GB2370173A

GB2370173A - Method for reducing light spill in projected digital images.

Info

Publication number: GB2370173A
Application number: GB0030508A
Authority: GB
Inventors: James Gillespie
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-12-14
Filing date: 2000-12-14
Publication date: 2002-06-19
Anticipated expiration: 2020-12-14
Also published as: GB2380632B; GB2380632A; GB2370173B; GB0030508D0; GB0229843D0

Abstract

A method for reducing light overspill 5B in a system projecting an image onto a screen 6 using a digital projector 2B, including editing an image centrally to ensure that the correct aspect ratio is achieved for each screen 6 to be projected on. Image editing may comprise stages of initial scanning, enhancement (e.g. to improve quality), the addition of special effects and, finally resizing and recording (Figure 6). The edited (formatted) image is supplemented with a black border (Figure 2) forming a composite image for projection.

Description

DIGITAL IMAGE DISPLAY METHOD The present invention is concerned with image display, and particularly, but not exclusively, with cinema projection suitable for displaying an image in the form of an advertisement. For the avoidance of doubt, the image may be static or moving.

Cinema screens are generally in one of two formats. These are Cinemascope 1M, with an aspect ratio of 2. 35 : 1, and Wide screen TM with an aspect ratio of 5: 3. Some cinema screens are made so that their effective size may be altered by the use of curtains or tabs ; however, light spill onto these is noticeable. Other screens are so called'floating screens'in which the size of the screens cannot normally be altered. These are mounted forward of the supporting wall of the cinema. However, light spill may still illuminate an area outside the screen on the supporting wall, if the aspect ratio if the image does not match that of the screen.

To explain light spill, reference will now be made to Figures 1 to 3.

Figure 1 shows a situation in the prior art where an image having an aspect ratio of 2.35 : 1 is shown on a screen 6 having an aspect ratio of 5 : 3. In this case a 35mm slide projector 2A is used. The slide projector 2A is placed at the rear of the viewing space 3 and the image is projected through the viewing space 3 to the screen 6 at the front of the viewing space 3. Light spill occurs at 5A horizontally outside the screen 6. This occurs because the image 9 projected from the slide projector 2A does not match the dimensions of the screen 6.

Figures 2 and 3 show the types of light spill 5 which may occur when using a slide projector 2A. Figure 2 shows a view of the front wall of a viewing space 3, with a screen 6A mounted thereon. The screen 6A has an aspect ratio of 5: 3 whereas the image 9 which is projected has an aspect ratio of 2. 35 : 1. A light spill area 5C occurs on the front wall horizontally on each side of the screen 6A because of the difference in these aspect ratios. Figure 3 shows a similar set-up of front wall and screen 6B. This time, light spill 5D occurs above and below the screen 6B, as now the screen 6B has an aspect ratio of 2. 35: 1 and the image 9 has an aspect ratio of 5: 3.

Cinema advertising currently takes three forms. These are film advertisements, slideson-film advertisements and slide advertisements. Film and slides-on-film advertisements are generally placed on celluloid and are then shipped to each cinema for use in celluloid film projectors. They have both images and sound. Slide advertisements are placed on slides and shipped to each cinema. These have only images and no sound. Slide advertisements are shown on a slide projector, which is provided in addition to the film projector in the cinema.

In celluloid film projectors, the only means for adjusting the size and proportions of the image is to use expensive lenses, which must be customised to the particular cinema.

This is because the ratio of the size of the cinema screen to the distance between the projection room and the screen differs from cinema to cinema. The lenses must be used to ensure that light spill does not occur.

In order to place a slide advertisement through a film projector, a series of frames must be created, even for a still image. This is why still slides are generally shown on a separate slide projector. In this way, single slides may be used rather than transferring the slides to 35mm film reels. In the case of a slide-on-film advertisement, such transferral is done so that sound may be added to the advertisement. However, this greatly increases the amount of material which must be shipped to the cinema, and the cost.

