GB2226468A

GB2226468A - Image processing system

Info

Publication number: GB2226468A
Application number: GB8829991A
Authority: GB
Inventors: Graham Malcolm Alexande Barber
Original assignee: Rank Cintel Ltd
Current assignee: Rank Cintel Ltd
Priority date: 1988-12-22
Filing date: 1988-12-22
Publication date: 1990-06-27
Anticipated expiration: 2008-12-22
Also published as: GB2226468B; GB8829991D0; WO1990007244A1

Abstract

An image processing system comprises a processor (5) which can address a store of digitised images (9) to retrieve an image to be altered. The image is displayed on a monitor (11). The processor is coupled to a tablet (1) and stylus (3) which can be manipulated to define the parameters of an area of the image that is to be removed. Once defined, the area is removed and substituted by data derived from an area surrounding the area removed or from the image of a previous frame. Thus, defects such as scratches and dirt marks on film may be masked.

Description

IMAGE PROCESSING SYSTEM This invention relates to image processing systems and more particularly to a method and apparatus for altering digitised images.

A particular problem associated with the storage of film is the tendency for the film to become damaged, scratched and acquire dirt. Such degradations detract from the quality of image that can be displayed. There is a need for a system that can process film to cover up or mask these acquired degradations and to enhance areas of the image where, for example, colours have faded.

The present invention seeks to overcome the problems associated with degraded film and to fulfil the need outlined above.

According to the invention there is provided a method for altering a digitally encoded image, comprising the steps of inputting the digitised image to a processor, defining a selected area of the image to be altered by means of a stylus on a drawing tablet, the stylus and tablet being in communication with the processor, removing from the digitally encoded image the defined selected area, and substituting into said removed selected area data derived from another area of the image.

Preferably, the digitally encoded image is an image formed from a film and the method comprises the further step of scanning a film to digitally encode an image stored on the filaX Preèrably, the digitised image is supplied from an inage store b 1i a plurality of digitised images.

A system embodying the invention allows a series of digitised images representing successive frames of a film to be processed individually by identifying and masking defective areas.

The invention also provides a method for altering a digitally encoded image, comprising the steps of inputting the digitised image and a further digitised image to a processor, defining a selected area of the digitised image to be altered by means of a table and a stylus which communicate with the processor, removing from the digitally encoded image, the defined selected area, and substituting into said removed selected area data derived from the further digitised image.

In a preferred embodiment of the invention the image to be altered is displayed on a monitor screen for ease of identification of defective areas.

The area to be substituted is defined by the stylus. The stylus may define a number of different parameters such as area, coordinate location, orientation and shape. These parameters may be varied by manipulation of the stylus on the tablet and the defined area may be superimposed on the image on the monitor screen.

Preferably, the data substituted in place of the removed area is taken from an annulus surrounding the defect. The data may be substituted by direct replication or by interpolation. The degree of interpolation may be controlled by a parameter set by manipulation of the stylus, for example by rotation of the stylus around its own axis. Alternatively, the data to be substituted may be taken from another frame, for example from a corresponding area of the-preceding frame.

Thus, the preferred embodiment provides a system in which a blemish or defect may be substituted by defining the size, shape, orientation and position of the blemish or defect using a stylus and data from an undamaged part of the film may be substituted in its place, with or without interpolation, where necessary to account for gradations in colour or intensity.

The invention also provides apparatus for altering a digitally encoded image, comprising processing means for storing the image to be altered, and a drawing tablet having a stylus for defining a selected region of the image to be altered, the processing means including means for operating on the stored image to remove from the stored image the defined selected area and means for substituting into said selected area data derived from another area of the digitised image.

Preferably the apparatus further includes an image store containing a plurality of digitised images, the processor including means for retrieving a selected digitised image from the image store.

The invention also provides apparatus for altering a digitally encoded image, comprising processing means for storing the image to be altered and at least one further image, and a drawing tablet having a stylus for defining a selected area of the image to be altered, the processing means including means for operating on the stored image to be altered to remove therefrom the defined selected area, and means for substituting into said selected area data derived from the further stored image.

An ilbeLdiment of the invention will now be described by way of e'aple only and with reference to the accompanying drawing, i which: Figure 1 shows a schematic block diagram of a system embodying the invention; and Figure 2 illustrates the signals which may be derived from the stylus.

The tablet 1 and stylus 3 illustrated in Figure 1 are known per se. A suitable tablet and stylus is the Max system marketed by Technical Data Systems of Lower Philips Road, Blackburn, England. The tablet is connected to a processor 5 via a data bus 7 by which various signals relating to the position and orientation of the stylus on the tablet may be communicated to the processor. The processor also communicates via an address bus and data bus with an image store 9 by which a digitised image may be retrieved from the store by the processor for adaptation. The processor further communicates with a monitor screen 11 on which both the image to be adapted and the stylus parameters may be displayed.

The digitised images in the store are formed by scanning a film frame by frame and storing the digitised representation of each frame at a separate memory location.

The stylus at any one time record five different parameters.

These are: i. Position of the stylus point on the table (expressed as a cartesian coordinates x,y); ii. Pressure of the stylus point on the tablet (z); iii. Angle of inclination of the stylus with respect to the x,y plane of the tablet (; iv. Angle of rotation of the stylus about its own axis **); and; v. Angle of orientation of the inclination of the stylus Ca > .

These five parameters are illustrated in Figures 2(a) and 2(e); for ease of understanding it should be noted that Figures 2(a), 2(d) And 2(e) are plan views of a tablet and Figures 2(b) and 2(c) are side views of the stylus applied to the tablet.

