Abstract:
The present invention relates to image processing in which an image resolution of input image data is compared to information of predetermined standard resolution, and the image data is judged to determine whether it includes specific information related to copy protection. Whether or not to perform judging is controlled based on the result of the comparison. Because the control technique of the present invention controls whether or not to perform the judgment based on the result of the c comparison, the control technique according to the invention provides an efficient judging processing, since no judgment is performed on low resolution image data which is not prone to counterfeiting.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to an image processing apparatus, an image processing method and a computer program product for judging whether image data include specific information related to copy protection. 
   2. Description of the Related Art 
   In connection with color copying machines, implementing an image recognition processing function to prevent counterfeiting of a copy-prohibited object, such as a banknote or valuable securities has been considered. One drawback of color copying machines is that they are expensive stand-alone devices. More recently, high quality copying has been attained using less expensive computers, computer peripheral apparatuses such as a color scanner and a color printer, and image processing software to edit an input and output image. A need has developed for using an image recognition processing function to prevent counterfeiting of a banknote and valuable securities for an inexpensive color image processing system using a color scanner and printer. 
   There are some known judging methods for judging whether an original is a copy-prohibited object or not. An original is judged based on a color spectrum distribution of image data (R,G,B data for each pixel) generated by scanning the original, and a comparison of the color spectrum distribution with copy-prohibited object data stored in a ROM, or based on a comparison of an image pattern of a part of the original(or the entire original) with a copy-prohibited object pattern stored in a ROM. The result of the judging is an evaluation value as to whether the original is a copy-prohibited object or not. 
   It is recently possible to make a copy-prohibited object by using a technology called digital watermark. The copy-prohibited object is altered to include information indicating whether the object is a copy-prohibited object. The process of making the copy-prohibited object is as follows. First, second digital information (sub-information) indicating that the object is copy-prohibited is attached to digital image data as the first digital information (main-information). Next, a printed document is made from the digital image data including the attached second information. Of course, the second digital information indicating that the object is copy-prohibited can be detected from the digital image data as a characteristic of the digital watermark. It is possible to detect the second digital information indicating that the object is copy-prohibited from newly-created image data which is created from the printed document by an image reading apparatus (e.g., a color scanner). This technology is called digital watermark and is increasingly used for prohibiting illegal copying of printed material. 
   In view of widespread use of computer peripherals to make color copies, a judging process chiefly made of software for a copy-prohibited object is preferable to a hardware one comprising many electrical circuits. Such a software process, however, uses too much processing power and takes too long to judge whether an image is of a copy-prohibited object or not and to process the image. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to address the above situation. 
   One particular object of the present invention is to provide an image processing apparatus and method and a computer program product that can avoid unnecessary processing and can provide a faster judgment of whether or not an object is copy-prohibited. 
   Another object of the present invention is to provide an image processing apparatus and method and a computer program product that have a new function not known before. 
   According to one aspect, the present invention, which achieves these objectives, relates to image processing in which an image resolution of input image data is compared to information of predetermined standard resolution and the image data is judged to determine whether it includes specific information related to copy protection, wherein whether or not to perform the judging is controlled based on the result of the comparison. 
   Because the control technique of the present invention controls whether or not to perform the judgment based on the result of the comparison, the control technique according to the invention provides an efficient judging processing, since no judgment is performed on low resolution image data which is not prone to counterfeiting. 
   The foregoing and still other objects, features and advantages of the present invention will become fully apparent from the following description to be taken in conjunction with the attached drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a diagram which shows the image processing apparatus of this invention. 
       FIG. 2  is a diagram which shows one embodiment of an image processing system of the present invention. 
       FIG. 3  is a block diagram that shows the main portion of  FIG. 2 . 
       FIG. 4  is a flow chart which shows the process sequence by using the construction of  FIG. 2  and  FIG. 3 . 
       FIG. 5  is a flow chart which shows the process sequence of a third embodiment. 
       FIG. 6  is a flow chart which shows a modification of the process sequence of  FIG. 4 . 
       FIG. 7  is a flow chart which shows a modification of the process sequence of  FIG. 4 . 
       FIG. 8  is a flow chart which shows a modification of the process sequence of  FIG. 5 . 
       FIG. 9  is a flow chart which shows a modification of the process sequence of  FIG. 5 . 
       FIG. 10  is a diagram which shows a sixth embodiment of the image processing system of the present invention. 
