CA1207908A - Method for checking patterns and apparatus to carry out such method - Google Patents
Method for checking patterns and apparatus to carry out such methodInfo
- Publication number
- CA1207908A CA1207908A CA000450242A CA450242A CA1207908A CA 1207908 A CA1207908 A CA 1207908A CA 000450242 A CA000450242 A CA 000450242A CA 450242 A CA450242 A CA 450242A CA 1207908 A CA1207908 A CA 1207908A
- Authority
- CA
- Canada
- Prior art keywords
- sensing elements
- pattern
- beta
- alpha
- patterns
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
- G06K7/10544—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation by scanning of the records by radiation in the optical part of the electromagnetic spectrum
- G06K7/10821—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation by scanning of the records by radiation in the optical part of the electromagnetic spectrum further details of bar or optical code scanning devices
- G06K7/10861—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation by scanning of the records by radiation in the optical part of the electromagnetic spectrum further details of bar or optical code scanning devices sensing of data fields affixed to objects or articles, e.g. coded labels
- G06K7/10871—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation by scanning of the records by radiation in the optical part of the electromagnetic spectrum further details of bar or optical code scanning devices sensing of data fields affixed to objects or articles, e.g. coded labels randomly oriented data-fields, code-marks therefore, e.g. concentric circles-code
Abstract
METHOD FOR CHECKING PATTERNS AND APPARATUS
TO CARRY OUT SUCH METHOD
Abstract A method and apparatus for checking deviations in dimensions and contrast of patterns 1 which are presented for checking purposes at a practically constant speed v of a continuously variably adjustable magnitude, in particular of identical patterns 1 printed on a repetitive fixed area 3 on a strip 2 of flat carrier material 30, each pattern 1 consisting of parallel lines of bar codes printed at pre-determined mutual distances, by optically forming an image of each pattern to be checked upon a fixed format and by taking several traverse images therefrom at an angle .beta. with respect to the direction 6 of the bars by means of the row(s) of closely arranged electrical sensing elements, said tra-verse images being read out serially and subsequently entered into an electronic arithmetic apparatus for comparison with a reference pattern.
TO CARRY OUT SUCH METHOD
Abstract A method and apparatus for checking deviations in dimensions and contrast of patterns 1 which are presented for checking purposes at a practically constant speed v of a continuously variably adjustable magnitude, in particular of identical patterns 1 printed on a repetitive fixed area 3 on a strip 2 of flat carrier material 30, each pattern 1 consisting of parallel lines of bar codes printed at pre-determined mutual distances, by optically forming an image of each pattern to be checked upon a fixed format and by taking several traverse images therefrom at an angle .beta. with respect to the direction 6 of the bars by means of the row(s) of closely arranged electrical sensing elements, said tra-verse images being read out serially and subsequently entered into an electronic arithmetic apparatus for comparison with a reference pattern.
Description
~%~
METHO~ FOR CHECKING PATTE~NS AND APPARATUS
TO CARRY OUT SUCH METHQD
, The present invention relates to a method for checking deviations in dimensions and contras-t of patterns whiçh are 5 presented For check;ng purposes at a practically constant speed of a continuously variably adjustable magnitude, in particular oF identical patterns printed on a repetitive fixed area on a strip of flat carrier material, each pattern con-sisting of parallel linss of bar codes printed at predetermined mutual distances, the angle ~ between the direction of the bars and the longitudinal direction of the strip of carrier material beina constant but capable of having any value between 0 and ¦180¦, using an optical electronic camera in which there is provided an image receiving system comprised o~ one or several rows of clasely arranged photosensitive electronic sensinà
elements with associated electronic circuits, an illuminating system and an electronic arithmetic apparatus.
Various methods for using optical electronic cameras for a diverse rnnge of applications are known from the relevant technical literature. A broad survey is provided in the article `" lZ(l 7~08 "Optische Datenerfassung mit CCD-Kameras" by Ing. (grad.) Alfred D-umlein in the journal "Elektronik", ~lo, 25 of Dec, 17, 19~2.
It is the main object of the present invention to provide a me-thod enabling the checking of in particular bar codes at high speed and with areat accuracy as to dimensions and contrast, said bar codes passing, in an arbitrary but repetitive pattern of mutual distances and at an arbitrary but practically constant speed, along such a camera system having one or several parallel 1~ rows of sensing elements, while firstly the checking operation can be performed independently o~ the print format and pattern position, and secondly checking is afforded over a large number of points .in the longitudinal direction of the bars by a small number of rows, even just one row, of sensing elements.
