IES79066B2 - Image processing - Google Patents

Abstract

An image processing method for photographic materials in which photographic, preferably negative, images are backlit, print exposure settings appropriate to the backlit image are compared against a plurality of pre-defined known print exposure settings. The comparison being achieved automatically using a density reading for the backlit image, a lookup table of pre-set tone, scale and colour reproduction data. The comparison also produces a suitable transfer optimisation identifier (T.O.I) for the image which facilitates electronic storage of the image. The TOI may also use a series of differently coloured masks which are applied to the final image to determine the colour hues at each point of the image.

Description

Image Processing The invention relates to image processing and more particularly to an image processing method for photographic materials.

A great deal of research and development work has been done in relation to the processing of such materials particularly in respect of the optical devices and chemical solutions used. While the developments made ensure that the captured image is so accurate a reproduction of the original that it is frequently beyond the ability of the human eye to detect a difference relatively little development has been done to address the shelf life of such images. That is to say that while the chemicals used have been developed to the point where breakdown of component elements is no longer a problem the archiving of such images has only recently being addressed.

The currently preferred method for long term storage of such images is, in brief, to digitise the originals and store them on compact disk. The advantages in storing images in this way are immediately apparent, for example once recorded, storage requirements are a fraction of those previously required. Additionally, the digitised nature of the images, greatly reduces the cost and time necessary for duplication. Such duplication may be required for backup safety purposes or indeed for use of the images. Similarly the images may be easily transmitted using relatively new technologies such as the internet and are not subject to the copy-of-a-copy image quality degradation sufferable by the originals. * < Suitable stratagems for storing images in this way onto compact disk are well known. For example that identified * - 2 and marketed by the Eastman Kodak Company under the name Kodak PCD Imaging Workstation 4220. Systems of this type are now highly developed. Much work has already been done in relation the accurate processing of presented images and equipment of this type has used and developed many of the discoveries made. One such image processing method is described in United States Patent Number 5,398,068 (Liu et al.) where images are coded using block based estimation to determine motion vectors for blocks of pixels in a frame. While it is not immediately apparent that the technologies are related the teachings of this and other digital signal processing techniques are widely employed as are the raster techniques for the video elements referred to in United States Patent Number ,448,302 (DesJardins). In addition to these developments, a great deal of work has been done on the optical devices used to record the digitised images. For example that described in United States Patent Number 5,412,634 illustrating the use of scanning techniques and focusing apparatus.

While the equipment and processes currently available are suitable for many applications they do not address problems associated with the wide variety of formats on which the original images may be presented. These formats may include but are not limited to, legacy archives in which images may be stored in a wide variety of photographic formats. The term legacy for the purposes of this specification is taken to include photographic archives which have been compiled over many decades and whose compilation chronicles the developments made in photographic storage of such images. It will be appreciated that in addition to the problems associated with the vast array or recording media such as glass plate images, (negatives on glass or positives on glass) transparencies, blank and white images, cepia images, slides, OHP's, prints, art works, documents, maps or film footage etc., that many of the originals have suffered the effects of time and are thus frequently in less than perfect condition. As a direct result, the cost of transferring such images is greatly increased both in terms of processing of the images and in terms of the cost associated with the expertise of the operating personnel given that a great deal of skill and expertise is required to operate the transfer equipment.

There is therefore a need for an improved image processing method which will overcome the aforementioned problems.

Accordingly there is provided an image processing method comprising the steps of:receiving a roll of photographic film housed within a film canister; extracting a film leader of the photographic film from the film canister attaching the film leader to a draw mechanism of a development unit; detecting an end of the photographic film when fully extracted from the canister and separating the photographic film from the film canister; drawing the photographic film draw mechanism over a series of rollers to fully immerse the photographic film in, sequentially: a developer bath, a bleach / fix submersion tank, and at least one stabiliser bath, for converting the photo into a negative image; mounting the negative image in a photographic printer wherein the negative image is backlighted; receiving print exposure settings appropriate to the backlight photographic image and comparing the received print exposure settings against a plurality of pre-defined known print exposure settings in combination with, a density reading for the backlight photographic image and a lookup table of pre-set tone, scale and colour reproduction data and in response to a match condition, backprinting a final delivered photographic print with a transfer optimisation identifier.

Advantageously, this transfer optimisation identifier applied to the back of the print facilitates transfer of the prints for transfer to compact disk or transfer to another medium by the laboratory. It allows such processing to be done with minimal operator intervention as the identifier automatically dictates all of the transfer parameters to be used.