The projectors currently used in slide projection also require that lenses be used. Again, this is to adjust the aspect ratio and ensure that the picture does not spill out onto a region outside the area of the screen. Each such lens must be tailored for the particular cinema in which it is to be used. While this light spill is corrected by the use of an adjustment lens designed specifically for the set up of the viewing space to be used, these lenses are expensive and tend to distort the image by squashing or distending it, to make it fit onto the screen. If such a lens is not used, either light spill occurs, or the image must be smaller than the screen in at least one dimension, to avoid it.

In addition to celluloid film projectors, digital light projectors (DLP) are now being introduced into some cinemas. These projectors run from digital media rather than 35mm film. They make use of new technology which reflects light from millions of mirrors, each mirror representing one pixel of the picture to be seen. Unfortunately, such digital projectors suitable for use with moving images currently cost around three times as much as a celluloid film projector and this can be prohibitive.

Conventional digital projectors, such as LCD type projectors, are not used in cinema as the quality given by them is not as high as film or new DLP type methods and so is generally unsuitable for such moving projections. However, slide advertisements need not be of the same picture quality, as the pictures are not"live action"and so quality is less of an issue.

It is therefore an object of the present invention to provide a more economical method of showing an image (particularly an advertisement), which eases transport to and use within a cinema, and which substantially avoids light spill outside the screen area upon projection.

According to one aspect of the present invention there is provided a method for displaying a digital viewable image by projecting it upon a screen, comprising preformatting the viewable image to have a predetermined outline, supplementing the viewable image with a substantially black border to form a composite image, providing the composite image to a digital projector, and using the digital projector to project the viewable image onto a viewing surface so that there is substantially no overspill of light from the projector outside the viewing surface.

According to a second aspect of the present invention there is provided a method for pre-formatting a digital viewable image to have a predetermined outline, comprising obtaining a digital viewable image, enhancing or otherwise manipulating the viewable image, altering the outline of the viewable image to a predetermined value, placing a black border along at least one edge portion of the formatted viewable image to produce a composite image, recording the composite image on a transportable storage medium, and recovering the composite image from the transportable storage medium.

By pre-formatting the digital image to the required outline (which would typically be a rectangle with a chosen aspect ratio) and applying the black border, a simple LCD digital projector may be used to display the images, rather than an expensive new DLP.

No adjustment lenses are required because the LCD projector can zoom the image to the correct size and whilst doing this no light spill will be created, because no light is projected from the black border.

An embodiment of the invention therefore reduces the cost of the projection apparatus and increases the ease of use. In an added advantage over celluloid film projectors, recording the image in a digital format can decrease transport costs and increase ease of use for the projection worker in the cinema. All that need be done is to place the medium in a suitable reader (for example, a CD-ROM or DVD reader) and use appropriate software and hardware to provide the images to the digital projector 2B. It is even possible to transmit certain types of images electronically, for example over a LAN or WAN or via the Internet.

In addition, by using a digital projector, rather than a traditional projector, it is possible to show computer generated animations as well as still slide-type images, without transferring the image to celluloid film, which would have been required previously.

The present invention may therefore provide a simple way to show static and moving images wherein the amount of light spill is substantially minimised without any loss of image, because the outline of the image is matched to the expected outline of the viewing surface, can be adjusted to provide a best-fit locally and need not cause light spill in the event of an imperfect match.

It is also possible to co-ordinate a soundtrack with the displayed images using a single medium to transport both the images and sound. These can be set to automatically start together so ensuring that the sound and images remain synchronized.

A specific embodiment of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a plan view of a cinema using projection methods according to the prior art; Figures 2 and 3 are views of a screen with an image projected onto it using projection methods according to the prior art ; Figure 4 is a plan view of a cinema using projection methods according to the invention; Figure 5 shows the processing applied to images in the present invention; and Figure 6 shows a flow diagram of the process of preparing the images.