According to the invention, said object is attuined by optically forming an image of each pattern to be checked upon a fixed format and by taking several traverse images therefrom at an anglef~ with respect to the direction of the bars by means of the row~s) of closely arranged electrical sens;ng ele-ments, said traverse images being read out serially and subse-quently entered into the electronic arithmetic apparatus for comparison with a reference pattern The images are formed, while the pattern passes in front of the camera, hy illumina-ting the pattern by means of a series of short liahting flashes whose repetition frequency is proportional to the speed of pas-sage of the pattern. Althouah image shifting (image blurring) due to the speed of passage of the pattern is already suppressed by applying very short lighting flashes ~approx, 21u sec), this ~could still give rise to undesirable inaccuracies resulting . . .
from image shifting, in the event of greater values of the `'` 1~07~
speed of passage. Such undesirable image shifting can, how-ever, be compensated for in the arithmetic apparatus on the basis of the measurement of the speed o~ travel of the strip of flat cqrrier material upon which the patterns have been printed.
Another obiect of the invention is to provide an appa-artus for carrying out the method according to the invention using an optical elec-tronic camera wherein there is provided an image receiving system comprising one or several rows of closely arranged photosensitive electrical sensing elements with associated electronic circuits, an illuminating system and an electronic arithmetic apparatus~ the camera being pro-vided on a frume, in a vertically adjust~ble relation, above and in transverse direction over the strip of flat carrier material upon which the patterns to be checked have been prin-tedl said camera being, in accordance with the invention, dis-posed on suid frame member so as to be rotatable about the optical axis of its lens assembly, The electrical motor drive means provided for adjusting the vertical, transverse and ro-tation settings are preFerably connected to the electronicarithmetic apparatus for -their control, This likewise applies to the drive means for adjusting the lens assembly.
Survey of the drawings.
Figs. lA-D show possible positions of the codes printed on a strip of carrier material;
Fi~. 2A illustrates the sPnsing of a code at several mo-ments using a single row of electrical sensing elements, per-pendicular with respect to the bars;
Fig. 2B illustrates the sensing of a code at several mo-- 30 ments using a single row of electrica~ sensing elements which ~2~
forms an angle~ ~ 90~ with the bars;
Fig~ 2C illustrctes the sensing of a code at several moments using more (2) rows of electrical sensing elements, perpendicular with respect to the bars;
Fig. 2D illustrates the sensing of a code at several rnoments using more (two) rows of electrical sensing elements which are disposed at an angle ~ + 9~ with respect to the bars;
Fig. 2E illustrates the sensing of a code at one moment using several (three) rows of electrical sensing elements;
FigO 3 is a disgrammatic representation of the construction of an optical electronic camera as used according to the present invention;
Fig 4 shows a block diagram of an apparatus according to the invention.
Figs~ lA-D show several examples of a strip of flat carrier material 2 haYing bar codes 1 printed thereon. The codes are in a fixed position of each repetitive, printed area;
the position o~ -the code, defined by the magnitude oF the angle d between the direction of the bars and the longitudinal direc-tion of the strip of carrier material, is arbitrary but obvious-ly cons-tant for a strip. For a given code, the ratio of the length a to the height b of the format is fixed; however, per strip, the printed code may have any arbitrary format which may be smaller or larger than the stand`ard-format dimensions.
In order to measure the codes, the optical camera is to be dis-placed in transverse direction over the strip of carrier mate-rial in such a manner that the optical axis intersects the con-necting line 4 through the centers of the printed codes. Fur-thermore, the camera height abov~ the carrier material and the lens setting should be set in a manner so as to obtain a sharp :
- ~
image having an image dil-nension usecd For the standard format The characteristic data for the code to be checked, i,e~ the specific pattern, is entered into the central processing unit as a reference pattern produced on the basis of the standard format, as is at the same time the magnification factor of the printed code with respect to the standard format.
For the various usual code types (UPC, EAN, etc.~ for the standard-code format, the nominal bar thicknesses, the widths of .he spaces between the bars and the tolerances thereof as well as .he tolerances as a function oF the magnification factor of the printed code with respect to -the standard format,are contained in the memory of the central processing unit used for carrying out the method according to the invention.
The bar thicknesses as measured are compared with the nominal bar thicknesses so as to determine the degree of the deviations, it heing furthermore determined whether the latter fall within or outside the tolerances.
Figs 2A-E illustrate with several examples the manner in which, in accordance with Cl number oF -traverses, the code can be sensed at several places across the entire format so as to obtain rneasurement data which are processed, in accordance with a specified proaram, by the arithmetic apparatus for the purpose of checking each code as to cleviations in dimensions and contrast In the figures, the arrow 5 represents the direc-tion and speed v of travel of the strip of carrier material.The direction of travel is obviously the same as the longitu-dinal direction of the strip of carrier material~ Tha angle between the direction of travel 5 and the direction o-f bar po-Sitioning 6 is indicated by d. The angle between the direction 7 of each row of sensing elements in the imagc area of the 7~901!~
-- 6 _ camera and the direction of bar positioning 6 is indicated by ~ , Fig. 2A illustrates the case in which one row of electri-cal sensing elements is used and the camera has been ro-tated about the optical axis in a rnanner so that ~ =90. During the passing of a code in the object area of the camera lens, the code is repetitively briefly illuminated several times, as a result of which a number of traverse-image specimens of the code are successi~ely received by the row oF sensing elements.