According to one aspect of the invention there is provided an image processing method comprising the steps of:receiving a raw photographic image and determining print exposure settings appropriate to the raw photographic image; and comparing the received print exposure settings against a plurality of pre-defined known print exposure settings in combination with, a generated density reading for the raw photographic image and a lookup table of pre-set tone, scale and colour reproduction data and in response to a match condition and linking the raw photographic image with a transfer optimisation identifier.

Beneficially allowing a great variety of photographic mediums to be stored at significantly reduced processing costs while also guaranteeing maximum availability of the transfer device as the transfer may be effected extremely quickly allowing a greater throughput of material.

Preferably the image processing method further comprising the steps of:identifying a no-match condition; analysing the photographic image in response to the no-match condition with a definable balance algorithm to index a saturation and contrast table; generating a new transfer optimisation identifier from the results of the analysis to define a new exposure setting type; and appending the new transfer optimisation identifier to the pre-defined known print exposure settings.

Thus, when a mew material or particular characteristic for a set of legacy images is encountered it may be quickly stored and held in memory for future reference. Each time this occurs the range of material which may be automatically processed is extended and the delay associated with identifying a new characteristic only occurs once.

Ideally the transfer optimisation identifier incorporates means for selectively applying a series of masks defining a two dimensional matrix across the final image to determine colour hues at each point in the image. In this way the most accurate image possible is reproduced.

The invention will be more clearly understood from the following description of one embodiment thereof given by way of example only with reference to the accompanying drawing in which: Fig. 1 is a flow diagram illustrating an image processing method in accordance with the invention.

With reference to the drawing and there is illustrated an image processing method in accordance with the invention illustrated generally by the numeral 1. In order not to unnecessarily obscure the present invention specific materials, chemicals and details of transfer optimisation parameters associated with said materials and chemicals have been referred to but briefly, as it will be appreciated, that the possible number of combinations would be excessive and would not aid clarity.

A roll of conventional exposed photographic film housed within a film canister is received in step 2 and the a film leader of the photographic film is extracted from the canister and when the end of the roll of film is detected a guillotine cuts away the empty canister in step 3. The film leader is attached to a draw mechanism of a development unit in step 4 and drawn over rollers in step 5. The drawing mechanism pulls the film from the canister into a developer bath in step 6 and following this into a bleach / fix submersion tank in step 7. In step 8 the film is progressed through three stabiliser baths where the exposed image is finally converted into a negative image before it is dried in step 9 and attached to a hanger in step 10 using the film leader.

When the film is fully dry it is loaded into a printer in step 11. The printer is operated normally in that the negative image is backlighted so that an operator may visually inspect the image to determine the most appropriate print settings which are inputted in stage 12. This inspection is a normal function of the printer in that it is common practice for the quality inspection department of development laboratory facilities to issue advisory notices to clients relating to exposure, lighting or composition details of prints where appropriate. An important feature of the invention is that in tandem with this backlighting of the negative a negative identification procedure is carried out so that when the final print is produced in step 14 it carries a transfer optimisation identifier. The negative identification procedure is achieved by automatically comparing the print exposure details selected by the operator in step 12 to a list of known exposure setting types A and simultaneously referenced using the density of negative with preset tone scale and colour reproduction data B in step 15. Where a match is not found, a further check is conducted in step 16 where the negative is analysed using a balance algorithm C and a saturation and contrast table D to define a new exposure setting type which is then store in the list A so that future negatives of this type will be immediately identified. The contrast table similarly applies a mask of selective shading to the final image which accurately lights the image and ensures correct edge definition of components parts of the image.

The transfer optimisation identifier defines a broad number of attributes for the image which will be ultimately stored. These attributes are referenced to the list and operate in the same way as a photographic filter to ensure the optimum quality of the delivered image. The attributes are stored as an indexed file having a data value readable by the storage device. The balance algorithm is responsible for the overall density and balance of an image by selectively applying a series of masks forming a matrix across the print to determine the quantities of red, green, blue, cyan, magenta, yellow hues to be applied to the final image as well as a lighting factor. The algorithm also compensates for under / over exposure of the raw photographic material by applying a second set of red, green, blue, cyan, magenta and yellow hues which act as a fine tune if necessary.

