The moire pattern is observed when different parts of tulle curtains are placed on top of each other.
The concept of "moiré" comes from fabric moire?!, in the finishing of which this phenomenon was used.
Moiré pattern occurs when digitally photographing and scanning reticles and other periodic images if their period is close to the distance between the photosensitive elements of the equipment. This fact is used in one of the mechanisms for protecting banknotes from counterfeiting: a wave-like pattern is applied to the banknotes, which, when scanned, can become covered with a very noticeable pattern that distinguishes the counterfeit from the original.
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Digital image processing
The appearance of moire during scanning
IN everyday life Moire often appears when scanning printed images. This occurs because the scanner re-rasterizes an image that already has the original raster in it. It can be more simply imagined this way: if you take a tracing paper with one ornament and put it on a tracing paper with the same ornament, but depicted from a different angle, then the resulting ornament will differ from both the first and the second. If you put them so that they coincide, then the first ornament will coincide with the second.
The round “rosettes” at the intersection of two rectangles result in the distortion of the image, which is visible in the first picture.
The appearance of moire during the screening process
Moire can also occur due to incorrect installation angles between the lines of primary colors when screening. Both are, in fact, the interference of two sets of raster lines. There are several types of moire rosettes, by the appearance of which you can often find out the cause of moire.
Scanning, in fact, is the modulation of signals in the scanner grid nodes by the brightness of the typographic raster nodes. IN general view the result is the product of two modulated sinusoids (gratings) with different periods spatial fluctuations. One
How to remove moire from a photo? Complete removal of moire takes place in two stages. Let's remove the colored moire first, and then the patterned one.
Open our image in Photoshop:
1. Removing colored moire.
Make a duplicate of the main layer ( Ctrl+J). Change the blending mode to Color(Color).
Choosing a tool Brush Tool (Brush), preferably with soft edges. To do this, change the brush settings Hardness(hardness) by 0% . Click Alt and hold it, the mouse cursor will turn into a pipette. We click on the photo in the place where we do not have moire and there is a primary color corresponding to the one on which we will remove the moire.
Letting go Alt, and move on to removing moire: carefully paint over all the places where there is moire; periodically the brush color will need to be changed to a more suitable one. If suddenly the wrong area of the photo is affected, we use Eraser tool (Lastic) or a mask.
Comparison of the initial image with the image after processing (clickable):
The colored moire was successfully removed, but in the photo there was a patterned moire all over the fabric. Therefore, below we will consider a method that will help us remove it.
2. Removing patterned moire.
Merge all layers ( Ctrl+E), and again create a duplicate ( Ctrl+J).
Let's go to the menu Filter->Blur->Gaussian Blur(Filter->Blur-> Gaussian blur), and increase the radius value until the moire stripes completely disappear. Let's see what value the parameter took Radius(Radius). In our example 10,5% . We remember it, but don’t apply the filter!
Let's go to the menu Filter->Other->High Pass (Filter->Others->Colorcontrast). For this filter, we set the radius value that we obtained earlier - 10,5%. Select blending mode Linear Light(Linear light) And Opacity(Opacity) — 50%.
Now let's invert the layer Image->Adjustment->Invert (Image->Edit-> Invert) or simplyCtrl+I. This is necessary so that the filter works to suppress, and not enhance, moire .
Now apply to this layer filter Filter->Blur->Gaussian Blur(Filter->Blur-> Gaussian blur). Slowly increase the blur radius from zero until the texture is preserved and moire does not appear and press OK.
Now you can experiment with Opacity(N opacity), in order to get a more suitable effect. It's okay if the image looks a little wrong. Assign a mask to our layer and fill it with black. Take the tool Brush Tool (Brush) we ask her white and carefully use the mask to go through the places where there is moire.
When two systems of contrasting stripes are superimposed, a pattern appears formed by their thickening in places where the stripes of one system fall into the spaces between the stripes of the other system. The occurrence of such patterns is called moire effect.
The simplest moiré pattern occurs when crossing under small angle two systems of equidistant parallel strips (lines). A small change in the angle of rotation of one of the systems leads to significant changes in the distance between the elements of the moire pattern.
A moire pattern is also formed when two non-intersecting systems of equidistant parallel lines are superimposed, when the step size of one of the systems is slightly different from the other. Moreover, the smaller the difference in pitch, the greater the distance between the moire fringes. This makes it possible to obtain a colossal increase (millions of times) in the difference in the width of the spaces between the lines. In other words, the moire effect makes it possible to visually detect, without the use of optical systems, minute deviations in almost identical periodic structures. Currently, the moire method is widely used to control the accuracy of dividing devices for the manufacture of diffraction gratings.
