Menu rImage
Image operations and color processing

Snap > Raster Snap ON/OFF
Snap modes

Menu: rImage > Snap

Description: Raster snap allows creating and editing objects, based on geometry of other raster objects. For example, you can draw a line, the end point of which coincides with another raster line end point, or stretch an arc so that its end point is placed on a characteristic point of raster line.
You can turn on raster snap at the time when AutoCAD is waiting for the entry of coordinates. In this case this mode is only applied to the next selected object. You can also setup one or several raster snap modes as running snaps. These modes stay active until you turn them off.
You can only use raster snap on monochrome raster image. When you select points on the image with raster snap mode on, a square raster snap pickbox appears on the cursor cross. When you place this pickbox on the object, the program finds an appropriate point on the object for the specified snap mode, and transfers the calculated coordinates to the current command. If there are several possible snap points, the closest one to the point specified is chosen.
The program highlights with a color marker the point, to which the snap is supposed to be made. If you hold the cursor over the object, a tooltip with the current snap mode name appears at the point. For each snap type a special marker is used. If there is any problem with precise snapping, you should zoom the image on the screen.
The marker bitmap color is specified in the WiseImage tab of the AutoCAD customizing dialog box in "Colors Section".

The raster snap operation is based on algorithms for raster object recognition. The program calculates vector objects, approximating the specified raster lines and snaps to the characteristic points of these vector objects. That is why the operation of the raster snap tools depends on the parameters set in the Options tab of the Conversion Options dialog box.

The raster snap is only influenced by three parameters of the Options tab: Max Width, Max Break and Approximation Accuracy.

Max Width - defines the maximum width of raster objects that the raster snap deals with.

Max Break - defines the length of the largest break that is ignored in a raster line. If raster line breaks are less than the specified value, it is recognized as an entire raster object.

Approximation Accuracy - defines the accepted deviation of raster symbol entities from their vector prototypes.

SNAP MODES

The raster snap modes implemented in WiseImage are the same as AutoCAD's object snap modes and work in the same way.

Endpoint-Snap to the raster objects endpoints (lines, arcs etc.).
Midpoint-Snap to the middle of raster objects (lines, arcs etc.).
Center-Snap to the center of a raster arc, circle.
Quadrant-Snap to the nearest quadrant (the point located under an angle 0, 90, 180 or 270 degrees from center) of arc, circle.
Nearest-Snap to the point of the raster object located closely to the indication point.
Intersection-Snap to the intersections of raster objects (lines, circles, arcs etc.).
Perpendicular-Snap to the point of the raster object lying perpendicular to another object or to its imaginary extension.
Tangent-Snap to the point on an arc or circle belonging to the tangent of another object.

See also: Quick Start "Getting started"

Convert to RGB
Convert to Indexed colors
Convert to Grayscale

Menu: rImage > Convert to > Convert to RGB, rImage > Convert to > Convert to Indexed colors, rImage > Convert to > Convert to Grayscale

Description: By converting monochrome images to RGB or greyscale you make it possible to apply color filters to the image (Blur, Unsharp, Median). Conversion color image to 8-bit indexed is the tool facilitating color management.

Brightness/Contrast

Menu: rImage > Brightness/Contrast

Toolbar: Raster Image

Description: You can adjust brightness, contrast, hue, and saturation for a single or several color and greyscale images.

Brightness sets relative color lightness or darkness. It is usually measured in percent ranging from 0% (black) to 100% (white).
Modifying contrast enables you to increase or reduce the image brightness range. An image with the same brightness value has zero contrast value. If the contrast value increases, it causes an increase of the brightness range, i.e. darkening dark colors and lightening light ones. Hue is a light wavelength reflected from or transmitted through an object. Usually hue is identified by the name of a color, such as red, orange, or green. Saturation is a degree of color purity. Saturation defines the ratio of grey and the specific hue and is measured as a percentage from 0 percent (grey) to 100 percent (fully saturated).

Equalize

Menu: rImage > Equalize

Toolbar: Raster Image

Description: This operation is applied for precise adjustment of image brightness, hue, and contrast. The command enables you to redistribute both image pixels average brightness and brightness by separate color pixel components (Red, Green, and Blue). It enables you to correct image pixel color, for example, to turn a pink background to pure white.

This dialog box represents the image histogram, displaying the averaged number of pixels, corresponding to each brightness value. The left part of histogram corresponds to low brightness value, and the right one corresponds to high brightness value (the lightest tones). The sliders in the bottom part of histogram indicate threshold values: the left black one is for the darkest value, the grey middle one is for the middle value, and the right white one is for the brightest pixel. The Levels box provides the numerical expression of current threshold values. You can select one of the four histograms: Master displays summary pixel brightness distribution, Red, Green, and Blue display distribution of the corresponding pixels color components. Using the Master histogram slides, you can proportionally modify the threshold value for all components at once. The histogram sliders Red, Green, and Blue modify brightness threshold values separately for the corresponding color component.

The eyedroppers are used to select threshold values from the image

The operation can be applied several times, consistently modifying an image pixel brightness distribution.

AutoCorrect

Menu: rImage > AutoCorrect

Toolbar: Raster Image

Description: This operation processes an image, using a predefined set of standard operations.
The set of applied operations is specified in the AutoCorrect section of the WiseImage tab from the AutoCAD Options dialog box.

When auto-correction is performed, the specified operations are applied step-by-step in the order they are arranged in the AutoCorrect tab.
If any of the specified operations cannot be performed, it is ignored, and the next operation starts.

