Method and apparatus for initiating data capture in a digital camera by text recognition

A digital camera takes photographs of printed material upon recognition of a specified text pattern. In one exemplary embodiment of the present invention, the process of photographing printed material based on text pattern recognition is partially manual. In a second embodiment of the present invention, the process is highly automated.

FIELD OF THE INVENTION

The present invention relates generally to digital cameras and, more specifically, to a method and associated apparatus for initiating data capture in a digital camera by the recognition of text patterns such as words or phrases.

BACKGROUND OF THE INVENTION

Digital cameras provide powerful features and convenience to hobbyists and professionals alike. In applications such as genealogy, for example, genealogists often search through large books or stacks of records for relevant information. Once relevant information is found on a particular page, a genealogist may take a photograph of the page using a digital camera.

Digital photography provides several advantages over traditional silver-emulsion-film photography. First, a user can see immediately on the display of the digital camera whether or not the photograph is acceptable. Secondly, the photograph is created directly in digital format and can be used immediately in printed reports, photo albums, Web pages, or e-mail messages. Although the foregoing advantages are significant, the task of searching through the pages of a book or a stack of records looking for relevant information can still be tedious and time consuming. Often, the search centers on finding a specific word such as a surname or an important phrase. Unfortunately, prior-art digital cameras do not aid the user in finding text patterns on a printed page. The task of searching for relevant pages is left entirely to the user.

It is thus apparent that there is a need in the art for an improved method or apparatus for locating relevant pages of printed material and digitally photographing them easily and efficiently.

SUMMARY OF THE INVENTION

According to one aspect of the invention, a method is provided for initiating data capture in a digital camera upon recognition of a text pattern. In one embodiment, the method comprises a manual two-pass approach. In another embodiment, the method is highly automated. According to another aspect of the invention, a digital camera for carrying out the method is also provided.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is a functional block diagram of a digital camera100in accordance with one embodiment of the present invention. InFIG. 1, user interface105comprises input device110, display115, and optional audible tone generator120. Input device110sends commands to controller125over data bus130to specify the modes of operation of digital camera100and acts as a source for text input. User interface105provides feedback to users via display115and optional audible tone generator120. Imaging device135converts an optical image received from optical system140to a digital image. The digital image may be stored temporarily in optional random access memory (RAM)145. Optical character recognition (OCR) module150converts digital images of printed material to text. Image compression module155compresses digital images to reduce their storage requirements. Non-volatile memory160provides long-term storage of digital representations. Throughout this detailed description, the term “digital representation” will be used to denote a text file, a digital image (compressed or uncompressed), a message digest, check sum, or any other digital representation of a target scene or any combination thereof.

In a typical implementation, imaging device135comprises a charge-coupled device (CCD), an analog-to-digital converter (A/D), a gain control, and a digital signal processor (DSP), as is well known in the art (not shown in FIG.1). Input device110typically comprises one or more buttons for selecting modes or acquiring text input. For example,FIG. 2shows one method in which a text pattern may be acquired in digital camera100, which may not include an alphanumeric keypad. Hereinafter, the term “text pattern” will be used to denote a textual string comprising one or more alphanumeric characters, including spaces. Scroll buttons205and210control which portion of alphanumeric character list215is visible on display220. Cursor225indicates which alphanumeric character is currently selectable. Pressing select button230adds the currently highlighted character to text pattern235to be searched. The same process of scrolling using scroll buttons205and210and selecting characters using select button230is repeated for each character in text pattern235until the entire text pattern has been specified. Optionally, user interface105may include a microphone and a speech recognizer for accepting voice input (not shown in FIG.1). One example of how voice input may be incorporated in a digital camera may be found in published European Patent Application EP-1014338A1. Yet another method for acquiring a text pattern in digital camera100is to retrieve a previously saved text pattern. For example, a text pattern may be read from a text file, or the previous text pattern for which a search was performed may be loaded by default until overridden by new input. Audible tone generator120is an optional component of digital camera100and has been included inFIG. 1for the purpose of illustration only. In some implementations, a flashing or persistent light, a vibrator, or other method of providing feedback to users may be preferable to an audible tone. Non-volatile memory160is typically flash memory. In some implementations, non-volatile memory160may be of the removable type, such as a memory stick or magnetic disk. Optical character recognition module150may be implemented in hardware, software, firmware, or a combination thereof. Image compression module155, which may be implemented in hardware, software, firmware, or a combination thereof, typically produces images in the popular JPEG format.