The processing program can be relatively simple because each individual traverse image always comprises the same number of bars and spaces, For a given length I of the row o-F electrical sensing elements having a certain number of sensing ele~ents, the accuracy of measurement is greatest if the length of the 1~ traverse is the greatest possible fraction of t, This is rea-lized only, however, lf the cocle is oriented in a manner so that the direction oF bar positioning roughly corresponds to that of the Longituclinal direction o, the strip of carrier ma-terial, Ey s~l~cting the nuMber of traverses n desired over the hei9h-t a of the printed code, the time increment ht be-tween the brief s~uential illuminations is recordecl as a function of the speed of travel v oF the carrier material, the angles ~ and ~ , the number o-f traverses n and the climensions a and b of the printed-code format. Assuming the first and last traverse to be in the vicinit~ oF the borders oF the code format, this relat;on will be:
q a2 ~ b2 ~os(~-90-~)- sin(~-90-~)- tg(l80-~)]
t = - = ~ ~ . ....
v v (n-t) in which ~ = bg tg b Obviously, ~ t should not be less than the so-called integration time, i.e. the time required for the entering into and trans fer from the electrical sensors of the electric image formed therein. The speed v is obviously to be measured in orcler to afford setting ~t. The ratio of the given length 1 of .he row of sensing elements to the length (or width) of the code image must be greater according as the orientation of the codes more and more approaches the situation in which the bars are posi-tioned perpendicularly to the longitudinal clirection of the strip of carrier material, while ~t may increase si~ultaneously.
Fig~ ~C illustrates the case of two parallel rows of elec-trical sensing elements, the camera being rotated, as in fig.
~A, about the cylinder axis in svch a manner that in this case = 90, as well. To this, Fundamentally the same remarks apply as those applicable to fig. 2A. In this case, however, a smaller number of illuminating pulses is sufficient to obtain the same number of traverses. The inaccuracy of measurement at corres-poncling values of the angle ~ is greater, however, than in the case described hereinbefore, since the length of the rows oF
sensing elements must be relatively grQater in order to ensure that, at the passing o~ the image of an obliquely oriented cocle, the upper and lower angular points do not fall outside the area covered by the rows~ Codes printed in such a manner that the bars are positioned perpendicularly to the longitudinal direc-tion of the strip of carrier material can, when traversing the bars at right angles in several locations, be checked only by making use of several rows of sensing elements with one illu-minating pulse being given per image passing (See fig, 2E).
A method universally useful for the entire range of the angle ~ is provided in figs. 2B and 2D by way of example for a camera having one row and a camera having two rows of sensing elements, respectively. The row(s) is (are) -then disposed at an angle ~ ~ 90 with respect to the bars. ~ccording to the angle ~ at which -.he codes are printed on the strip of carrier ~aterial, the angle ~ can be chosen in a manner so that the ratio of the imaae size to the length o~ a row is as great as possible, thus enabling the optical resolution factor of the row to be used as effectively ns possible. ,~t an increasing speed v of the code-printed strip oF carrier material, image shifting will occur notwithstanding the use of a very short illuminating pulse. This can be compensated on the basis of a measurement of the $peed of travel v by means of a program provided to this effect in the electronic arithmetic apparatus so as to enhance the accuracy of measurement.
Fig. 3 is a diasrammatic representation of a camera to be used for carrying out the method, ~ frame 20 carries two guide rods 21, 22 ancl there is provided in a slidable relation there-along a carriage 23 which via the bearings 24, 25 carries the camera body 26. Saicl camera body can thus move in the clirection perpendicular to the plane of drawing ancl around the opticcl axis 27, It contains an optical imaging s~stem ~8, cliayramma-ticall~J indicated, and the holder ~ for the sensing elements, In order to keep -the lat-reI at the temperature which is most favorable to the operation, the holder 2, for the sensing ele-ments can be c0019cl by rneans of a Peltier element, not shown, - 25 The carrier material 30 with the bar codes to be checked passes in the direction o~ the arrow ~1 over -.he guide plate 3~, and the illumination oF the bar codes to be checked is effected by means of a flash-light source 33, shown cliagrammatically.
Fig~ 4 shows the block diagram of the complete apparatus by which the method accordina to the invention can be carried out. The central processing unit 40 of the electronic arithmetic ~L%~
_ 9 _ appclratus receives c!ata entering thereinto pertainincJ to the speecl of the web o~ material 30 obtained via the speed sensor 41, and pertaining to the r~lative position of the patterns obtained by means oF the encocler 4~ which is, for example, coupled with a roller whose circumferential speed is propor-tional to .he speec! of travel of the web of material. This roller may he, for instance, a roller of a comple-te printing machilte The mutual positions of the various patterns can be entered into i-he central processina unit by manually bringing a number of successive bar-code patterns under the camera ~6 and enterina a suitable setting sianal into the processing unit after proper positioning of ihe pattern.
