GB2415800A - Image correlation apparatus - Google Patents

Abstract

An image correlation apparatus comprises an imaging device for capturing images of a plurality of target objects and adapted to record the times at which the images are captured, a data management means adapted to store at least known data corresponding to the plurality of target objects, and a sensing means adapted to sense the image captures and to notify the data management means of the times at which the image captures are sensed for each of the plurality of target objects. The data management means is further adapted to correlate the times at which the images are captured with the times at which the image captures are sensed, so as to match the captured images to the corresponding stored known data for each of the plurality of target objects. The sensing means may be a flash sensor.

Description

241 5800

IMAGE CORRELATION

This invention relates to image capture and data processing techniques for image correlation.

The use of digital imaging devices, such as digital cameras, is becoming increasingly more widespread throughout the photographic community. The ease of use of the cameras, coupled with their ability to provide on-thespot images has led digital imaging to be embraced by both amateurs and lo professionals alike. Moreover, unlike conventional techniques which may involve photographic film and developing chemicals, the operating costs of digital imaging can be very low, since following the initial outlay for the equipment no consumable costs need be incurred. Typically thereafter, the photographer need only download the images to an appropriate personal computer for storage and/or direct viewing of the images.

The ability to readily capture and store digital images is advantageous, particularly if it is desired to capture images of a plurality of target objects during a particular photographic session. Moreover, digital storage of the images is significantly more convenient than having to physically store a plurality of photographic prints or negatives, which can be damaged during storage or misplaced. Digital storage also allows copies of the images to be readily and effortlessly communicated to interested parties, via email or a suitable computer storage medium, such as a floppy disc or CD-ROM for 2s instance.

A particularly useful application of digital imaging is in obtaining images of students in educational establishments. The images may complement administrative details previously stored in an electronic database or so arrangement of record files, such as name, address, age and admissions number etc. with visual identity information, which can be beneficial to teachers/lecturers and administrators within the establishment for identification purposes.

Typically, there are two conventional techniques of matching digital images taken of students against their administrative details. One is based on a manual log made by the photographer, teacher or photographer's assistant, at the time of the image capture i.e. recording the exposure number and the student's name, which then allows the digital image to be downloaded and lo linked to the corresponding database entry after the photographic session has ended. The other allows the digital image to be downloaded and linked to the student's database entry directly following the image capture.

However, as can be readily appreciated both these techniques can be laborious and generally slow, particularly if many students are imaged, and may prolong the photographic session for all concerned. Any prolongation of the session can be particularly disadvantageous to the students since it may disrupt classes/lectures, and may incur further costs to either, or both, the educational establishment and the photographer.

so An object of the present invention is to provide an image correlation apparatus which is simple to use and reliably matches batches of images of target objects to data corresponding to the target objects.

A further object of the present invention is to provide an image correlation apparatus that can match batches of images of target objects to data corresponding to the target objects without the aid of manual intervention.

According to a first aspect of the present invention there is provided an image correlation apparatus, comprising: an imaging device for capturing images of a plurality of target objects and adapted to record the times at which the images are captured; a data management means adapted to store at least known data corresponding to the plurality of target objects; and s a sensing means adapted to sense the image captures and to notify the data management means of the times at which the image captures are sensed for each of the plurality of target objects; wherein the data management means is further adapted to correlate the times at which the images are captured with the times at which the lo image captures are sensed, so as to match the captured images to the corresponding stored known data for each of the plurality of target objects.

According to a second aspect of the invention there is provided a method of image correlation, comprising the steps of: capturing images of a plurality of target objects using an imaging device and recording the times at which the images are captured; storing at least known data corresponding to the plurality of target objects in a data management means; and sensing the image captures using a sensing means and to notifying no the data management means of the times at which the image captures are sensed for each of the plurality of target objects; wherein the data management means correlates the times at which the images are captured with the times at which the image captures are sensed, so as to match the captured images to the corresponding stored :5 known data for each of the plurality of target objects.

