Sony XCST70 Product Brochure (Glossary of Camera Technology) - Page 3

Glossary One-push WB (One-push White Balance): Fixed white balance mode that can be automatically readjusted as required by the user (One-push WB Trigger), assuming that a white object, in suitable lighting conditions and occupying more than half of the image area, is seen by the camera. PAL (Phase Alternation, Line): Color video standard pioneered in Europe but also used in many other parts of the world. PAL uses 625 scanning lines per picture, 25 pictures (frames) per second, each frame is made up of two sequential fields containing respectively the odd and the even lines (interlace). Partial Enhance: An advanced function of the Digital Signal Processing (DSP) technology that allows a particular color to be selected and its hue, saturation and detail altered. This function gives the subject a pleasing complexion with a softer image while maintaining the sharpness of other areas, and vice versa. The designated active area of partial enhance can be set with the digital circuits by simply adjusting the Area Detect Cursor. Pixel: Picture element. PowerHAD: PowerHAD is further improvement of the Hyper HAD CCD technology, where the microscopic lenses focus more light onto the light sensors thus increased sensitivity and reduced smear. Progressive Scan: CCD design that allows the acquisition of both odd and even fields at the same time. Progressive scan makes full vertical resolution possible in Donpisha mode. RGB (Red, Green, Blue): The primary colors of light that produce a color video image. In video, RGB refers to a system in which these three primary colors are kept isolated and delivered from the source to the display device over separate wires. This system results in high-quality pictures. RGB signals are used in some broadcast video equipment and computers. Restart / Reset: Special mode in which the CCD readout cycle is stopped and restarted in synchronization with an external event. In the Stop mode, the CCD still accumulates picture information. RS-232C: Serial data transmission standard for computers which can also be used to control camera functions. Scalable scanning: Capability of a camera to output a picture corresponding to an user defined sub-zone of the sensor. Applied in IEEE 1394 digital cameras featuring the Format_7 output option (XCD-X700, XCD-SX900). Screen Mode: Partial see-through mode on HMD allowing the user to view the surrounding environment by adjusting the transparency of the screen in the area only around the picture. SDK: Software Development Kit. S-Donpisha: Asynchronous shutter mode used with external HD/VD sync. CCD starts to accumulate electrons when the external trigger pulse is received and stops when the VD pulse is received. Therefore the accumulation time (shutter speed) is decided by the length of time between the trigger pulse and VD input. Sensitivity: Lens iris aperture required to provide a video output signal of standard level at a specified light input. In general, sensitivity is measured using an 89.9% reflectance grey scale chart illuminated by a 3200∞ K illuminance at 2000 lux (color camera) or 400 lux (B/W camera), for a video output level of 100%. S/N (Signal to Noise Ratio): The ratio, usually expressed in dB (decibels), between the normal signal output and the noise level within an electronic signal. Smear: Undesirable artifact of CCDs that appears in the picture as a vertical streak above and below a very bright object in the scene. Smear is caused by parasitic light getting into the vertical transfer registers. It is greatly reduced by the microlens-type of CCD used in Hyper HAD and Power HAD sensors. Almost suppressed in FIT CCDs. Slow shutter: Shutter mode with an integration time longer than 1/50 s (PAL) or 1/60 s (NTSC). Like long-term integration, the slow shutter function increases camera sensitivity when shooting slow-moving or fixed subjects. Unlike long-term integration, continuous normal video is output in slow shutter mode by use of a built-in video memory. The output picture is compatible with normal monitors and recorders. Square pixel: Used to qualify a CCD sensor where the centers of the pixels are equally spaced horizontally and vertically. Pictures captured from this type of non-square pixel sensor need to be software corrected in order to achieve the correct picture geometry. Strobe Synchronization : This function is designed to capture fast moving, full frame images by firing a strobe light in a dark lighting condition. The camera synchronizes the timing of the external trigger and can output a full frame image. Using an external frame memory synchronized with the input of external trigger signal, the Write Enable (WEN) pulse is output. The use of the WEN pulse allows for easy capture of full frame still images. This function requires a frame grabber board. Sync (Synchronization): When synchronized, the horizontal and vertical timing of a camera output are locked to an external signal coming, for example, from another camera. Picture outputs from both sources are then precisely synchronized and can be mixed. When mixing color signals, the subcarriers of the two signals also have to be in synchronism. Subcarrier: The 4.43 MHz (PAL) or 3.59 MHz (NTSC) signal that is used as a carrier for the color information. This subcarrier is modulated in amplitude by the color saturation and in phase by the color hue. A sample of the unmodulated subcarrier is placed before the start of each horizontal line, and is called the Color Burst. U and V: The names given to the two video color difference signals (R-Y and B-Y) in their coded form in the PAL or NTSC color systems. See also Y/R-Y/B-Y. Ultra mount: Type of camera mount in which there is 6.7 mm clearance between the lens rear mounting surface and the camera's CCD. VBS (Video + Burst + Sync): The composite video signal, including color information. VD (Vertical Drive): Signal used to synchronize the field rate of a camera to an external source. Mostly used in B/W together with HD (Horizontal Drive). Vertical Resolution: Number of equally spaced horizontal black-to-white or white-to-black transitions that a camera is able to reproduce. Indicates the amount of vertical details that can be perceived. Vertical resolution is limited by the number of scanning lines that are fixed by the TV standard. VISCA' (Video System Control Architecture): RS-232C serial control protocol intended to interface up to seven items of video equipment on one computer link. V-Lock Sync: see Genlock. VS (Video + Sync): The composite monochrome video signal commonly used as the genlock signal in B/W systems. WB (White Balance): In a color camera, white balance is the process of adjusting the values of its color differences signals so that a white object in a scene illuminated by a particular source of illumination is displayed as a white or grey (i.e. no chrominance). The normal color reference illuminant has a color temperature of 3200 K, equivalent to a halogen lamp. The human eye is a subjective device, constantly readjusting its color balance according to the lighting context (our eye knows what must be seen as white). Unlike the human eye, a camera is an absolute measurement device, and its color balance has to be adjusted to suit the color temperature of the light illuminating the scene, for example sunlight is different from 3200 K. Several adjustment modes are available, fixed values (pre-adjusted), One-push, automatic tracking. See also One-push WB and ATW. Y/C (also called S-Video): Separate signals for the Luminance and Chrominance parts of the video signal. Allows higher picture resolution and suppresses cross color effects. Connector is the 4-pin mini-DIN. Y/R-Y/B-Y: Three signals, luminance (Y) and two color difference signals R-Y (red minus luminance) and B-Y (blue minus luminance) which together carry the brightness and color information of color images . Color difference signals have no light intensity information, and cannot be displayed separately from Y. Compared to RGB signals, they can travel over longer cables lengths without significant resolution loss, and allows different spatial resolutions for luminance and color. Typically used for high-end visual applications. Also known as component signals. See also U and V signals. Zoom Triggered AF: The camera is normally in fixed focus mode, but AF (Auto Focus) is temporarily switched on each time the zoom ratio of the camera lens is changed.