The signal suppliecl by the imaye sensors is transmitted via the interface 43 to the central processing unit 40. Tl1e keyboard 44 affords entering all clat neces~ary For the proper functioning of the apparatus.
The apparatus may be provided with a printer 45 for pro-duciny printouts o~ measurement results, and a monitor 46 on which the rnomentary results are rendered visible. The various setting functions ~or the camera: vertical setting, transverse setting, setting of rotation and focusing are di~grammatically indicatecl by the blocks 47-~0; the control signals emanating therefrom are transmittecl to the camera 2O
h'hen forminy each traverse image there is the possibility of cletermining the degree of contrast OT the transitions between bar and space; this is a technique known per se.
~ s has been c!escribed, forming the momentary images is possibIe by pulsating illumination of the pattern using a flash lamp 33 controlled from the central processing unit 40. However, forming the momentary images can also be achieved by excitation (activation) of the sensing elements in the sampling rhythm.
METHO~ FOR CHECKING PATTE~NS AND APPARATUS
TO CARRY OUT SUCH METHQD
, The present invention relates to a method for checking deviations in dimensions and contras-t of patterns whiçh are 5 presented For check;ng purposes at a practically constant speed of a continuously variably adjustable magnitude, in particular oF identical patterns printed on a repetitive fixed area on a strip of flat carrier material, each pattern con-sisting of parallel linss of bar codes printed at predetermined mutual distances, the angle ~ between the direction of the bars and the longitudinal direction of the strip of carrier material beina constant but capable of having any value between 0 and ¦180¦, using an optical electronic camera in which there is provided an image receiving system comprised o~ one or several rows of clasely arranged photosensitive electronic sensinà
elements with associated electronic circuits, an illuminating system and an electronic arithmetic apparatus.
Various methods for using optical electronic cameras for a diverse rnnge of applications are known from the relevant technical literature. A broad survey is provided in the article `" lZ(l 7~08 "Optische Datenerfassung mit CCD-Kameras" by Ing. (grad.) Alfred D-umlein in the journal "Elektronik", ~lo, 25 of Dec, 17, 19~2.
It is the main object of the present invention to provide a me-thod enabling the checking of in particular bar codes at high speed and with areat accuracy as to dimensions and contrast, said bar codes passing, in an arbitrary but repetitive pattern of mutual distances and at an arbitrary but practically constant speed, along such a camera system having one or several parallel 1~ rows of sensing elements, while firstly the checking operation can be performed independently o~ the print format and pattern position, and secondly checking is afforded over a large number of points .in the longitudinal direction of the bars by a small number of rows, even just one row, of sensing elements.
According to the invention, said object is attuined by optically forming an image of each pattern to be checked upon a fixed format and by taking several traverse images therefrom at an anglef~ with respect to the direction of the bars by means of the row~s) of closely arranged electrical sens;ng ele-ments, said traverse images being read out serially and subse-quently entered into the electronic arithmetic apparatus for comparison with a reference pattern The images are formed, while the pattern passes in front of the camera, hy illumina-ting the pattern by means of a series of short liahting flashes whose repetition frequency is proportional to the speed of pas-sage of the pattern. Althouah image shifting (image blurring) due to the speed of passage of the pattern is already suppressed by applying very short lighting flashes ~approx, 21u sec), this ~could still give rise to undesirable inaccuracies resulting . . .
from image shifting, in the event of greater values of the `'` 1~07~
speed of passage. Such undesirable image shifting can, how-ever, be compensated for in the arithmetic apparatus on the basis of the measurement of the speed o~ travel of the strip of flat cqrrier material upon which the patterns have been printed.
Another obiect of the invention is to provide an appa-artus for carrying out the method according to the invention using an optical elec-tronic camera wherein there is provided an image receiving system comprising one or several rows of closely arranged photosensitive electrical sensing elements with associated electronic circuits, an illuminating system and an electronic arithmetic apparatus~ the camera being pro-vided on a frume, in a vertically adjust~ble relation, above and in transverse direction over the strip of flat carrier material upon which the patterns to be checked have been prin-tedl said camera being, in accordance with the invention, dis-posed on suid frame member so as to be rotatable about the optical axis of its lens assembly, The electrical motor drive means provided for adjusting the vertical, transverse and ro-tation settings are preFerably connected to the electronicarithmetic apparatus for -their control, This likewise applies to the drive means for adjusting the lens assembly.
Survey of the drawings.