Moiré appears in an electron micrograph of two crystals superimposed so that their atomic lattices are almost identical. Any defect that disrupts the regularity of the crystal structure is clearly visible in the moire pattern. The magnification is such that it allows one to see displacements of atoms, the magnitude of which is less than the diameter of the atom itself.
If two lattices of equidistant parallel straight lines, slightly different in step size, are moved one relative to the other in a direction perpendicular to the lines, then the stripes of the moiré pattern will move at a speed much greater than the relative speed of movement of the lattices themselves. In this case, the direction of their movement coincides with the direction of the relative displacement of the lattice with a smaller step. Thus, a small movement of one of the gratings results in a large movement of the moiré fringes, which is easy to detect and measure.
Application example:
A method for determining deformations from a pattern of moire fringes, characterized in that, in order to increase the accuracy of measuring deformations, the ratio of the speeds of mutual movement of the deformed and reference meshes and the speed of movement of the moire fringe is determined, and the magnitude of the deformations is judged by the value of this ratio.
The described manifestation of the moire effect has long been used in all measuring instruments with nondus, such as a micrometer or caliper.
The moiré effect can be used to visualize minute changes in the refractive index of transparent media by placing them between gratings. For example, you can visually study the dynamics of the dissolution of two substances.
The same principle allows for express analysis of the quality of optical parts. The lenses are placed between the gratings; the presence of a convex lens increases the elements of the moire pattern, while a concave lens decreases them. In this case, both lenses rotate the pattern in opposite directions at an angle proportional to the focal length. In places where the structure or shape of the lenses is inhomogeneous, the pattern lines are distorted.
Another example of optical control:
An interference method for measuring the wedge shape of optical transparent plates, which consists in focusing a beam of light from a laser using a lens into the plane of a hole in the screen, behind which a controlled plate is installed, differing in that, in order to increase the accuracy and productivity of measurements, from the controlled plate with its In a fixed position, a transparent copy of the interference rings is obtained, the plate is rotated in its plane by 180, the interference pattern is superimposed on the copy, and the wedge shape of the platinum is measured using the width of the moiré fringes formed from the overlap.
A variety of moiré patterns can be created by combining lattices formed by a wide variety of lines, such as concentric circles, spiraling wavy or radial lines radiating from a point, and even families of evenly spaced dots. In this way, it is possible to simulate many complex physical phenomena, such as the interaction of electrostatic fields, wave interference, and others. Some problems of architectural acoustics are solved using similar methods.
In Japan, it has been proposed to use the moire effect to compile topographic maps of objects. The object is photographed through a grid of thin threads, casting a clear shadow on it. The shadow is deformed in accordance with the relief of the object and when it interacts with the real lattice, a moiré pattern appears, superimposed on the image of the object. In the photograph, the distance between the moire lines corresponds to the depth of the relief. This method is very effective, for example, in studying the deformation of rapidly rotating parts, in analyzing the flow of a surface layer of liquid around bodies in medical anatomical studies.
The versatility of the moire method, the simplicity of converting various quantities with its help, close to IFR, high resolution - all this suggests that inventors will turn to the moire effect more than once in their practice.
Moiré pattern
The appearance of moire when two linear gratings are superimposed.
Moire pattern(moire, from French. moire) - a pattern that occurs when two periodic mesh patterns are superimposed. The phenomenon is due to the fact that the repeating elements of the two patterns follow with slightly different frequencies and either overlap each other or form gaps.
The moire pattern is observed when different parts of tulle curtains are placed on top of each other.
The concept of "moiré" comes from fabric moire, in the finishing of which this phenomenon was used.
Moiré pattern occurs when digitally photographing and scanning reticles and other periodic images if their period is close to the distance between the photosensitive elements of the equipment. This fact is used in one of the mechanisms for protecting banknotes from counterfeiting: a wave-like pattern is applied to the banknotes, which, when scanned, can become covered with a very noticeable pattern that distinguishes the counterfeit from the original.
Digital image processing
The appearance of moire during scanning
Most often in everyday life, moire appears when scanning printed images. This occurs because the scanner re-rasterizes an image that already has the original raster in it. It can be more simply imagined this way: if you take a tracing paper with one ornament and put it on a tracing paper with the same ornament, but depicted from a different angle, then the resulting ornament will differ from both the first and the second. If you put them so that they coincide, then the first ornament will coincide with the second.
The round “rosettes” at the intersection of two rectangles result in the distortion of the image, which is visible in the first picture.
The appearance of moire during the screening process
"Divers". The sky is painted with uneven horizontal lines, and at low resolutions you get moiré.
Moire can also occur due to incorrect setting of angles between the lines of primary colors during screening. Both are, in fact, the interference of two sets of raster lines. There are several types of moire rosettes, by the appearance of which you can often find out the cause of moire.
