Alignment correction for read scan raster fields

Claim 2

In a method for preparation for reading information from a data carrier, the information being defined by contrasting data markings arranged on the carrier within a particular area on the carrier bounded by an upper and/or a lower boundary which is not necessarily delineated by a contiguous marking, whereby above the lower or below the upper boundary markings are provided having extension transverse to the boundary, there being space free from markings below the lower and above the upper boundaries, the method including providing a scanning raster defined by a scanning line extending in a first direction and shifting the scanning line in a second direction transverse to the first direction, and providing a video signal in response to scanning by means of the raster, the method further including orienting the scanning raster so that the scanning lines run at least approximately parallel to the boundaries, the improvement comprising: providing video signal manifestation of passage of the scanning lines across at least one of the boundaries, the passage defined by passage across plural markings as preceded or succeeded by absence of such passage; providing representation of different phases of such passages in and along the respective scanning lines for different ones of the scanning lines in the same raster field; selecting a plurality of such lines in association with different phases of these lines to establish a representation of angular misalignment between the direction of the scanning lines and the direction of the boundaries; and correcting the orientation of the raster field in accordance with the latter representation, prior to reading of the data by operation of the corrected raster field.

Claim 3

In a method as in claim 1, wherein the data carrier has additionally a characteristic line pattern extending in front of the data markings with respect to the direction of the scanning line, and including processing the video signal for detecting on each scanning line, the line pattern when traversed, the different phases of passages being provided with reference to detection of the line pattern.

Claim 4

In a method as in claim 1, wherein the selecting step includes counting the number of lines between a first one that traverses a first section of the one boundary, and a second one that traverses a second section of the one boundary, the first and second sections represented by different phases on a scanning line in relation to the data area.

Claim 5

In a method for preparation for reading information from a data carrier, the information being defined by contrasting data markings arranged on the carrier within a particular area on the carrier bounded by an upper and/or a lower boundary which is not necessarily delineated by a contiguous marking, whereby above the lower or below the upper boundary, markings are provided having extension transverse to the boundary, there being space free from markings below the lower and above the upper boundaries, the method including providing a scanning raster defined by a scanning line extending in a first direction and shifting the scanning line in a second direction transverse to the first direction, and providing a video signal in response to scanning by mEans of the raster, the method further including orienting the scanning raster so that the scanning lines run at least approximately parallel to the boundaries, the improvement comprising: detecting for each of two different, sequential scanning lines, the relative phase of video signal train portions of uniform amplitude and the onset or the tail end of train portions with plural sequential signal excursions as representing passage of scanning across plural contrasting markings; calculating representation of a misalignment angle from the spacing between the two lines and the difference in the said respective phases; and correcting the read raster orientation on basis of the calculated representation.

Claim 6

In a method for preparation for reading information from a data carrier, the information being defined by contrasting data markings arranged on the carrier within a particular area on the carrier bounded by an upper and/or a lower boundary which is not necessarily delineated by a contiguous marking, whereby above the lower or below the upper boundary, markings are provided having extension transverse to the boundary, there being space free from markings below the lower and above the upper boundaries, the method including providing a scanning raster defined by a scanning line extending in a first direction and shifting the scanning line in a second direction transverse to the first direction, and providing a video signal in response to scanning by mEans of the raster, the method further including orienting the scanning raster so that the scanning lines run at least approximately parallel to the boundaries, the improvement comprising: detecting for each of two different, sequential scanning lines, the relative phase of video signal train portions of uniform amplitude and the onset or the tail end of train portions with plural sequential signal excursions as representing passage of scanning across plural contrasting markings; calculating representation of a misalignment angle from the spacing between the two lines and the difference in the said respective phases; and correcting the read raster orientation on basis of the calculated representation.

Claim 7

Method as in claim 4, wherein the number of lines between the two different lines is fixed.

Claim 8

Method as in claim 4, wherein the phases are fixed and the number of lines between the two different lines is ascertained for said calculation.

Claim 9

In a method for preparation for reading information from a data carrier, the information being defined by contrasting markings arranged on the carrier within a particular area on the carrier bounded by an upper and/or a lower boundary which is not necessarily delineated by a contiguous marking, whereby above the lower or below the upper boundary, markings are provided having extension transverse to the boundary, there being space free from markings below the lower and above the upper boundaries, the method including providing a scanning raster defined by a scanning line extending in a first direction and shifting the scanning line in a second direction transverse to the first direction, and providing a video signal in response to scanning by means of the raster, the method further including orienting the scanning raster so that the scanning lines run at least approximately parallel to the boundaries, the improvement comprising: storing digitized representation of the video signal separately for a plurality of the scanning lines which have obliquely crossed one of the boundaries; distinguishing between passage across space free from markings and space occupied by markings; providing analog representation of the signal to obtain analog signals, separate for each such line, and of the relative length of the portion of the respective scanning line that passed across markings and the marking field; processing the analog signals to obtain a representation of the angular misalignment between the scanning raster lines and of the direction of the one boundary; and correcting the raster field on basis of the representation, prior to reading of the data by operation of the corrected raster field.

Claim 10

In a method for preparation for reading information from a data carrier, the information being defined by contrasting markings arranged on the carrier within a particular area on the carrier bounded by an upper and/or a lower boundary which is not necessarily delineated by a contiguous marking, whereby above the lower or below the upper boundary, markings are provided having extension transverse to the boundary, there being space free from markings below the lower and above the upper boundaries, the method including providing a scanning raster defined by a scanning line extending in a first direction and shifting the scanning line in a second direction transverse to the first direction, and providing a video signal in response to scanning by means of the raster, the method further including orienting the scanning raster so that the scanning lines run at least approximately parallel to the boundaries, the improvement comprising: storing digitized representation of the video signal separately for a plurality of the scanning lines which have obliquely crossed one of the boundaries; distinguishing between passage across space free from markings and space occupied by markings; providing analog representation of the signal to obtain analog signals, separate for each such line, and of the relative length of the portion of the respective scanning line that passed across markings and the marking field; processing the analog signals to obtain a representation of the angular misalignment between the scanning raster lines and of the direction of the one boundary; and correcting the raster field on basis of the representation, prior to reading of the data by operation of the corrected raster field.