       FIG. 11  is a block diagram that shows the main portion of  FIG. 10 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  is a block diagram which shows an image processing apparatus of this invention. 
   Input image data control means  110  controls a resolution of an image which is read by image data source  120  as an image scanner. Image data generating means  130  generates image data of an image resolution which is controlled by input image data control means  110 . Memory  140  stores the image data generated by image data generating means  130 . Data attaching means  150 , which is controlled by main control means  200  based on the image resolution controlled by input image data control means  110 , attaches digital data to the image data stored in memory  140 . Image character recognition means  160 , which is controlled by main control means  200  based on the image resolution controlled by input image data control means  110 , judges whether the image data stored in memory  140  belongs to a copy-prohibited object. 
   Recognition information output means  170  outputs a recognition result of the image character recognition means  160 . Recognition information receiving means  180  displays the recognition result on a display or the like, and receives the recognition result information and informs the image processing apparatus&#39;s user that an original based on said image data is a copy-prohibited object. Image data output means  190  outputs sequentially an output image. 
   Each function block in  FIG. 1  has the following description. Image data generating means  130  generates image data of a resolution which is indicated from an indicating means (unshown) of input image data control means  110  and is based on a preset image on image data source  120  and an indication by a user of the image processing apparatus. Information of the image resolution indicated by a user of the image processing apparatus is output to main control means  200  at the same time. Main control means  200  controls data attaching means  150 , image character recognition means  160  and recognition information output means  170  based on the information of the image resolution output from input image data control means  110 . 
   The First Embodiment 
   Information indicating that an object is copy-prohibited is attached to an original by using a technology called digital watermark in one preferable embodiment of this invention. 
   An original of the copy-prohibited object is formed by printing the image data with the attached information indicating that the object is copy-prohibited. The digital image data, with its attached information indicating that the object is copy-prohibited, is made by attaching second digital information indicating that the object is copy-prohibited to the first digital information which is a source of the printing object. The digital watermark may be any kind of digital watermark, such as one attached to a specific frequency of image information as invisible information or visible information that is difficult for human eyes to see, like yellow dots. 
   In an inexpensive color scanner or printer, it is preferable to carry out counterfeit prevention of a copy-prohibited object less expensively than in a comparatively expensive color copying machine as stated above. It is an effective answer to judge the copy-prohibited object by using a software process, but the software judging process has a problem related to processing speed. Accordingly, the present invention checks the possibility of whether a printing image based on an original could be used as a counterfeit, in accordance with image resolution. The possibility is the degree of risk that someone would mistake the counterfeit for a genuine one. 
   The following is a detailed explanation, which is made with reference to the drawings, of the preferred embodiments of this invention.  FIG. 2  shows one embodiment of an image processing system of the present invention. Image scanner  1  is an image input apparatus and a personal computer  2  processes image data input by image scanner  1 . Cable  3  connects image scanner  1  and personal computer  2  and communicates the image data. 
     FIG. 3  is a block diagram that shows the main portion of  FIG. 2 . CPU  11  is a central processing unit, RAM  12  is random access memory and ROM  13  is read only memory. Display control unit  14  controls display  15  and operation input unit  16  is a keyboard or a mouse. Connection I/O  17  is used for connecting operation input unit  16  to the image processing system. External memory unit  18  is a hard disk or a memory card etc. Connection I/O  19  is used for connecting external memory unit  18  to the image processing system. Bus  20  is used for communicating image data or other data. Image scanner  21  is the same as image scanner  1  in  FIG. 2 . Connection I/O  22  is used for receiving image data from image scanner  21  and sending control signals to image scanner  21 . Interface unit  23  is a communication unit like a network. 
     FIG. 4  is a flow chart which shows a process sequence based on performing a process of the system shown in  FIG. 2  and  FIG. 3 . A program that describes the process sequence of  FIG. 4  is stored in ROM  13  in advance or in external memory unit  18  and then the program is moved into RAM  12 . 
   CPU  11  executes the program to perform the process of this embodiment by software processes. The program is preferably a part of a scanner driver. 