Scanning, in fact, is the modulation of signals in the scanner grid nodes by the brightness of the typographic raster nodes. In general form, the result is a product of two modulated sinusoids (gratings) with different periods of spatial oscillations. One harmonic may have a larger period equal to the sum of the periods of both gratings, which causes moire. The second always has a period equal to the modulus of the difference between the grating periods and disappears because it cannot be implemented at a given scanning resolution.
Paints that affect moire
Moiré ribbon
When printing with any set of inks, the most intense (dark) ink, which has a value of 30 to 70% over a large area, can produce moire. That is, if in our CMYK photograph the black channel does not dominate (<10-15%) то вероятность возникновения различимого глазом муара минимальна. Таким образом можно почти не обращать внимание на жёлтый канал CMYK фотографии. Угол поворота растра между самыми проблемными каналами должен быть как можно ближе к 45°.
When printing “solid” (that is, with a fill of >95%), the concept of “raster inclination angle” practically disappears (even if we are talking about photography).
See also
Links
Wikimedia Foundation. 2010.
See what “Moiré pattern” is in other dictionaries:
The appearance of moire when two linear gratings are superimposed. Moire on the ribbon of the Order of St. Andrew the First-Called. Moire pattern (moire, from the French moiré) is a pattern that occurs when two periodic mesh patterns are superimposed. The phenomenon is due to the fact that... ... Wikipedia
Along with silk, velvet, satin and brocade, the hero of our today’s article rightfully takes its place among materials associated with luxury and wealth. Moire fabric is one of the most elegant fabrics; its exquisite shine and almost holographic patterns have served as inspiration for many artists and poets.
Photos close up:
Description and history
How can you describe moire? The main difference between moire is its special pattern, similar to wood layers or waves. The unusual nature of moire even gave rise to the term “moire effect.” And the name itself - “moiret” - translated from French means “creating waves”. And this definition fully gives an idea of the “moire effect”.
Initially, moire fabric was silk; this fabric began to be produced in France at the end of the 18th century. At that time, the material personified luxury and was available only to the richest people. Luxurious ladies' and men's toilets were made from moire fabric, wedding dresses. And the moire ribbon, in itself, was considered a badge of honor worn on the chest.
To tell everything about moire, you would need a whole book - this material has such a rich history.
Pictured is moiré fabric:
So what is moiré material? This is a plain weave fabric, which is created from silk, cotton or synthetic threads. The thickness of the moire and its density can be different, but the canvas is always monochromatic.
How is a moire pattern created on fabric? The fabric undergoes a calendering procedure - treatment with highly heated cylinders, which compress the weft threads and move them to the side. This deformation creates the effect of light refraction, and the displacement creates exquisite patterns.
You can purchase material consisting of polyester at a price of 800 rubles. Cost of matter from natural fiber starts from 3500 rubles. 
Compound
Previously, the material was made either entirely from silk, or from silk thread in the warp, and cotton thread in the weft.
With the development of the textile industry and the invention of synthetic fiber, polyester appeared in the composition of the material, as well as acetate and viscose - fibers based on wood cellulose. 
Species
Actually, there are only two types:
- Grimoire. Dense material with fine optical patterns and bright tints.
- Moiret antique. Thin material with voluminous large shimmers
Velvet moire
Perhaps we’ll add a few words about the velvet-moiré fabric. This is a material that is visually similar to the hero of our article, but has nothing in common with it in terms of production method. In the description of velvet-moire fabric you will find the same moire patterns, but they do not appear on the fabric using the calendering method.
So what is velvet moiré fabric? This is a fabric with thick pile, where the pattern is obtained by combining fibers of different colors and lengths.
Find out what helps him to be so beautiful in another article.
Properties
Positive characteristics:
- Sophisticated and elegant appearance
- The material holds its shape perfectly
- Highly durable
- Draps well
Flaws:
- Difficulties in care
- At improper storage Stable creases form on the fabric, which are then very difficult to get rid of
Application
Moiré fabric is a classic that will never go out of style. It is still widely used:
- Evening dresses and wedding dresses
- Concert costumes
- As a binding material for luxury gift folios
- Curtains, drapes
- Insignia
- Furniture upholstery (with the condition that the furniture will not be used every day)
Care
- If the material is made of natural silk, and therefore expensive, it is better to entrust the cleaning to professionals
- You can care for fabrics of a lower class at home - hand wash in water no more than 30 degrees, do not rub or twist too much
- Iron from the wrong side, waiting until the product is completely dry
- Store hung or carefully folded
- If creases have formed as a result of storage, the product must be held over steam in the right places, and then ironed from the inside out
