A
Aspect Ratio
There are two kinds of aspect ratio that you need to be aware of when working with 2D images; the image aspect ratio and the pixel aspect ratio.The image aspect ratio is the ratio of the width of the image to the height of the image. It's important when resizing an image to keep this ratio as close to unchanged as possible or the image may become distorted.The pixel aspect ratio is the shape of the pixels in the image. For computers this is normally square (1:1) or close to it depending on the monitor settings. For some video sources, however, the pixels may be slightly rectangular.
B
Black on Edge
The minimum or maximum number of pixels on the vertical or horizontal edge of an image or document.BMP
The Microsoft Windows Bitmap file format is based on the Microsoft Windows internal bitmap data structures. The BMP format is very widely used and it is quick and easy to read. Although most BMP files are uncompressed, a type of run length encoding is supported.Brightness
A ThumbnailXpress method that enhances the brightness attributes of the pixels in the bitmap. Positive settings produce brighter pixels while negative settings produce darker pixels.
C
CCITT
CCITT is the most widely used compression scheme for transmitting binary (black and white) image data. CCITT was established by the International Telegraph and Telephone Consultative Committee. The Group 3 and Group 4 CCITT compression standards are widely used for transmitting fax data. CCITT compressed images are typically stored in the TIFF image format.Container
Gets the container for the component. An object implementing the IContainer interface that represents the component's container, or a null reference (Nothing in Visual Basic) if the component does not have a site.Contrast
A ThumbnailXpress method that enhances the contrast attributes of the pixels in the bitmap. Positive settings produce a higher contrast image while negative settings produce a lower contrast image. Images with a higher contrast have a higher frequency of pixel intensities near the ends of the intensity spectrum while images with a lower contrast have a higher frequency of pixels near the middle of the intensity spectrum.CreateObjRef
Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.
D
DCOM
Microsoft's extension of their Component Object Model (COM) to support objects distributed across a network. DCOM is currently implemented only by Microsoft for Microsoft Windows; and by Software AG, under the name "EntireX", for Unix and IBM mainframes. DCOM serves the same purpose as IBM's DSOM protocol. DCOM is an object model, but has no provisions for inheritance.DCX
An image format containing multiple PCX images. A DCX file can contain a maximum of 1024 images.DDB
Microsoft Device Dependent Bitmap. The actual in-memory information used to display an image.DEP
Data Execution Prevention (computer security).Despeckle
A modified median filter primarily used for reducing noise in document images. Despeckling divides the image into pixel groups and uses the brightness value to adjust brightness spikes. This filter will reduce noise in a black and white document image with minimal distortion of document text.DIB
Microsoft Device Independent Bitmap. An alternative file extension used by the Microsoft Windows Bitmap.DICOM
Digital Imaging and Communication, a standard for handling digital medical images.Dispose
Releases the resources used by the Component.Disposed
Adds an event handler to listen to the Disposed event on the component. When you create a Disposed delegate, you identify the method that handles the event.Dithering
A technique used in computer graphics to create the illusion of varying shades of gray on a monochrome display or printer, or additional colors on a color display or printer. Dithering relies on treating areas of an image as groups of dots that are colored in different patterns. Akin to the print images called halftones, dithering takes advantage of the eye’s tendency to blur spots of different colors by averaging their effects and merging them into a single perceived shade or color. Depending on the ratio of black dots to white dots within a given area, the overall effect is of a particular shade of gray. Dithering is used to add realism to computer graphics and to soften jagged edges in curves and diagonal lines at low resolutions.
E
Emboss
A ThumbnailXpress method that causes the foreground of an image to appear raised from background. Embossing gives the image a raised metallic-like lookePIC
Accusoft enhanced PIC image format. This high performance image compression combines the patented ELS arithmetic coder with the high performance Accusoft JPEG libraries. The result is a new and unbeatable compression technology. The ePIC compression has significant advantages over standard JPEG. Most importantly it produces smaller file sizes and decompresses extremely quickly. ePIC images can be password encrypted. These images can also be 'zoomed' or scaled to larger, arbitrary sizes.Equalize
A ThumbnailXpress method that is a point process used for adjusting the contrast of an image. A frequency histogram of the colors of the image is computed and adjusted to equalize the colors across the full spectrum of intensity values. The equalized colors are applied to each pixel in the image.EXIF
EXchangeable Image File format (Japan Electronic Industry Development Association, JEIDA), compressed image format used in digital cameras.
