Comparison and linking of images. Stereo identification

The idea of ​​recording the coordinates of the point at which they were taken with each photograph appeared at the dawn of digital photography and was implemented almost immediately. Today this idea has come to the masses and has acquired many services. From the very beginning, the implementation of the idea at the hardware level arose and continues today, when a GPS receiver directly communicates with the camera, either it is built into it, or connected to it via a serial port, or is installed on the camera and receives a signal that a picture has been taken from flash sync terminal. Sony also released the GPS-CS1 device, which simply records the coordinates every 15 seconds, and then they are synchronized in time with the images taken, and the information about the coordinates is recorded in the file. Considering that today and GPS receivers, and cameras became quite common in Everyday life you may not need to buy additional device, you can use the GPS receiver and camera you already have, all that remains is to bind the coordinates to specific images. Previously, there was a significant limitation associated with the fact that the GPS navigator's memory was full, and you had to download information to your computer every day. If you rarely shot, and GPS was used in navigation, then it is likely that, having arrived from the hike, you will only be able to retrieve information about the last day. Now, when GPS navigators have the ability to record the paths traveled on memory cards, the issue of its shortage is almost completely removed. On the Internet, you can find dozens of programs designed to snap photos to coordinates. A more or less complete list can be found and. There are commercial ones among them, but most of them are free and even open-source. source codes... I tried to try many of them, but if for some reason the program did not start working correctly right away, then I did not try to figure it out, but went straight to the next one. Therefore, it is very likely that among those programs that I rejected, there are also worthy ones that will start working immediately and without problems on a different hardware configuration. I also did not consider commercial programs, since they demos make a deliberate error about a kilometer, and it seemed to me unreasonable to waste time on them in the presence of a large number of open programs.

In addition, the number of programs in question was reduced, since I had rather specific additional requirements. Namely: to record the coordinates, the Etrex Venture Cx navigator was used, which saves the coordinate data in the GPX (GPS Exchange Format) format. The format is standard, but it turns out that Garmin and some software developers understand this standard differently. Fortunately, there is universal programs converting one format to another. And among them I would single out. In particular, in this program, you can ask to convert the GPX format taken from Garmin navigator, into the same format, but the result of this transformation will be understood by all programs.

The second requirement was that I wanted to immediately snap photos in RAW format, so that all obtained from the original photos were already with marked coordinates, and there would be no need to determine the coordinates again in time when the picture was taken. Because over time, as it turned out, there are quite a few problems. And if you multiply them by the fact that the converted files are made and processed in different time, and the original time information of the picture may be lost or after a while you may not be able to remember in which time zone you shot. Many of the programs I have reviewed have quite sophisticated settings for correction. possible problems with the setting of times. However, it is best to immediately set up the navigator and camera so that these problems do not arise. My navigator has the ability to choose how the track is recorded - automatic or at a specified time interval. IN automatic mode, if you move quickly, then a lot of points are written, but if you stand still, then they are not written at all. This allows you to get a track record of the same quality, whether you are walking or driving. However, if you shoot from one point for a long time, then a situation may arise when at the time of shooting the GPS navigator did not record the coordinates, since they did not differ from those recorded half an hour ago. In many programs, you can set the time interval in which the coordinates are considered to coincide with the taken picture. However, the lack of information can mean not only that you were not moving, but also that the signal from the satellite was lost. In this case, if the interval is large enough, then the image can be assigned coordinates that differ significantly from the true ones. Therefore, I recommend setting timed recording at 10 second intervals. If you are not shooting from the bus window, then the accuracy will be more than sufficient.

