Video enhancement system

• US 4,625,330 A
• Filed: 12/19/1983
• Issued: 11/25/1986
• Est. Priority Date: 12/19/1983
• Status: Expired due to Fees

• Current Assignee: NCR Corporation
• Original Assignee: NCR Corporation
• Inventors: Higgins, Raymond L.
• Primary Examiner(s): Boudreau, Leo H.
• Application Number:
  US06/562,787
• Time in Patent Office: 1,072 Days
• Field of Search: 382/55, 382/54, 382/52, 382/27, 382/4, 358/166, 358/167, 358/284
• US Class Current: 382/273
• CPC Class Codes: G06V 30/10 Character recognition
• CPC Class Codes: G06V 30/162 Quantising the image signal

Abstract

A system and method are disclosed for enhancing analog video pulses. In a preferred embodiment of the invention, raw video pulses from a video camera are each converted into a multi-bit signal having an associated one of eight levels of quantization. Scans of multi-bit signals are selectively stored in an array of shift registers to form a preselected configuration of multi-bit signals, including a multi-bit center signal. The center signal is compared with the two multi-bit signals to its left, to its right, above it and below it in four respective PROMs to determine if the center signal is possibly one of the two or three highest level multi-bit signals of a character segment. Four-bit comparison codes (left and right horizontal codes and above and below vertical codes) are respectively outputted from these four PROMs. The right and left horizontal codes are compared in a horizontal axis decision PROM, while the above and below vertical codes are compared in a vertical axis decision PROM. In response to these comparisons the horizontal and vertical axis decision PROMs respectively determine again if that center signal is possibly one of the two or three highest level multi-bit signals of a character segment. Four-bit outputs from the axis decision PROMs are compared in an output PROM which decides whether the center signal should be a first or a second binary value.

Claims

1. In an optical character reader including a video camera for optically scanning a character on a document to develop successive scans of analog pixel signals representative of the character image being scanned, a video enhancement system comprising:

means for converting each analog pixel signal into a multi-bit pixel signal having an associated one of a plurality of levels of quantization;

means for storing scans of multi-bit pixel signals to form a preselected configuration of multi-bit pixel signals including a multi-bit center pixel signal;

first means for comparing said center pixel with each of a plurality of subregions of multi-bit pixel signals in said preselected configuration to develop a plurality of comparison codes;

second means for selectively comparing said comparison codes to develop a plurality of second codes; and

third means for comparing said second codes to determine whether said center pixel signal should be a first value or a second value;

said plurality of subregions of multi-bit pixel signals comprising the respective two multi-bit pixel signals to the left of, to the right of, above and below the center pixel signal; and

said first means comprising;

a first PROM for comparing the center pixel signal with the two multi-bit pixel signals to the left of the center pixel signal;

a second PROM for comparing the center pixel signal with the two multi-bit pixel signals to the right of the center pixel signal;

a third PROM for comparing the center pixel signal with the two multi-bit pixel signals above the center pixel signal; and

a fourth PROM for comparing the center pixel signal with the two multi-bit pixel signals below the center pixel signal, each of the first, second, third and fourth PROMs outputting a comparison code as a function of its determination as to whether the center pixel signal is possibly one of the two or three highest level multi-bit pixel signals of a character segment.

2. The system of claim 1 wherein said second means comprises:

a fifth PROM for comparing the comparison codes from said first and second PROMs; and

a sixth PROM for comparing the comparison codes from said third and fourth PROMs, each of the fifth and sixth PROMs outputting a second code as a function of its determination as to whether the center pixel signal is possibly one of the two or three highest multi-bit pixel signals of a character segment.

3. The system of claim 2 wherein said third means comprises:

a seventh PROM responsive to the second codes from said fifth and sixth PROMs for deciding whether the center pixel signal should be a first value or a second value.

4. The system of claim 3 wherein:

said converting means is an analog-to-digital converter for converting each analog pixel signal into a multi-bit pixel signal having an associated one of eight levels of quantization.

5. The system of claim 4 wherein:

said storing means is an array of shift registers.