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EP-4740172-A1 - METHOD FOR SELECTIVELY BLURRING AN IMAGE

EP4740172A1EP 4740172 A1EP4740172 A1EP 4740172A1EP-4740172-A1

Abstract

The invention relates to a method for selectively blurring a current sharp image, comprising the steps of: - defining an area of the current image, referred to as sharp area (2), in which the image remains unchanged and around which blur must be generated, referred to as area to be blurred; - calculating, from the position of the sharp area in the current image, a blur matrix applicable to the area to be blurred, wherein a blur intensity to be applied depends on a distance d1 between a considered portion of the area to be blurred and the sharp area; and - modifying the current sharp image by applying the calculated blur matrix to the current sharp image.

Inventors

  • LEGROS, ERIC
  • PETITGRAND, Sylvain
  • LUONG, BRUNO

Assignees

  • Fogale Optique

Dates

Publication Date
20260513
Application Date
20230708

Claims (16)

  1. 1. A method of selectively blurring a current sharp image comprising the steps of: - define an area of the current image, called the sharp area (2), in which the image remains unchanged and around which blur must be generated, called the area to be blurred, - calculate, from the position of the sharp area in the current image, a blur matrix applicable to the area to be blurred, of which a blur intensity to be applied is a function of a distance dl between a considered portion of the area to be blurred and the sharp area, - modify the current sharp image by applying the calculated blur matrix to the current sharp image.
  2. 2. Method according to the preceding claim, in which the calculation of the blur matrix is carried out as a function of depth information P associated with at least part of the pixels of the current image.
  3. 3. Method according to claim 1 or 2, in which the calculation of the blur matrix is carried out from an angle formed between an axis connecting the clear zone (2) and a position, called the observation position, at which the eyes (4) of an observer are estimated to be positioned relative to the current displayed image, and an axis connecting the observation position and a considered portion of the zone to be blurred.
  4. 4. Method according to claim 1 or 2, comprising a calculation of an area or a dimension of the net zone (2) as a function of a distance d2, called the observation distance, between a position, called the observation position, at which the eyes (4) of an observer are estimated to be positioned relative to the current displayed image and the net zone.
  5. 5. Method according to claims 1 or 2, in which the calculation of the blur matrix is carried out as a function of a distance d3 between a position, called the observation position, at which the eyes (4) of an observer are estimated to be positioned relative to the current displayed image, and a considered portion of the area to be blurred.
  6. 6. Method according to any one of the preceding claims, in which the calculation of the blur matrix is carried out as a function of optical parameters of the human eye.
  7. 7. A method according to any one of claims 3 to 5 or claim 6 taken in combination with one of claims 3 to 5, comprising the step of obtaining the observation position.
  8. 8. Method according to any one of the preceding claims, in which the clear zone (2) is obtained from at least one image of the eyes (4) of the observer, the clear zone corresponding to the zone of the current image displayed, called the attention zone (7), on which the observer's gaze is focused.
  9. 9. Method according to any one of claims 3 to 7 or claim 8 taken in combination with one of claims 3 to 5, in which, for each point of a perimeter (21) of the net zone (2), an axis connecting a point considered on the perimeter of the net zone to the observation position and an axis connecting a center of the net zone to the observation position form an angle between 1 and 6°.
  10. 10. A method according to any preceding claim, wherein the blur matrix comprises at least two sets each comprising a distinct blur coefficient to be applied to the area to be blurred.
  11. 11. Method according to the preceding claim, in which, for each set of the matrix, the calculation of the blur coefficient of a set considered is carried out by applying a point spread function, called PSF, to the set considered, each blur coefficient being calculated by applying a different PSF.
  12. 12. Method according to the preceding claim, in which the PSF describes the response of an imaging system from which the current image is obtained and in which the PSF is a function of: - a distance between an optical sensor of the imaging system and an object of a scene imaged by said optical sensor of the imaging system, and/or - a distance between a part of the imaging system and the optical sensor of the imaging system, and/or - a distance between a part of the imaging system and an object in the scene imaged by the optical sensor, and/or - a state of the imaging system, such as a zoom or focus or numerical aperture setting of the imaging system, and/or - of the information contained in each pixel or group or block of pixels of the convolved image, and/or - of each position in the image field, in particular according to the depth of the object, and/or - of each pixel or group or block of pixels, in particular as a function of the depth information contained in each pixel or group of pixels, and/or - one or more angles between the optical sensor and the imaging system.
  13. 13. A method according to any one of claims 8 to 12, wherein the blur coefficient of a set, or each blur coefficient of each set, of the matrix varies within the set.
  14. 14. Data processing device comprising means arranged and/or programmed and/or configured to implement the method according to any one of claims 1 to 13.
  15. 15. Computer program comprising instructions which, when the program is executed by a computer, cause the latter to implement the method according to any one of claims 1 to 13.
  16. 16. A computer-readable medium comprising instructions which, when executed by a computer, cause the computer to implement the method according to any one of claims 1 to 13.

