DLP big-screen television display system can show the audience more shocking, vivid images, with the audience on the screen television screens increasingly demanding high-quality, big-screen television display in the Arts, news, feature programs such as the application of the ever the more extensive. The current big-screen television display there are mainly three categories: large-screen television display CRT, LCD big-screen television display and DLP big-screen television display. CRT projection for RGB fired three shots, with the current imaging principle similar to the TV, LCD for LCD, DLP projection for the digital micromirror electronic form. These three big-screen television display imaging principle varied, all have different strengths and weaknesses, so applications also vary.
Early television system using DMD optical path through the projector lens was big screen images DLP projector display system includes signal main memory, DMD, light source, filters and by Prism, projection lens, and so on. As part of its core DMD, control digital image formation. In the midst of DMD are 508,800 to the rotation Aluminum micromirror, each micromirror a corresponding pixels, each micromirror have independent control of the on-off light capacity, allowing light through, micromirror "open", rotary + l0a, not allowing light through, micromirror "off", then rotating 10 a, in the absence of access to normal work, micromirror at 0°.
Big-screen television display for CRT general, this big-screen television display splicing technology is mature, widely used, but it is irreparably flawed, is the brightness of the lower, in a single, middle-, 1.40 Dark. Polarization dependent on the LCD, the light source in 50% of the optical polarization effect because people can not into LCD, brightness and can not improve a lot, and the image is black and white vertical lines marked, not normally used for television. DLP currently the most advanced technology, and the most appropriate use of television.
Regardless of the type of big-screen television display, in the studio application, has its peculiarities. Below from the DLP principle of the discussion in this special environment of debugging methods.
DMD micromirror rotation by digital video signals in the control, such as digital video signal to the PWM signal sites, using pulse width size of the micromirror to control the on-off light duration. Micromirror remain in the "open" state and the longer the time, the mirror corresponding to the higher the pixel brightness. As micromirror "open" to "close" between conversion speed very quickly, so images can not see flicker, the use of such rapid conversion micromirror can control since the pixel gray-scale and color of the level. DLP source of light through optical projection system to be directed DMD, DMD, in the "on" state of micromirror projector will be reflected light through a lens on screen square pixel, this entire DMD "on" the state of micromirror reflection on the projection screen in the form of images.
The number to distinguish DMD DLP There are three different models, namely, single-chip DLP model, two DLP model, three DLP model. Three DLP model offers the highest brightness. Single-chip DLP model, white light source through the condenser focusing on the dichroic round, dichroic round of the RGB color filter components, through dichroic round exposure to light after the DMD, with dichroic round of the rotation , RGB color will be three sequential irradiation DMD, dichroic round and RGB color signal synchronization, that is the hour when the light strikes into the DMD DLP projection display systems for treating red light signal; the same green or blue light irradiation to the DMD, the system handled Blue green light or signal. Thus, the naked eye will RGB color signal composition and feeling for color images. Three-color separation using RGB round, the white-light source will be 2/3 the filter absorption (because each time only through a primary color light), so in this mode, is the black-and-white color projector brightness projector three times.
The three models, no longer needed dichroic round, from the light source by RGB prism divided into three primary colors, while output to three DMD, three separate processing RGB DMD three primary colors, compared with the single-chip DLP, each of trichromatic Image extended to three times so that the light output also increased to three times. As images of time longer, allowing for a higher level gray-scale (such as 10-bit up to 12 bit), this will further enhance the image quality. This model suitable for large-screen projection greater brightness and high places.
Two models of DLP projector DLP metal halogen lamp as the light source, the output spectrum in the red light was relatively small. Two models adopted the single-chip DLP DLP model dichroic filter systems and three DLP model beam separation system, cleverly solved the metal halogen lamp light output spectrum in the red too few problems. Two DLP using color filters magenta and yellow, red and magenta filters allow blue through yellow and red filters were allowed through the green, red light will be so long through filters, Blue and green and will be staggered through. Through the filters, the color of light will be fired at by a group prism, separating the red light projection to a DMD, and the blue and green alternate projection on to another one DMD. Compared with the single-chip DLP, two DLP consider a color temperature balance as much as possible can be a real force to restore Yi color. In the studio, the luminescence of the lights, no sunlight into people, these lights are the color temperature of 3200 K standards, therefore, must also set up cameras in the 3200 K stalls.
