IMAGE PROCESSING APPARATUS, IMAGE PROCESSING METHOD, AND STORAGE MEDIUM

• US 20160080603A1
• Filed: 08/25/2015
• Published: 03/17/2016
• Est. Priority Date: 09/12/2014
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Song, Wei, Iguchi, Ryosuke, Miyake, Nobutaka, Ishida, Yuki
• Granted Patent: US 9,602,691 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06T 1/005 Robust watermarking, e.g. average attack or collusion attack resistant
• CPC Class Codes: G06T 2201/0051 Embedding of the watermark in the spatial domain
• CPC Class Codes: G06T 2201/0065 Extraction of an embedded watermark; Reliable detection
• CPC Class Codes: H04N 1/00278 with a printing apparatus, e.g. a laser beam printer
• CPC Class Codes: H04N 1/00307 with a mobile telephone apparatus constructional features of portable telephone sets H04M1/0202; mobile radio systems H04W84/00
• CPC Class Codes: H04N 1/00827 Arrangements for reading an image from an unusual original, e.g. 3-dimensional objects
• CPC Class Codes: H04N 1/32352 Controlling detectability or arrangements to facilitate detection or retrieval of the embedded information, e.g. using markers for decoding, detection or retrieval operations H04N1/32149 and subgroups take precedence
• CPC Class Codes: H04N 2201/0081 Image reader H04N2201/0091 - H04N2201/0094 take precedence
• CPC Class Codes: H04N 2201/327 which are undetectable to the naked eye, e.g. embedded codes
• CPC Class Codes: H04N 2201/3271 Printing or stamping

Abstract

Upon capturing a digital watermark-embedded print product by an image capturing device held by the hand of a user and extracting embedded information, the relative speed between the hand-held image capturing device and the print product changes, failing in extracting the embedded additional information. In an embodiment, the image capturing device performs continuous shooting for every small area to read the print product. A shoot image is analyzed to calculate the feature amount of the image. Information about an image capturing quality characteristic generated at the time of capturing the print product is estimated, and a change of the feature amount accompanying the image capturing quality characteristic is predicted based on the estimation result. A code indicated by the watermark is determined based on the calculation result and the prediction result.

Claims

1. An image processing apparatus comprising:

an input unit configured to input an image obtained by capturing, by an image capturing device, a print product in which a digital watermark is embedded;

an obtaining unit configured to obtain information about a moving direction of the image capturing device with respect to the print product in image capturing of the print product; and

a determination unit configured to, based on the information obtained by said obtaining unit and frequency characteristics in a partial area of the image input by said input unit determine a code corresponding to the digital watermark embedded in the partial area.

2. The apparatus according to claim 1, wherein

said input unit inputs a plurality of images obtained by performing a continuous shooting of different areas on the print product, and

said determination unit determines a code corresponding to a partial area in each of the plurality of images.

3. The apparatus according to claim 1, wherein said obtaining unit obtains information about the moving direction of the image capturing device based on a detection result of a sensor of the image capturing device.

4. The apparatus according to claim 1, wherein

in a case where the partial area contains a frequency component higher than a predetermined frequency, said determination unit determines a code based on the frequency component, and

in a case where the partial area does not contain a frequency component higher than the predetermined frequency, said determination unit determines a code based on the information obtained by said obtaining unit.

5. The apparatus according to claim 1, wherein information is embedded in the digital watermark on the print product by modulating the frequency characteristics of the image.

6. The apparatus according to claim 5, wherein the information is embedded in the digital watermark by associating a difference in a band of the modulation with a code.

7. The apparatus according to claim 1, further comprising a detection unit configured to detect a geometric shift between the print product included in the image input by said input unit and the image captured by the image capturing device.

8. The apparatus according to claim 7, wherein said determination unit predicts, as a change of an image capturing quality characteristic, a change of the frequency characteristics of the image input by said input unit based on the geometric shift detected by said detection unit, and information from a sensor that is integrated in the image capturing device and detects a motion of the image capturing device, and

said determination unit determines the code based on the prediction.

9. The apparatus according to claim 1, wherein said determination unit obtains the frequency characteristics by applying a filter regarding the frequency characteristics to an image input by said input unit.

10. The apparatus according to claim 1, wherein said obtaining unit obtains information about a blur of the image.

11. The apparatus according to claim 1, wherein said determination unit determines the code based on the information obtained by said obtaining unit, the frequency characteristics, and an image capturing condition of the image capturing device.

12. The apparatus according to claim 1, wherein said determination unit uses information about power in each specific band as the frequency characteristic, and determines the code based on the information.

13. The apparatus according to claim 12, wherein the information is information associated with deviation of power in said each specific band.

14. The apparatus according to claim 12, wherein the information is information associated with attenuation of power in said each specific band.

15. The apparatus according to claim 1, wherein the image capturing device is integrated in the image processing apparatus.

16. An image processing method comprising:

inputting an image obtained by capturing, by an image capturing device, a print product in which a digital watermark is embedded; and

based on information about a moving direction of the image capturing device with respect to the print product in image capturing of the print product, and frequency characteristics in a partial area of the input image, determining a code corresponding to the digital watermark embedded in the partial area.

17. A non-transitory computer readable storage medium which stores a computer program to be executed in a processor of an image processing apparatus, the program comprising:

inputting an image obtained by capturing, by an image capturing device, a print product in which a digital watermark is embedded; and

based on information about a moving direction of the image capturing device with respect to the print product in image capturing of the print product, and frequency characteristics in a partial area of the input image, determining a code corresponding to the digital watermark embedded in the partial area.