The next global problem is what time to set in the camera. If you are traveling, or taking pictures in the fall or spring, when the time can change, then setting the local time in the camera seems to me a bad idea, especially since the idea of ​​local time is completely discredited today. The sun is at its zenith over my house in Moscow in the summer at 13:15. Today, means of transport allow you to travel many thousands of kilometers, and it is wiser to use the universal time, and not explain at what time and taking into account what time period you made an appointment. The navigator keeps a protocol in UTC (Coordinated Universal Time). Therefore, it makes sense to set the same time on the camera and never change it, regardless of travel or season. Given that I record coordinates at 10-second intervals, I prefer to call this time the old-fashioned GMT (Greenvich Meridium Time). This option is more informative, since it means that the countdown is from local time on the Greenwich meridian and, with the accuracy I set, does not differ from UTC. Knowing your own coordinates and this time, you can always easily calculate when your sun will be at its highest point, that is, local noon. All this information is by no means useless for the photographer, since it allows one to imagine where and where the light will fall from at the intended point of shooting. All the troubles are from the sciences, therefore, probably, the people who called the morning noon, tried to quickly send everyone who taught geography at school to an insane asylum.

So, if our camera and navigator are set at the same time, then in the future we can ignore the Time Zone settings. Programs for binding photos to coordinates

GPicSync

For the initial batch processing of the photographs taken, I chose the program.

Spartan graphical interface, working only with folders, viewing only JPEG, but it does its job and quickly enough. Note that there are quite a few programs that work from command line, which can argue with this one in asceticism, but I do not like working with the keyboard :-) The program uses and. Distributed under the GPL license. There are versions for Windows and Linux. Russian language is supported.

It works with folders at once, allows you to batch convert many photos at once, works with RAW, understands GPX files from Garmin, records coordinates in EXIF, allows you to add automatically to keywords IPTC is the nearest place names, which it takes from databases on the Internet. In addition to writing coordinate information to photo files, it also creates a file in KML format or KMZ.

KML (Keyhole Markup Language) is an XML-based markup language used to represent 3D geospatial data in a program Google earth, which bore the name "Keyhole" prior to its acquisition by Google. KMZ are the result of compressing KML files in a ZIP manner. For more details see

Google Earth is free.

If you want to navigate in field conditions (without fast Internet) to find out where you took the pictures, they must be put on some card that is saved in your laptop. To do this, you can use the above GPS program Babel and convert to WPT format for viewing in the program, or again to GPX format, but already with the included waypoints marking the pictures taken, for viewing in the program, i.e., put the photos on the very map on which you were guided, when using their GPS navigator.

For working with individual photographs, there may be good choice program .

This program is written in Java and, as a result, is equally easy to run without reinstalling both under Windows and under Linux. Additionally, it is distributed under the GNU License. General Public License. The program can do everything: work with RAW files; view them; write coordinates to EXIF; view the position of photos on satellite images through the Google Earth program; add geographic names to keywords using information from the site. To achieve this versatility, the program uses external modules third-party developers that need to be installed separately:,.

The program allows you to export photos not only to Google Earth, but also, without installing additional programs, to control the position of the shooting point through.

Of the minuses of this program, it should be noted that it is very slow, that is, it can take about a minute to prepare for viewing a photo in RAW format, and without conversion it does not understand Garmin files. The program is used to communicate with a GPS receiver and to convert files it must be run separately. Some place names can be inserted in Cyrillic, which would be welcome, but some viewers refuse to work with such files :-(

The program is updated very often, so there is a hope that it will be improved :-)

COPIKS PhotoMapper

If you only work with files in JPEG format and only under Windows, the program would be a good choice.

She also very effectively copes with the task of packing photographs previously referenced to coordinates into KMZ format... You can see what it looks like by downloading the 500 KB file.

Locr GPS Photo

For post-processing and posting photos on the Internet, a program can be useful.

It is also convenient in that it allows you to superimpose photographs on space images and maps provided by different companies. You can choose between Google, Microsoft and YAHOO.

I never learned how to bind photos with its help, because I did not find a way to convert GPX into an acceptable NMEA format. Therefore, for me, its main purpose is to post photos on the Internet. This is not the only service that provides a similar service, you can post photos on the Internet and on the website.

A convenient addition turned out to be a program that allows you to edit coordinates manually, find a survey point in Google Earth using data recorded in EXIF, and also carry out the reverse operation - write down the coordinates of a survey point found on a space image in EXIF.

