Method of and apparatus for detecting the image fields contained on a strip of film

Claim 3

A method according to claim 1, including producing an ''''image'''' signal when at least one of the indications coded with the binary one value occurs and producing a ''''no image'''' signal when no indication exceeds said first predetermined threshold.

Claim 4

A method according to claim 2, including preferring all those first signals which coincide with respect to time with signal changes from ''''no image'''' to ''''image'''' signals and preferring all those second signals which coincide in respect to time with signal changes from ''''image'''' to ''''no image'''' signals.

Claim 5

A method according to claim 3, including suppressing the first of two neighbouring of said first signals when the time between the occurrence of those two neighbouring signals is less than the time taken to scan one quarter of a predetermined standard image field and suppressing the second of two neighbouring of said second signals when the time between the occurrence of those two neighbouring signals is less than the time taken to scan one quarter of a predetermined standard image field.

Claim 6

A method according to claim 3, including suppressing the first and last of three neighbouring of said first signals when the time of occurrence between the first and last of the three neighbouring signals is less than the time taken to scan one quarter of a predetermined standard image field and suppressing the second and third of three neighbouring of said second signals when the time of occurrence between the first and last of the three neighbouring signals is less than the time taken to scan one quarter of a predetermined standard image field.

Claim 7

A method according to claim 3, including suppressing the first of two neighbouring of said first signals when the time between the occurrence of those two neighbouring signals is less than the time taken to scan one quarter of a predetermined image field and suppressing the second of two neighbouring of said second signals when the time between the occurrence of those two neighbouring signals is less than the time taken to scan one quarter of said standard image field, the suppression of said first and second signals taking place only when the time of occurrence between adjacent signals is at most equal to twice the time of scanning the spaces between image fields.

Claim 8

A method according to claim 3, including suppressing the first and last of three neighbouring of said first signals when the time of occurrence between the first and last of the three neighbouring signals is less than the time taken to scan one quarter of a predetermined standard image field, and suppressing the second and third of three neighbouring of said second signals when the time of occurrence between the first and last of the three neighbouring signals is less than the time taken to scan one quarter of said standard image field, the suppression of said first and second signals taking place only when the time of occurrence between adjacent signals is at most equal to twice the time of scanning the spaces between image fields.

Claim 9

A method according to claim 6, wherein within a time interval which is at most equal to twice the time of scanning the space between image fields both preferred and non-preferred first signals occur, the non-preferred first signals are suppressed in the further processing of the Signals and wherein within a time interval which is at most equal to twice the time of scanning the space between image fields both preferred and non-preferred second signals occur, the non-preferred second signals are suppressed in the further processing of the signals.

Claim 10

A method according to claim 7, wherein within a time interval which is equal to twice the time of scanning the space between image fields both preferred and non-preferred first signals occur, the non-preferred first signals are suppressed in the further processing of the signals and wherein within a time interval which is equal to twice the time of scanning the space between image fields both preferred and non-preferred second signals occur, the non-preferred second signals are suppressed in the further processing of the signals.

Claim 11

A method according to claim 3, including a. evaluating each of two successive preferred first and second signals as the most probable image start and most probable image end when the time between their occurrence is not greater than the time taken to scan a predetermined standard image field plus the standard space between fields and not smaller than the time taken to scan the standard image field minus the standard space; b. if the condition stipulated under a) is not fulfilled, evaluating a succession of a preferred first signal and a non-preferred second signal as the most probable image start and most probable image end when the time between their occurrence is not greater than indicated in a); c. if none of the conditions stipulated under a) and b) are fulfilled, evaluating a succession of a nonpreferred first signal and a preferred second signal as the most probable image start and most probable image end when the time between their occurrence is not greater than indicated in point a); d. if none of the conditions stipulated in a) to c) are fulfilled, evaluating a succession of a non-preferred first signal and a non-preferred second signal as the most probable image start and most probable image end when the time between their occurrence is not greater than indicated in point a); e. if none of the conditions stipulated in a) to d) are fulfilled, evaluating a preferred first signal as the most probable image start; f. if none of the conditions stipulated in a) to e) are fulfilled, evaluating a preferred second signal as the most probable image end; g. if none of the conditions stipulated in a) to f) are fulfilled, evaluating a non-preferred first signal as the most probable image start; and h. if none of the conditions stipulated in a) to g) are fulfilled, evaluating a non-preferred second signal as the most probable image end.

