Digital processor for extracting data from a binary image

• US 3,968,475 A
• Filed: 11/11/1974
• Issued: 07/06/1976
• Est. Priority Date: 11/11/1974
• Status: Expired due to Term

• Current Assignee: Sperry Rand Corporation
• Original Assignee: Sperry Rand Corporation
• Inventors: McMahon, Donald H.
• Primary Examiner(s): Thesz, Joseph M.
• Application Number:
  US05/522,666
• Time in Patent Office: 603 Days
• Field of Search: 340/146.3 E, 340/146.3 J, 340/146.3 Y, 340/146.3 WD
• US Class Current: 382/124
• CPC Class Codes: G06V 40/1347 Preprocessing; Feature extraction

Abstract

A digital processor for extracting data from a binary image in which the image is divided into an array of sample areas, each sample area containing an array of binary data spaces. Patterns formed by adjacent data spaces within the sample sample represent local line orientations from which the image characteristics are determined. Sample areas linearly arrayed in the direction in which the image is scanned are simultaneously processed to extract the line orientation information contained therein.

Claims

1. A digital processor for extracting data from an image contained within an array of binary data spaces comprising:

means for detecting data contained in each of said binary data spaces and for providing an output representative thereof;

means for storing binary data having an input responsive to said output of said detecting means and providing a plurality of outputs each of which is representative of the binary data in one of said binary data spaces, said outputs and said output of said detecting means collectively representative of a rectangular sample space consisting of data spaces in adjacent rows and columns of said array, said sample space having a configuration that is determined by the binary data of said data spaces comprising said sample space;

decoder means for receiving data from said detecting means and said storage means and providing therefrom data representative of said sample space configuration having a plurality of inputs, one responsive to said output of said detecting means and each of the remaining plurality of inputs responsive to one of said plurality of outputs of said storage means and a plurality of outputs each representative of a predetermined sample space configuration; and

plurality of counting means each having an input responsive to one of said plurality of outputs of said decoder means for providing a count of each of said predetermined sample space configuration contained within a predetermined multiplicity of sample spaces, said multiplicity of sample spaces forming a sample area consisting of a predetermined sub-array of data spaces.

2. A digital processor according to claim 1 further including count means responsive to said output of each of said counting means for transmitting data from each of said counting means to an external device wherein said transmitted data is further processed.

3. A digital processor according to claim 1 wherein said storage means comprises:

first means for storing one bit of binary data having an input responsive to said output of said detecting means and an output coupled to one of said plurality of inputs of said decoder means;

second means for storing a multiplicity of bits of binary data having an input responsive to said output of said detector means and an output coupled to one of said plurality of inputs of said decoder means;

third means for storing one bit of binary data having an input responsive to said output of said second storage means and an output coupled to one of said plurality of said inputs of said decoder means whereby said outputs of said first, second and third storage means, together with said output of said detector means form a sample space consisting of a two-by-two sub-array of data spaces in adjacent rows and columns of said array.

4. A digital processor according to claim 1 in which said detector means comprises:

a photomultiplier;

means coupled to said photomultiplier for amplifying a signal received therefrom and providing an output representative thereof; and

a Schmitt trigger having an input responsive to said output of said amplifier means and an output which is coupled to said input of said storage means.

5. A digital processor according to claim 1 wherein each of said counting means comprises:

a presettable counter having an input responsive to one of said plurality of outputs of said decoder means and an output; and

a shift register having an input and an output and storage means for a plurality of digital words therebetween, responsive to said output of said presettable counter at said input and said shift register input of said presettable counter responsive to said output whereby said output of said presettable counter provides said count of said predetermined sample space configuration contained within said sample area.

6. A method for extracting data from an image contained within an array of binary data spaces comprising the steps of:

scanning said binary data spaces in a raster scan fashion;

forming an array of rectangular sample spaces each consisting of data spaces in adjacent rows and columns of said array;

accumulating a count in a counter of the total number of alike sample spaces in a sample area for each scan line of said raster scan, a sample area consisting of a predetermined multiplicity of sample spaces;

transferring said accumulated count from said counter to a storage means after said scan line has completely traversed all of said sample spaces in a sample area, said storage means providing an output total when said accumulated count is transferred;

storing said total in said storage means in such a manner that said transferred count and said output total are from adjacent sample areas along the direction of said scan;

feeding back said output total of said storage means to said counter, when a given sample area is about to be scanned by a scan line, said output total being the accumulated count over all previous scan lines for said given sample area; and

transferring the count accumulated by said counter to a digital computer after a given sample area has been completely scanned.

7. The method of claim 6 wherein said step of forming an array of sample spaces comprises the steps of:

storing data from a previous scan of data spaces in a storage means such that data entered into said storage means and exited therefrom, as a result of said data entry, are from adjacent data spaces of the instant and previous scans respectively;

delaying said entered data and said exited data one data space interval; and

combining said entered data, said exited data, said delayed entered data and said delayed exited data to form a sample space of adjacent rows and columns.