According to a third aspect of the invention there is provided a further method of image correlation, comprising the steps of: sensing times of image captures from a sensing means and recording said sensed times against known data corresponding to a plurality of target objects which are the subjects of said image captures; receiving, from an imaging device, captured images of said plurality of target objects, each image including data representing the time at which the image was captured; correlating the sensed times and the image capture times; and associating each of the captured images with a respective one of the known data.

Embodiments of the present invention will now be described in detail by way of example and with reference to the accompanying drawing in which: Figure 1 is a schematic representation of an image correlation apparatus according to a preferred embodiment of the present invention.

With reference to figure I there is shown an image correlation apparatus 10 according to the preferred embodiment of the present invention. The apparatus 10 comprises an imaging device 12, a data management means 14 and a sensing means 16.

The imaging device 12 may be any suitable digital imaging device, such as a digital camera, which can capture digital images of a plurality of target objects (not shown) and is capable of recording the times at which the images are captured. Preferably, the recorded times are measured with reference to an internal clock (not shown) within the imaging device 12.

The imaging device 12 preferably includes a memory 18 to store each of the images 111...1]N in a separate image file, each file having at least one header field to record the time of the image capture try tcN By way of example' as shown in figure 1, the files are named as 0001 jpg to OOONjpg so (where N is a positive integer > I), however it is to be appreciated that any suitable image file format may be used, including, but not limited to' JPEG, GIFF, TIFF and BM1P.

The memory 18 may be any suitable permanent or removable memory s storage device, such as, but not limited to, Smart Media_, Compact Flash' M and proprietary memory cards and sticks. Alternatively, the memory may also be external to the imaging device 12, with the imaging device 12 communicating with the Hickory using conventional techniques, for example, a hard-wire connection.

The imaging device 12 also preferably includes a flash wit 20 suitable for emitting light to illuminate each target object during an image capture. The flash unit 20 may be a conventional 'white light' type and may have a flash duration which is typically short, for example about 0. 05 to I second, but s may be altered by the photographer depending on the light levels within the vicinity ofthe target objects.

Herein, any reference to 'image capture' is to be taken as referring to the capturing of an image of a target object by the imaging device 12, the to captured image being at least a 2-dimensional representation of the object.

I-Ience, 'time of image capture' is to be taken as the time at which the imaging device captures an image of the target object, and is the time tC'...tcN recorded in the headers ofthe image files.

as Further, any references herein to 'target object' or to 'target objects' are to be taken as referring to objects funning the main composition of an image and for which data corresponding to the object is known a priori. In the preferred embodiments, the objects may be students enrolled at an educational establishment and the corresponding data (shown as Data #1 to Data #In in figure I) may be administrative details, such as, but not limited to, name, address, age, subjects taken and admissions number for instance.

in preferred embodiments, the sensing means 16 is adapted to sense the image captures and to notify the data management means 14 of the times tS.

tsN at which the image captures are sensed for each of the target objects. The sensing means 16 preferably includes a flash sensor 17 which is adapted to sense the light emitted by the flash unit 20 of the imaging device 12 which is associated with an image capture. The flash sensor 17 in may be any suitable light detector which has a response time of less than, or substantially equal to, the flash duration of the flash unit 20 and is capable of notifying the data management means 14 in response to detecting the light emitted by the flash unit 20...DTD: In alternative embodiments, the imaging device 12 includes a transmitter (not shown) preferably connected to a Mash sync port on the device 12 for transmitting a signal to the sensing means 16 during an image capture, and the sensing means 16 includes a receiver (not shown) adapted to sense the transmitted signal associated with the image capture. In this way, when the so sensing means 16 receives a transmitted signal it becomes aware that an image capture has taken place, and therefore need not rely on sensing the light emitted from the flash unit 20. This arrangement can be particularly advantageous in situations where more than one photographer is active during a photographic session, since the receiver may be adapted to respond only to signals from the corresponding transmitter, thereby avoiding any possible interference from other cameras. The transmitter and receiver may be conventional devices and may operate in any region of the electromagnetic spectrum or may be ultrasonic. The transmitter preferably includes at least one hot-shoe mount/adaptor for mounting to, or close-by, the imaging device 12, while the receiver may include at least one hot-shoe mount/adaptor for mounting on a tripod etc. Alternatively, the imaging device 12 may be directly connected to the s sensing means 16 by way of a hard-wire connection (not shown), making use of a video out, or flash synch, port on the camera for instance, and can therefore communicate an electrical signal to the sensing means 16 at the time of an image capture.