Claim 12

A method according to claim 10, wherein for each of the conditions stipulated in a) to h), in the event of their fulfillment, a possible image position pulse Q is produced and a determined weight is assigned to each of these position pulses, the highest weight is assigned to the Q signals produced by fulfillment of condition a) and lower weights, declining in status from b) to h), are assigned to the Q signals produced by fulfillment of the conditions b) to h), and that the image positions are determined by taking this weight into account.

Claim 13

A method according to claim 11, wherein a position signal Q1 with a high weight is assigned to each fulfillment of one of the conditions b) to d) and a position signal Q2 with a lower weight is assigned to each fulfillment of one of the conditions e) to h), these two weights being so selected that the higher is more than twice as great as the lower, and that the simultaneous occurrence of a Q1 signal and a Q2 signal is allocated to each fulfillment of the condition a), so that for the fulfillment of the condition a) the highest weight is obtained.

Claim 14

A method according to claim 12, wherein only Q signals are used and these are grouped in respect of time in such a manner that the Q signals belonging to suCcessive image fields come to lie within an interval, referred to hereinbelow as grouping interval, which is shorter than half the standard image field length.

Claim 15

A method according to claim 13, wherein the length of each grouping interval is fixed so as to amount to about two (n-1) times the standard space width.

Claim 16

A method according to claim 13, wherein the grouping of the Q signals is effected so that in each grouping interval the Q signals occur in the same sequence as the images from which they originate from one another in the film.

Claim 17

A method according to claim 13, wherein within intervals which are shorter than the standard image field length at least two sub-intervals K1, K1 etc., are determined by the occurrence of Q signals, one such sub-interval always being initiated on the occurrence of a Q signal originating from the first image field of the region considered and one such sub-interval always being terminated on the occurrence of a Q signal originating from the last image field of the same region, while on the occurrence of Q signals originating from image fields lying therebetween one such sub-interval is always initiated and is terminated simultaneously on during one timing period, that in the sub-intervals so determined the weight of all the Q signals (Q1, Q2) occurring there, including the initiating and terminating signals, are added together, and that for the purpose of determining the image positions only the sub-interval with the highest total weight, which constitutes a preferred grouping interval, is utilised in each case.

Claim 18

A method according to claim 16, wherein in each of the aforesaid intervals only two sub-intervals are allowed, so that in the case of Q signals which occur after the end of the second sub-interval no further sub-intervals are initiated.

Claim 19

A method according to claim 16, in which out of each of the preferred grouping intervals only those Q signals (Q1, Q2) are used as actual marking signals which originate from the image field lying furthest forwards in the region in question, and that in the event of no such Q signal existing only the Q signals originating from the following image field are taken into account, and so on.

Claim 20

A method according to claim 18, in which the marking signals selected from the preferred grouping intervals are so connected that each of these signals marks an image field which lies n image fields upstream of the grouping interval from which the respective marking signal was selected.

Claim 21

Apparatus for detecting image fields on a strip of film comprising, means for scanning the strip in a direction along its length with a beam of radiation to provide indications of the densities of all of a plurality of separate adjacent areas across the strip, means for electronically processing the density indications to produce upon detecting a predetermined change in density in a predetermined number of said areas a first signal indicating the beginning and a second signal indicating the end of an image field and means for utilising the signals obtained by scanning at least two standard image field lengths plus standard space widths to determine the actual image positions, said scanning means including a plurality of photosensitive cells and a light source projecting light through said film onto said cells, said cells being arranged in a direction transverse to the direction of movement of said strip and said electronic processing means including means allocating one binary value to all those density indications which exceed a first predetermined threshold value and the other binary value to all those density indications which do not exceed said first predetermined threshold value, the first and second signal being produced upon the presence of a predetermined number of said one binary values simultaneously.