Over the past year, the idea has received strong support among the masses, and soon any point on the earth's surface can be seen not only from space, but also from ground level. Turning on the layer "Geography on the Internet / Panoramio" in Google Earth, you will see that the earth is literally strewn with marks of survey points, clicking on which, you can see the photo.

Graphic objects (pictures and images) located in Word document, as a rule, can be moved with the text or snapped to a specific fragment text document(paragraph, page borders, line, etc.).

To do this, enter the menu command FORMAT ® Picture (Autoshape, Inscription or others) and in the corresponding dialog box on the tab Position click on the button Additionally and then open the tab Picture position and set the switch Move with text... Usually travel mode graphic objects installed with the text in Word by default.

To display the binding, you need to enter the command SERVICE ® Parameters and in the tab View dialog box Parameters set switch Snapping objects... When this switch is set after isolation graphic object next to it (on the left margin) will be displayed anchor symbol (marker) in the form of an anchor.

Anchor symbols are displayed only in page (and Web document) layout mode and only for pictures and objects located outside the text layer(for which one of the modes is set wrap text).

When working with a document containing a graphic object, it is recommended not only to set the display of anchor symbols, but also to display non-printable characters (paragraph markers) on the screen. Because when you delete, move or copy a paragraph, near which the anchor symbol (anchor) is installed, the graphic object (picture or image) "attached" to this paragraph is deleted (moved, copied) along with the paragraph.

Sometimes it is required that the graphic object remains anchored to the same paragraph whenever it is moved, i.e. was "rigidly" tied to a specific fragment of the document, for example, a picture to its title. In this case, in the Additional Layout dialog box on the Picture Position tab, activate the switch Set binding, after which the castle image will be added to the anchor image anchor marker.

Creating formulas

Complex mathematical equations, expressions and formulas created using the built-in formula editor in Word can be inserted as objects into a Word document - a program Microsoft Equation.

Equations and formulas created in this way are static objects, i.e. they do not perform calculations and cannot be edited directly in the text.

To start the formula editor, use the command Insert ® Object... In the opened dialog box Inserting an object in the tab Creation select item Microsoft Equation 3.0. After that, the menu of the formula editor program and the toolbar will appear on the screen. Formula.

In addition, to launch the formula editor, you can use the button Formula editor.

When creating formulas, the buttons on the formula editor toolbar are used to select symbols and patterns, and the keyboard is used to enter numbers and variables in the designated spaces.

The formula editor toolbar (Formula) contains two rows of buttons. In the top row - in the line characters there are buttons for inserting mathematical symbols into the formula - Greek letters, mathematical and logical operators, superscripts, etc. Bottom row buttons allow you to insert templates , including symbols for fractions, square roots, integrals, sums, products, matrices, various brackets, etc. Many templates contain special fields (black or empty squares) for entering text and inserting characters.

Entering and editing formulas is completed by pressing the ESC key or closing the formula editor panel. You can also left-click anywhere in the document field outside the formula input area. The entered formula is automatically inserted into the text as an object. Then it can be moved to any other place in the document via the clipboard. To edit the formula directly in the document, just execute on it double click... This automatically opens the formula editor window.

Create tables and work with tables in Word

Word allows you to format data generated documents in the form of tables.

table- the form of organizing data by columns and rows, at the intersection of which the cells are located. Data of any type can be placed in the cells of the table: text, numbers, graphics, pictures, formulas, etc.

A Word table can contain 63 columns and 32,767 rows (compare, in Excel, 256 columns and 65,536 rows). Different rows of the same table can contain a different number of columns. Table cells have addresses formed by the column name (A, B, C,…) and the row number (1,2 3,…).

In a Word document, tables are created at the location of the cursor. By default, lines in the table are indicated by a dotted line (which is not printed).

You can create a new table in Word format:

1.Using the command horizontal menu window TABLE ® Add (Insert) ® Table... In the dialog box that appears Insert a table set the dimension of the table - the number of rows and columns and set the column width parameters.

