Inpainting is the process of reconstructing lost or deteriorated parts of images

Digital image

A digital image is a numeric representation of a two-dimensional image. Depending on whether or not the image resolution is fixed, it may be of vector or raster type...

 and videos

Digital video

Digital video is a type of digital recording system that works by using a digital rather than an analog video signal.The terms camera, video camera, and camcorder are used interchangeably in this article.- History :...

. For instance, in the case of a valuable painting

Painting

Painting is the practice of applying paint, pigment, color or other medium to a surface . The application of the medium is commonly applied to the base with a brush but other objects can be used. In art, the term painting describes both the act and the result of the action. However, painting is...

, this task would be carried out by a skilled image restoration

Art conservation and restoration

Conservation-restoration, also referred to as conservation, is a profession devoted to the preservation of cultural heritage for the future. Conservation activities include examination, documentation, treatment, and preventive care...

 artist. In the digital world, inpainting (also known as image interpolation or video interpolation) refers to the application of sophisticated algorithms to replace lost or corrupted parts of the image data (mainly small regions or to remove little defects).

Applications

There are many objectives and applications of this technique.

In photography and cinema, is used for film restoration; to reverse the deterioration (e.g., cracks in photographs or scratches and dust spots in film; see infrared cleaning

Infrared cleaning

Infrared cleaning is a technique used by some film scanners and flatbed scanners to reduce or remove the effect of dust and scratches upon the finished scan. It works by collecting an additional infrared channel from the scan at the same position and resolution as the three visible colour channels...

). It is also used for removing red-eye, the stamped date from photographs and removing objects to creative effect.

This technique can be used to replace the lost blocks in the coding and transmission of images, for example, in a streaming video. It can also be used to remove logos in videos.

Computerized

A common method is to use differential equation

Differential equation

A differential equation is a mathematical equation for an unknown function of one or several variables that relates the values of the function itself and its derivatives of various orders...

s (such as Laplace's equation

Laplace's equation

In mathematics, Laplace's equation is a second-order partial differential equation named after Pierre-Simon Laplace who first studied its properties. This is often written as:where ∆ = ∇² is the Laplace operator and \varphi is a scalar function...

) with Dirichlet boundary conditions for continuity (a seamless fit).

Other methods follow isophote

Contour line

A contour line of a function of two variables is a curve along which the function has a constant value. In cartography, a contour line joins points of equal elevation above a given level, such as mean sea level...

 directions (in an image, a contour of equal luminance), to do the inpainting.

Manual computer methods include using a clone tool

Clone tool

The clone tool, as it is known in Adobe Photoshop, GIMP, and Corel PhotoPaint, is used in digital image editing to replace information for one part of a picture with information from another part...

 or healing tool, to copy existing parts of the image to restore a damaged texture. Texture synthesis

Texture synthesis

Texture synthesis is the process of algorithmically constructing a large digital image from a small digital sample image by taking advantage of its structural content...

 may also be used.

Exemplar-based image inpainting attempts to automate the clone tool process. It fills "holes" in the image by searching for similar patches in a nearby source region of the image, and copying the pixels from the most similar patch into the hole. By performing the fill at the patch level as opposed to the pixel level, the algorithm reduces blurring artifacts caused by prior techniques.

External links

• Inpainting and the Fundamental Problem of Image Processing, SIAM
• Image Inpainting, by the Image Processing Group at UCLA.
• Image and Video Inpainting by Guillermo Sapiro.
• Video Inpainting by Kedar Patwardhan.
• Program which realizes image inpainting by SoftOrbits.
• Resynthesizer. An open source Gimp plug-in for inpainting and texture expanding.
• Program which implements image inpainting by Teorex
• Mathematica Inpaint function.