Claim 22

Apparatus for detecting image fields on a strip of film comprising, means for scanning the strip in a direction along its length with a beam of radiation to provide indications of the densities of all of a plurality of separate adjacent areas across the strip, means for electronically processing the density indications to produce upon detecting a predetermined change in density in a predetermined number of said areas a first signal indicating the beginning and a second signal indicating the end of an image field and means for utilising the signals obtained by scanning at least two standard image field lengths plus standard space widths to determine the actual image positions, said scanning means including a plurality of photosensitive cells and a light source projecting light through said film onto said cells, said cells being arranged in a direction transverse to the direction of movement of said strip and said electronic processing means including means allocating one binary value to all those density indications which exceed a first predetermined threshold value and the other binary value to all those density indications which do not exceed said first predetermined threshold value, the first and second signal being produced upon the presence of a predetermined number of said one binary values simultaneously.

Claim 23

Apparatus according to claim 20, in which said electronic processing means further includes means producIng an ''''image'''' signal when at least one of the indications coded with the binary one value occurs means producing a ''''no image'''' signal when no indication exceeds said first predetermined threshold means selecting all those first signals which coincide with respect to time with signal changes from ''''no image'''' to ''''image'''' signals and means selecting all those second signals which coincide in respect to time with signal changes from ''''image'''' to ''''no image''''

Claim 24

Apparatus for detecting image fields on a strip of film each field being of substantially the same size and being spaced one from another along said strip by a substantially constant amount, the apparatus comprising, means advancing said film step by step in equal increments of length, a light source positioned to illuminate said film, a plurality of photocells arranged in a line across said film substantially transverse to the direction of advancement of the film, to receive light from said source after the light has passed through the film, an electronic processing unit coupled to said cells and responsive to electrical outputs therefrom representing the intensity of the light falling on said cells and thus representing the density of the areas of said film through which said light passes to said cells, to indicate the beginning or end of each image area said electronic processing unit comprising means producing a first signal when a predetermined number of said cells produce simultaneously an electrical output of a value greater than a first threshold value, means differentiating said first signal to produce a second signal, means generating a third signal when the value of said second signal exceeds a second threshold value and a fourth signal when the value of said second signal exceeds a third threshold value, said third and fourth signals each indicating respectively the beginning and end of an image field, means producing a fifth signal indicating that at least one of said cells produces an electrical output of a value greater than the first threshold value, means producing a sixth signal indicating that none of the cells produces an electrical output of a value greater than the first threshold value, and means for selecting a third signal which is produced during a predetermined time interval in which a fifth signal is produced to indicate the beginning of an image field and for selecting a fourth signal which is produced during a predetermined time interval in which a sixth signal is produced to indicate the end of an image field.

Claim 25

Apparatus for detecting image fields on a strip of film each field being of substantially the same size and being spaced one from another along said strip by a substantially constant amount, the apparatus comprising, means advancing said film step by step in equal increments of length, a light source positioned to illuminate said film, a plurality of photocells arranged in a line across said film substantially transverse to the direction of advancement of the film, to receive light from said source after the light has passed through the film, an electronic processing unit coupled to said cells and responsive to electrical outputs therefrom representing the intensity of the light falling on said cells and thus representing the density of the areas of said film through which said light passes to said cells, to indicate the beginning or end of each image area said electronic processing unit comprising means producing a first signal when a predetermined number of said cells produce simultaneously an electrical output of a value greater than a first threshold value, means differentiating said first signal to produce a second signal, means generating a third signal when the value of said second signal exceeds a second threshold value and a fourth signal when the value of said second signal exceeds a third threshold value, said third and fourth signals each indicating respectively the beginning and end of an image field, means producing a fifth signal indicating that at least one of said cells produces an electrical output of a value greater than the first threshold value, means producing a sixth signal indicating that none of the cells produces an electrical output of a value greater than the first threshold value, and means for selecting a third signal which is produced during a predetermined time interval in which a fifth signal is produced to indicate the beginning of an image field and for selecting a fourth signal which is produced during a predetermined time interval in which a sixth signal is produced to indicate the end of an image field.