Method and apparatus for reading mark sheets

Claim 2

Apparatus for reading a mark sheet provided with plural mark rows, each of which includes a reference mark (102A), a misalignment detection mark (102B) and mark writing regions (102C), characterized by means (103-109) for scanning said reference mark and said detection mark for each mark row to detect misalignment of said mark sheet with respect to said apparatus; means (100) for selecting a scan window and/or a group of scan lines for each mark row in response to said detected misalignment; and means (125) for scanning said mark writing regions in each mark row by use of said scan window and/or said selected group of scan linesto read information represented in each mark row.

Claim 3

The apparatus according to claim 1, further including: means for responding to the detected misalignment at the scan of one mark row to select a group of scan lines for next mark row to be scanned.

Claim 4

The apparatus according to claim 1, further including: means for detecting said reference mark in a first mark row to activate said means for scanning said reference mark and said misalignment detection mark.

Claim 5

Apparatus for reading a mark sheet provided with plural mark rows, each of which includes a reference mark (102A), a distance detection mark (102B) and mark writing regions (102C), which apparatus reads said mark sheet by use of predetermined nominal scan window addresses, characterized by means for scanning said reference mark and said distance detection mark in a first mark row to detect the distance between said reference mark and said distance detection mark in said first mark row; means for modifying said nominal scan window addresses based upon a difference between said detected- distance and a nominal distance to form actual scan window addresses for said first mark row; means for scanning said mark writing regions in said first mark row by use of said adtual scan window addresses; means for detecting shift of position of said reference mark in a second mark row in the direction of said mark row with respect to said apparatus to shift said actual scan window addresses by the detected shift amount to form actual scan window addresses for said second mark row; and means for scanning said mark writing regions in said second mark row by use of said actual scan window addresses for said second mark row.

Claim 6

Apparatus for reading a mark sheet provided with plural mark rows, each of which includes a reference mark (102A), a distance detection mark (102B) and mark writing regions (102C), which apparatus reads said mark sheet by use of predetermined nominal scan window addresses, characterized by means for scanning said reference mark and said distance detection mark in a first mark row to detect the distance between said reference mark and said distance detection mark in said first mark row; means for modifying said nominal scan window addresses based upon a difference between said detected- distance and a nominal distance to form actual scan window addresses for said first mark row; means for scanning said mark writing regions in said first mark row by use of said adtual scan window addresses; means for detecting shift of position of said reference mark in a second mark row in the direction of said mark row with respect to said apparatus to shift said actual scan window addresses by the detected shift amount to form actual scan window addresses for said second mark row; and means for scanning said mark writing regions in said second mark row by use of said actual scan window addresses for said second mark row.

Claim 7

Apparatus for reading a mark sheet provided with plural mark rows, each ot which includes a reference mark (102A), a skew detection mark (102B) and mark writing regions (102C), which apparatus reads said mark sheet by use of predetermined nominal scan window addresses and scan lines, characterized by means for scanning said reference mark and said skew detection mark in a first mark row to detect skew of said mark sheet with respect to said apparatus; means for selecting a group of scan lines for said first mark row in response to said detected skew; means for detecting a distance between said reference mark and said skew detection mark in said first mark row; means for modifying said nominal scan window addresses based upon a difference between said detected distance and a nominal distance to form actual scan window addresses for said first mark row; means for scanning said mark writing regions in said first mark row by use of said actual scan window addresses and at least one scan line in said group of scan lines; means for selecting a group of scan lines for a second mark row based upon said detected skew; means for detecting shift of position of said reference mark in said second mark row in the direction of said mark row with respect to said apparatus to shift said actual scan window addresses for said first mark row by the detected shift to form actual scan window addresses for said second mark row; and means for scanning said mark writing regions in said second mark row by use of said actual scan window addresses for said second mark row and at least one scan line of said group of scan lines for said second mark row.

Claim 8

Apparatus for reading a mark sheet provided with plural mark rows, each ot which includes a reference mark (102A), a skew detection mark (102B) and mark writing regions (102C), which apparatus reads said mark sheet by use of predetermined nominal scan window addresses and scan lines, characterized by means for scanning said reference mark and said skew detection mark in a first mark row to detect skew of said mark sheet with respect to said apparatus; means for selecting a group of scan lines for said first mark row in response to said detected skew; means for detecting a distance between said reference mark and said skew detection mark in said first mark row; means for modifying said nominal scan window addresses based upon a difference between said detected distance and a nominal distance to form actual scan window addresses for said first mark row; means for scanning said mark writing regions in said first mark row by use of said actual scan window addresses and at least one scan line in said group of scan lines; means for selecting a group of scan lines for a second mark row based upon said detected skew; means for detecting shift of position of said reference mark in said second mark row in the direction of said mark row with respect to said apparatus to shift said actual scan window addresses for said first mark row by the detected shift to form actual scan window addresses for said second mark row; and means for scanning said mark writing regions in said second mark row by use of said actual scan window addresses for said second mark row and at least one scan line of said group of scan lines for said second mark row.

