Images and Graphics in Multimedia

Published by Emil Abraham,


Painting and Drawing Tools
Painting and drawing tools, as well as 3-D modelers, are perhaps the most important items in the toolkit because, of all the multimedia elements, the graphical impact of the project will likely have the greatest influence on the end user. If the artwork is amateurish, or flat and uninteresting, both the creator and the users will be disappointed.
Painting software, such as Photoshop, Fireworks, and Painter, is dedicated to producing crafted bitmap images. Drawing softwares, such as CorelDraw, FreeHand, Illustrator, Designer, and Canvas, is dedicated to producing vector-based line art easily printed to paper at high resolution.
Some software applications combine drawing and painting capabilities, but many authoring systems can import only bitmapped images. Typically, bitmapped images provide the greatest choice and power to the artist for rendering fine detail and effects, and today bitmaps are used in multimedia more often than drawn objects.
Vector-drawn objects are described and drawn to the computer screen using a fraction of the memory space required to describe and store the same object in bitmap form. A vector is a line that is described by the location of its two endpoints.
Some vector- based packages such as Macromedia’s Flash are aimed at reducing file download times on the Web, and may contain both bitmaps and drawn art. The anti-aliased character shown in the bitmap of Color Plate 5 is an example of the fine touches that improve the look of an image.

Look for these features in a drawing or painting packages:
  • An intuitive graphical user interface with pull-down menus, status bars, palette control, and dialog boxes for quick, logical selection
  • Scalable dimensions, so you can resize, stretch, and distort both large and small bitmaps
  • Paint tools to create geometric shapes, from squares to circles and from curves to complex polygons
  • Ability to pour a color, pattern, or gradient into any area
  • Ability to paint with patterns and clip art
  • Customizable pen and brush shapes and sizes
  • Eyedropper tool that samples colors
  • Auto trace tool that turns bitmap shapes into vector-based outlines
  • Support for scalable text fonts and drop shadows
  • Multiple undo capabilities, to let you try again
  • Painting features such as smoothing coarse-edged objects into the background with anti-aliasing, airbrushing in variable sizes, shapes, densities, and patterns; washing colors in gradients; blending; and masking
  • Support for third-party special effect plug-ins
  • Object and layering capabilities that allow you to treat separate elements independently
  • Zooming, for magnified pixel editing
  • All common color depths: 1-, 4-, 8-, and 16-, 134-, or 313- bit color, and grayscale
  • Good color management and dithering capability among color depths using various color models such as RGB, HSB, and CMYK
  • Good palette management when in 8-bit mode
  • Good file importing and exporting capability for image formats such as PIC, GIF, TGA, TIF, WMF, JPG, PCX, EPS, PTN, and BMP

Image Editing Tools
Image-editing application is specialized and powerful tools for enhancing and retouching existing bitmapped images. These applications also provide many of the feature and tools of painting and drawing programs and can be used to create images from scratch as well as images digitized from scanners, video frame-grabbers, digital cameras, clip art files, or original artwork files created with a painting or drawing package.
Here are some features typical of image-editing applications and of interest to multimedia developers:
  • Multiple windows that provide views of more than one image at a time
  • Conversion of major image-data types and industry-standard file formats
  • Direct inputs of images from scanner and video sources
  • Employment of a virtual memory scheme that uses hard disk space as RAM for images that require large amounts of memory
  • Capable selection tools, such as rectangles, lassos, and magic wands, to select portions of a bitmap
  • Image and balance controls for brightness, contrast, and color balance
  • Good masking features
  • Multiple undo and restore features
  • Anti-aliasing capability, and sharpening and smoothing controls
  • Color-mapping controls for precise adjustment of color balance
  • Tools for retouching, blurring, sharpening, lightening, darkening, smudging, and tinting
  • Geometric transformation such as flip, skew, rotate, and distort, and perspective changes
  • Ability to resample and resize an image
  • Ability to create images from scratch, using line, rectangle, square, circle, ellipse, polygon, airbrush, paintbrush, pencil, and eraser tools, with customizable brush shapes and user-definable bucket and gradient fills
  • Multiple typefaces, styles, and sizes, and type manipulation and masking routines
  • Filters for special effects, such as crystallize, dry brush, emboss, facet, fresco, graphic pen, mosaic, pixelize, poster, ripple, smooth, splatter, stucco, twirl, watercolor, wave, and wind.

