RU2600171C1 - Device for production of wide-format image - Google Patents

Abstract

FIELD: image forming devices.

SUBSTANCE: invention relates to systems of reproducing television images, as well as to systems of computer engineering systems, and more specifically to colour video projection equipment. Result is achieved by that, device for obtaining images comprises a video processor, which controls drivers of RGB lasers, a flat mirror. Nonlinear distortions arising during row-wise rendering of an image in a vertical plane, are eliminated by synchronisation of non-linear movement of flat mirror with a stepper motor or galvo-motor, and distortions in horizontal plane are eliminated by changing brightness and illumination time of pixels depending on their position in row.

EFFECT: high image quality characteristics.

1 cl, 5 dwg

Description

The invention relates to systems for reproducing television images, as well as to computer systems, and more particularly to a color video projection technique.

At the heart of any two-dimensional image laser projector is the principle of line-by-line (pixel by pixel) image rendering. To create a stable image that the human eye can perceive, it is necessary to draw frames with a frequency of at least 18 Hz. To do this, it is necessary to deflect the laser beam in the vertical and horizontal planes and, by controlling the modulation of the laser beam, draw an image frame by frame.

To obtain a high-quality wide-format image, it is necessary to ensure a high rate of deflection of the laser beam by a significant angle.

The prior art solution is described in patent US 2014/0293139, IPC H04N 9/31, G03B 21/20, 2014.10.02, which uses a microelectromechanical system (in the foreign literature uses the abbreviation MEMS), which is based on the deformation of a silicon wafer , which, almost perfectly, obeys Hooke's law.

A disadvantage of the known solution is that at a sufficiently high speed of movement of the reflecting surface, the angle by which it can be deflected is very small (of the order of several degrees).

The technical solution is also known from the patent of the Russian Federation No. 2464603, IPC G02B 26/10, 2012.10.20, in which optical systems from several lenses are used to increase the deflection angle, which allows reaching deflection angles of the order of ten degrees.

The disadvantage of this device is that using it to obtain a widescreen image is difficult.

The closest in technical essence to the claimed one is a device for obtaining a widescreen image containing a video processor that controls the drivers of RGB RGB, a flat mirror (Electronic devices of printing equipment: Part 2. Lasers in printing: Training manual / Edited by A. Sidorov M .: Publishing house of MGUP, 2001, 284 p.). In the known solution, a multifaceted mirror is used to deflect the beam in the horizontal plane, and a flat mirror is used to deflect the beam in the vertical plane, the shape and number of faces of which depends on the parameters of the image being formed.

The known device uses a mechanical scan of the image, allowing you to deflect the laser beam at large angles. Despite the simplicity of using mechanically deflected mirrors, the known technical solution has the following disadvantages: mutual synchronization of vertical and horizontal scans is difficult, the occurrence of nonlinear geometric distortions of the generated image, as well as the high complexity of the technological manufacturing of polyhedral mirrors.

The invention is aimed at eliminating these disadvantages.

The technical result is to improve the quality characteristics of images by eliminating geometric distortions of the generated image, reducing the manufacturing cost by replacing a multifaceted mirror deflecting the laser beam in a vertical plane with a flat mirror.

The claimed technical result is achieved due to the fact that in the device for obtaining a widescreen image containing a video processor that controls the drivers of RGB RGB lasers, a flat mirror, nonlinear distortions arising from line-by-line drawing of the image in a vertical plane are eliminated by synchronizing the nonlinear movement of the flat mirror with a step or a galvanic motor, and horizontal distortions are eliminated by changing the brightness and time of exposure of pixels depending on their position in the system e.

The invention is illustrated by the following graphic materials:

in FIG. 1 shows a graph of a change in the width of a pixel depending on its position in a row;

in FIG. 2 shows a graph of the dependence of the laser on time on the position of a pixel in a row;

in FIG. 3 shows a graph of the dependence of the power of the glow of the pixel depending on the position of the pixel in the row;

in FIG. 4 shows a graph of the change in the angle of rotation of the mirror depending on the line number;

in FIG. 5 shows a block diagram of a device for obtaining a widescreen image.

When a flat two-dimensional image is formed in the horizontal and vertical planes, geometric distortions of the image are formed. In FIG. 1, you can see the change in the width of the pixel depending on its position in the line, for comparison, two rows of pixels are shown: the first - without distortion (desired), and the second - with distortion. As can be seen from FIG. 1, the pixel width varies depending on its position in the line. To eliminate these distortions, the system uses laser modulation.

In FIG. Figure 2 shows a graph of the possible dependence of the laser on time on the position of a pixel in a row. For convenience, the center of the graph has a zero count.

With this approach, the time of the glow of the pixels at the beginning and end of the line will be different, and therefore the brightness of the pixels will be different. To equalize the brightness of the image, in addition to modulating the on-time of the pixel, the laser power is also modulated.