FIG. 3is a flowchart illustrating the operation of digital camera100in accordance with one exemplary embodiment of the present invention. At305, controller125determines whether or not text-recognition mode has been activated. If so, a text pattern to be recognized is acquired at310by one or more of the methods previously described. A target scene at which to aim digital camera100is selected at315. In typical applications, the target scene is a page in a book or other printed material compatible with OCR technology. Upon receipt of a continue command from user interface105at320, imaging device135produces a digital image, which may be stored temporarily in RAM145, at325. OCR module150converts the digital image to a text file at330. The text file may also be stored temporarily in RAM145. At335, controller125searches for the text pattern that was acquired at310. If the text pattern is recognized, an audible tone is emitted at340. Upon receipt of a confirmation command at345, imaging device135produces a refined digital image at350of whatever target scene is currently being received from optical system140. The purpose of this arrangement is to provide both a quick search to determine whether a text pattern is present on a printed page and a subsequent follow-up second pass in which a user may align digital camera100more precisely to take a final photograph of the page. However, the confirmation command at345may be replaced by different techniques in other embodiments of the present invention. For example, the refined digital image may be captured automatically after a predetermined delay following the recognition of the text pattern at335.

Controller125determines at355in what format output data should be saved in non-volatile memory160. Depending on which format or formats have been specified, image compression (e.g., for JPEG output), OCR, or other format conversion may need to be performed on the refined digital image at355. At360, a digital representation of the target scene is saved in non-volatile memory160. At365, controller125checks for a termination command. If none is received, control returns to315, where a new target scene is selected. If a termination command is received, digital camera100exits text-recognition mode at370. If the text pattern is not recognized at335, control proceeds to365.

The embodiment described in connection withFIG. 3exemplifies a manual two-pass approach to the process of text recognition and picture taking. Specifically, the continue command at320and the confirmation command at345are intended to give the user maximum control over the final digital representation saved, but such a manual approach is by no means the only manner in which the present invention may be embodied. For example, a greater degree of automation may be introduced to speed up the taking of multiple photographs and to provide greater convenience to the user.

FIG. 4is a flowchart illustrating the operation of digital camera100in accordance with another embodiment of the present invention. The method of operation shown inFIG. 4incorporates a higher degree of automation than that shown in FIG.3. InFIG. 4, text-recognition mode is activated at305, a text pattern to be recognized is acquired at310, and a target scene is selected at315, as described in connection with FIG.3. As soon as text-recognition mode becomes active, or, optionally, after a brief predetermined delay, imaging device135produces at325a temporary digital image of whatever target scene is currently being received from optical system140. Note that controller125does not wait for a continue command in this particular embodiment. The temporary digital image is converted to a text file at335, and controller125searches the text file for the text pattern that was acquired at310. If the text pattern is not recognized, control proceeds to365. If no terminate command is received at365, control returns to315. Otherwise, text-recognition mode is exited at370.

If the text pattern is recognized at335, a test is performed at410to ensure that the current target scene is different from the previous target scene for which a digital representation was saved in non-volatile memory160. Such an approach allows the operations at315,325,330,335, and410to be performed in a loop, thereby freeing the user from the need to indicate via user interface105when to take each successive photograph. Thus, in the embodiment associated withFIG. 4, digital camera100automatically determines when a new target scene is present and responds by capturing a digital image and saving a digital representation of the target scene in non-volatile memory160, when the text pattern acquired at310is recognized. Hereinafter, a target scene for which a digital representation has been saved will be referred to as a “saved target scene.” There are many ways apparent to those skilled in the art in which the test at410may be implemented. In the particular embodiment associated withFIG. 4, the text files associated with the current and the previous saved target scenes are compared. Examples of comparison techniques include comparing the position of the text pattern acquired at310in the current text file to its position in the text associated with the previous saved target scene. Another solution is to compare the text immediately surrounding the text pattern acquired at310in the two text files. Other solutions include identifying and comparing page numbers within the text files or comparing the first few words of the text in the two text files. Still another solution is to compare message digests of the two text files computed using, for example, a digital hashing function such as MD5. In some implementations, direct comparison of the digital images associated with the current and the previously saved target scenes may be advantageous.

If the text pattern at410is recognized for the first time since the activation of text-recognition mode, there is no previous text with which to compare, so control automatically proceeds to340, where an audible tone is emitting signaling that the text pattern has been recognized. From355, control proceeds as explained in connection with FIG.3.

The present invention may be modified to combine elements of manual confirmation and automation in ways different from that indicated in FIG.3andFIG. 4without departing from the principles of the invention.