lo The sensing means 16 preferably notifies the data management means 14 by way of a single pulsed signal, which is interpreted by the data management means 14 as an indication that an image capture has taken place. The single pulsed signal does not itself convey any time data and therefore the data management means 14 must refer to a reference clock signal, associated is with the data management means, in order to determine the time at which the signal was notified.

Alternatively, the sensing means 16 may include a reference clock signal itself and may notify the data management means 14 by way of a data so packet, which includes the time of the sensed image capture tS'...tsN. The data management means 14 thereby records the time within the data packet as being the time at which the image capture was sensed.

Preferably, the data management means 14 comprises a software as implemented data manager responsible for reading and writing record data to at least one sequential data file. The data manager includes a graphical user interface (GUI) which allows a user to access record data related to the plurality of target objects. It is to be appreciated that any form of data file may be used in accordance with the present invention, and that the use of a so sequential data file is not intended to be limiting. The data manager is adapted to facilitate the correlation of the times at which the images are captured tC...tcN with the times at which the image captures are sensed ts...t.SN, so as to match the captured images 111...1 IN to the corresponding data for each of the plurality of target objects.

In alternative embodiments, the data management means 14 may be any suitable database capable of electronically storing data corresponding to the target objects in a structured and retrievable form, with the role of the data manager being replaced by programmable database control code. Hence, lo any references herein to "record file" or "record data" are to be taken to also include database entries and database data, respectively.

in preferred embodiments, the image correlation apparatus 10 further comprises a personal computer (not shown) adapted to host the data nanagement means 14. The personal computer may be any suitable computer that has an operating system capable of supporting file management and file T/O (Input/Output) operations, and at least one port allowing connection to the sensing means 16. The personal computer also includes an internal clock which may be preferably associated with the data So management means 14 to provide a reference clock signal.

Preferably, the sensing means 16 is adapted to include at least one corresponding port connector, suitable for connection to the at least one port of the personal computer. In the preferred embodiment, the at least one port :5 and the port connector are adapted to conform to a USB standard interface type' but may alternatively, be adapted to conform to a serial or RS232 port interface type, or a parallel port interface type.

The data management means 14 and the sensing means 16 are able to so communicate via the at least one port of the personal computer. Preferably, the sensing means 16 is connected to the computer using a hard-wire connection, such as a USB cable.

In alternative embodiments, the sensing means 16 may include a pair of infra-red or wireless transceivers, one of which is adapted to connect to the at least one port of the computer, via a USB standard interface type, and the other forming part of an assembly with the flash sensor 17. In these alternative embodiments, the data management means 14 and sensing means 12 are able to communicate using infra-red signals or wireless o network protocols, such as Bluetooth or WiFi.

During a photographic session, a teacher or administrator is typically seated at the personal computer and uses the data manager GIJI to access record files corresponding to the plurality of students to be photographed. At the time a particular student steps forward to be photographed by the photographer, the teacher or administrator selects the record file corresponding to that student, which includes the administrative details for that individual. The photographer then captures an image of the student using the imaging device 12, with the time of image capture tC...tcN being so recorded. Advantageously, the photographer does not need to maintain a manual record of the details of the target object, since verification of the student's identity is performed by the teacher or administrator. In this way, as each successive student is being photographed, the teacher or administrator performs verification of the student's identity and actively selects the corresponding record file for that student. The sensed time may be written to the record file itself, or may be written to a sequential data file, along with the student details (e.g. student or admissions number) by the data manager.