An embodiment of the invention will be described in which the invention is used in a cinema having a screen as the viewing surface with a rectangular outline having an aspect ratio of 2.35 : 1. This aspect ratio is known as CinemascopeTM. It is possible to adapt an image to fit into aspect ratios other than 2.35 : 1. Other aspect ratios which could be used include 5: 3, and 1.85 : 1. It is, of course, possible that the outline may not be rectangular at all. It may be oval or circular or irregular. It will also be readily appreciated that the invention could be used in any situation where it is desired that parts of an image do not overspill a viewing surface such as a screen, and that the viewing surface may also be oval, circular or irregular.

Referring to Figure 4, the method comprises using an LCD digital projector 2B, which is connected to an image supply unit 1B, to project an image 9 onto a screen 6. Any type of digital projector capable of showing the image clearly may be used. LCD projectors are preferred as they are relatively cheap and easy to use, while giving the required image quality. The image supply unit 1B is a computer and CD-ROM. The digital projector 2B is placed at the rear of the viewing space 3, and the screen 6 is placed at the front of the space 3. The projector 2B projects the image 9 onto the screen 6. In an alternative embodiment, the projector 2B is placed behind the screen 6 so that it is on the opposite side of the screen 6 to the viewing space 3. In this case, the image 9 must be reversed, as projected, in order that the image 9 is correct when viewed from the viewing space 3.

The image 9 from the digital projector 2B is zoomed by adjusting the digital projector 2B until a first dimension of the image 9 matches a corresponding dimension of the screen 6. Light spill is avoided because, if the remaining dimension of the image 9 is shorter than the corresponding dimension of the screen 6, no light is projected outside of the image 9 in this dimension due to the presence of the black (i. e. non-light projecting) border 10,11, 12.

The method of pre-formatting the image comprises a series of procedures. A flow chart of these steps is shown in Figure 6. Five procedures in all are carried out. However, some of these steps may not be needed, depending on the requirements of the image 9.

Additional features, not mentioned, may be included in addition to those described below. The first three procedures involve the production, enhancement and manipulation of the digital image 9; the fourth is the use of that digital image to construct an advertisement, whilst the fifth is the storage of the final composite image onto a CD-ROM.

The process begins with the transfer of the image onto a standard computer in digital format. The original image may take a wide variety of forms, and could be: a photograph, line art, a print, a digital still image, a drawing, video, text in both printed and hand-written formats, clip art, a painting or printed matter, for example. The transfer of an original image to the computer is achieved by use of appropriate means such as a flatbed scanner or a rotary or hand held optical scanner, for example. Further, if the image is already a digital image, direct transfer via hard linking of a digital camera or other digital equipment or transfer of material stored on CD-ROM, floppy disk or other storage media compatible with the computer can be used.

Alternatively, images and text could also be produced directly on the computer without the need for an original source, with the aid of suitable imaging software, such as Adobe Photoshop or Corel Draw.

Once within the computer in digital form, the image 9 is stored for later retrieval as and when needed.

If usable text in ASCII format is to be extracted from an original image, this is achieved by use of suitable Optical Character Recognition software (such as Caere Omnipage Prom) which will allow the extracted text to be stored in the form of a text document.

The next step in the process is image enhancement. Transfer of an original image into digital format can lead to a loss of quality and therefore loss of quality in the final product, so image enhancement is employed to rectify this. However, image enhancement may not be required if the image is already of a suitable quality. In this case, this step may be bypassed. If necessary, enhancement can be applied making use of suitable imaging software, such as that listed above. Such software allows adjustment to the contrast, gamma, sharpness, hue, brightness and other visual elements that make up the image 9, as required.

At this stage, using the imaging software, various special effects or other effects may be added to the image 9 as necessary. For example, alteration of the image 9 with various filters. The image 9 may also benefit from the cropping feature typically built into such imaging software.

Once the quality of digital image 9 is to the required standard, it is resized to an aspect ratio of 2. 35: 1 and stored in a format that is compatible with the final stages of the advertisement production for instance, a bitmap (bmp) format.

At this stage, it is possible to create other effects such as an animated image or use several images to create a montage or single layered image. It is also possible to convert specific text into an image displaying that text, or overlaying text onto an image. This is done using the software described above.

