Extracting textual information from a video sequence

Apparatus for extracting an image representing textual information from a video sequence, comprising:

• a source of a video sequence having a plurality of frames, each containing an image of the textual information;
• and
• a processor, coupled to the video sequence source, responsive to all of the plurality of frames, for generating a single array representing an image of the textual information;
• wherein the processor comprises:
• a circuit, coupled to the video sequence source, for locating the textual information image in each of the plurality of frames and generating a stack of text image arrays, respectively corresponding to the plurality of frames, each containing an image which is substantially only of the textual information;
• and
• a circuit, coupled to the locating circuit, and responsive to all of the arrays in the stack of text arrays, for extracting an image of the textual information into a single array;
• wherein the extracting circuit comprises:
• circuitry, responsive to the stack of text arrays, for generating a stack of binary arrays, respectively corresponding to the stack of text arrays, each binary array containing binary data representing the textual information image in the corresponding text array;
• circuitry, responsive to the stack of binary arrays, for performing a genetic algorithm search using the stack of binary arrays as an initial population to find an optimum binary image;
• and providing the optimum binary image in the single array as the textual information image
• wherein the genetic algorithm circuitry comprises circuitry for:
• selecting individual arrays from the stack of binary arrays, from a population which will survive to the next generation according to the relative desirability of the individual arrays;
• crossing-over random pairs of selected individual arrays with a probability χ;
• mutating random selected individual arrays with a probability μ1 wherein the selected, crossed-over and mutated individual arrays form a stack of binary arrays representing a new generation;
• and
• repeating the selecting, crossing-over and mutating steps;
• and
• wherein the selecting circuitry comprises circuitry for calculating the desirability g(h1) of an individual array h1 according to the equation:
• g ⁢ ⁢ ( h l ) = ∑ c ∈ C ⁢ V c ⁡ ( z ) + ∑ j = 1 n ⁢ [LeftDoubleBracketingBar] z - h j [RightDoubleBracketingBar] 2 2 ⁢ σ 2
• where z is an estimate of the textual information image, Vc(z) is the clique energy function, and σ is the variance.

Apparatus for extracting an image representing textual information from a video sequence, comprising:

• a source of a video sequence having a plurality of frames, each containing an image of the textual information;
• and
• a processor, coupled to the video sequence source, responsive to all of the plurality of frames, for generating a single array representing an image of the textual information;
• wherein the processor comprises:
• a circuit, coupled to the video sequence source, for locating the textual information image in each of the plurality of frames and generating a stack of text image arrays, respectively corresponding to the plurality of frames, each containing an image which is substantially only of the textual information;
• and
• a circuit, coupled to the locating circuit, and responsive to all of the arrays in the stack of text arrays, for extracting an image of the textual information into a single array;
• wherein the extracting circuit comprises:
• circuitry, responsive to the stack of text arrays, for generating a stack of binary arrays, respectively corresponding to the stack of text arrays, each binary array containing binary data representing the textual information image in the corresponding text array;
• circuitry, responsive to the stack of binary arrays, for performing a genetic algorithm search using the stack of binary arrays as an initial population to find an optimum binary image;
• and providing the optimum binary image in the single array as the textual information image;
• and
• wherein:
• each array in the stack of binary arrays is arranged as a plurality of rows, each row having a plurality of pixels, each pixel having a binary value;
• the stack of binary arrays is modeled on a Markov random field having a second order neighborhood, and a single non-zero clique consisting of four pixels arranged in a square.

A method for extracting an image representing textual information from a video sequence, comprising the steps of:

• receiving a sequence of video frames, each including an image of the textual information;
• locating the textual information in each frame of the video sequence to form a stack of text arrays, each array containing data representing substantially only the textual information;
• extracting a single textual image array representing the image of the textual information from the stack of text arrays, wherein the extracting step comprises the steps of:
• generating a stack of binary arrays, respectively corresponding to sequence of video frames:
• extracting the single textual image array from the stack of binary arrays by performing a genetic algorithm search using the stack of binary arrays as an initial population to find an optimum binary image;
• and
• providing the optimum binary image in the single array as the textual information image.

A method for extracting an image representing textual information from a video sequence, comprising the steps of:

• receiving a sequence of video frames, each including an image of textual information;
• locating the textual information in each frame of the video sequence to form a stack of text arrays, each array containing data representing substantially only the textual information;
• and
• extracting a single textual image array representing the image of the textual information from the stack of text arrays;
• wherein the extracting step comprises the steps of:
• generating a stack of binary arrays, respectively corresponding to sequence of video frames;
• extracting the single textual image array from the stack of binary arrays using a genetic algorithm;
• wherein the genetic algorithm comprises the steps of:
• using the stack of binary arrays as an old generation;
• selecting individual arrays to survive to a next generation according to the relative desirability of the individual array;
• crossing-over random pairs of selected arrays with probability χ;
• mutating random selected arrays with probability μ1 to form a new generation;
• repeating the selecting, crossing-over, and mutating steps with the new generation;
• and
• wherein the selecting step comprises the step of calculating the desirability g(h1) of an individual array h1 according to the equation:
• g ⁢ ⁢ ( h l ) = ∑ c ∈ C ⁢ V c ⁡ ( z ) + ∑ j = 1 n ⁢ [LeftDoubleBracketingBar] z - h j [RightDoubleBracketingBar] 2 2 ⁢ σ 2
• where z is an estimate of the textual information array, V(z) is the clique energy function, and σ is the variance.