2. Using the Add Table button on the standard toolbar. To define the configuration of a new table, you need to paint over the required number of columns and rows of the table with the left mouse button pressed.

3. In latest versions Word now has the ability to create tables by drawing them with a "pencil" using the mouse. This button is on the toolbar Tables and borders.

4. Previously typed text can be converted to tabular representation using the command TABLE ® Convert ® Convert to Table provided that the text is prepared using special line and column separators: end-of-paragraph characters ( Enter), tabs ( Tab) or others.

Word also allows converting the table back to plain text using the menu command TABLE ® Convert ® Convert to Text.

The number of rows and columns originally specified (when creating a Word table) can be changed by adding new or removing existing rows and columns.

To add a new line at the end of the table, place the cursor in the last cell of the table and press the key Tab.

You can also use the clipboard (menu commands EDIT ® Copy, Cut, Paste).

To delete a table, you must select it along with paragraph marker next to the table and press the key Delete... If you select a table without a paragraph marker following the table, then pressing the key will delete only its contents... You can also use the command to delete the entire table TABLE ® Delete ® Table by first placing the cursor inside the table.

What's New for Working with Tables in Word 2000

In the version of Word 2000, for the convenience of working with tables, there are new tools and capabilities that were not in previous ones versions of Word:

Moving the table entirely with the mouse - drag the table move marker with the mouse - a non-printable character that appears on the left above top line tables;

· Resizing the table while maintaining the proportions of the sizes of rows and columns (using the table resizing marker in the lower right corner of the table);

Text flow around the table (the flow options are set in the same way as for figures - the command TABLE ® Table Properties);

Creation of nested tables - a table cell can contain another table (for example, using the command TABLE ® Add ® Table);

· Creation of diagonal borders and lines inside the cell, drawing borders "with a pencil" or using the buttons on the toolbar External boundaries;

Setting cell margins and spacing between cells, etc. (cell margins determine the gap between the cell border and the text in it; to set cell margins and determine the amount of spacing between cells - the command TABLE ® Table properties ® Table tab ® Parameters button).

Many problems of thematic decoding are reduced to mutual comparison of images formed with the help of sensors of different physical fields. A striking example development of remote control methods of natural resources and ecosystem dynamics (so-called monitoring) can serve, which boils down to comparing images of the same territory obtained at different times and / or using various sensors... The most commonly used are optical, radar, radio-thermal, magnetic and other fields. The joint use of different physical fields requires preliminary processing of the corresponding images, for example, in order to translate the images into one spectral region.

In practice, images of the same object or area, obtained at different times or with the help of different sensors, can differ significantly from one another. This results in a number of important snapping tasks, as well as accurate mutual geometric and amplitude correction for subsequent joint analysis. In any case, this requires the establishment of a correspondence between the elements of the original images, which boils down to the selection of the so-called reference (in another way, reference or conjugate) points on the images, which can be used to coordinate images with simultaneous geometric correction. (Points on two images are called conjugate if they are images of one point in the scene). For example, aerospace computer monitoring assumes the presence of a discrete time observation with a small time interval, and therefore, when a moving camera captures the brightness image of the observed object (optical surface) in the form of a sequence of images, this image from image to image is deformed due to perspective distortions and changes in position cameras. The geometry of the corresponding deformations is modeled by projective transformations, which constitute a wider class than the well-known transformations of Euclidean geometry (suffice it to say that lengths and angles in projective geometry are not preserved, but parallel lines can intersect!).

Reconstruction of the spatial relief from stereo images leads to the problem of identification: establishing the exact coordinate (pointwise) correspondence of the elements of stereo images. The solution to this problem is to select pairs of reference fragments and estimate the parameters of the "divergence" of the corresponding points (this is called binocular disparity in stereophotogrammetry), which can be used to restore the geometric transformation function and evaluate the surface of a three-dimensional scene (relief).

