Granted Patent B2

US 7,460,711 · App. 10/927,712 · Granted Dec 2, 2008

Abstract

Claims (37)

1. A method for reading a meter, comprising:

capturing an image of digits displayed by the meter for any fully visible digit;

determining a vertical position of the digit;

retrieving a symbol from a symbol mask set;

aligning the symbol and the digit according to the vertical position of the digit;

correlating the symbol and the digit, and

for two digits in transition such that each of the two digits in transition is partially visible:

determining an antipodal vertical position of the two digits in transition;

retrieving an intermediate portion between adjacent symbols from the symbol set;

aligning the intermediate portion and the two digits in transition according to the antipodal vertical position of the two digit; and

correlating the intermediate portion and the two digits in transition.

2. The method of claim 1 , further comprising repeating said retrieving, said aligning, and said correlating for other intermediate portions from the symbol mask set, wherein the two digits in transition are determined to have values of two symbols in one intermediate portion from the symbol mask set that produces a highest correlation value.

3. The method of claim 1 , wherein:

the symbol mask set comprises a single mask image comprising the symbols in a sequential order; and

said retrieving an intermediate portion between adjacent symbols from the symbol mask set comprises retrieving a portion of the mask image according to the antipodal vertical position.

4. A method for reading a meter, comprising:

capturing an image of digits displayed by the meter;

roughly locating the digits in the image by correlating the entire image against symbols from a symbol mask set;

after said roughly locating, precisely locating the digits by correlating the digits against the symbols that are rotated, resized, and repositioned to maximize correlation between the symbols and the digits;

determining nominal center positions of the digits;

storing the nominal center positions of the digits in a nonvolatile memory;

capturing another image of the digits displayed by the meter;

locating a region of interest according to one of the nominal center positions of the digits;

for a fully visible digit in the region of interest;

determining a vertical position of the digit;

retrieving a symbol from the symbol mask set;

aligning the symbol and the digit according to the vertical position of the digit; and

correlating the symbol and the digit; and

for two partially visible digits in the region of interest;

determining an antipodal vertical position of the two digits;

retrieving an intermediate portion between adjacent symbols from the symbol mask set;

aligning the intermediate portion and the two partially visible digits according to the antipodal vertical position of the two partially visible digits; and

correlating the intermediate portion and the two partially visible digits.

5. The method of claim 4 , further comprising repeating said retrieving, said aligning, and said correlating for other intermediate portions from the symbol mask set, wherein the two digits are determined to have values of two symbols in one of the intermediate portions from the symbol mask set that produces a highest correlation value.

6. The method of claim 4 , wherein;

the symbol mask set comprises a single mask image comprising the symbols in a sequential order; and

said retrieving an intermediate portion between adjacent symbols from the symbol mask set comprises retrieving a portion of the mask image according to the antipodal vertical position.

Assignments (13)