In an alternative arrangement, each student to be photographed may be issued with a label including a barcode pattern, prior to, or during, the photographic session. The barcode pattern contains data related to the student s details, which preferably includes the student number or s admissions number. As each student steps forward to be photographed, he/she hands the label to the teacher, or administrator, who then scans the barcode using a suitable barcode reader connected to the personal computer.

As the photographer captures an image, the image capture time 4...tCN is recorded in the image file, while the corresponding sensed image capture lo time tS...tsN is written to the record file, or sequential data file, by the data manager. The sensed time tS...tsN is entered against the corresponding student number, or admissions number, which is written to the record file, or sequential data file, when the barcode pattern is scanned.

t5 The bareoded label may include, but is not limited to, any one of the following: a tag, a sticker, a badge or a substantially pocket-sized card.

As will be appreciated, the sequence in which the students are photographed can be random, since the teacher or administrator need only select the so corresponding record file using the GUI, or scan a bareoded label. However, should it be preferred to photograph the students in alphabetic order, or in class number order etc., this Can be readily accommodated, since the teacher need only select the record files or seen the bareoded labels in the required order.

in alternative embodiments, the selection of record files, or scanning of barcoded labels, may be avoided if the record files are sorted in a predetermined order and the photographer captures images of successive students strictly in accordance with that order. Of course, this method will so only work provided there exists a strict one to one Correspondence with the number and sequence of images and the number and scqucncc of record files.

In preferred embodiments, the data manager actively filters the sensed image capture times of multiple images of the same target object, in order to discard images the photographer believes are somehow un-usable (e.g. due to movement of the student during the image capture). This provides the photographer with the opportunity to obtain another image of the target object until he/she is happy with the captured image. The data manager lo filters the sensed times by successively discarding the previously sensed time, such that the most recently sensed image capture is deemed to correspond to the desired image. The data manager continues to overwrite any existing sensed image capture time, in the corresponding record file or sequential data file, with the most recently sensed time, until the next target object is selected or scanned.

In other preferred embodiments, the data manager filters multiple images by allowing a teacher or administrator to add a flag to record files, or the sequential data file, against those target objects having multiple recorded so sensed image capture times tsj...tsN. The flag may be entered against the recorded sensed times, so as to mark the time, or times, prior to the most recently recorded time as being invalid during the subsequent correlation.

This allows images which are deemed un-useable by the photographer to be discarded during correlation, as corresponding invalid times are ignored.

The flag preferably comprises a bit flag, although it is to be appreciated that any suitable means of flagging the record file and marking the sensed image captured times may be used.

In alternative embodiments, the data manager is adapted to allow a second so or subsequent image to be captured for a particular target object, to enable 1] the photographer to obtain multiple images for each student (e. g. front and side profiles etc.). To accommodate multiple images, the data manager preferably records multiple sensed image capture times Is' . tsN in the same record file or against the same student number in the sequential data file, with each sensed time corresponding to a respective image of that target object.

the active selection of record files, or scanning of barcoded labels, places the teacher or administrator in control of the target object sequence, and Can lo therefore select the order in which the images are captured. This can be particularly advantageous, since not only can images be re-taken, or multiple images captured, for a particular target object, but record files may also be skipped over, should the student be absent or unable to attend the photographic session at that time for instance.

By way of example, the target object sequence could be selected so that all female students are photographed first, or that siblings are photographed one after another for instance.

Hence, upon completion of the photographic session, the imaging device 12 will contain a plurality of captured images 11...1 1 N. each having a recorded time of image capture 4...tCN, and the times at which the image captures were sensed tS...tsN will be recorded in the corresponding record isles, or the sequential data file.

In preferred embodiments, the plurality of image files are downloaded to the personal computer and are stored on a suitable storage device, such as a hard drive which may be interrogated by the data manager. The data manager is able to access the image files to determine the times at which the so images were captured tc...tN. Preferably, the data manager places the image capture times try. . .tCN into a memory of the computer for use during the subsequent correlation, the times being referenced by the use of memory pointers.