However, the DLP big-screen displays speaking, the halogen lamp light source is used, the color temperature of 6500 K, and Sunlight basically the same, if not the color temperature transferred to 3200 K, through cameras, television sets see in the big screen Green image is the image, clearly this is not what we had hoped for. As everyone knows, the color temperature is that the concept of the light source spectral components. The iron, tungsten, and other standard blackbody heating started from absolute zero, as the temperature increased, and issued a color of the visible light, light colors, with the temperature rising gradually changing. When their heated to 800 K, a dark bold red light; coupled with the temperature, Mountain Dark red into Amber: When heated up to 560 OK, the yellow color from sunlight into that white light, similar to sunlight; continue to increase temperature to 2500 OK, the color gradually from white into blue.
In the production of television programs, people want screen scenes, the characters accurate color reduction, color fidelity and ensure high quality color screen. To achieve this, the light source color temperature balance color reproduction is one of the major conditions.
The so-called color temperature balance refers to the use of cameras and color temperature of light source color temperature consistent, the same scene several different light color temperature consistent. Cameras to their own use; 3 filter options, First 3200 K stall lighting color film, and the second is 5600 K color film solar stalls, and the third is 5600 K + 1/4ND (gray color-film solar] stalls. Cameras with what color temperature shooting, shooting targets depends on the color temperature and the surrounding environment. cameras in low color temperature stalls, and the target of shooting and the surrounding environment as a high color temperature, then shooting the image of a green color temperature of cameras in high-stall, and the shooting Object and the surrounding environment is a low color temperature, then shooting scenes like red. Therefore, the color temperature stalls camera shooting targets with the color temperature and the surrounding environment to the extent possible, consistent, big-screen television display debugger is through computer RS232 interface and the control software, run on debugging method is divided into two types of firms, the market adjustment phase and video decoding system adjustments.
1. Visit the phase adjustment when the big-screen television display mechanical adjustment has been completed, the first line is, the phase adjustment. It determines the splicing of the screen is correct. Specific process are as follows: First the input side yen video signal. The combination of large-screen display mode. Measurements and observations with ulnar combination of the box straight Wang Jian Ping, a round without distortion, and the central Habitat big screen.
2. Video Decoder System video decoding system adjustments related to the adjustment of the big-screen image contrast, brightness, color temperature, nonlinear distortion, hue and color saturation. These indicators observed by the adjustment of the method is clearly inappropriate. Block diagram of the cameras installed in 3200 K, as mentioned below debugging method, the monomer and Ping Group Taiwan must adjust tune when monomer single off their cameras at, and with the vertical center of the monomer, every single show integrity of the image, adjusting the composition screen, the screen shows complete portfolio images, the camera screen at the center of the Taiwan group. As cameras to prevent the location of the impact of large-adjusted error, try to maximize the number of cameras farther.
In Manage Vls10II software for brightness; black level is wrong, for contrast; each ladder Level range wrong, then they tune gamma correction. These three indicators are interrelated, we must adjust to repeatedly until satisfaction. Adjust color temperature, white large-signal input, RGB adjustment menu, the first R transferred to the biggest (because the color temperature light source for 560 OK, red light on the corresponding 3200 K appears less), then in accordance with the camera's color display Wen, vector oscilloscope in the location and white color monitor subjective evaluation. G, B signals repeatedly debugging until satisfaction. The consistency between the various screen adjustment, we should at least to the red light That screen as a benchmark, the other screen can not be transferred to the biggest red light on the. Color and color saturation adjustments, large-screen color of the input signal oscilloscope observation vector of each vector changes.
Adjust contrast, brightness and nonlinear distortion, ladder-wave input signal, according to the oscilloscope waveform display adjustments. The rate is wrong, in the amplitude and phase for each adjustment.
Debugging in the above process, must pay attention to the consistency between the screen adjustments. Various indicators debugging is not isolated, and they have asked the mutual ties, repeated adjustments are inevitable.
Big-screen television display in the studio application, must pay attention to color temperature adjustments. In the debugging process, relying on computers and the naked eye it is difficult to achieve the desired effect. Therefore, we must understand the principles on the basis of research debugging methods to make big-screen television display on the stage play its due role.