SECURITY PRINTING USING MIXED SPOT SIZES IN STOCHASTIC OR FREQUENCY MODULATED HALFTONE IMAGES

1 - 7 . (canceled)

8 . A method of securely rendering a security feature in an image printed with digital image data, comprising:

printing the image with an ink-jet printer;

placing on a print sheet a plurality of drops; and

printing with at least two drop sizes among the plurality of drops to embed information within an image comprising at least one of a stochastic halftone image or a frequency modulated (FM) halftone image.

9 . The method of claim 8 further comprising: rendering a part of the image with a first drop among the plurality of drops and a remaining portion of the image with a second drop among the plurality of drops, wherein the second drop is smaller in size than the first drop.

10 . The method of claim 8 further comprising:

rendering the image using two states including a first state and a second state, wherein the first state among the two states utilizes larger sized drops as compared to the second state during a halftone rendering of the image; and

controlling a contrast of the rendering of the image according to differences in a mixing ratio of larger drops with respect to smaller drops among the plurality of drops.

11 . The method of claim 8 further comprising:

controlling by a contone image, a continuous modulation of the mixing of the varying drop sizes among the plurality of drops to embed the information within the stochastic halftone image or the FM halftone image.

12 . The method of claim 8 wherein the plurality of drops comprises more than two drops, wherein the more than two drops are used to create differentiations in the mixing.

13 . The method of claim 8 further comprising:

detecting the embedded information by capturing an image of the embedded information; and

processing the image to reveal a hidden security mark in the embedded information.

14 . The method of claim 8 further comprising:

capturing video containing the embedded image;

decoding the video of the embedded image in real time; and

displaying on a display screen, a decoded image containing the embedded image on a display screen.

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18 . A system for securely rendering a security feature with image data to be printed, comprising:

at least one processor and a memory, the memory storing instructions to cause the at least one processor to perform:

providing within the image data, data relating to a plurality of spots; and

within the image data, mixing spots of at least two spot sizes among the plurality of spots to embed information within an image comprising at least one of a stochastic halftone image or a frequency modulated (FM) halftone image.

19 . The system of claim 18 wherein the instructions are further configured for rendering a part of the image with a first spot among the plurality of spots and a remaining portion of the image with a second spot among the plurality of spots, wherein the second spot is smaller in size than the first spot.

20 . The system of claim 18 wherein the instructions are further configured for:

rendering the image using two states including a first state and a second state, wherein the first state among the two states utilizes larger sized spots as compared to the second state during a halftone rendering of the image; and

controlling a contrast of the rendering of the image according to differences in a mixing ratio of larger spots with respect to smaller spots among the plurality of spots.

21 . The system of claim 18 wherein the instructions are further configured for:

controlling by a contone image, a continuous modulation of the mixing of the varying spot sizes among the plurality of spots to embed the information within the stochastic halftone image or the FM halftone image.

22 . The system of claim 18 the plurality of spots comprises more than two spots, wherein the more than two spots are used to create differentiations in the mixing.

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32 . A method of printing an image of a uniform patch, the uniform patch having an appearance of a uniform halftone, the uniform patch having at least a first region and a second region, wherein the first region comprises a first relative proportion of spots of a first size and spots of a second size, and the second region comprises a second relative proportion of spots of the first size and spots of the second size, the method comprising:

using switch data associated with a hidden image to distinguish between the first region and the second region;

the switch data causing modulation of one of amplitude or frequency of spots in print data associated with at least one region.

33 . The method of claim 32 further comprising preparing the first region and the second region with different compositions of spots including small spots and large spots.

34 . The method of claim 32 further comprising using a hidden image to select the first region or the second region to print at least a part of the image.

35 . The method of claim 34 further comprising filtering and adjusting a density of the image to reveal the hidden image.

36 . The method of claim 35 wherein filtering and adjusting a density of the image further involves bandpass filtering and subsequent smoothing of the image.

37 . The method of claim 32 further comprising forming the image as a final composite image for printing by combining portions rendered of the first region and the second region.

38 . The method of claim 32 further comprising embedding information with the image, wherein the image comprises at least one of a: stochastic halftone image or a frequency modulated halftone image.

39 . The method of claim 38 further comprising displaying a decoded image containing the embedded information in the image.

40 . (canceled)