In the system of the invention, each stylus parameter represents a particular parameter in locating and defining an area of the stored image that is to be removed and in choosing the area of the image from which replacement data is to be taken. The parameters previously defined have the following meaning: i. Coordinates x,y locate and define the centre of the area that is to be removed, normally a defect caused by dirt, scratching or discolouration; ii. The pressure signal z defines the radius of the area to be removed - the greater the pressure on the stylus, the greater the area to be removed; iii.The angle of inclination e defines the shape of the area to be processed: e = 900 defines a circular area, kt f 900 denotes an elliptical area, the smaller the angle -8, the greater the eccentricity of the ellipse; iv. Angle indicates the orientation of the major and minor axes of the ellipse relative to the X, Y axes of the grid; and V. Angle SL varies the degree of interpolation and/or replication used to replace the removed defect with information from an annulus of the digitised image that surrounds the defect.

In operation, the user selects an image to be altered from the image Store 9 by addressing the store appropriately. The data representing the digitised image is then inputted into the processor 5 and displayed on the monitor 11. The user can then examine the displayed image and locate any defects. The processor may be equipped with means for zooming in on any selected area of the image and for panning across the image.

Once a defect has been located, the operator applies the stylus 3 of the tablet. By varying the pressure and orientation of the stylus, the shape and area of the area to be removed can vary. A representation of the area is displayed on the monitor. The operator at the same time chooses the degree of interpolation and or replication that is to be used in correcting the defect once the area selected has been removed.

Once the x, y, z, , At, and DL parameters have been selected, the processor, on command from the user, repairs the defect identified by removing an area of the stored image defined by the x, y, z, 4 and 0e parameters and substituting in its place data in accordance with the selected parameter, 1L .

The substitution data is visible on the monitor before substitution takes place and before it is committed to being written into the digitised image.

The data which replaces the removed area may be a simple replication of the data contained in an annulus around the defect. Alternatively, interpolation may be used to ensure a gradated change in the data across the defect. Interpolation would be necessary, for example, where the colour or intensity in the area surrounding the defect varies, indicating that the area obliterated by the defect was also not of constant colour or intensity.

The system has an 'undo' operating mode allowing cancellation of any substitution that has been made and restores the image to its original form.

Multiple working of a defect is also possible. That is to say, once a given area has been treated, the treated area may again be worked on to refine the correction. Thus, for example, badly damaged areas may be worked on several times until the quality of repair is satisfactory.

Once the image has been restored, it may be returned to the image store, either at the same address or at a separate address. A fresh image may then be transferred to the store for restoring.

The stylus and digitiser may also be used to select a palette by acting to freeze the input. When images are being supplied from a telecine, the stylus and digitiser may control the frame drive so that the operator can freeze a frame which is observed as being blemished or use the stylus to move back through previous frames (or forwards) at slow speed to identify and freeze damaged frames to enable them to be repaired.

As we as repairíl7 defects in an image, the system described may be used to enhance areas of the image; either to highlight areas or to restore areas of the image where the colour has faded. Enhancement may be, for example, by enhancing specific detail of the image or by applying smoothing algorithms.

Claims

1. A method for altering a digitally encoded image, comprising the steps of inputting the digitised image to a processor, defining a selected area of the image to be altered by means of a tablet and a stylus which communicate with the processor, removing from the digitally encoded image, the defined selected area, and substituting into said removed selected area data derived from another area of the image.

2. A method according to Claim 1, wherein the substituted data is derived from an area adjacent to the defined selected area.

3. A method for altering a digitally encoded image, comprising the steps of inputting the digitised image and a further digitised image to a processor, defining a selected area of the digitised image to be altered by means of a tablet and a stylus which communicate with the processor, removing from the digitally encoded image, the defined selected area, and substituting into said removed selected area data derived from the further digitised image.

4. A method according to any preceding claim wherein the digitised image is supplied from an image store holding a plurality of digitised images.

5. A method according to any preceding claim wherein the image to be altered is displayed on a monitor screen.

6. A method according to any preceding claim wherein the posi.ti.om, shape, size or orientation of the area to be altered are defined by parameters set by manipulation of the stylus.

7. A method according to Claim 2 wherein the substituted data is interpolated from the surrounding area.

8. A method according to Claim 3 wherein the substituted data is interpolated from an area of the further digitised image.

9. A method according to Claim 7 or 8 wherein the degree of interpolation is defined by a parameter set by manipulation of the stylus.

10. A method according to any preceding claim further comprising the step of scanning a film to digitally encode an image stored on that film.

11. Apparatus for altering a digitally encoded image, comprising processing means for storing the image to be altered, and a drawing tablet having a stylus for defining a selected area of the image to be altered, the processing means including means for operating on the stored image to remove from the stored image the defined selected area and means for substituting in said selected area data derived from another area and the digitised image.

12. Apparatus for altering a digitally encoded image, comprising processing means for storing the image to be altered and at least one further image, and a drawing tablet having a stylus for defining a selected area of the image to be altered, the processing means including means for operating on the stored image to be altered to remove therefrom the defined selected area, and means for substituting into said selected area data derived from the further image.

13. Apparatus according to Claim 11 or 12 comprising an image store containing a plurality of digitised images, the processor including means for retrieving a selected digitised image from the image store.

14. Apparatus according to any one of Claims 11 to 13 wherein the processor is linked to a monitor, whereby the image to be altered can be displayed on the monitor and the parameters of the area to be removed defined by the stylus can be superimposed on the image.

15. A method of altering a digitised image substantially as herein described with reference to the accompanying drawing.

16. Apparatus for altering a digitised image substantially as herein defined with reference to the accompanying drawings.