Each cinema that is to receive an advertising sequence supplies the aspect ratio of that particular cinema screen 6, (in this embodiment 2.35 : 1). This aspect ratio will then be used when producing the image 9 to ensure that it fits the proportions of the screen 6. It is possible to constrain the image 9 within the required proportions at any one or more stages of the process. Suitable stages are once the image enhancement stage has been carried out, and once the image manipulation stage has been carried out.

Figure 5 shows constraining the image 9 within a black border 10,11, 12, in order to ensure that any mismatch between the image 9 and the screen 6 does not cause light spill. The borders 10,11, 12 occupy the space between the perimeter of the image 9 and the perimeter of the projection element of the LCD projector 2B.

The next step is construction of the final advertisement. Each advertisement uses a combination of one or more of the stored images and text. Using multimedia software such as Macromedia Flashy Animation Prote, MediatorPro, or StudioPCTVTM, it is possible to position each element of the advertisement and give each element its own behavioural pattern to follow within the advertisement. Within the multimedia software, each image or text can be given its own animation effect. For example, an image can be made to dissolve into another image. Images and text, as well as the advertisement in its entirety can be made unique with the use of special effects built into the software or custom effects created by the user, using the multimedia software. Such effects include image and text blending, fading, scrolling, revolving and zooming.

Other effects may also be introduced. For example, the image can be dissolved, moved up and down, zoomed in or out, tipped, reversed, masked etc.

Movement and events within the advertisement are controlled by a timeline sequence that triggers the all the in-built effects of the advertisement. This timeline sequence can also be made to control any sound which is added to the advertisement. This sound can be stored on the medium, for instance in MP3 format and so transported on the same medium as the images of the advertisement.

The next step is media storage and distribution. Once an advertisement or sequence of advertisements is finalised the entire production is transferred to a CD-ROM. This can be done using any standard CD writer.

The series of advertisements are stored in a self-executing slide show on either a CD ROM, DVD or hard-drive. This minimises the setting up required at the cinema, and also ensures ease of use. To do this, each element that makes up the advertisement or advertising sequence is stored, including images, text, effects, background proportions and the order in which the advertisements are to be shown, along with the software and coding required to show the sequence as a stand-alone. Alternatively, the images may be stored on a CD-ROM, DVD or computer hard-drive independently. In the current embodiment, a stand-alone package intended for CD-ROM distribution is used.

Once the automated advertisement display has been prepared it can be transported to the individual cinemas. This is done by sending a CD-ROM containing the images to each cinema.

Preferably, the advertising sequence is played directly from the CD-ROM containing the advertising sequence, without first installing the sequence to the hard drive of the computer which is, in turn, attached to the LCD projector 2B. However, the images may be transferred from the CD-ROM to the hard drive of the computer to be played at a later stage, or otherwise stored in the cinema. The advertising sequence will automatically start and loop through the entire sequence of advertisements until manually halted. Alternatively, the sequence may be manually controlled. A suitable projector 2B would be a Mitsubishi X300TM, which can receive input from both computers or DVD discs and has a high light output for an LCD (2000 Lumens). It can be run in series when one source is required to drive more than one LCD projector.

Any standard type of computer may be used to replay the advertising sequence, as long as suitable software, for instance as mentioned above, is available. The computer driven system is mounted in a suitable location and the LCD projector 2B is mounted in the projection room, generally on a slide projector platform/porthole in the projection area of the cinema. Optionally, a graphics card which allows networking to standard television monitors may be incorporated into the computer, for example, a Matrox TM G400 32MB 2-Head-Sgram AGP Graphics Card. The option of using such a graphics card is preferred because it allows monitors to be used to view the advertisements and provides a secondary display in public areas. It also reduces the number of media discs to be distributed, as by using a Graphics Card, a monitor and LCD can both operate from the same signal so reducing the number of sources required.