F
Flate
The lossless deflate compression algorithm is based on two other compression algorithms: huffman encoding and LZ77 compression.Float
Denotes a simple type that stores 32-bit floating-point values.
G
Gamma
A non-linear brightness transform. Gamma values greater than 0 and less that 1.0 generate exponential curves that dim and image. Gamma values greater than 1.0 generate exponential curves that brighten an image.GDI
Acronym for Graphical Device Interface. In Windows, a graphics display system used by applications to display or print bitmapped text (TrueType fonts), images, and other graphical elements. The GDI is responsible for drawing dialog boxes, buttons, and other elements in a consistent style on screen by calling the appropriate screen drivers and passing them the information on the item to be drawn. The GDI also works with GDI printers, which have limited ability to prepare a page for printing. Instead, the GDI handles that task by calling the appropriate printer drivers and moving the image or document directly to the printer, rather than reformatting the image or document in PostScript or another printer language.GetLifetimeService
Retrieves the current lifetime service object that controls the lifetime policy for this instance.GIF
Graphical Interchange File, originally developed by CompuServe as a machine independent format. GIF is one of the most popular image formats for storing 8-bit digitized images. GIF files are typically smaller than uncompressed formats like BMP due to the LZW compression algorithm that GIF uses.Grey-scale
If the pixels of a grey-scale image have N bits, they may take values from zero, representing black up to 2^N-1, representing white with intermediate values representing increasingly light shades of grey. If N=1, the image is not called grey-scale, but could be called monochrome.
H
Halftone
Pertaining to pictures in which gradation of tone in the photograph is reproduced by a graduated system of dotted and checkered spots, usually nearly invisible to the unaided eye, produced by the interposition between the camera and the object of a screen. The name alludes to the fact that this process was the first that was practically successful in reproducing the half tones of the photograph.Hue
One of the 3 components of the HSL (Hue, Saturation and Luminance ) color space. The hue component controls the overall color space of an image. Adjusting the hue of the image adjusts the color spectrum from red through yellow, green, blue, and violet.
I
ICO
Microsoft Windows Icon file format.Inverse
To reverse something or change it to its opposite. For example, to invert the colors on a monochrome display means to change light to dark and dark to light. In a digital electrical signal, to replace a high level by a low level and vice versa. This type of operation is the electronic equivalent of a Boolean NOT operation.IOD
Information Object Definition.IPTC
The International Press Telecommunications Council, not the International Petroleum Technology Conference.
J
JIF
An alternative image file extension used for a JFIF compliant JPEG file. Because many early versions of JPEG contained a JPG extension but did not adhere to the JFIF specifications, the JIF extension was created to identify JPEG files that are JFIF compliant. As the popularity of JPEG grew, JFIF compliance became synonymous with the JPG extension and thus the JIF extension is rarely used.JPEG
The JPEG (Joint Photographic Experts Group) standard is one of the most important image data compression standards. It is widely used in many industries including graphic arts, desktop publishing, medical imaging, and many more. It is also becoming one of the most widely used image formats on the Internet. Although JPEG supports a lossless mode, it most commonly uses lossy compression. This allows JPEG to achieve very high compression ratios. JPEG compression uses several compression modes. First, an image is transformed to the frequency domain using the discrete cosine transform. The smaller valued frequency components are discarded leaving only the larger valued components. The remaining components are DPCM coded and then Huffman coded. Fortunately, ImagXpress™ handles all of this for you! The compression level is adjustable. Higher quality settings produce a larger image file size with higher image quality. Lower quality settings produce a smaller image file size with lower image quality. Typically, we have found that compression ratios of 10:1 or 15:1 (A 640x480x24-bit image is 921,600 bytes; a 15:1 compressed image would compress to only 61k) produce generally acceptable image quality for photographic type images. Images compressed at higher ratios begin to show more noticeable and sometimes objectionable artifacts and clarity loss. JPEG is a 24-bit format and works only with 24-bit images. If you compress an 8-bit image, ImagXpress™ automatically converts it to 24-bit to do the compression, however, you will obtain better quality when the source image is 24-bit because 8-bit images only contain 256 colors. JPEG works best with photographic type images. It does not work well with solid colors, 16-color images, cartoon like images, or drawings. Progressive JPEG is a multiple-scan sequential JPEG format that is becoming popular on the Internet for the ability to display images in progressively clearer segments.
