Method for the automatic or semiautomatic distance measurement and focusing of the image of an object onto a focal plane

Claim 2

In a method for automatic distance measurement including the steps of (a) examining two line shaped image sections so as to locate respective linear image segments thereof which have a maximum correlation as to respective corresponding light intensities along the lengths of the respective image segments, (b) conducting a correlation examination by comparing different image segments of the two line shaped image sections in a predetermined order as a sequence of comparison steps, such that the identification of the comparison step giving rise to a maximum correlation provides a measure of distance, and (c) utilizing the identification of the comparison step giving rise to the maximum correlation to provide an automatic distance indication, the improvement wherein (d) the examining of the two line shaped image sections pursuant to step (a) above is effected by storing image element signals in successive stages of first and second shift registers in accordance with the light intensities of successive elemental regions of the respective line shaped image sections, and (e) the conducting of the correlation examination pursuant to step (b) above is effected by (e1) during each comparison step, reading out in parallel at one respective end of each shift register from a number of shift register stages corresponding to the number of elemental regions which represent the length of an image segment, (e2) comprising corresponding image element signals of the respective subsets of image element signals read out from the respective shift registers during the comparison step, so as to compare the corresponding segments of the respective line shaped image sections, and (e3) after each reading out of respective subsets of image element signals at the respective one ends of the respective shift registers, alternately shifting the image element signals of the first shift register toward its one end and again executing a comparison step, and alternately shifting the image element signals of the second shift register toward its one end and again executing a comparison step, so that subsets of image element signals corresponding to segments of the two image sections are respectively supplied for comparison with each other in a predetermined order and during a sequence of comparison steps defined by the alternate shifting of the image element signals in the first and second shift registers.

Claim 3

A method according to claim 1, with the examining of the two line shaped image sections comprising the steps of subjecting first and second lines of image sensing elements associated with the respective stages of the first and second shift registers to the light intensities of successive elemental regions of the respective line shaped image sections so as to generate image element signals, and transferring the respective image element signals to respective stages of the first and second shift registers in parallel.

Claim 4

A method according to claim 2, with the image element signals transferred to the respective shift register stages being obtained by integration of the outputs of the image sensing elements over a measuring duration.

Claim 5

A method according to claim 3 with the integration of the outputs of the image sensing elements being effected over a measuring duration which is a function of the average light intensity of the respective image sections.

Claim 6

A method according to claim 2, wherein the image sensing elements comprise detector diodes (D 1 , D 2 ) with series connected transfer transistors (T 11 , T 12 ), the transferring of the respective image element signals to the respective stages of the first and second shift registers being effected by actuating the transfer transistors for a measuring duration.

Claim 7

A method according to claim 2, wherein analog outputs of the image sensing elements are converted to binary digital form as a result of the operating characteristics of transistors associated with the respective stages of the first and second shift registers.

Claim 8

A method according to claim 6, with the correlation examination being effected by supplying subsets of image element signals in binary digital form from the respective one ends of the first and second shift registers to respective first and second inputs of exclusive OR gates such that the number of active outputs from such OR gates is a measure of the degree of correlation between the respective corresponding image element signals of the subsets of image element signals being compared.

Claim 9

In a method for automatic distance measurement and focusing of the image of an object onto a focal plane, said method including the steps of (a) examining two elongated image sections so as to locate respective image segments thereof which have a maximum correlation as to respective corresponding light intensities along the lengths of the respective image segments, (b) conducting a correlation examination by comparing different image segments of the two image sections in a predetermined order as a sequence of comparison steps, such that the identification of the comparison step giving rise to the maximum correlation provides a measure of the distance the object from the focal plane, and (c) utilizing the identification of the comparison step giving rise to the maximum correlation to provide an indication of focal distance and to focus the object onto the focal plane, wherein the improvement comprises (d) the examining of the two line shaped image sections pursuant to step (a) above being effected by storing image element signals in successive stages of first and second shift registers in accordance with the light intensities of successive elemental regions of the respective image sections, and (e) the conducting of the correlation examination pursuant to step (b) above being effected by (e1) during each comparison step, reading out in parallel from a predetermined number of output-supplying shift register stages corresponding to the number of elemental regions which represent the length of an image segment, (e2) comparing corresponding image element signals of the respective subsets of image element signals read out from the respective shift registers during the comparison step, so as to compare the corresponding segments of the respective image sections, and (e3) after each readout out of respective subsets of image element signals at the respective output-supplying shift register stages of the respective shift registers, alternately shifting the image element signals of the first shift register toward its output-supplying shift register stages and again executing a comparison step, and alternately shifting the image element signals of the second shift register toward its output supplying shift register stages and again executing a comparison step, so that subsets of image element signals corresponding to each of the segments of the two image sections are respectively supplied for comparison with each other in a predetermined order and during a sequence of comparison steps, defined by the alternate shifting of the image element signals in the first and second shift registers.