Figs. lA-D show possible positions of the codes printed on a strip of carrier material;
Fi~. 2A illustrates the sPnsing of a code at several mo-ments using a single row of electrical sensing elements, per-pendicular with respect to the bars;
Fig. 2B illustrates the sensing of a code at several mo-- 30 ments using a single row of electrica~ sensing elements which ~2~
forms an angle~ ~ 90~ with the bars;
Fig~ 2C illustrctes the sensing of a code at several moments using more (2) rows of electrical sensing elements, perpendicular with respect to the bars;
Fig. 2D illustrates the sensing of a code at several rnoments using more (two) rows of electrical sensing elements which are disposed at an angle ~ + 9~ with respect to the bars;
Fig. 2E illustrates the sensing of a code at one moment using several (three) rows of electrical sensing elements;
FigO 3 is a disgrammatic representation of the construction of an optical electronic camera as used according to the present invention;
Fig 4 shows a block diagram of an apparatus according to the invention.
Figs~ lA-D show several examples of a strip of flat carrier material 2 haYing bar codes 1 printed thereon. The codes are in a fixed position of each repetitive, printed area;
the position o~ -the code, defined by the magnitude oF the angle d between the direction of the bars and the longitudinal direc-tion of the strip of carrier material, is arbitrary but obvious-ly cons-tant for a strip. For a given code, the ratio of the length a to the height b of the format is fixed; however, per strip, the printed code may have any arbitrary format which may be smaller or larger than the stand`ard-format dimensions.
In order to measure the codes, the optical camera is to be dis-placed in transverse direction over the strip of carrier mate-rial in such a manner that the optical axis intersects the con-necting line 4 through the centers of the printed codes. Fur-thermore, the camera height abov~ the carrier material and the lens setting should be set in a manner so as to obtain a sharp :
- ~
image having an image dil-nension usecd For the standard format The characteristic data for the code to be checked, i,e~ the specific pattern, is entered into the central processing unit as a reference pattern produced on the basis of the standard format, as is at the same time the magnification factor of the printed code with respect to the standard format.
For the various usual code types (UPC, EAN, etc.~ for the standard-code format, the nominal bar thicknesses, the widths of .he spaces between the bars and the tolerances thereof as well as .he tolerances as a function oF the magnification factor of the printed code with respect to -the standard format,are contained in the memory of the central processing unit used for carrying out the method according to the invention.
The bar thicknesses as measured are compared with the nominal bar thicknesses so as to determine the degree of the deviations, it heing furthermore determined whether the latter fall within or outside the tolerances.
Figs 2A-E illustrate with several examples the manner in which, in accordance with Cl number oF -traverses, the code can be sensed at several places across the entire format so as to obtain rneasurement data which are processed, in accordance with a specified proaram, by the arithmetic apparatus for the purpose of checking each code as to cleviations in dimensions and contrast In the figures, the arrow 5 represents the direc-tion and speed v of travel of the strip of carrier material.The direction of travel is obviously the same as the longitu-dinal direction of the strip of carrier material~ Tha angle between the direction of travel 5 and the direction o-f bar po-Sitioning 6 is indicated by d. The angle between the direction 7 of each row of sensing elements in the imagc area of the 7~901!~
-- 6 _ camera and the direction of bar positioning 6 is indicated by ~ , Fig. 2A illustrates the case in which one row of electri-cal sensing elements is used and the camera has been ro-tated about the optical axis in a rnanner so that ~ =90. During the passing of a code in the object area of the camera lens, the code is repetitively briefly illuminated several times, as a result of which a number of traverse-image specimens of the code are successi~ely received by the row oF sensing elements.
The processing program can be relatively simple because each individual traverse image always comprises the same number of bars and spaces, For a given length I of the row o-F electrical sensing elements having a certain number of sensing ele~ents, the accuracy of measurement is greatest if the length of the 1~ traverse is the greatest possible fraction of t, This is rea-lized only, however, lf the cocle is oriented in a manner so that the direction oF bar positioning roughly corresponds to that of the Longituclinal direction o, the strip of carrier ma-terial, Ey s~l~cting the nuMber of traverses n desired over the hei9h-t a of the printed code, the time increment ht be-tween the brief s~uential illuminations is recordecl as a function of the speed of travel v oF the carrier material, the angles ~ and ~ , the number o-f traverses n and the climensions a and b of the printed-code format. Assuming the first and last traverse to be in the vicinit~ oF the borders oF the code format, this relat;on will be:
q a2 ~ b2 ~os(~-90-~)- sin(~-90-~)- tg(l80-~)]
t = - = ~ ~ . ....
v v (n-t) in which ~ = bg tg b Obviously, ~ t should not be less than the so-called integration time, i.e. the time required for the entering into and trans fer from the electrical sensors of the electric image formed therein. The speed v is obviously to be measured in orcler to afford setting ~t. The ratio of the given length 1 of .he row of sensing elements to the length (or width) of the code image must be greater according as the orientation of the codes more and more approaches the situation in which the bars are posi-tioned perpendicularly to the longitudinal clirection of the strip of carrier material, while ~t may increase si~ultaneously.
Fig~ ~C illustrates the case of two parallel rows of elec-trical sensing elements, the camera being rotated, as in fig.