The image files are preferably downloaded via a second port on the personal computer, using a conventional hard-wire connection, such as, but not limited to, a USB cable, serial or RS232 cable or parallel cable.

Alternatively, the image files may be downloaded by removing the memory 18 from the imaging device 12 and using any suitable memory reading lo device connected to the personal computer e.g. a memory card reader.

In the preferred embodiment, the data manager includes at least one correlation algorithm 22 which is adapted to match the captured images to the corresponding known data for each of the plurality of target objects. 'Idle correlation algorithm 22 is preferably implemented as a software module within the data manager and can be coded in any suitable programming language, such as, but not limited to, Visual Basic, C++, C and FORTRAN.

In preferred embodiments, the data manager and correlation algorithm 22 are implemented as a Visual Basic application.

In preferred embodiments, the correlation algorithm 22 correlates using a time difference based correlation method. A time difference correlation is particularly advantageous, since it is not necessary to synchronise the internal clock of the imaging device 12 and the reference clock signal associated with the data management means 14. The correlation algorithm 22 determines from the image capture times try tCN' which image was captured first, and matches the first image 11 to the corresponding data against which the first sensed image capture time to is recorded.

In practice, the memory of the imaging device 12 may not be completely empty prior to the current photographic session, and may contain earlier captured images of unrelated target objects. However, earlier images do not interfere with the matching process, since the correlation algorithm 22 automatically rejects the times of any earlier image captures, by monitoring the number of matches during subsequent algorithmic loops. If no matches are detected during successive loops of the algorithm, the algorithm decides that the first image capture time must be incorrect e.g. does not correspond to an image of the current photographic session, and will therefore select the lo next chronologically arranged image capture time as the first image capture time of the photographic session. In this way, any earlier images captured prior to the photographic session will be rejected in favour of a later image which actually corresponds to the first image of the session, which thereby allows the images to be matched to the corresponding data.

The first image capture time tc' becomes a reference time to which a time difference for each remaining image capture time tC2. tcN is calculated.

Hence, by way of example, the time dil'I'erence for the With image for instance, is AtCN-c = tCN - tot, which corresponds to the interval of time JO elapsed between capturing the first image 1 1 and the last image 1 I N Time differences for the sensed image capture times tS...tsN are preferably calculated in a corresponding manner and are measured relative to the time ofthe first sensed image capture tin.

:5 Thereafter, the correlation algorithm 22 preferably begins to match the differences in the times of image capture to the differences in the times of sensed image capture, such that an image captured 30 seconds after the first image] l for instance, is matched to a record file including a sensed time which is 30 seconds later than the first sensed time to, and so on, until all so the images are matched.

However, in practice, it is found that the imaging device 12 may introduce a small and possibly variable delay between capturing an image and time tagging the corresponding image flc. Such delays may typically arise from read-out delays and software latencies within the camera, and may therefore introduce uncertainty into the correlation, since the image file may include an image capture time tC,...tcN which is written to the file after the sensor has sensed the image capture. The delays may typically be about 4 seconds for a conventional digital camera, and may therefore cause some images not lo to be matched during the correlation, since the dil'f'erences in image capture time may not correspond to the differences in sensed image capture time.

Hence, in preferred embodiments to avoid the possibility of not matching captured images 11. .. I I N to the corresponding data, the correlation algorithm 22 is adapted to add a variant time interval to each of the dil'ferences in the times at which the images are captured. Alternatively, the variant time interval may be added to each of the times try ted before the time differences are calculated.. The effect of adding a variant time interval to the time difference, or time tC...tcN, is to introduce a variance, or error, so on the time measurement, which compensates for any possible delays introduced into the recorded image capture times. The variant time interval acts to increase the likelihood that the image will be matched and therefore increases the robustness, and reliability, of the correlation algorithm 22. In the preferred embodiment, the variant time interval, is in the range of about 0 seconds to about lO seconds, and is most preferably, in the range of about O seconds to about 4 seconds. During a particular correlation the variant time interval is preferably fixed, however, the variant time interval may alternatively be variable, such that the correlation algorithm 22 may incrementally adjust the interval so as to automatically compensate for any JO variations in the inherent delays.