   Reading image resolution, designated by the image system user, is stored in RAM  12  in step  10 . In step  20 , CPU  11  judges whether the designated image resolution {Rin} is less than a predetermined first standard resolution {T 1 }, e.g. 100 dpi [dot/inch]. This process is the first judgment. If the designated image resolution {Rin} is less than the predetermined first standard resolution {T 1 }, the process flows to step  40 . On the other hand, if the designated image resolution {Rin} is as high as the predetermined first standard resolution {T 1 }, the process flows to step  30 . As a result, a judgment of whether a scanned image is of a copy-prohibited object is not performed when the scanned image&#39;s resolution is less than a predetermined resolution since a printout of the scanned image is useless as a counterfeit. It is faster to print an image when the image resolution is less than the first standard density because the judgment of whether the object is copy-prohibited is not executed. 
   In step  30 , CPU  11  judges whether the designated image resolution {Rin} is less than the predetermined second standard resolution {T 2 }, e.g. 300 dpi [dot/inch]. This judgment is a second judgment. If the designated image resolution {Rin} is less than the predetermined second standard resolution {T 2 }, the process flows to step  41 . On the other hand, if the designated image resolution {Rin} is as high as the predetermined second standard resolution {T 1 }, the process flows to step  60 . It can be expected that a counterfeiter who scans a copy-prohibited object designates high resolution scanning. Accordingly, judgment as to whether a scanned image is of a copy-prohibited object executes when the scanned image has a high resolution. 
   In step  40  or  41 , CPU  11  judges that the image data of that image resolution is a low risk of counterfeiting and indicates, through the connection I/O  22 , that the color image scanner  21  is scanning an original on the flatbed at the user&#39;s designated image resolution. The image scanner scans the original. The image data based on the original is sent and stored in RAM  12  through the connection I/O  12 . After step  40 , the process of  FIG. 4  flows to step  90 . After step  41 , the process of  FIG. 4  flows to step  50 . 
   In step  50 , the image resolution is not high enough and is not suitable for inputting a vivid copy-prohibited object, but CPU  11  takes measures to prevent a counterfeit of the copy-prohibited object by way of caution. Specifically, CPU  11  attaches the product number of personal computer  2  or color image scanner  1  and the user ID information to the image stored in RAM  12 . The attached information is registered when a driver of the color image scanner  1  is installed. If the image stored in RAM  12  is printed or is output to an external apparatus through a network, it is thus possible to identify the person or apparatus that scanned the copy-prohibited object by using the attached information. The attachment is performed by the technology of digital watermark. After step  50 , the process of  FIG. 4  flows to step  90 . 
   In step  60 , since there is a possibility of inputting the copy-prohibited object as a vivid image, CPU  11  judges that image data of that image resolution has a high risk of counterfeiting and performs extraction of digital watermark data attached to the copy-prohibited object from the image stored in RAM  12 . CPU  11  indicates, through connection I/O  22 , to color image scanner  21  to scan an original on the flatbed at a lower image resolution than the user&#39;s designated one. Color image scanner  21  scans the original at the lower image resolution. The image data generated by the scanning is sent to RAM  12  through the connection I/O  22 . This scanning is carried out by using a well-known function of a color image scanner driver. After step  60 , the process of  FIG. 4  flows to step  70 . 
   In step  70 , CPU  11  judges whether the lower resolution image data generated by the scanning is of a copy-prohibited object or not. If CPU  11  judges that the lower resolution image data belongs to a copy-prohibited object, the process flows to step  80 . On the other hand, if CPU  11  judges that the lower resolution image data is not of a copy-prohibited object, the next process is step  42 . Step  42  is the same as step  40  or  41 , and the process flows thereafter to step  90 . 
   In Step  80 , the lower resolution image data generated by the scanning is output as a processed image. Specifically, the lower resolution image data generated by the scanning is output 1) after converting color or changing image size, and/or 2) after attaching any symbol or figure as a processed image. The processed image is not equal to the scanned image data. 
   It is easy to make the processed image from the image stored in RAM  12  by using a well-known image processing program module corresponding to 1) and 2) under CPU  11 &#39;s control. The processed image is output to external memory unit  18  as an image data file through the connection I/O  19 . The process terminates when step  80  has finished. 
   In step  90 , the image data scanned in step  42  is output to external memory unit  18  as an image file through the connection I/O  19 , when CPU  11  judges that the lower resolution image data generated by the scanning is not of a copy-prohibited object. The process terminates when step  90  has finished. 
