Video test pattern generators provide a convenient and effective way to calibrate, test and troubleshoot video display devices such as HDTVs, projectors, LCD (liquid crystal display) screens and CRT (cathode ray tube) monitors for the ideal viewing experience.
Specific patterns are produced by the video test pattern generators to determine a variety of performance criteria, including: video resolutions, brightness and uniformity, purity and color saturation, linearity, edge geometry, sharpness, stability, etc. By comparing the video input pattern to the video output on a display unit, it is possible to determine how accurately a monitor displays the video it receives and if any defects can be rectified. Some video test pattern generators also allow a user to test digital and/or analog audio signals through generated frequency waves. Using the corresponding video cable needed, simply connect the video test pattern generator to the supported display unit to run the test patterns on the screen. No other video source, such as a computer, DVD player or set-top box is needed for the testing process. If multiple display units are to be compared, the use of a video splitter can ensure that the same pattern is displayed on all desired monitors and subsequently calibrated so that the video output is identical on all screens.
Three of the most common video test patterns are: color bars, grayscale charts and crosshatch, with each serving a distinct function. Several variations of the color bar test pattern exist, with the most well-known being the SMPTE color bar, which are used to test analog NTSC video. All color bar test patterns serve the same purpose of testing and calibrating color saturation, balance and brightness. Most grayscale charts consist of a gradient of monotone bars with the goal being to obtain a smooth range of neutral grays from pure black to white. Adjustments can be made to brightness and contrast to achieve the optimal display. Crosshatch patterns are used to check and calibrate centering, aspect ratio, convergence, and both vertical and horizontal linearity. Other test patterns can range from focusing on one or two specific issues to universal patterns that cover most key aspects.
Most video test pattern generators are compact, portable devices that allow easy field calibration, testing and maintenance of many applications such as: production line quality assessment; studio equipment for both installers and users; television sets by TV engineers or technicians; digital signage configurations with extenders, switches, splitters or video wall processors; and discerning home theater users. High-end models tend to support multiple video signal types while lower-end models offer a more limited and specific selection. Video Products Inc (VPI) offers a wide selection of video test pattern generators that can fulfill the needs of varying applications.
VPI’s MONTEST-HDMI and MONTEST-HDMI-LC respectively provide a high-quality and low-cost option for testing HDMI or DVI display units. The low-cost unit can generate 34 video test patterns, 48 timings and a single audio tone. In comparison, the MONTEST-HDMI provides 39 distinct test patterns, 35 resolution and timing settings, and a range of analog and digital audio signals via a built-in sine wave tone generator. It can also be controlled via the IR remote control or RS232 in addition to its front panel buttons. Both units can test for HDCP compliance and support HDTV resolutions up to 1080p.
The MONTEST-LCD signal generator supports analog computer monitors, LCD displays and video projection systems with the following four connectors: VGA, MAC II, SUN and RGHHV for BNC. It can generate four video patterns with 16 colors and intensity control, and over 100 frequencies that cover a wide range of monitor types.
The MONTEST-HDSDI can generate eight video test patterns and seven timings up to 1080p resolution at full broadcast quality, making it ideal for testing and maintaining studio equipment such as monitors, cabling and recording equipment. It also supports single-tone audio testing and dual SDI output for side-by-side comparison of displays.
All encompassing, the MONTEST-DA supports both analog and digital video signals, including: HDMI, DVI, NTSC, PAL, component Y/Pb/Pr, S-video, VESA, and more. It not only provides a variety of video test patterns, but also allows a user to play stored video and audio files from an embedded 80G hard drive. Remotely control the unit via its RS232-port. Supporting stereo audio test signals, DDC2B, and HDCP, the unit can scale a source to fit a display based on its EDID data. The MONTEST-DA is an ideal, comprehensive solution for applications that need to test, calibrate and maintain various display types.
Video test pattern generators are necessary for achieving optimal displays in many different settings and VPI’s range of MONTEST video test pattern generators can help both consumers and businesses achieve the highest quality their display units can deliver.