In preferred embodiments, the correlation algorithm 22 continues to loop through the list of image capture times until the maximum number of matches have been found i.e. corresponding to the number of sensed image captures. With each match found, the data manager creates new record data, which contains the filename of the image file and the matched student data (shown as Dataxf#l to Dataxf#N in figure 1). Preferably, the data manager updates the sequential data file with the new record data upon completion of the correlation algorithm 22, or alternatively, updates the sequential data file with the new record data with each match found.

Upon completion of the correlation algorithm 22, the sequential data file contains record data corresponding to each matched image, along with the filename of each respective image file. The sequential data file may then be transferred, or copied, from the personal computer to a portablestorage medium, e.g. floppy disk, CD, or USB storage device, for subsequent use by the photographer at a photographic studio, for example, to produce named prints of the students etc. Additionally, or alternatively, the sequential data file may be used to automatically update the educational establishment's records by integrating the data within the file into an existing electronic so record system or administrative database.

Any images not matched to corresponding data, upon completion of the algorithm 22, will typically correspond to discarded images for which the sensed image capture time was overwritten in the record file, or sequential data file, and may be subsequently deleted.

In those embodiments where a bit flag is used to denote an invalid image capture time, where more than one image was captured for a particular target obj ect, the correlation algorithm 22 is preferably configured to so discard that recorded time from subsequent correlation steps. In this way, only the most recent image captured for the target object will be matched to the corresponding data for that target object.

It is to be appreciated that the correlation method need not be limited to a time difference based method, and that other methods of correlating the times of image capture and the sensed image capture times may be used. In particular, in other embodiments, the imaging device 12 and data management means 14 may be initially synchronised so that the image capture times and sensed image capture times are substantially similar. In lo this arrangement, the correlation algorithm 22 could be adapted to apply a variable variant time interval, which is initially set to a nominal small interval, in the range of about 1 second to about 10 seconds. The time interval is successively increased with each pass of the algorithmic loop, to an optimum correlation interval which would be dependent on synchronization errors and the inherent delay in the imaging device 12. The variant time interval is preferably incremented in steps of about 5 seconds to about 10 seconds. The optimum correlation interval is preferably found at the point where all of the captured images 1 l I... 1 IN are matched to the corresponding data, which corresponds to completion of the correlation JO algorithm 72.

IIowever, it should be noted that if the optimum correlation interval is exceeded during correlation of the recorded times, to tCN and to tSN, spurious matching may result which could give rise to captured images ?5 111...11N being matched to incorrect corresponding data. Therefore, the at least one correlation algorithm 22 preferably monitors the number of matching results per pass through the algorithmic loop (i.e. con esponding to a successive increment of the variant time interval) in order to determine whether the number of matched results exceeds the number of captured JO images I I. . . I 1 N I 1'this occurs, the correlation algorithm 22 will preferably reset the first variant time interval to the nominal small interval for those erroneous times and will re-start the correlation with a smaller incremental step of about]O seconds to about 20 seconds until only a single match is found.

In alternative embodiments, the variant time interval may he fixed at an optimum correlation interval, which can be pre-selected by the photographer prior to the correlation, based on his knowledge of the frequency of image captures within the photographic session. This can lo reduce the amount of time needed to perform the correlation, but may be susceptible to spurious matching.

In other alternative embodiments, the optimum correlation interval could be determined by manually referencing one recorded captured image time to a recorded sensed image capture time tS...tsN, the difference in times then being supplied to the correlation algorithm 22 for subsequent automatic matching of the remaining batch of captured images to the corresponding known data. Alternatively, the optimum correlation interval could be pre- selected during the photographic session by manually introducing a known So clock offset between the internal clock of the imaging device 12 and the reference clock signal in the data management means 14, or sensing means 16.