Claim 11

In a method for preparation for reading information from a data carrier, the information being defined by contrasting markings arranged on the carrier within a particular area on the carrier bounded by an upper and/or a lower boundary which is not necessarily delineated by a contiguous marking, whereby above the lower or below the upper boundary, markings are provided having extension transverse to the boundary, there being space free from markings below the lower and above the upper boundaries, the method including providing a scanning raster defined by a scanning line extending in a first direction and shifting the scanning line in a second direction transverse to the first direction, and providing a video signal in response to scanning by means of the raster, the method further including orienting the scanning raster so that the scanning lines run at least approximately parallel to the boundaries, the improvement comprising: providing a line pattern having extension transverse to the boundaries and located to one side of the data as between the boundaries and extending above and below the boundaries; detecting the passage of each scanning line across the line pattern, when passing across the scanning line; generating a first and a second window as phase sections for each scanning line, and having a fixed phase relation to the detection of passage of the scanning line across the line pattern, the first window being relatively early, the second window being relatively late with reference to the instant of detection of the line pattern; determining two scanning lines in the raster which pass across one of the boundaries when the boundary is respectively traversed upon occurrence of the first and second window, the determining including differentiation between passage of scanning lines across marker free space and passage across at least two markings in the particular area; determining by how many scanning lines in the raster these two determined scanning lines are apart; and correcting the angular orientation of the raster on the basis of the second determining step prior to reading of the data by operation of the corrected raster field.

Claim 12

In a method for preparation for reading information from a data carrier, the information being defined by contrasting markings arranged on the carrier within a particular area on the carrier bounded by an upper and/or a lower boundary which is not necessarily delineated by a contiguous marking, whereby above the lower or below the upper boundary, markings are provided having extension transverse to the boundary, there being space free from markings below the lower and above the upper boundaries, the method including providing a scanning raster defined by a scanning line extending in a first direction and shifting the scanning line in a second direction transverse to the first direction, and providing a video signal in response to scanning by means of the raster, the method further including orienting the scanning raster so that the scanning lines run at least approximately parallel to the boundaries, the improvement comprising: providing a line pattern having extension transverse to the boundaries and located to one side of the data as between the boundaries and extending above and below the boundaries; detecting the passage of each scanning line across the line pattern, when passing across the scanning line; generating a first and a second window as phase sections for each scanning line, and having a fixed phase relation to the detection of passage of the scanning line across the line pattern, the first window being relatively early, the second window being relatively late with reference to the instant of detection of the line pattern; determining two scanning lines in the raster which pass across one of the boundaries when the boundary is respectively traversed upon occurrence of the first and second window, the determining including differentiation between passage of scanning lines across marker free space and passage across at least two markings in the particular area; determining by how many scanning lines in the raster these two determined scanning lines are apart; and correcting the angular orientation of the raster on the basis of the second determining step prior to reading of the data by operation of the corrected raster field.

Claim 13

In a method for preparation for reading information from a data carrier, the information being defined by contrasting markings arranged on the carrier within a particular area on the carrier bounded by an upper and/or a lower boundary which is not necessarily delineated by a contiguous marking, whereby above the lower or below the upper boundary, markings are provided having extension transverse to the boundary, there being space free from markings below the lower and above the upper boundaries, the method including providing a scanning raster defined by a scanning line extending in a first direction and shifting the scanning line in a second direction transverse to the first direction, and providing a video signal in response to scanning by means of the raster, the method further including orienting the scanning raster so that the scanning lines run at least approximately parallel to the boundaries, the markings defining individual characters, each character being defined by a code having particular format to distinguish between legal and illegal characters; the improvement comprising: providing a particular line pattern transverse to the boundaries and not being a legal character; processing the video signal as provided during each one of sequential line scans in each instance following a traversal of the line pattern by the respective scanning lines, including determining whether the markings traversed define legal or illegal characters; determining the number of illegal characters as following directly detection of the line pattern or as following a number of legal characters, towards the end of the data field in representation of angular misalignments of the raster field; and correcting the orientation of the angular alignment on basis of the representation so that all characters traversed are legal during the next attempt to read the data.

Claim 14

In a method for preparation for reading information from a data carrier, the information being defined by contrasting markings arranged on the carrier within a particular area on the carrier bounded by an upper and/or a lower boundary which is not necessarily delineated by a contiguous marking, whereby above the lower or below the upper boundary, markings are provided having extension transverse to the boundary, there being space free from markings below the lower and above the upper boundaries, the method including providing a scanning raster defined by a scanning line extending in a first direction and shifting the scanning line in a second direction transverse to the first direction, and providing a video signal in response to scanning by means of the raster, the method further including orienting the scanning raster so that the scanning lines run at least approximately parallel to the boundaries, the markings defining individual characters, each character being defined by a code having particular format to distinguish between legal and illegal characters; the improvement comprising: providing a particular line pattern transverse to the boundaries and not being a legal character; processing the video signal as provided during each one of sequential line scans in each instance following a traversal of the line pattern by the respective scanning lines, including determining whether the markings traversed define legal or illegal characters; determining the number of illegal characters as following directly detection of the line pattern or as following a number of legal characters, towards the end of the data field in representation of angular misalignments of the raster field; and correcting the orientation of the angular alignment on basis of the representation so that all characters traversed are legal during the next attempt to read the data.