~A, about the cylinder axis in svch a manner that in this case = 90, as well. To this, Fundamentally the same remarks apply as those applicable to fig. 2A. In this case, however, a smaller number of illuminating pulses is sufficient to obtain the same number of traverses. The inaccuracy of measurement at corres-poncling values of the angle ~ is greater, however, than in the case described hereinbefore, since the length of the rows oF
sensing elements must be relatively grQater in order to ensure that, at the passing o~ the image of an obliquely oriented cocle, the upper and lower angular points do not fall outside the area covered by the rows~ Codes printed in such a manner that the bars are positioned perpendicularly to the longitudinal direc-tion of the strip of carrier material can, when traversing the bars at right angles in several locations, be checked only by making use of several rows of sensing elements with one illu-minating pulse being given per image passing (See fig, 2E).
A method universally useful for the entire range of the angle ~ is provided in figs. 2B and 2D by way of example for a camera having one row and a camera having two rows of sensing elements, respectively. The row(s) is (are) -then disposed at an angle ~ ~ 90 with respect to the bars. ~ccording to the angle ~ at which -.he codes are printed on the strip of carrier ~aterial, the angle ~ can be chosen in a manner so that the ratio of the imaae size to the length o~ a row is as great as possible, thus enabling the optical resolution factor of the row to be used as effectively ns possible. ,~t an increasing speed v of the code-printed strip oF carrier material, image shifting will occur notwithstanding the use of a very short illuminating pulse. This can be compensated on the basis of a measurement of the $peed of travel v by means of a program provided to this effect in the electronic arithmetic apparatus so as to enhance the accuracy of measurement.
Fig. 3 is a diasrammatic representation of a camera to be used for carrying out the method, ~ frame 20 carries two guide rods 21, 22 ancl there is provided in a slidable relation there-along a carriage 23 which via the bearings 24, 25 carries the camera body 26. Saicl camera body can thus move in the clirection perpendicular to the plane of drawing ancl around the opticcl axis 27, It contains an optical imaging s~stem ~8, cliayramma-ticall~J indicated, and the holder ~ for the sensing elements, In order to keep -the lat-reI at the temperature which is most favorable to the operation, the holder 2, for the sensing ele-ments can be c0019cl by rneans of a Peltier element, not shown, - 25 The carrier material 30 with the bar codes to be checked passes in the direction o~ the arrow ~1 over -.he guide plate 3~, and the illumination oF the bar codes to be checked is effected by means of a flash-light source 33, shown cliagrammatically.
Fig~ 4 shows the block diagram of the complete apparatus by which the method accordina to the invention can be carried out. The central processing unit 40 of the electronic arithmetic ~L%~
_ 9 _ appclratus receives c!ata entering thereinto pertainincJ to the speecl of the web o~ material 30 obtained via the speed sensor 41, and pertaining to the r~lative position of the patterns obtained by means oF the encocler 4~ which is, for example, coupled with a roller whose circumferential speed is propor-tional to .he speec! of travel of the web of material. This roller may he, for instance, a roller of a comple-te printing machilte The mutual positions of the various patterns can be entered into i-he central processina unit by manually bringing a number of successive bar-code patterns under the camera ~6 and enterina a suitable setting sianal into the processing unit after proper positioning of ihe pattern.
The signal suppliecl by the imaye sensors is transmitted via the interface 43 to the central processing unit 40. Tl1e keyboard 44 affords entering all clat neces~ary For the proper functioning of the apparatus.
The apparatus may be provided with a printer 45 for pro-duciny printouts o~ measurement results, and a monitor 46 on which the rnomentary results are rendered visible. The various setting functions ~or the camera: vertical setting, transverse setting, setting of rotation and focusing are di~grammatically indicatecl by the blocks 47-~0; the control signals emanating therefrom are transmittecl to the camera 2O
h'hen forminy each traverse image there is the possibility of cletermining the degree of contrast OT the transitions between bar and space; this is a technique known per se.
~ s has been c!escribed, forming the momentary images is possibIe by pulsating illumination of the pattern using a flash lamp 33 controlled from the central processing unit 40. However, forming the momentary images can also be achieved by excitation (activation) of the sensing elements in the sampling rhythm.
Claims (9)
1. A method for checking deviations in dimensions and contrast of patterns which are presented for checking purposes at a practically constant speed of a continuously variably ad-justable magnitude, in particular of identical patterns printed on a repetitive fixed area on a strip of flat carrier material, each pattern of parallel lines of bar codes printed at prede-termined mutual distances, the angle .alpha. between the direction of the bars and the longitudinal direction of the strip of carrier material being constant but capable of having any value between 0 and ¦180°¦, using an optical electronic camera in which there is provided an image receiving system comprised of one or several rows of closely arranged photosensitive elec-trical sensing elements with associated electronic circuits, an illuminating system and an electronic arithmetic apparatus, in which an image is optically formed of each pattern to be checked upon a fixed format by taking several traverse images therefrom at an angle .beta. with respect to the direction of the bars by means of the row(s) of closely arranged electrical sensing elements, said traverse images being read out serially and subsequently entered into the electronic arithmetic appa-ratus for comparison with a reference pattern.