   The original as a print document, which is made from the digital image data with attached information indicating that the object is copy-prohibited as a digital watermark, is scanned by color image scanner  21 . The judgment of whether the object is copy-prohibited in step  80  is performed by extracting the digital watermark from the scanned image data. 
   In step  80 , it is possible to select another process in which the image data generated by the scanned image is not output at all. As a result, the image of the copy-prohibited object cannot be input in the first place. Of course, it may be good to give warning indicating that the original is copy-prohibited. The warning is displayed on the display  15  through display control unit  14 . The warning has the advantage of stopping mischief and preventing the mistake of using a copy-prohibited object for the original. 
   It is possible to prevent a counterfeiter from reading a copy-prohibited object by high image resolution. Additionally, a process speed of this embodiment&#39;s image processing system which judges whether an object is copy-prohibited by using software and a CPU is faster because a judgment of whether the object is copy-prohibited is not performed for an image read with low image resolution. This embodiment&#39;s image processing system does not judge an image read with middle range resolution because a possibility of reading a copy-prohibited object is not high enough, and then the middle range resolution image is attached with information. It is thus possible to stop the software judgment from consuming too much time. 
   Second Embodiment 
   The judgment of whether an object is copy-prohibited, in step  70  of the first embodiment, is performed using photo electrical converted image data generated from a print object&#39;s added information, using digital water mark, to indicate whether the object is copy-prohibited. 
   For the judgment of whether an object is copy-prohibited, in step  70 , it is possible to use another method. For example, an original may be judged based on a color spectrum distribution based on image data (R,G,B data for each pixel) generated by scanning the original and a comparison of the color spectrum distribution with copy-prohibited object data stored in a ROM or a comparison of an image pattern of a part of the original (or the entire original) with a copy-prohibited object pattern stored in a ROM. The result of the judging is an evaluation value as to whether the original is a copy-prohibited object or not. 
   In this case, the evaluation value (e.g., the sum of the absolute value of the comparing result or the correlation between the image data (pattern) and data (pattern) stored in a ROM) is judged on the basis of a predetermined threshold. If the sum of the absolute value of the comparing result is not over the predetermined threshold, the original is judged to be a copy-prohibited object. If the sum of the absolute value of the comparing result is over the predetermined threshold, the original is not judged to be a copy-prohibited object. If the correlation is over the predetermined threshold, the original is judged to be a copy-prohibited object. If the correlation is not over the predetermined threshold, the original is not judged to be a copy-prohibited object. 
   Third Embodiment 
   In the first embodiment and second embodiment, if an original is not judged as a copy-prohibited object, the original image is output without information attached to the original image. It is possible to attach information to the original image in step  51 , which is the same as step  50  and performed after step  42 . A flowchart of this process is shown in  FIG. 5 .  FIG. 5  and  FIG. 4  are the same except for step  51 . 
   Fourth Embodiment 
   In step  30  of the first, second and third embodiments, if the user-designated image resolution is less than the predetermined second standard resolution, the specific data is attached to the image data in step  50 . It is possible to replace step  50  with step  71 , which is the same as step  70 , or to perform both step  50  and step  71 . 
     FIG. 6  is a flowchart which performs the first above-mentioned change to  FIG. 4 . In step  71 , after reading an image in step  41 , a judgment of whether an object is copy-prohibited is performed. If CPU  11  judges that the image is of a copy-prohibited object, the process flows to step  80 . On the other hand, if CPU  11  judges that the image is not of a copy-prohibited object, the process flows to step  90 . The rest of the steps in  FIG. 6  are the same as in  FIG. 4 . 
     FIG. 7  is a flowchart which performs the other change mentioned above for  FIG. 4 . In step  71 , after being attached with data in step  50 , a judgment of whether the object is copy-prohibited is performed like in step  70 . If CPU  11  judges that a read image is of a copy-prohibited object, the process flows to step  80 . On the other hand, if CPU  11  judges that the image is not of a copy-prohibited object, the process flows to step  90 . It is possible to reduce process speed by not first reading the image at low resolution, because the image resolution is already somewhat lower to begin with in this case. The rest of the steps in  FIG. 7  are the same as  FIG. 4 . 
     FIG. 8  is a flowchart which performs the first above-mentioned change to  FIG. 5 . In step  71 , after reading an image in step  41 , a judgment of whether an object is copy-prohibited is performed. If CPU  11  judges that the image is of a copy-prohibited object, the next process is step  80 . On the other hand, if CPU  11  judges that the image is not of a copy-prohibited object, the process flows to step  90 . The rest of the steps in  FIG. 8  are the same as in  FIG. 5 . 