Aerospace 2D images always represent 3D objects on the earth's surface. Even images of areas that appear to be practically flat are always distorted due to the curvature of the earth's surface and the inhomogeneity of the spatial characteristics of the sensors used. The purpose of the geometric correction of images is to adequately represent the objects of the earth's surface on them, the comparability of various images (at different times or obtained from different types equipment) and transforming them into a map projection for the purpose of a comprehensive analysis of aerospace and cartographic materials.

In some tasks of thematic processing, it is advisable to carry out geometric correction after the classification of the image. This, first of all, applies to those cases when the spectral reflective properties of the objects of study are the main characteristic necessary to obtain correct results. If, in the process of thematic classification, reliable data of ground surveys or the results of multi-time observations, including those presented in the form of cartographic materials, are used, then the geometric correction must be performed before the start of thematic interpretation, and in the most careful way. In cases where processing is carried out on an area with a complex relief, for accurate comparison of the objects under study with the map, it may be necessary to orthorectification of the image using a three-dimensional digital elevation model.

Geometric correction is also necessary for landscape-indication interpretation, where geomorphological structural features of landscapes and their interconnections play an important role, as well as in all tasks related to the selection of spatially localized objects. Compilation of accurate photographic plans and mosaics of images also requires preliminary geometric correction.

Georeferencing and geometric correction of aerospace images in most cases is associated with one or another type of cartographic projection. Cartographer system iches which projection is any system designed to represent a sphere or ellipsoid of revolution (like the Earth) on a plane. There are many different projection methods. Since projecting a sphere onto a plane inevitably leads to distortion of surface objects, each projection system has some properties, such as maintaining distances, angles, or areas. According to these properties, projections are distinguished, respectively, equidistant, conformal and equal.

The expediency of using one or another type of projection from the listed is determined by the nature of the measurements that are supposed to be performed in the process of solving the problem. For example, in equal area projections (with the preservation of areas), a circle of a certain diameter drawn anywhere on the map will have the same area. This is useful when comparing different land use objects, determining the density of objects on a map, and in many other applications. However, in this case, the shape and mutual distances in some parts of the map may be distorted.

There are various cartographic coordinate systems for determining the position of a point on the map (in the image). Each coordinate system generates a grid, the nodes of which are denoted by a pair of numbers X, Y (on digital image column number and row number). Each data projection system on the map is associated with a specific cartographic coordinate system.

In packages for processing aerospace images, there are three types of operations associated with the use of a coordinate grid. Further see beat. 24, 25.

Transforming images with geometric correction. Obtaining a transformation matrix by control points, estimating errors. Ways to recalculate pixel values ​​when transforming an image.

Rectification (transformation)- the process of converting data from one grid system to another using polynomials nth degree... Since the pixels on the new grid may not coincide with the pixels on the original grid, it must be re-selected. Resampling is the process of interpolating (extrapolating) pixel values ​​to a new coordinate grid.

Image snapping. Many applied problems use the analysis of images of one territory obtained different types equipment or at different times of shooting. To be able to compare images pixel by pixel, you need to convert them to unified system coordinates and "fit" the images to each other. It is not necessary to use a cartographic coordinate system. If none of the images used has been transformed into a map projection, they can be analyzed by fitting one to the other in the coordinate system of one of the images.

One of the common techniques used in the process of interactive visual decryption is to increase the resolution, and, consequently, the information content of multispectral images by combining them with a panchromatic image of a higher spatial resolution. At the first stage, the cross-linking of the multispectral and panchromatic images is performed. Then the multi-zone image is stretched to a panchromatic scale and the brightness is recalculated according to a certain rule. When using the simplest multiplicative rule, the j-ro value of the pixel Ij at the output in j-channel is determined by the product: where is the original pixel value, I rap -

the value of the corresponding pixel in the panchromatic channel.