In preferred embodiments, the data manager may use the data within the :5 sequential data file to re-name the matched image files, such that the filenames include at least the admissions number of the student, thereby allowing easy file archiving and subsequent retrieval. The data manager may also preferably update the header infonnation in each image file to include at least the admissions number of the student forming the subject of so the image. Where there is more than one image file matched to a record file (due to multiple image captures for a particular target object), the rc- named image filenames are also numbered accordingly.

Advantageously the image correlation apparatus of the present invention can correlate images of target objects with corresponding data for the target objects without the aid of manual intervention.

It will be recognised that the image correlation apparatus of the present invention described herein has the considerable advantage that it can use lo existing digital imaging devices, sensors and computing resources and therefore offers a fast, efficient and economical method of correlating images and data.

Although the image correlation apparatus of the present invention is ideal for matching images of students to administrative data corresponding to the students, it will be recognised that one or more of the principles can extend to other types of target oh ject and related data.

Other embodiments are taken to be within the scope of the accompanying claims.

Claims (35)

1. An image correlation apparatus, comprising: an imaging device for capturing images of a plurality of target s objects and adapted to record the times at which the images are captured; a data management means adapted to store at least known data corresponding to the plurality of target oh jects; and a sensing means adapted to sense the image captures and to notify the data nanagement means of the times at which the image captures are lo sensed for each ol'the plurality of target objects; wherein the data management means is further adapted to correlate the times at which the images are captured with the times at which the image captures are sensed, so as to match the captured images to the corresponding stored known data for each of the plurality of target objects.

2. 'l'he image correlation apparatus of claim l, wherein the data management means is adapted to record the time at which an image capture is sensed for a particular target object against the corresponding known data for that target object.

3. The image correlation apparatus of claim l or claim 2, wherein the imaging device includes a memory for storing each of the images in a separate image file having a header field to record the time of image capture.

4. The image correlation apparatus of any preceding claim, wherein the imaging device includes a flash unit for emitting light to illuminate each target object during an image capture.

5. The image correlation apparatus of claim 4, wherein the sensing means includes a flash sensor adapted to sense the emitted light associated with an image capture.

6. The image correlation apparatus of any preceding claim, further comprising a personal computer adapted to host the data management means and having at least one port allowing connection to the sensing means.

o

7. The image correlation apparatus of claim 6, wherein the data management means and the sensing means are able to communicate via the at least one port using any one of the following means: a hard-wire connection, infra-red transceivers and wireless network protocols.

8. The hnage correlation apparatus of any of claims I to 7, wherein the sensing means notifies the data management means by way of a single pulsed signal.

9. The image correlation apparatus of any of claims I to 7, wherein the JO sensing means notifies the data management means by way of a data packet, including the time of the sensed image capture.

10. The image correlation apparatus of any preceding claims, wherein the imaging device is a digital camera and each image is a 2-dimensional As representation of one of the plurality of target objects.

] I. The image correlation apparatus of any preceding claim, wherein the data management means includes at least one correlation algorithm.

12. The image correlation apparatus of claim 1] wherein the correlation algorithm is adapted to match the first captured image to the con^esponding data against which the first sensed image capture time is recorded.

13. The image correlation apparatus of' claim 12, wherein the correlation algorithm is adapted to calculate a time difference for each of the times at which images arc captured, relative to the time of the first captured image.

14. The image correlation apparatus of claim 13, wherein the correlation lo algorithm is adapted to calculate a time difference for each of the times at which image captures arc sensed, relative to the time of the first sensed image capture.

15. The image correlation apparatus of claim 14, wherein the correlation algorithm is adapted to match the time differences of the image capture times to the time dit'ferences of the sensed image capture times, so as to match the captured images to the corresponding known data for each of the plurality of target objects.

so

16. The image correlation apparatus of any of claims 13 to 15, wherein the at least one correlation algorithm is adapted to add a variant time interval to each of the time differences of the image capture times, prior to matching with the time dit'ferences of the sensed image capture times.