Description

DESCRIPTION TITLE: Process for selective blurring of an image Technical field The present invention relates to the modification, in particular in real time, of displayed images. The invention relates to the dynamic visualization of displayed images. The invention also aims at the immersive observation of displayed images. State of the prior art In the state of the art, we know the tools and software for modifying or retouching images. More or less powerful, these software programs offer features including image blurring filters. There are several filters, or blurring methods, commonly used such as radial blur, average blur or the Gaussian filter which is the most widespread. Depending on the software, it is possible to more or less customize the blur filter parameters to modify, for example, the area to be blurred or the intensity of the blur. The methods and processes of the state of the art aim to provide the user with functionalities allowing him to personalize and control the blur he wishes to apply to an image. One aim of the invention is to propose a method of blurring an image allowing: - to selectively blur an image displayed while being observed by a user, and/or - to blur a part and/or certain areas of the image displayed during observation, and/or - to restore, on the displayed image, a particular blur effect, and/or - to modify, in real time, a displayed image to reproduce a particular blur effect, and/or - to modify, in real time, a stream of displayed images to reproduce a particular blur effect. Presentation of the invention For this purpose, a method of selective blurring, called a method, of a current sharp image is proposed. The method comprises the steps of: - define an area of the current image, called the sharp area, in which the image remains unchanged and around which blur is generated, called the area to be blurred, - calculate, generate or determine, from the position of the sharp area in the current image, a blur matrix to be applied or applicable to the area to be blurred, of which a blur intensity to be applied is a function of a distance between a portion, a part or an area considered in the area to be blurred and the sharp area, - modify the current sharp image by applying the calculated blur matrix to said current sharp image. The method may comprise a step of displaying, preferably on a display medium or display, the current image. Preferably, the method comprises, subsequent to the modification of the current clear image, a step of displaying the image, preferably on the display medium or display, thus modified. Preferably, the display is made in front of an observer. Preferably, the user's attention focused on the image defines the blurring law. The image may, depending on the uses, be displayed on a display other than that of the observer and/or transmitted and/or archived. In this application, "area" may be understood to mean a pixel, a group of pixels or an object of the current image. Preferably, the blur is generated over the entire image except the sharp area. The current sharp image may change over time. By blur matrix, it can be understood a matrix of coefficients determining, by correspondence to the image or to a part of the image, a blur intensity to be applied in each zone, each pixel, of the image. This blur intensity can correspond to a width at half-height of a point dispersion function called PSF. The blur intensity can be supplemented where appropriate by other parameters defining for example the shape of the PSF function. To obtain the blur, one can for example calculate the value of a pixel considered of the modified image by that obtained by the sum of the multiplications of the coefficients of the matrix representing the PSF with the pixels of the so-called current sharp image, in a neighborhood of the pixel considered. The current sharp image may not be completely sharp everywhere. The method may include taking into account the degree of lack of sharpness of certain areas of the image to reduce accordingly the intensity of the blur coefficients in order to obtain a blurring of the modified image depending essentially only on the blurring law explained in the following paragraphs, and not or very little on the initial blurs of the current sharp image. In the present invention, part, portion, zone or area of an image, in particular of the current image, may be understood to mean a pixel or a group of pixels of the image. It can be understood by blur matrix, a matrix or grid of coefficients or a table of coefficients. The matrix can contain a set of coefficients of distinct nature and/or distinct intensity. The coefficients of the blur matrix can coincide with the pixels or with groups of pixels of the pixel table of the current sharp image and/or of the modified image. According to the invention, it may be understood as "function of", for example "the blur matrix applicable to the area to be blurred is a function of a distance between a considered part