Geo referencing- the process of assigning geographic coordinates to image pixels. Geo-referencing is reflected only in information about geographic coordinates in the image file. In this case, the image grid does not change. The image can be georeferenced, but not rectified. In the case when spherical (geodetic) coordinates (latitude, longitude) are assigned to image pixels, it is called digital model, in contrast to a digital map, which always has a specific cartographic projection and a plane (geographic) coordinate system. The digital model can be converted to any digital map by means of rectification. The rectification process always requires a preliminary geographic referencing of the image, since any cartographic projection is always associated with a specific coordinate system. In the case of linking an image to an image, georeferencing is required if one of the images is already linked.

The rectification process includes the following steps:

1) the choice of control points (GCP - Ground Control Points);

2. calculation and testing of the transformation matrix;

3) formation of a new image with information about the coordinate grid in the file header; in this case, the pixels are re-sampled.

Control Points (GCP) are reliably identifiable image elements with known coordinates. The most correct are the coordinates obtained from geodetic control points or from JPS receivers. However, in many cases it is necessary to use scanned paper maps or vector layers of electronic maps in formats compatible with the processing package, for example, shapefiles from ArcView or coverages from ARC / INFO. When using cartographic materials for rectification, it is necessary to take into account that in the process of generalization when moving from a larger scale of a map to a more

When small, the size and position of some objects are distorted. This is allowed in order to preserve the characteristic features of the territory and the most important topographic objects in one sense or another. First of all, this applies to highly indented coastlines, deltas and river branches, lakes in arid lands, etc. The most reliable control points are hydraulic network nodes without characteristic features, road junctions and other objects of a fairly simple shape. The scale of the map should be comparable to the pixel size of the image (the error of displaying linear objects on a paper map is about 0.4 mm).

Transformation matrix- this is a table of coefficients of polynomial transformation in the transition from the original grid of coordinates to the calculated one. For a polynomial transformation of the nth order, the polynomial equations have the following form:

where index

For n = 1 (linear transformation), Eqs. (1) are conventional system linear equations kind

Coefficients and are calculated from the coordinates of control points by the least squares method. The coordinates of each control point contribute to the overall approximation error (Fig. 1). At the stage of testing the transformation matrix, the mean square of the error and the contribution to the error of the coordinates of each control point are displayed in the windows of the transformation procedure, which allows the analyst to adjust the position of control points to minimize errors or replace the least successful control points. Rice. one.

In rectification procedures, polynomials up to the third order inclusive are most often used, although the ERDAS package allows polynomials up to the 5th order. Linear transformation is most often used to align scanned maps or already rectified images. For rectification of space images, polynomials of the second and third order are usually used.

Recalculation of pixel brightness values ​​when transforming an image.

When transforming the image, the nodes of the rectangular grid, in which the new image will be presented, will be completely different from the pixels that were in the nodes of the original grid. Therefore, the brightness values ​​of pixels must be recalculated in accordance with their new coordinates. There are three main ways to convert these values: nearest neighbor, bilinear interpolation, and bicubic convolution.

In the nearest neighbor method, a pixel with coordinates (x, y), the brightness value of which in the new coordinate grid is unknown, is assigned the value that has the nearest pixel in the new grid with a known brightness value. This method is most often used when transforming already classified (index) images, where the brightness of a pixel corresponds to the index of its thematic class.

Pixel coordinates

Fig. 2. Linear interpolation in Y coordinate.

At bilinear interpolation

The unknown pixel brightness is calculated on the assumption that in the local area of ​​the image, the brightness, depending on the value of the coordinates, changes according to a linear law (Fig. 2). That is, the desired brightness value is the coordinate V m points (Y m, V m) a straight line defined by the brightness of the two nearest pixels to the right and to the left, respectively. The calculation is performed taking into account both X and Y coordinates, which is why interpolation is called bilinear.

Because the this method has a smoothing effect, bilinear interpolation is advisable to use for images that do not have pronounced structural features. Most often these are images of undeveloped territories - forests and tundra tracts, deserts, oceans and seas.

At bicubic convolution pixel value with coordinates (X r, Y r), calculated by

the pixel values ​​inside the 4x4 window, as shown in Figure 3.