Image Manipulation
Manual Photo Manipulation
In the days of yore, before the advent of Photoshop, photographers painstakingly performed alterations manually using the following methods:
  • Airbrushing: An airbrush is a small, air-operated painting tool that sprays dyes and inks. In the pre-digital era, freehand airbrushing has been employed to alter photographs by concealing the signs that a photo has been "doctored" or retouched. During the dictatorship of Joseph Stalin, "undesirable" officials have been removed from photographs during the Great Purge using airbrushes.
  • Darkroom manipulation: Another non-digital method of altering photographs, darkroom manipulation involves dodging, burning, and masking – techniques that are said to be similar to digital manipulations with the exception that everything is done by hand.
  • Double exposure: A skilled photographer employs double exposure for artistic effect but it can occur accidentally, producing a blurry picture. Some non-digital cameras offer a "double exposure" option, but for those whose cameras don’t have this feature, they can simply use a filter, which can be used to cover part of the lens for the first shot, followed by covering another part of the lens for the second snapshot.
  • Negative scratching: This old school photo manipulation technique employs techniques such as soft focus, exotic printing processes, special filters and lens coating, and darkroom manipulation to convey "personal artistic expression."
Contemporary Photo Manipulation: Digital Techniques
Photo manipulation doesn’t just cover the techniques employed within a darkroom. It also refers to image editing done on a computer, more commonly known as photoshopping or photoshop. As you probably know, the term comes from the popular image editor created by Adobe Systems but there are other similar programs such as Corel Paint Shop Pro Photo, Microsoft Paint, Ulead PhotoImpact, and Macromedia Freehand.
These tools are often utilized by photographers and by graphic designers. With digital editing, you can apply different textures to uneven surfaces, remove color casts, transform regular pictures to cool 3D photos, and lots more. Below are some digital photo manipulation techniques that you can try to makeover a simple image from plain to amazing.
  • Doctoring: Nowadays, ad agencies and magazine editors authorize the use of photo manipulation software to hide a subject’s imperfections — or in some cases, highlight the subject’s flaws. Doctoring is quite useful for the before and after photos of weight loss ads but remains a controversial and often frowned-upon practice.
  • Age progression: To "age-progress" a person’s face means to make the subject look older than he or she actually is in a photograph. Age progression is used by law enforcement agencies to identify subjects and is now used for photo manipulation purposes. You can age-progress a subject using Photoshop.
  • Fading smoke effect: Smoke has been used to create abstract photography. Nowadays, Photoshop and Illustrator are used to create stunning fading smoke effects.
  • Colour combustion: Colour combustion is a photo manipulation technique that incorporates several simple photo manipulation techniques, combining a number of different images to produce a new and digitally-enhanced image. After providing a concept, you can begin collecting stock images for your digital collage. Add, adjust, alter, cut, draw, paint, and modify as you see fit. The image and colours are only limited by your imagination.
  • Photo cutouts: In some cases, you only want the subject and not his or her background. A photo cutout sounds like a simple solution but there are actually a number of different ways to do it. You can use the magnetic lasso or the good old magic wand tool for simple photo cutouts. However, no one tool fits all situations. You’ll need to combine several techniques before you can produce a seamless photo cutout.

Using charts and diagrams
Visual representations help us to understand data quickly. When you show an effective graph or chart, your report or presentation gains clarity and authority, whether you're comparing sales figures or highlighting a trend. The main functions of a chart are to display data and invite further exploration of a topic. Charts are used in situations where a simple table won't adequately demonstrate important relationships or patterns between data points.
Many word processing softwares (MS Word, Apple Pages, Libre Office), spreadsheet softwares (MS Excel, Numbers) as well as a myriad of online services (Google Docs, Google Sheets, Adobe Spark, Canva, Lucidchart, Venngage) allow you to create charts and diagrams.
  • Line Graphs: One of the graphs you will likely use most often is a line graph. Line graphs simply use a line to connect the data points that you plot. They are most useful for showing trends and for identifying whether two variables relate to (or "correlate with") one another. Examples of trend data include how sales figures vary from month to month, and how engine performance changes as the engine temperature rises.
  • Bar Graphs: Another type of graph that shows relationships between different data sets is the bar graph. In a bar graph, the height of the bar represents the measured value: the higher or longer the bar, the greater the value.
  • Pie Charts: A pie chart compares parts to a whole. As such, it shows a percentage distribution. The pie represents the total data set, and each segment of the pie is a particular category within the whole. To use a pie chart, the data you are measuring must depict a ratio or percentage relationship. Each segment must be calculated using the same unit of measurement, or the numbers will be meaningless.
  • Venn Diagrams: Venn diagrams show the overlaps between sets of data. Each set is represented by a circle. The degree of overlap between the sets is depicted by the amount of overlap between the circles. A Venn diagram is a good choice when you want to convey either the common factors or the differences between distinct groups.


OCR Software
Often there will be multimedia content and other text to incorporate into a multimedia project, but no electronic text file. With optical character recognition (OCR) software, a flat-bed scanner, and a computer, it is possible to save many hours of rekeying printed words, and get the job done faster and more accurately than a roomful of typists.
OCR software turns bitmapped characters into electronically recognizable ASCII text. A scanner is typically used to create the bitmap. Then the software breaks the bitmap into chunks according to whether it contains text or graphics, by examining the texture and density of areas of the bitmap and by detecting edges. The text areas of the image are then converted to ASCII character using probability and expert system algorithms.