L
Little-endian
Describes a computer architecture in which, within a given 16- or 32-bit word, bytes at lower addresses have lower significance (the word is stored "little-end-first"). The PDP-11/VAX families of computers, Intel microprocessors, plus a lot of communications and networking hardware are little-endian. The term is sometimes used to describe the ordering of units other than bytes; most often, bits within a byte.Lock
A lock, represented by the Visual Basic keyword "SyncLock Statement," or the C# keyword "lock Statement", allows a single thread of execution to obtain exclusive execution rights on an object. Although using locks will guarantee that multiple threads do not simultaneously access an object, they can cause significant performance degradation.Luminance
One of the 3 components of the HSL (Hue, Saturation and Luminance) color space. Luminance controls the overall brightness of an image.
M
Matrix
A matrix filter, also called convolution, alters each pixel's color based on its current color and the colors of any neighboring pixels. The ImagXpress™ Matrix method uses a 3x3 matrix. The numbers in the matrix are coefficients. When a pixel is processed, its color value is multiplied by the coefficient in the center of the matrix, and any pixels within the 3x3 grid are multiplied by the corresponding coefficients in the matrix. The sum of the products becomes the target pixel's new value. The Divisor is simply the coefficient denominator. The matrix method is typically used for sharpening, softening, and edge enhancement.Mosaic
A mosaic divides the bitmap into tiles of a specified size. All of the pixels in each tile are averaged and changed to the average color.Multithreading
Multithreading, or free threading, refers to the ability of a program to execute multiple threads of operation simultaneously. An example of a multithreaded application might be a program that receives user input on one thread, performs a variety of complex calculations on a second thread, and updates a database on a third thread. In a single-threaded application, a user might spend idle time waiting for the calculations or database updates to finish. In a multithreaded application, these processes can proceed in the background so user time is not wasted. Multithreading can be a powerful tool to use in component programming. By writing multithreaded components, you can create components that perform complex calculations in the background while leaving the user interface free to respond to user input. Although multithreading can be a powerful tool, it can also be difficult to apply correctly. Improperly implemented multithreaded code can degrade application performance, or even cause frozen applications. (See MSDN).
N
Negate
An ImagXpress™ method that creates a color negative of an image.Noise
An ImagXpress™ method that adds random pixels to the bitmap.
O
Orthogonal
Used loosely to mean mutually independent or well separated. It describes sets of primitives or capabilities that, like linearly independent vectors in geometry, span the entire "capability space" and are in some sense non-overlapping or mutually independent. For example, in logic, the set of operators "not" and "or" is described as orthogonal, but the set "and", "or", and "not" is not (because any one of these can be expressed in terms of the others).
P
PBM
Portable bitmap image format, a very simple uncompressed 1-bit (black and white) image format.PGM
Portable Graymap image format. PGM is a very simple uncompressed 8-bit grayscale image format.PNG
Portable Network Graphics (pronounced "ping") provides a portable, legally unencumbered (royalty-free), well-compressed, well-specified standard for lossless bitmapped image files. The initial motivation for developing PNG was to provide a royalty-free alternative to GIF. The design retains many of the features of GIF that make it an attractive format for transmission of images, such as lossless compression and progressive display capabilities. Additionally, it provides several advantages including 24-bit image support and generally better compression, although decompression is typically somewhat slower than GIF.PPM
Portable Pixmap image format, a very simple uncompressed 24-bit image format.
