An A/D converter is a device used to convert an analog charge into digital form. The principle feature of something in analog format is that it is continuous. Bit depth refers to the number of bits of color or grayscale information that can be recorded per pixel. A CCD, or charge-coupled device, is a solid-state, light-sensitive chip receptor that converts light into an analog charge. Digital format refers to data stored with measured values and distinct points or positions. A drum scanner is a type of scanner that scans images mounted on a rotating drum. Dynamic range refers to the gradations from light to dark that a digital imaging device can read or produce. A film scanner is a specially designed CCD scanner that captures images from various types of film. A handheld scanner is a small scanner that is moved across a page or image by hand. A histogram is a graphic display of highlight, midtone, and shadow values that correspond to the number of pixels affected in each part of the tonal scale. Interpolation is a mathematical technique used to increase the apparent resolution of an image. Layers are a feature of image editing programs that create multiple, editable levels of a single piece of artwork. A mask is a feature of image editing programs that protects a specified area of an image from changes, filters, and other effects applied to the rest of the image. Mottling refers to the blotchy or cloudy appearance of an image, instead of a smooth, continuous tone. Newton’s rings are an undesirable color pattern that results from interference between the exposure light and its reflected beam from the closest adjacent surface. Optical character recognition is a system used to translate the bitmap image of scanned text into ASCII characters. Paint effects are a feature of image manipulation programs that contain several tools that allow the user to create and color images. Quantizing is a filtering process that determines the amount and selection of data to eliminate, which makes it possible to encode data with fewer bits. Resolution refers to the sharpness and clarity of an image. Retouching tools are tools used in image manipulation programs to modify images in ways similar to methods used in darkroom photography. The scan area is the section of a scanning device on which images are placed for scanning. A scanner measures the color densities of an original, stores the measurements as digital information, manipulates or alters the data, and uses the data to create four color separations. Screen ruling refers to the number of ruled grid lines per inch (lpi) on a halftone screen. Spatial resolution refers to the ability of a digital imaging device to address data in horizontal and vertical dimensions. The sweet spot is a 3 or 4″ area in the center of a flatbed scanner at which the scanner scans material at full resolution. Tonal resolution refers to the number of bits of color or grayscale information that can be recorded per pixel. Unsharp masking is a feature of some scanners that increases tonal contrast where light and dark tones come together at the edges of the images. Well sites refer to hundreds or thousands of photosensitive elements on a CCD. XY scanning technology is scanning technology that optimally positions the scanning head along the XY axis.
REVIEW QUESTIONS:
- What is the difference between analog and digital format?
- What is a CCD?
- What is a histogram?
- What is the sweet spot?
- What is the difference between tonal and spatial resolution?
Answer:
- Analog format is continuous, while digital format consists of values measured at distinct points.
- A CCD is a solid-state, light-sensitive chip receptor that converts light into an analog charge.
- A histogram is a graphic display of highlight, midtone, and shadow values that correspond to the number of pixels affected in each part of the tonal scale.
- The sweet spot is a 3″ or 4″ area in the center of a flatbed scanner at which the scanner scans material at full resolution.
- Tonal resolution refers to the number of bits of color or grayscale information that can be recorded per pixel, while spatial resolution refers to the ability of a digital imaging device to address data in horizontal and vertical dimensions.
A histogram provides a display of the pixel information. Typical storage devices used for images captured by common point and shoot cameras include the lens, viewfinder, LCD, batteries, flash, image stabilization, exposure modes, image capture time, and lighting conditions. Layers allow the user to create multiple levels of artwork that reside on separate, overlapping layers in the same document.
Filters are used to apply special effects, such as patterns and textures, to bitmap images. A mask is the image manipulation tool used to protect an area of an image from changes and effects applied to the rest of the image.