2. A method according to claim 1, in which, when using a single row of electrical sensing elements, for all values of .beta., except 0° and 180°, and for all values of .alpha., on the condition that .beta. ? 90° and .beta. ? 270° when .alpha. = 90° or .alpha. = 270°, the traverse images are obtained at several consecutive moments separated by a time increment .DELTA.t, the direction of the row of sensing elements not being parallel to the direction of travel of the carrier material.
3. A method according to claim 1, in which, when using more rows of electrical sensing elements, for all values of .beta., except 0° and 180°, and for all values of .alpha., on the condition that .beta. ? 90° and .beta. ? 270° when .alpha.= 90° or .alpha.= 270°, the traverse images can be obtained both at the same moment and at several consecutive moments separated by a time increment .DELTA.t, the di-rection of the row of sensing elements not being parallel to the direction of travel.
4. A method according to claim 1, in which, in the event of more than one row of electrical sensing elements being used, the traverse images are all obtained at the same moment when .beta. = 90° and ¦.alpha.¦= 90°.
5. A method according to claim 1, in which the images are formed, while the pattern passes in front of the camera, by illuminating the pattern by means of a series of short lighting flashes whose repetition frequency is proportional to the speed of passage of the pattern.
6. A method according to claim 5, in which in the arithmetic apparatus can compensate for image shifting on the basis of the measurement of the speed of travel of the strip of flat carrier material upon which the patterns have been printed.
7. An apparatus for carrying out the method according to claim 1 by using an optical electronic camera wherein there is provided an image receiving system comprised of one or se-veral rows of closely arranged photosensitive electrical sensing elements with associated electronic circuits, an illuminating system and an electronic arithmetic apparatus, the camera being provided on a frame, in a vertically adjustable relation, above and in transverse direction over the strip of flat carrier material upon which the patterns to be checked have been printed, wherein the camera is disposed in the frame so as to be rotatable about the optical axis of its lens assembly.
8. An apparatus according to claim 7, wherein the elec-tronic drive means provided for adjusting the vertical, trans-verse and rotation settlings are connected to the electronic arithmetic apparatus for their control thereof.
9. An apparatus according to claim 7, wherein the elec-tronic drive means provided for the adjustment of the lens assembly are connected to the electronic arithmetic apparatus for their control thereof.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL8301054 | 1983-03-25 | ||
| NL8301054A NL8301054A (en) | 1983-03-25 | 1983-03-25 | METHOD FOR CHECKING PATTERNS AND DEVICE THEREFOR |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1207908A true CA1207908A (en) | 1986-07-15 |
Family
ID=19841598
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000450242A Expired CA1207908A (en) | 1983-03-25 | 1984-03-22 | Method for checking patterns and apparatus to carry out such method |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4646353A (en) |
| EP (1) | EP0123336A1 (en) |
| JP (1) | JPS59180672A (en) |
| AU (1) | AU571500B2 (en) |
| CA (1) | CA1207908A (en) |
| NL (1) | NL8301054A (en) |
| NZ (1) | NZ207623A (en) |
Families Citing this family (22)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL8501460A (en) * | 1985-05-22 | 1986-12-16 | Philips Nv | METHOD FOR IDENTIFYING OBJECTS INCLUDING A CODE FIELD WITH DOT CODE, DEVICE FOR IDENTIFYING SUCH A DOT CODE, AND PRODUCT USING SUCH A DOT CODE |
| JPH0756665B2 (en) * | 1986-05-22 | 1995-06-14 | 大日本印刷株式会社 | Print bar code automatic monitoring device |
| US4710615A (en) * | 1986-06-26 | 1987-12-01 | Ncr Corporation | CCD bar code scanner |
| US4860226A (en) * | 1986-09-09 | 1989-08-22 | Martin Edward L | Method and apparatus for bar code graphics quality control |
| JPS63167989A (en) * | 1986-12-29 | 1988-07-12 | Isowa Ind Co | Bar code print inspecting device for corrugated cardboard printing machine |
| US4988852A (en) * | 1988-07-05 | 1991-01-29 | Teknekron Transportation Systems, Inc. | Bar code reader |
| CA2049866C (en) * | 1990-12-28 | 1998-06-30 | Raymond L. Higgins | System and method for optical recognition of bar-coded characters |