Claim 10

In a method for automatic distance measurement and focusing of the image of an object onto a focal plane, said method including the steps of (a) examining two elongated image sections so as to locate respective image segments thereof which have a maximum correlation as to respective corresponding light intensities along the lengths of the respective image segments, (b) conducting a correlation examination by comparing different image segments of the two image sections in a predetermined order as a sequence of comparison steps, such that the identification of the comparison step giving rise to the maximum correlation provides a measure of the distance the object from the focal plane, and (c) utilizing the identification of the comparison step giving rise to the maximum correlation to provide an indication of focal distance and to focus the object onto the focal plane, wherein the improvement comprises (d) the examining of the two line shaped image sections pursuant to step (a) above being effected by storing image element signals in successive stages of first and second shift registers in accordance with the light intensities of successive elemental regions of the respective image sections, and (e) the conducting of the correlation examination pursuant to step (b) above being effected by (e1) during each comparison step, reading out in parallel from a predetermined number of output-supplying shift register stages corresponding to the number of elemental regions which represent the length of an image segment, (e2) comparing corresponding image element signals of the respective subsets of image element signals read out from the respective shift registers during the comparison step, so as to compare the corresponding segments of the respective image sections, and (e3) after each readout out of respective subsets of image element signals at the respective output-supplying shift register stages of the respective shift registers, alternately shifting the image element signals of the first shift register toward its output-supplying shift register stages and again executing a comparison step, and alternately shifting the image element signals of the second shift register toward its output supplying shift register stages and again executing a comparison step, so that subsets of image element signals corresponding to each of the segments of the two image sections are respectively supplied for comparison with each other in a predetermined order and during a sequence of comparison steps, defined by the alternate shifting of the image element signals in the first and second shift registers.

Claim 11

A method according to claim 8, with the examining of the two elongated image sections comprising the steps of subjecting first and second lines of image sensing elements associated with the respective stages of the first and second shift registers to the light intensities of successive elemental regions of the respective elongated image sections so as to generate image element signals, and transferring the respective image element signals to respective stages of the first and second shift registers in parallel.

Claim 12

A method according to claim 9, wherein analog outputs of the image sensing elements are converted to binary digital form as a result of the operating characteristics of transistors associated with the respective stages of the first and second shift registers.

Claim 13

A method according to claim 10, with the correlation examination being effected by supplying subsets of image element signals in binary digital form from the respective one ends of the first and second shift registers to respective first and second inputs of exclusive OR gates such that the number of active outputs from such OR gates is a measure of the degree of correlation between the respective corresponding image element signals of the subsets of image element signals being compared.

Claim 14

A method according to claim 9, with the image element signals transferred to the respective shift register stages being obtained by integration of the outputs of the image sensing elements over a measuring duration.

Claim 15

A method according to claim 12, with the integration of the outputs of the image sensing elements being effected over a measuring duration which is a function of average light intensity of the respective image sections.

Claim 16

A method according to claim 9, wherein the image sensing elements comprise detector diodes (D 1 , D 2 ) with series connected transfer transistors (T 11 , T 12 ), the transferring of the respective image element signals to the respective stages of the first and second shift registers being effected by actuating the transfer transistors for a measuring duration.