Deskew Auto
Deskew Manual

Menu: rImage > Deskew > Auto, rImage > Deskew > Manual

Toolbar: Deskew

Description: This operation enables you to correct an image skew resulting from scanning. The whole image is rotated about its central point in order to eliminate either horizontal or vertical skew. When deskewing, the new image size automatically expands to fit the deskewed image.

There are three ways to deskew an image. You can define a deskew line by specifying two points in the image. This line deviation from either horizontal or vertical axis determines the skew angle. You can also deskew image by typing a skew angle in the appropriate editing box. Also, you can apply the automatic procedure of skew angle calculation

Crop Auto
Crop Auto by Frame
Crop By Rectangle
Crop By Clip

Menu: rImage > Crop > Auto, rImage > Crop > By Frame, rImage > Crop > By Rectangle, rImage > Crop > By Clip

Toolbar: Crop

Description: Family of crop operations lets you reduce an image size to a specified rectangular image area size. You can define this area by specifying a rectangle on the image or by specifying a clipping boundary. You can also crop an image applying a procedure, which automatically finds image "empty" margins and crops them.

See also: Quick Start "Raster Editing"

Change Size

Menu: rImage > Change Size

Toolbar: Raster Image

Description: This operation is used to resize an image in order to adjust its size to specified values. It may be necessary after deskewing or image cropping, and also when you obtain an image of non-standard size after scanning. If the new image size is less that the original one, the image is cropped. If the new image size is more that the original one, margins are added to the image. All changes can be observed in the preview window.

Change Size dialog contains all necessary resizing options.

See also: Quick Start "Raster Editing"

Resample

Menu: rImage > Resample

Toolbar: Raster Image

Description: Resampling is used to resize an image by modifying its resolution or size in pixels.
An image can be resampled in the three following ways: by changing the image size in pixels, by changing the actual image size with fixing size in pixels, and by changing the actual image size without fixing size in pixels.

All three resampling methods are available in Resample dialog.

See also: Quick Start "Raster Editing"

Mirror by X axis
Mirror by Y axis

Menu: rImage > Mirror > By X axis, rImage > Mirror > By Y axis

Toolbar: Mirror

Description: You can mirror an image about either vertical or horizontal axis crossing the image center

See also: Quick Start "Raster Editing"

Rotate 90-ccw
Rotate 180
Rotate 90-cw
Rotate Custom Angle

Menu: rImage > Rotate > 90-ccw, rImage > Rotate > 180, rImage > Rotate > 90-cw, rImage > Rotate > Custom Angle

Toolbar: Rotate

Description: You can rotate an image about its central point using three fixed rotation angles (90, 180 and 270 degrees) or an arbitrary angle. When rotating by an arbitrary angle, the new image size automatically expands to fit the rotated image.

See also: Quick Start "Raster Editing"

4-point correction

Menu: rImage > 4-point correction

Toolbar: WiseImage

Description: Four-point correction is a simple way to eliminate trapezoid, parallelogram or projective distortions in images (technical drawings mainly). This procedure is based on the assumption that an image frame and its contents are distorted in the same way. This procedure can be used to correct image geometry if its frame has a shape of trapezium or parallelogram, rather than rectangular.

You can automatcally detect page frame, specify it by mouse clicks or use preset internal page frame values (set in Tools > Options > WiseImage > Papers > Modify dialog, in Internal Frame section).

See also: Quick Start "Calibration"

Binarization

Menu: rImage > Binarization

Toolbar: WiseImage

Description: Binarization creates monochrome raster images, containing black-and-white representation of color objects. For example, from one image of a scanned map you can extract and place to separate monochrome layers the objects of different color: isolines, roads, rivers, and other objects. Applying binarization, you create a new monochrome image of a specified color, which is placed on the specified layer. Using the specific criterion the program defines which pixels of the original (color or greyscale) image should become black (foreground pixels), and which ones should become white (background pixels), and then generates a monochrome image and places it on a new raster layer. The criterion for division of pixels into two sets is defined by the selected binarization method and its parameters (threshold values or a set of color range). The selection of pixels is controlled by the settings, specified in the Binarization dialog box.

Range by Grey converts pixels that have grey values within all specified ranges to foreground dots. Other pixels are converted to background dots.

With Range by RGB method you can convert color pixels of the specified RGB ranges to image dots.

Method Range by HSV allows you to convert pixels of analogous colors to image dots. Analogous colors are closely related colors in the human perception of color, e.g. red - orange, dark green - light green, etc.

Threshold by Grey converts color pixels with brightness values above the specified level to background dots, and pixels below this level to image dots.
This method may be used for converting both color and greyscale images. When converting a greyscale image, WiseImage uses its grey levels. When converting a color image, the grey levels are defined by the brightness value of color dot.

When using Threshold by RGB, you should define three threshold levels for the Red, Green, and Blue components. WiseImage converts color dots with Red, Green and Blue values below the appropriate threshold levels to black dots (image dots) of the monochrome image.

Color Reduction

Menu: rImage > Color Reduction

Toolbar: WiseImage

Description: Operation that excludes image dots that fall within specified color range, i.e. categories.

In Color Reduction dialog box you can create categories and preview operation results.

Color Separation

Menu: rImage > Color Separation

Toolbar: WiseImage

Description: Operation that separates color image dots in non-overlapping sets, i.e. categories. It is used to extract the colors the original image was created with. The objects of one sort are usually marked with the same color; therefore you are able to separate necessary image objects. Operation places the dots of each category in a separate monochrome image. The original color image is not changed.

In Color Separation dialog box you can create categories and preview operation results.

Separation by Size

Menu: rImage > Separation by Size

Toolbar: WiseImage

Description: This operation allows you to extract raster objects with a size within a specified range onto separate layer.



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Menu rImage Image operations and color processing

Menu rImage
Image operations and color processing