The convolution used in ERDAS Imagine has a rather complex form and gives a complex effect of low-pass and high-pass filters. That is, it provides, on the one hand, some increase in contrast, on the other hand, smoothing of individual small details. In general, the effect of the method depends on the type of image, but it can be used if there are pronounced structural elements in the image.

Fig. 3. Window selection for bicubic convolution.

Up-resolution of multispectral images using panchromatic images high resolution... The main stages of the process. Ways of implementing this procedure in the ERDAS Imagine package.

In the ERDAS Imagine package, you can increase the spatial resolution of a multi-zone image, having a black-and-white (i.e. panchromatic) image of the same area. The process includes two stages: 1) reduction of a pair of images to a single coordinate system; 2) actually increasing the resolution. Despite the fact that the second stage is performed in ERDAS Imagine in one procedure, it also includes 2 tasks: 1) bringing images to a single scale, that is, stretching a multizonal image to a panchromatic scale; 2) combining images and recalculating the brightness values ​​of pixels in each channel using the value of the corresponding pixel in the panchromatic channel. The simplest way recalculation - multiplicative, where the new brightness is calculated by the formula: where is the original pixel value, I rap is the value of the corresponding pixel in the panchromatic channel

The obtained values ​​are then scaled, and, as you can see, at a higher detail, the brightness ratios across the channels for each type of objects are preserved. Execution in the ERDAS Imagine program:

1 Open the image in Viewer No. 1 panAtlanta.img from the EXAMPLES folder. This image has already been georeferenced. The characteristics of a map projection can be viewed using the function Utilities-> Layer Info.

2 In the new Viewer # 2, open the multi-zone image tmAtlanta.img. This image will be used as a working image.

3 The first step in the process will be to link the working multispectral image to the panchromatic one. Select the function in Viewer No. 2 Raster- > Geometric Correction. In the window Set Geometric Model choose a polynomial model.

4 In the window Polynomial Model Properties set the degree of the polynomial that will be used when transforming the image. In this case, a second-order polynomial is sufficient.

5 In the window Geo Correction Tools select the circle with the cross to create a set of anchor points. In the opened window GCP Tool Reference Setup the mode must be set Existing Viewer. After confirmation (OK), you will see a window asking you to specify the window (Viewer) of the image to which the snapping will be performed. Click inside the panchromatic window and confirm your choice in the message box that appears. After that, you will open all the tools for transforming the image by anchor points.

6 Ground control points are created in the mode of the pressed "circle with a cross" button from the ground control points editor (table GCP Tools). It is more convenient to indicate these points inside small auxiliary windows, the position of which is shown by rectangles on the main images. The size and position of these rectangles is adjusted with the cursor while the arrow key is pressed. The size can be adjusted by hooking the corner of the rectangle in the crosshair with the cursor, the position is changed by moving the crosshair lines. Points should be applied in pairs on both images. If you first put several points on one, and then several points on the other, the program will not be able to identify them. Anchor points should be evenly spaced across the image, otherwise only that one will be correctly transformed for you.

an area with more dots and the rest of the image will be heavily distorted.

If the point is not well plotted, it can be removed as follows. Select the corresponding line in the table by clicking on the left gray field where the line numbers are indicated. Then press the right mouse button on the same field. From the pop-up menu, select Delete Selection. In the same menu, you can cancel the selection using the command Select None or, conversely, select all rows (Select All)

7 After specifying a certain number of control points, you will automatically create a transformation matrix with polynomial coefficients calculated by these points. Approximation errors for each point are shown in the field "RMS Error", and the contribution of each point to the error is in the field "Contrib". Offsets of a point in X and Y are shown in the fields "X Residual" and "Y Residual" respectively. You can move the point in the Viewer; however, the errors will change. All errors must be of the order of 0.1 or lower for an acceptable transformation. Try to shorten these errors by moving the cursor along X and Y. If this fails, then delete the unfortunate point. To delete, select its row in the table by clicking on the leftmost (gray) field. After that, right-click on this gray field to call the pop-up menu and select Delete Selection

8 After typing a certain number of control points, the program will automatically calculate the transformation polynomial for you. To check if this polynomial is calculated correctly, apply one or two control points on one of the images in those areas where you have not yet put them. If at the same time they appear on another image at the same points, then the polynomial is selected correctly. Otherwise, continue the process of forming control points until you obtain the required accuracy.