Claim 10

Method for reading a mark sheet provided with plural mark rows, each of which includes a reference mark, a distance detection mark and mark writing regions, said mark sheet being read by use of predetermined nominal scan window addresses, said method comprising: scanning said reference mark and said skew detection mark in a first mark row to detect a distance between said reference mark and said distance detection mark in said first mark row; modifying said nominal scan window addresses based upon a difference between said detected distance and a nominal distance to form actual scan window addresses for said first mark row; scanning said mark writing regions in said first mark row by use of said actual scan window addresses; detecting shift of position of said reference mark in a second mark row to shift said actual scan window addresses by the detected shift amount to form actual scan window addresses for said second mark row; and means for scanning said mark writing regions in said second mark row by use of said actual scan window addresses for said second mark row.

Claim 11

Method for reading a mark sheet provided with plural mark rows, each of which includes a reference mark, a distance detection mark and mark writing regions, said mark sheet being read by use of predetermined nominal scan window addresses, said method comprising: scanning said reference mark and said skew detection mark in a first mark row to detect a distance between said reference mark and said distance detection mark in said first mark row; modifying said nominal scan window addresses based upon a difference between said detected distance and a nominal distance to form actual scan window addresses for said first mark row; scanning said mark writing regions in said first mark row by use of said actual scan window addresses; detecting shift of position of said reference mark in a second mark row to shift said actual scan window addresses by the detected shift amount to form actual scan window addresses for said second mark row; and means for scanning said mark writing regions in said second mark row by use of said actual scan window addresses for said second mark row.

Claim 12

Method for reading a mark sheet provided with plural mark rows, each of which includes a reference mark, a distance and skew detection mark and mark writing regions, said mark sheet being read by use of predetermined nominal scan window addresses and scan lines, said method comprising: scanning said reference mark and said detection mark in a first mark row to detect skew of said 'mark sheet with respect to a reader; selecting a group of scan lines for said first mark row in response to said detected skew; detecting the distance between said reference mark and said detection mark in said first mark row; modifying said nominal scan window addresses based upon the difference between said detected distance and a nominal distance to form actual scan window addresses for said first mark row; scanning said mark writing regions in said first mark row by use of said actual scan window addresses and at least one scan line in said group of scan lines; selecting a group of scan lines for a second mark row based upon said detected skew; detecting shift of position of said reference mark in said second mark row in the direction of said mark row with respect to said reader to shift said actual scan window addresses for said first mark row by the detected shift to form actual scan window addresses for said second mark row; and scanning said mark writing regions in said second mark row by use of said actual scan window addresses for said second mark row and at least one scan line of said group of scan lines for said second mark row.

Claim 13

Method for reading a mark sheet provided with plural mark rows, each of which includes a reference mark, a distance and skew detection mark and mark writing regions, said mark sheet being read by use of predetermined nominal scan window addresses and scan lines, said method comprising: scanning said reference mark and said detection mark in a first mark row to detect skew of said 'mark sheet with respect to a reader; selecting a group of scan lines for said first mark row in response to said detected skew; detecting the distance between said reference mark and said detection mark in said first mark row; modifying said nominal scan window addresses based upon the difference between said detected distance and a nominal distance to form actual scan window addresses for said first mark row; scanning said mark writing regions in said first mark row by use of said actual scan window addresses and at least one scan line in said group of scan lines; selecting a group of scan lines for a second mark row based upon said detected skew; detecting shift of position of said reference mark in said second mark row in the direction of said mark row with respect to said reader to shift said actual scan window addresses for said first mark row by the detected shift to form actual scan window addresses for said second mark row; and scanning said mark writing regions in said second mark row by use of said actual scan window addresses for said second mark row and at least one scan line of said group of scan lines for said second mark row.

Claim 14

The method according to claim 7 or 8, further including: detecting said reference mark in said first mark row to activate said means for scanning said reference mark and said distance and/or skew detection mark in said first mark row.