherein the computing device comprises a printer for printing at least one of the content and the pattern to the product.
34. A computer program, comprising machine readable instructions, wherein said program is arranged, in association with said machine, to apply a data encoding pattern to a product, by: analysing a content to be applied to the product; adapting a parameter of at least a marking of said pattern on the basis of the analysis; and applying the content and the or each adapted marking to the product.
35. A method substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
36. A device substantially as hereinbefore described with reference to and as shown in the accompanying drawings.