The principal advantage of having the transfer optimisation identifier applied to the back of the print is evidently that when the client returns the prints for transfer to compact disk to the laboratory they may be processed with minimal operator intervention as the identifier automatically dictates all of the transfer parameters to be used. This obviously reduces processing costs but also guarantees maximum availability of the transfer device as the transfer may be effected extremely quickly allowing a greater throughput of material to be processed. This is particularly important given marketing trends for such laboratories to deliver any customer order in the shortest possible time. The other less obvious advantage relates to the quality of the delivered print for clients who will not ultimately transfer prints to compact disk in that operators setting unusual print parameters for a backlight negative will cause no match to be found in step 15 alerting a laboratory manager. The manager can then validate the parameter selection to overcome possible operator error or if appropriate advise the client if the failure to match is due to the inexperience of the client or as a result of photographic equipment malfunction. This positively impacts on client satisfaction and additionally means that the skill level requirement for the print unit operator is significantly reduced with a corresponding cost saving.

When an alternative material to conventional photographic film is received for transfer to compact disk the process is largely similar in that images suitable for backlighting for example glass plate images, slides, OHP's and the like are processed as above. As a result of the age and condition of the various legacy archives to be processed it is not uncommon for certain types of images to cause a not match condition even though materials of this type have previously been processed. However as a greater variety of raw photographic material types are processed the incidence of no-match conditions reduces significantly. Furthermore, it is envisaged that to reduce the number of possible entries in the list of known exposure setting types interpolation techniques may be used to determine appropriate parameters for a given material between two known thresholds. Obviously where there is a genuine requirement for extremely high quality images or where there is sufficient supply of a given material type the laboratory manager may intervene to impose the addition of a new transfer optimisation identifier.

When materials such as prints are received the process may be effected by using a sophisticated camera under control conditions to create a photographic film to be used in the process. The transfer optimisation identifier thus produced will be inputted to the compact disk generator to act as a filter while the image is scanned using a suitable high definition scanner or if suitable the photographic image itself may be used.

It will thus be appreciated that the invention provides for a greatly improved image processing method capable of handling a far greater range of raw image material type than was heretofore possible. Furthermore, it does so with minimal intervention at a greatly reduced cost and with lower operator skill levels than was heretofore possible.

It will further be appreciated that the raw material types are not limited to those mentioned. For example it is anticipated that the images may be delivered electronically across a telecoms line such as ISDN or on diskette and that this digital image may be processed as a backlight negative. Similarly while the invention is described with reference to the storage onto compact disk the optimised images may alternatively be store on disk or tape.

The invention is not limited to the embodiment hereinbefore described but may be varied in construction and detail within the scope of the appended claims.

Claims (5)

Claims

1. An image processing method comprising the steps of :receiving a roll of photographic film housed within a film canister; extracting a film leader of the photographic film from the film canister attaching the film leader to a draw mechanism of a development unit; detecting an end of the photographic film when fully extracted from the canister and separating the photographic film from the film canister; drawing the photographic film draw mechanism over a series of rollers to fully immerse the photographic film in, sequentially: a developer bath, a bleach / fix submersion tank, and at least one stabiliser bath, for converting the photo into a negative image; mounting the negative image in a photographic printer wherein the negative image is backlighted; receiving print exposure settings appropriate to the backlight photographic image and comparing the received print exposure settings against a plurality of pre-defined known print exposure settings in combination with, a density reading for the backlight photographic image and a lookup table of pre-set tone, scale and colour reproduction data and in response to a match 5 condition, backprinting a final delivered photographic print with a transfer optimisation identifier.

2. An image processing method comprising the steps of :10 receiving a raw photographic image and determining print exposure settings appropriate to the raw photographic image; comparing the received print exposure settings against a plurality of pre-defined known print 15 exposure settings in combination with, a generated density reading for the raw photographic image and a lookup table of pre-set tone, scale and colour reproduction data and in response to a match condition and linking the 20 raw photographic image with a transfer optimisation identifier.

3. An image processing method as claimed in claim 1 or claim 2 further comprising the steps of:identifying a no-match condition; 25 analysing the photographic image in response to the no-match condition with a definable balance algorithm to index a saturation and contrast table; generating a new transfer optimisation identifier from the results of the analysis to define a new exposure setting type; and appending the new transfer optimisation 5 identifier to the pre-defined known print exposure settings.

4. An image processing method as claimed any preceding claim wherein the transfer optimisation identifier incorporates means for selectively applying a series 10 of masks defining a two dimensional matrix across the final image to determine colour hues at each point in the image.

5. An image processing substantially hereinbefore described with reference to the accompanying drawing.