9 After you get a transformation matrix of acceptable accuracy, you can proceed to the very process of transforming the image. (Resampling). In the window Geo Correction Tools select the oblique square tool. In the Resample window that opens, open a new file in own folder to record the result of image transformation. On the right, set the desired image pixel conversion method and click OK.

10 Output the result to a new Viewer and make sure that the transformation is done correctly.

11 In the block Interpreter select menu item Spatial Enhancement, and in the opened submenu - the function Resolution Merge. In the window that opens, in order from left to right, open the files: 1) panchromatic image; 2) a multi-zone image transformed by you; 3) the output you are going to get. You can select the modes that are installed by default. Click OK.

12 Open the result and make sure it exists. If it is missing, try using a different pixel-counting mode.

In addition to the ability to add images to page content using the FilePicker from the TinyMCE visual editor, developers and designers in CMS Made Simple have long been looking for the possibility of the so-called association of one image and a page. What is it for? Here are some examples:

To create a graphical menu that displays not text, but an image. Check out an interesting example of a Mac-style graphical menu, or a graphical menu with hierarchy at the bottom of the site after the word Portfolio.

To create a list of pages (like a teaser) with an image attached to each page.

To restrict page editors who are unable to shrink and neatly insert images into content. In this case, they are asked to select from the list one of the already loaded pictures, which is then inserted in the template in the right place of the desired size. Or the ability to download images, which will shrink when loading automatically.

At the moment, there are three options for linking an image to a page (at least I don’t know others).

Option 1: Image on the Options tab

This was the very first attempt at linking an image to a page, which is still available on the tab. Options when editing a page. Here you can select one of the images in the list of files that were previously uploaded to the folder uploads / images... The path to this folder can be changed only globally in the general site settings (Site Administration " General settings, tab Page editing settings). The selected image becomes available in the menu template via a variable $ node-> image, and its sketch through $ node-> thumbnail... With this option, only one image can be associated with one page, i.e. 1: 1.

Option 2: Image via the (content_image) tag

Second try. The tag is added to the main site template. If you add the tag several times, then you can attach multiple images for the same page. IN admin panel in this case, a dropdown is displayed for me to select the uploaded files (as in option 1), and on the page itself it issues HTML tag img. (content_image) is more intelligent than the first option, in particular, it allows you to customize the folder in which the images are stored.

But its big drawback, like the first option, is that the images that can be selected from the list are must be pre-loaded to the system using the file manager or in the Image Management item. If you (for educational purposes) removed the "Insert / Edit Image" button from the visual editor in order to prohibit their direct insertion into the content of the site, then your editor must first load the images, and then edit the page. The second drawback: if there are a lot of these images, then the list turns out to be huge and it can be easy to get confused in it.

Option 3: Using the GBFilePicker Module

Extremely flexible. It allows not only to select already uploaded images, but also to load them "on the fly" while editing the page, as well as to delete and even edit already uploaded ones. without leaving the content editing page... The list of images in the drop-down menu can be shown or disabled (for example, if there are already 100 images in the folder, then the list is most likely useless).

Several examples of how this tag might look in the admin interface on a page with content editing, depending on the parameters used.

Module features: reducing files when loading, excluding certain files from the list by suffix or prefix in the file name, the ability to restrict extensions for uploaded files, the ability to restrict access to files depending on the user, creating thumbnails. And I especially love this module because it is not only the name of the file in the list, but also its sketch to the editor shows that it is extremely convenient for the forgetful.

This option, so far, is the best that I see in CMS Made Simple. This is what my site editors grasp intuitively.

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