     FIG. 9  is a flowchart which performs the other above-mentioned change to  FIG. 5 . In step  71 , after being attached with data in step  50 , a judgment of whether the object is copy-prohibited is performed like in step  70 . If CPU  11  judges that a read image is of a copy-prohibited object, the process flows to step  80 . On the other hand, if CPU  11  judges that the image is not of a copy-prohibited object, the process flows to step  90 . The rest of the steps in  FIG. 9  are the same as in  FIG. 5 . 
   Fifth Embodiment 
   The above-mentioned process of attaching data or judging whether an object is copy-prohibited is performed for color scanned image data based on user-designated image resolution. The process is not only performed for the color scanned image data, but also for other input image data. The other image input data is input from interface unit  23  shown in  FIG. 3  as communication means like a network or a detachable storage medium (e.g., smart media, compact flash, magnetic optical disk) which is connected to a un-shown drive unit of the image process system in  FIG. 3  and stores color image data. The attached information, in step  50 , is the network address of the sender apparatus that sent the image data through interface unit  23  or the number of the detachable memory. 
   The above-mentioned judging program for determining if an object is copy-prohibited is included in a communication program (ex. Internet browser soft ware) or a program for obtaining image data from a storage medium. 
   CPU  11  controls the input image resolution information of stored image data in step  10  in this case. Image data stored on the detachable memory being attached to the un-shown drive unit is read through an I/O unit, which is connected the drive unit of the detachable memory. The image resolution information in step  10  and the image data in steps  40 ,  41  and  42  may be input through an interface unit connected to a network like the Internet. 
   Sixth Embodiment 
   Image data including the processed image data and the scanned image data is output as an image data file to external memory unit  18  (a hard disk of this image processing system) through the connection I/O  19 . However, image data may be output to a color printer or an external apparatus through a network and an interface unit. In this case, the information attached in step  50  is a product number or a network address of a send side apparatus or a receive side apparatus. In this embodiment, a copy-prohibited object judging program includes a program for using communication through a network or printer driver. 
     FIG. 10  indicates an example of an image processing system of this embodiment. Image scanner  101  is an image input apparatus and a personal computer  102  processes image data and outputs processed image data to color printer  104  as an output apparatus. 
     FIG. 11  is a block diagram that shows the main portion of  FIG. 10 . Connection I/O  25  connects to an image output apparatus like a color printer. Other components of  FIG. 11  are the same as in  FIG. 3 . In this case, image output in steps  80  and  90  in  FIGS. 4 ,  5 ,  6 ,  7 ,  8  and  9  is replaced with image output to a color printer  24  connected through I/O  25 . Image data in steps  80 ,  90  may be output through an interface unit connected to a network like the Internet. 
   Seventh Embodiment 
   When the color printer outputs an object image in the sixth embodiment, information is attached to the object image by using the digital watermark method in step  50  and step  51 . However, it is possible to attach information like a serial number in a printed image as unknown color information for an image processing system user. 
   OTHER EMBODIMENTS 
   The object of the present invention can also be achieved by providing a storage medium that stores program codes for performing the aforesaid processes to a system or an apparatus, reading the program codes with a computer (e.g., CPU, MPU) of the system or apparatus from the storage medium, and then executing the program. 
   In this case, the program codes read from the storage medium realize the functions according to the above-mentioned embodiments, and the storage medium storing the program codes constitutes the invention. 
   Further, the storage medium, such as a floppy disk, a hard disk, an optical disk, a magneto-optical disk, CD-ROM, CD-R, a magnetic tape, a non-volatile type memory card, and ROM can be used for providing the program codes. 
   Furthermore, besides the aforesaid functions according to the above embodiments being realized by executing the program codes which are read by a computer, the present invention includes a case where an OS (Operating System) or the like working on the computer performs a part or entire processes in accordance with designations of the program codes and realizes functions according to the above embodiments. 
   The image processing system judges a risk of a read image being used as a forgery based on a user&#39;s indicated image reading resolution and reduces a process time for prohibiting forgery which is usually performed for every image even when there is little risk. 
   As a result, a process using software for prohibiting forgery is efficient and it is possible to increase the overall process speed of the image processing system.