In an alternative embodiment, a DVD player is used in the cinema, instead of the CD ROM and computer combination, the advertising sequence having been saved to a DVD, rather than a CD-ROM. This has the advantage that a Computer is not required, so simplifying the system. Any standard domestic DVD player can be utilised with the system. This gives the benefits of ease of installation, locational flexibility and ease of operation. The DVD driven system is mounted in the projection room, generally on the slide projector platform/porthole, and the LCD projector 2B may be mounted on top, as this gives a compact arrangement. The LCD projector 2B is linked to the DVD player via the LCD projector manufacture's network cabling.

It is also possible to use a method of direct connection to the cinema rather than a storage media, for instance, data comprising the images could be sent via telephone line utilising a modem, or satellite directly to the cinema in question. In short, any method which is suitable for sending digital data could alternatively be employed to send the images.

To assist in set-up, a test screen can be brought up before the advertising sequence begins. The LCD projector 2B is then adjusted so that the image 9 is in the centre of the cinema screen 6. Then, the zoom is adjusted to fill the screen 6 with the maximum image size 8. The projected image 9 will exactly fill the cinema screen 6 as it has been custom tailored to fit that particular cinema screen 6, with no light spill 5.

It should be noted further that the black borders 10,11, 12 allow the image 9 to be designed to fit a standard format, rather than match a specific screen 6. In such a case, the image 9 is zoomed until a first dimension fits the corresponding dimension of the screen 6. Any gap between the image 9 and the screen edge will not show, due to the black border 10,11, 12 surrounding the image 9. Whilst this method is slightly less preferred from the point of view of accuracy of image 9 to screen 6 matching, it does have significant cost benefits because a single advertising sequence can be bulkrecorded and distributed to a large number of cinemas, each of which may have its own individual screen aspect ratio.

The present invention has been described above purely by way of example and many modifications and variations can be made within the spirit of the invention.

The invention also consists in any individual features described or implicit herein or shown or implicit in the drawings or any combination of any such features or any generalisation of any such features in combination.

Unless the context clearly requires otherwise, throughout the description and the claims, the words"comprise", "comprising"and the like are to be construed in an inclusive as

opposed to an exclu opposed to an exclusive or exhaustive sense ; that is to say, in the sense of"including but not limited to".

Claims

CLAIMS: 1. A method for displaying a digital viewable image by projecting it upon a viewing surface, comprising pre-formatting the viewable image to have a predetermined outline, supplementing the viewable image with a substantially black border to form a composite image, providing the composite image to a digital projector and using a digital projector to project the viewable image onto the viewing surface so that there is substantially no overspill of light from the projector outside the viewing surface.
2. A method according to Claim 1, wherein the screen and projector are in a cinema.
3. A method according to Claim 1, wherein the projectable image is stored on a transportable storage medium.
4. A method according to Claim 3, wherein the transportable storage medium is a CD-ROM.
5. A method according to Claim 3, wherein the transportable storage medium is a DVD.
6. A method according to Claim 3,4 or 5 wherein a series of digital viewable images are displayed in sequence.
7. A method according to Claim 6, wherein a sound track is also provided on the transportable storage medium.
8. A method according to Claim 7, wherein the sound track and image sequence are synchronized.
9. A method according to any preceding claim, wherein the projector is an LCD projector.
10. A method for pre-formatting a digital viewable image to have a predetermined outline comprising: obtaining a digital viewable image; enhancing or otherwise manipulating the viewable image; altering the outline of the viewable image to a predetermined value; placing a black border along at least one edge portion of the formatted viewable image to produce a composite image; recording the composite image on a transportable storage medium; and recovering the composite image from the transportable storage medium.
11. A method according to any preceding claim, wherein the viewable image is formatted to have an outline having an aspect ratio of 2. 35 : 1.
12. A method according to any of Claims 1 to 8, wherein the viewable image is formatted to have an outline having an aspect ratio of 5: 3.
13. A method for projecting a pre-formatted image, substantially as hereinbefore described with reference to Figures 4 to 6 of the accompanying drawings.