Text Editing and Word Processing Tools
A word processor is usually the first software tool computer users rely upon for creating text. The word processor is often bundled with an office suite.
Word processors such as Microsoft Word and WordPerfect are powerful applications that include spellcheckers, table formatters, thesauruses and prebuilt templates for letters, resumes, purchase orders and other common documents.

Animation Tools
Animation and digital movies are sequences of bitmapped graphic scenes (frames, rapidly played back. Most authoring tools adapt either a frame or object oriented approach to animation. For creating animations Macromedia Flash or Adobe Flash are the industry standard. A file created in Flash is called a movie. A movie in Flash occupies very less file size, and hence is more popular for the Web. You can also create presentations and 2D Animations using Flash.

Stop motion is an animated filmmaking technique in which objects are physically manipulated in small increments between individually photographed frames so that they will appear to exhibit independent motion or change when the series of frames is played back.
Video Formats
A video format describes how one device sends video pictures to another device, such as the way that a DVD player sends pictures to a television or a computer to a monitor. More formally, the video format describes the sequence and structure of frames that create the moving video image.
Video formats are commonly known in the domain of commercial broadcast and consumer devices; most notably to date, these are the analog video formats of NTSC, PAL, and SECAM. However, video formats also describe the digital equivalents of the commercial formats.

QuickTime
QuickTime is a multimedia framework developed by Apple Inc. capable of handling various formats of digital video, media clips, sound, text, animation, music, and several types of interactive panoramic images.

Multimedia framework
A multimedia framework is a software framework that handles media on a computer and through a network. A good multimedia framework offers an intuitive API and a modular architecture to easily add support for new audio, video and container formats and transmission protocols.
A framework supports certain file types and codecs natively.

API
An application programming interface is an interface or communication protocol between different parts of a computer program intended to simplify the implementation and maintenance of software. An API may be for a web-based system, operating system, database system, computer hardware, or software library.
  • Encoding and transcoding video and audio from one format to another.
  • Decoding video and audio, and then sending the decoded stream to the graphics or audio subsystem for playback. In Mac OS X, QuickTime sends video playback to the Quartz Extreme (OpenGL) Compositor.
  • A plug-in architecture for supporting additional codecs (such as DivX).

Video Compression
Compression basically means reducing image data. A digitized analog video sequence can comprise of up to 165 Mbps of data. To reduce the media overheads for distributing these sequences, the following techniques are commonly employed to achieve desirable reductions in image data:
> Reduce color nuances within the image
> Reduce the color resolution with respect to the prevailing light intensity
> Remove small, invisible parts, of the picture
> Compare adjacent images and remove details that are unchnagedbetween two images
The first three are image based compression techniques, where only one frame is evaluated and compressed at a time. The last one is or video compression technique where different adjacent frames are compared as a way to further reduced the image data. All of these techniques are based on an accurate understanding of how the human brain and eyes work together to form a complex visual system.
As a result of these subtle reductions, a significant reduction in the resultant file size for the image sequences is achievable with little or no adverse effect in their visual quality. The extent, to which these image modifications are humanly visible, is typically dependent upon the degree to which the chosen compression technique is used. Often 50% to 90% compression can be achieved with no visible difference, and in some scenarios even beyond 95%.

Codec vs. Format
A codec is a compression standard. Raw video or audio is compressed when encoding, and decompressed (decoded) on playback. MP3 is an audio codec – a compression standard that MP3 players know how to decode, and MP3 encoders know how to encode. There are hundreds of codecs out there; some of the more important ones are H.264, HEVC, MPEG-2, Theora, VP8, VP9, JPEG2000, DivX, XviD, and the WMV family (video) and MP3, AAC, Vorbis, and the WMA family (audio).
A format is a file container that holds one or more codecs – video, audio, or even data. The container format contains information about the video, audio, and data tracks that it holds. Some example container formats are mov (Quicktime), mp4, ogg, and avi.

Lossless compression
There are two basic categories of compression; lossless and lossy. Lossless compression is a class of algorithms that will allow for the exact original data to be reconstructed from the compressed data. That means that a limited amount of techniques are made available for the data reduction, and the result is limited reduction of data. GIF is an example of lossless images compression, but is because of its limited abilities not relevant in video surveillance.
Lossy compression
Lossy compression on the contrary means that through the compression data is reduced to an extent where the original information can not be obtained when the video is decompressed. The difference is called the artifacts.

Codec


Lossless codecs. These codecs (H.264, Lagarith, Huffyuv) reproduce a video as-is, without any quality loss. Videos encoded with lossless codec usually have great quality but take a lot of hard drive space.

Lossy codecs. Although lossycodecs (Xvid, DivX, VP3, MPEG4) lose some amount of video information, videos with such codecs occupy less space than lossless ones. Lossycodecs can be transformative, predictive, or a combination of both types. The 1st type cuts up the original file and quantizes it into a more efficient space. The 2nd ones get rid of all unnecessary data and also save space.