R
RGB
Red Green Blue. Bitmapped images are most generally stored as RGB data. Each pixel or data point in a true color (24-bit) image contains 3 components, red, green and blue, that describe the color of the pixel. Each of the components can have a value between 0 and 255, 0 being the darkest shade of color and 255 being the lightest shade of color. Since each component can be stored in one byte (8-bits), the 3 components take up 3 bytes or 24-bits per pixel. 8-bit images contain one byte (8-bit) indexes for each pixel that map to a color table called a palette which contains a maximum of 256 RGB entries. Likewise, 4-bit images contain 4-bit indexes for each pixel that map to a palette which contains a maximum of 16 RGB entries. 1-bit images contain 1-bit per pixel. Each bit in a 1-bit image represents either black or white.RLE
Run Length Encoding. It is a lossless algorithm that only offers decent compression ratios in specific types of data.
S
Saturation
One of the 3 components of the HSL (Hue, Saturation, and Luminance) color space. Saturation controls the purity of a color. Higher saturations result in richer, deeper colors. Lower saturations result in paler colors.Scalar
In programming, any data type that stores a single value (a number or Boolean), as opposed to an aggregate data type that has many elements. A string is regarded as a scalar in some languages (PERL) and a vector of characters in others (C).Sharpen
An ImagXpress™ method that is used to sharpen an image. The sharpen filter uses a high-pass convolution matrix filter to accentuate high frequency detail in the image.Single
Value type represents a single-precision 32-bit number with values ranging from negative 3.402823e38 to positive 3.402823e38, as well as positive or negative zero, PositiveInfinity, NegativeInfinity, and not a number (NaN).Soften
An ImagXpress™ method that is used to soften an image. The soften filter uses a low-pass convolution matrix filter to accentuate low frequency detail in the image.
T
TGA
Targa Image File) format was developed by TrueVision for its Targa line of products. TGA is one of the earliest image formats and was the first popular format to support 24-bit color. TGA supports uncompressed and RLE compressed formats.Thread-safe
An application using this component can use multiple controls running in the same process, where they don't interfere with each other. The thread creating the control owns the control and is the only thread that can interact with it.TIFF
Tag Image File Format, originally released by Aldus Corporation is a standard file format found in most paint, imaging, and desktop publishing programs. TIFF is extremely powerful, flexible, and extensible. However, because of its many nuances and its wide scope, TIFF can be a difficult format to understand as well as a difficult format to support. ImagXpress™ supports a wide range of TIFF 6.0 formats including uncompressed, CCITT RLE, CCITT Group 3 Fax, CCITT Group 4 Fax, LZW, Pack Bits, JPEG, and deflate compression types. ImagXpress™ supports black and white, RGB, and RGB palette images but it does not support transparency mask, CMYK, YCbCr, or CIELab.twip
Twips describe the sizes of characters produced by dot matrix printers, which were constrained to multiples of either 12 or 10 dots per inch.
V
Void structure
Indicates a method that does not return a value; that is, the method has the void return type.
W
Wintel
A term describing the combination of Microsoft Windows operating system running on PCs with Intel or compatible processors. Dominance of the wintel platform began with MS-DOS on PCs with Intel's 8-bit 8088 processors in 1979.WMF
The Microsoft Windows Metafile format is used to store vector and bitmap image data. Because of its popularity and wide use, many Windows and non-Windows applications support WMF.WSQ
Wavelet Scalar Quantization (WSQ) Gray-Scale Fingerprint Image Compression Specification based on the results of the NIST (National Institute of Standards and Technology) review. The benefit of WSQ fingerprint-specific compression is reduced file size. A sample fingerprint with a resolution of 589 pixels by 605 pixels, 8-bit grayscale results in a file size of 325 KB when compressed with the standard lossless compression technology LZW.