| US5194720A (en) * | 1991-04-25 | 1993-03-16 | Eastman Kodak Company | Method and apparatus for performing on-line integrated decoding and evaluation of bar code data |
| US7387253B1 (en) * | 1996-09-03 | 2008-06-17 | Hand Held Products, Inc. | Optical reader system comprising local host processor and optical reader |
| US5698833A (en) * | 1996-04-15 | 1997-12-16 | United Parcel Service Of America, Inc. | Omnidirectional barcode locator |
| US5939697A (en) * | 1996-04-29 | 1999-08-17 | Webscan, Inc. | Bar code evaluation system architectures and methods of calibration |
| US7270273B2 (en) | 2001-01-22 | 2007-09-18 | Hand Held Products, Inc. | Optical reader having partial frame operating mode |
| EP1354291B1 (en) * | 2001-01-22 | 2006-08-02 | Hand Held Products, Inc. | Optical reader having partial frame operating mode |
| US7268924B2 (en) * | 2001-01-22 | 2007-09-11 | Hand Held Products, Inc. | Optical reader having reduced parameter determination delay |
| US7203361B1 (en) | 2001-03-16 | 2007-04-10 | Hand Held Products, Inc. | Adaptive digitizer for optical reader |
| US7331523B2 (en) | 2001-07-13 | 2008-02-19 | Hand Held Products, Inc. | Adaptive optical image reader |
| US20040134988A1 (en) * | 2003-01-09 | 2004-07-15 | Hand Held Products, Inc. | Analog-to-digital converter with automatic range and sensitivity adjustment |
| US7852519B2 (en) | 2007-02-05 | 2010-12-14 | Hand Held Products, Inc. | Dual-tasking decoder for improved symbol reading |
| US8628015B2 (en) | 2008-10-31 | 2014-01-14 | Hand Held Products, Inc. | Indicia reading terminal including frame quality evaluation processing |
| US8587595B2 (en) | 2009-10-01 | 2013-11-19 | Hand Held Products, Inc. | Low power multi-core decoder system and method |
| DE102014222693B4 (en) * | 2014-11-06 | 2019-10-02 | Moba - Mobile Automation Ag | DEVICE FOR DETERMINING THE TEMPERATURE OF A ROADWORK MATERIAL RAISED BY A CONSTRUCTION MACHINE AND A CONSTRUCTION MACHINE WITH SUCH A DEVICE |
| US9686428B2 (en) * | 2015-02-26 | 2017-06-20 | Konica Minolta, Inc. | Equipment to determine line width of check image and image-forming apparatus using the same |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3600556A (en) * | 1969-04-21 | 1971-08-17 | Scanner | Apparatus for machine reading randomly positioned and oriented information |
| US3728677A (en) * | 1971-05-10 | 1973-04-17 | Stanford Research Inst | Rotation-independent reading of rectangular insignia |
| US3701098A (en) * | 1971-06-15 | 1972-10-24 | Scanner | Device for machine reading of information without manipulation of the information carrier |
| DE2329041A1 (en) * | 1973-06-07 | 1975-01-02 | Anker Werke Ag | TV camera electron beam aligning system - enables standard cameras to be used to read goods tickets |
| US3852573A (en) * | 1973-11-16 | 1974-12-03 | Scanner | Alignment correction for read scan raster fields |
| US4140271A (en) * | 1975-04-17 | 1979-02-20 | Nippondenso Co., Ltd. | Method and apparatus to read in bar-coded information |
| JPS5282396A (en) * | 1975-12-29 | 1977-07-09 | Fujitsu Ltd | Printing and inspecting apparatus of bar code |
| FR2341900A1 (en) * | 1976-02-20 | 1977-09-16 | Mitsubishi Electric Corp | INFORMATION READING SYSTEM |
| US4282425A (en) * | 1979-07-25 | 1981-08-04 | Norand Corporation | Instant portable bar code reader |
| JPS5849907B2 (en) * | 1979-11-20 | 1983-11-07 | 日本電気精器株式会社 | Barcode symbol printing quality inspection equipment |
| US4387298A (en) * | 1981-11-27 | 1983-06-07 | Burroughs Corporation | Recognition logic circuit for bar code reader systems |
| US4500776A (en) * | 1982-11-08 | 1985-02-19 | Vadim Laser | Method and apparatus for remotely reading and decoding bar codes |
-
1983
- 1983-03-25 NL NL8301054A patent/NL8301054A/en not_active Application Discontinuation
-
1984
- 1984-03-19 US US06/591,276 patent/US4646353A/en not_active Expired - Fee Related
- 1984-03-22 CA CA000450242A patent/CA1207908A/en not_active Expired
- 1984-03-23 NZ NZ207623A patent/NZ207623A/en unknown
- 1984-03-23 JP JP59054622A patent/JPS59180672A/en active Pending
- 1984-03-23 EP EP84200417A patent/EP0123336A1/en not_active Withdrawn
- 1984-03-27 AU AU26145/84A patent/AU571500B2/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| EP0123336A1 (en) | 1984-10-31 |
| NL8301054A (en) | 1984-10-16 |
| AU571500B2 (en) | 1988-04-21 |
| US4646353A (en) | 1987-02-24 |
| JPS59180672A (en) | 1984-10-13 |
| AU2614584A (en) | 1984-11-22 |
| NZ207623A (en) | 1988-01-08 |
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| MKEX | Expiry |