| | | The georeferencing can be performed in two ways: ► Global: from the calibration points defined the tool calculates some transformation parameters valid for the whole image. ► Local: the image is subdivided into zones and for each of them transformation parameters are calculated. By this system it is then possible to correct locally the deformations and the distortion the sheet has gone through, returning an image that adapts perfectly to the check points assigned. Check points can be inserted and modified directly on screen. For map georeferencing an automatic system for generating the reference grid is available, where the tool inserts check points; it is then sufficient to modify the grid lines and the tool will update the position of check points; thanks to this system the time needed for the definition of calibration points is drastically reduced. Rasta allows to georeferencing raster images in different ways: ► Barycentric; ► Six parameters affine transformation for map georeferencing (it needs at least three points); ► Nomographic: for photo rectification of flat surfaces (it needs at least four points). The georeferenced image can be saved on disk and used as a base to make or to update a new cartography or to be digitized with CAD functions. Image editing Rasta possesses many functions which allow to modify both the image geometric aspect (form, size) and its visual effect (color, contrast, brilliance, etc.). With Rasta it is possible to work on the image, to delete or copy internal parts both simply shaped (rectangle or ellipse) and of complex shape through the definition of a closed polyline. There are different functions for image elaboration, among which: color inversion, change of resolution, change in the number of colors, filter on average color, contour sharpening, etc. Mosaicing The georeferencing procedure can be repeated for all the images necessary to cover a given area. If the images are superimposed, it is possible to cut some parts in order to obtain a seamless image. If it is necessary to work with one image a procedure is available which joins together all the images to form one. Creation of presentation documents Rasta can be used to create presentation documents of great visual effect whenever it is necessary to furnish the drawings with photos, manuscripts, documents, which, therefore, will not be treated as enclosures. Rasta is equipped with desktop publishing-oriented functions. | | Filter on average color (average filter): Changes the color of each pixel in a bitmap to the average color of pixels in its neighborhood. This results in a blur effect; Filter on median color (median filter); Changes the color of each pixel in a bitmap to the median color of pixels in its neighborhood. This is similar to the filter on average color, but it is used for noise reduction, rather than a blur effect; Contour accentuation/attenuation (sharpen): Increases or decreases the sharpness of the image in the specified bitmap; Removes noise effect (despeckle): Removes speckles from a bitmap. Typically, this function is used to clean up scanned images (such as FAX images); Color depth (posterize): adjusts color depth by setting the number of bits per each channel; Color hue: Changes the hue of colors in a bitmap by rotating the color wheel; Color saturation: Increases or decreases the saturation of colors in a bitmap; Transformation of a color image into a half-tone image; Transformation of a color image into a grey-scale image; Change of image resolution with dithering algorithms; Sline detection with Laplace or line-segment methods; Edges detection with Gradient directional filter, with Sobel algorithm, Prewitt algorithm, Shift and Difference algorithm; Embossed effect. | | |
| | | Vectorization The images loaded on Rasta can be automatically vectorized, thanks to an algorithm developed by SierraSoft. The automatic vectorizator is parametric and can therefore be adapted to different image typologies (type and size). Managed formats TIFF, BMP, PCX, Photo CD (PCD), FlashPix (FPX)JPEG, JFIF, JTIF, WMF, PHOTO SHOP 3.0 (PSD), PNG, TARCA (TGA), EPS, SUN Raster format (RAS), Word Perfect (WPC), Macintosh Pict (PCT) and others. Rasta can export images loaded on a format different from the original and also the clipboard copy-paste is supported. Supported Scanners All scanners and digital cameras using Twain driver. Image editing ► Proportional resize; ► Width and height-unrelated sizing; ► Horizontal and vertical mirror; ► Rotation; ► Function for multiple junction of images (mosaicing); ► Crop function for rectangular, elliptical, generic surfaces through definition of a closed polyline; ► Selection, inside the image, of however shaped areas (rectangular, elliptical, or closed polyline) to be copied, deleted, or filled with a different color; ► Color inversion; ► Change of display-printing sequence; ► Imagine transparence; ► Change of color palette; ► Imagine rectification (deskew): Rotates the specified bitmap to straighten it. This function is intended for images, such as scanned documents, that are mainly horizontal lines of text. The results are less predictable with other types of images; ► Autotrim function: Trims the current bitmap, removing blank space around the edges; | | |