Correcting Image Capture Distortion

Abstract

The present disclosure relates generally to improving readability of machine-readable information, despite signal capture distortion. One claim recites an apparatus comprising: memory for storing input data; an electronic processor programmed for: altering a digital watermark or a digital watermarking process to pre-distort a digital watermark signal, wherein the altering is intended to counteract or compensate for expected distortion so as to enable machine-based detection of an embedded, pre-distorted digital watermark signal despite the expected distortion, wherein the expected distortion includes distortion associated with optical capture of the input data; and embedding the pre-distorted digital watermark signal in the input data. Of course, other claims and combinations are provided as well.

1 . A method comprising:
 obtaining input data;   using a programmed processor, altering a digital watermark or a digital watermarking process to pre-distort a digital watermark signal, wherein the altering is intended to counteract or compensate for expected distortion so as to enable machine-based detection of an embedded, pre-distorted digital watermark signal despite the expected distortion, wherein the expected distortion includes distortion associated with optical capture of the input data; and   embedding the pre-distorted digital watermark signal in the input data.   
     
     
         2 . The method of  claim 1  further comprising printing or engraving the input data including the pre-distorted digital watermark signal. 
     
     
         3 . The method of  claim 1  wherein the input data comprises data representing an image or video. 
     
     
         4 . The method of  claim 1  wherein the altering utilizes a model of the distortion resulting from optical capture. 
     
     
         5 . The method of  claim 1  wherein the expected distortion includes blurring resulting from optical capture of the printed or engraved input data. 
     
     
         6 . The method of  claim 5  wherein the blurring is associated with lens focal length. 
     
     
         7 . The method of  claim 5  wherein the blurring—left uncompensated for—would result in a loss of high frequency information of the digital watermark signal upon signal detection. 
     
     
         8 . The method of  claim 1  wherein said act of altering alters a phase of the digital watermark signal relative to the expected distortion. 
     
     
         9 . The method of  claim 8  wherein an altered phase of the digital watermark signal causes the digital watermark signal to be less readable in the absence of the expected distortion. 
     
     
         10 . The method of  claim 1  wherein expected distortion is modeled as a convolution of the input data with a predetermined function. 
     
     
         11 . The method of  claim 10  wherein the predetermined function is approximated by a Bessel function. 
     
     
         12 . The method of  claim 1  wherein the expected distortion is associated with lens focal length. 
     
     
         13 . A non-transitory computer readable medium comprising instructions or circuitry to perform the method of  claim 1 . 
     
     
         14 . An apparatus comprising:
 memory for storing input data;   an electronic processor programmed for:
 altering a digital watermark or a digital watermarking process to pre-distort a digital watermark signal, wherein the altering is intended to counteract or compensate for expected distortion so as to enable machine-based detection of an embedded, pre-distorted digital watermark signal despite the expected distortion, wherein the expected distortion includes distortion associated with optical capture of the input data; and 
 embedding the pre-distorted digital watermark signal in the input data. 
   
     
     
         15 . The apparatus of  claim 14  in which the electronic processor controls printing or engraving of the input data including the pre-distorted digital watermark signal. 
     
     
         16 . The apparatus of  claim 14  wherein the input data comprises data representing an image or video. 
     
     
         17 . The apparatus of  claim 14  wherein the altering utilizes a model of the distortion resulting from optical capture. 
     
     
         18 . The apparatus of  claim 14  wherein the expected distortion includes blurring resulting from optical capture of the printed or engraved input data. 
     
     
         19 . The apparatus of  claim 18  wherein the blurring is associated with lens focal length. 
     
     
         20 . The apparatus of  claim 18  wherein the blurring—left uncompensated for—would result in a loss of high frequency information of the digital watermark signal upon signal detection. 
     
     
         21 . The apparatus of  claim 14  wherein the altering alters a phase of the digital watermark signal relative to the expected distortion. 
     
     
         22 . The apparatus of  claim 21  wherein an altered phase of the digital watermark signal causes the digital watermark signal to be less readable in the absence of the expected distortion. 
     
     
         23 . The apparatus of  claim 14  wherein expected distortion is modeled as a convolution of the input data with a predetermined function. 
     
     
         24 . The apparatus of  claim 23  wherein the predetermined function is approximated by a Bessel function. 
     
     
         25 . The apparatus of  claim 14  wherein the expected distortion is associated with lens focal length.