17. The image correlation apparatus of any preceding claim, wherein the data management means is adapted to maintain at least one sequential data file, to store record data for each matched captured image and corresponding known data.

18. The image correlation apparatus of claim 1, wherein the imaging device includes a transmitter for transmitting a signal to the sensing means during an image capture' and the sensing means includes a receiver adapted to sense the transmitted signal associated with the image capture.

19. The image correlation apparatus of claim 18, wherein the transmitter and receiver are each adapted to operate in any region of the electromagnetic spectrum.

lo

20. A method of image correlation, comprising the steps of: capturing images of a plurality of target objects using an imaging device and recording the times at which the images are captured; storing at least known data corresponding to the plurality of target objects in a data management means; and sensing the image captures using a sensing means and notifying the data management means of the times at which the image captures are sensed for each of the plurality of target objects; wherein the data management means correlates the times at which the images are captured with the times at which the image captures are sensed, so as to match the captured images to the corresponding stored known data for each of the plurality of target objects.

21. The method of image correlation of claim 20, wherein the data management means correlates using at least one correlation algorithm.

22. The method of image correlation of claim 21, wherein the correlation algorithm matches the first captured image to the corresponding data against which the first sensed image capture time is recorded.

23. The method of image correlation of claim 22, wherein the correlation algorithm calculates a time difference for each of the times at which images are captured, relative to the time of the first captured image.

24. T he method of image correlation of claim 23, wherein the correlation algorithm calculates a time difference for each of the times at which image captures are sensed, relative to the time of the first sensed image capture.

lo

25. The method of image correlation of claim 24, wherein the correlation algorithm matches the time differences of the image capture times to the time differences of the sensed image capture times, so as to match the captured images to the corresponding known data for each of the plurality of target objects.

26. The method of image correlation of claims 20 to 25, further comprising the step of maintaining at least one sequential data file, to store record data for each matched captured image and corresponding known data.

27. A method of image correlation comprising the steps of: sensing times of image captures from a sensing means and recording said sensed times against known data corresponding to a plurality of target objects which are the subjects of said image captures; receiving, from an imaging device, captured images of said plurality of target objects, each image including data representing the time at which the image was captured; correlating the sensed times and the image capture times; and associating each of the captured images with a respective one of the known data.

28. The method of claim 27, wherein the step of sensing includes receiving input from a user identifying a selected one of a plurality of existing record files, each file containing known data corresponding to one of the plurality of target objects.

29. The method of image correlation of claim 27 or claim 28, wherein correlating step matches the first captured image to the corresponding data against which the first sensed image capture time is recorded.

30. The method of image correlation of claim 29, wherein the correlating step calculates a time difference for each of the times at which images are captured, relative to the time of the first captured image.

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31. The method of image correlation of claim 30, wherein the correlating step calculates a time difference for each of the times at which image captures are sensed, relative to the time of the first sensed image capture.

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32. The method of image correlation of claim 31, wherein the correlating step matches the time differences of the image capture times to the time differences of the sensed image capture times, so as to match the captured images to the corresponding known data for each of the plurality of target objects.

33. The method of claim 30, wherein the correlating step includes the step of adding a time interval to each of the time differences of the image capture times, prior to associating each of the captured images with a respective one of the known data.

34 A computer program product, comprising a computer readable medium having thereon computer program code means adapted' when said program is loaded onto a computer, to malice the computer execute the procedure of any one of claims 27 to 32.

35. An apparatus for image correlation comprising: means for sensing times of image captures and recording said sensed times against known data corresponding to a plurality of target objects which are the subjects of said image captures; lo means for receiving, from an imaging device, captured images of said plurality of target objects, each image including data representing the time at which the image was captured; means i-or correlating the sensed times and the image capture times, and means for associating each of the captured images with a respective one of the known data.