In FIG. Figure 3 shows a possible graph of the dependence of the power of the luminescence of the pixel depending on the position of the pixel in the row.

Thus, when forming the image, the duration and brightness of the pulse glow are formed depending on the position of the pixel in the row, which eliminates image distortion in the horizontal plane.

Vertical scan is designed to deflect the laser beam in a vertical plane. A flat mirror is used as a material for deflecting a laser beam. Depending on the location of the laser projector relative to the plane on which the image is formed, various geometric distortions occur. So, for example, when placing the projector in the center of the screen, distortions of the generated image will be similar to distortions in the horizontal plane.

To eliminate distortions in the vertical plane, the mechanisms used in horizontal scanning are not suitable. Due to the fact that the rotation speed in the horizontal plane is constant and cannot be promptly changed, the time for drawing the line is constant. A stepper or a galvanic motor is used as a drive for the movement of a reflecting flat mirror. When imaging, both scans take time to reach the angles of the reflective surfaces. Sometimes they use the concept of "dead time" - this is the time during which the system is inactive. In our case, the image is not formed. Depending on the geometry of the relative position of the reflecting surfaces, the “dead time” can reach up to 30% of the total time of drawing the line. Therefore, the movement of a flat mirror occurs for the amount of "dead time" by an angle that determines the position of the next line for drawing.

In FIG. 4 shows a graph of changes in the angle of rotation of the mirror depending on the line number.

The principle of operation of the device is based on the controlled deviation of the laser beam from the reflective surfaces of a multifaceted and flat mirror in the vertical and horizontal planes. Three color channels are used to form a color image.

In FIG. 5 shows a block diagram of a device that operates as follows.

The communication and control unit 1 reads information from the internal image storage source (message receiving unit 2), writes data to the internal memory of the video processor 3. The vertical 4 and horizontal 5 scan control units generate image synchronization pulses entering the video processor 3. When a resolution signal is received the operation of the device, the video processor 3 generates an analog signal for laser drivers 6, which is amplified by them. In the process of image formation, the gamma correction unit 7 monitors the radiation power of the lasers 8 and corrects it. When a new image arrives via external communication channels (message receiving unit 2), the communication and control unit 1 overwrites the internal memory of the video processor 3 and the playback cycle is repeated.

The blocks that make up the device work as follows.

Message receiving unit 2 maintains stable communication with an external server via wireless channels. Message receiving unit 2 has Wi-Fi and GSM modules for receiving and transmitting information.

The communication and control unit 1 controls the operation of the system, as well as the initial data preparation for the video processor 3. The communication and control unit 1 receives, processes and executes communication messages from an external communication server - message receiving unit 2; prepares primary data for image formation by video processor 3; monitors the proper operation of the internal units of the device; makes a decision to suspend the operation of the device for self-testing in case of emergency operation, as well as for cleaning protective glass. All blocks in relation to the block of communications and control 1 are subordinate.

The video processor 3 generates a video signal and corrects non-linear distortions of the generated image. The video processor 3 receives and processes video information from the communications and control unit 1; generates a signal for three color channels; changes the power of lasers depending on external lighting; eliminates the nonlinearity of the formed image; processes data from the gamma correction unit 7; promptly makes changes to the generated video signal.

The laser driver 6 supports the stable operation of the laser diode. The laser driver 6 converts the input analog voltage to a control current, and also limits the maximum allowable laser current 8.

The gamma correction unit 6 measures the power of the laser 8 and transmits the corrective information to the video processor 3. The gamma correction unit 6 measures the power of the laser radiation in each channel; measures ambient light; measures the residual life of the lasers 8; calculates information to adjust the output power of the signal of the video processor 3; transmits the calculated data to the video processor 3.

The thermal stabilization unit of the lasers 9 maintains the required temperature in each channel of the lasers 8. The thermal stabilization unit of the lasers 9 monitors the trouble-free operation of the laser 8, information about which is sent to the emergency operation control unit of the device 10. The internal thermal stabilization unit 11 controls and maintains the internal climate of the device. The internal thermal stabilization unit 11 is autonomous, the operating temperature of the internal thermal stabilization unit 11 is not fixed and lies in the range from +10 to + 40 ° С. Monitoring the operation of the internal thermal stabilization unit 11 is carried out by the emergency operation monitoring unit of the device 10.

The vertical control unit 4 generates a control signal for the rotational speed of the flat mirror and synchronizes the rotational speeds of the vertical scan with the horizontal rotation speed. The vertical control unit 4 receives the clock from the horizontal unit 5; depending on the intensity of the incoming clock pulses generates a control signal for the rotation speed of a flat mirror; produces clock pulses for video processor 3.

The horizontal control unit 5 generates a control signal for the rotational speed of the polyhedral mirror. The horizontal control unit 5 generates vertical synchronization signals. The operation of vertical and horizontal blocks is autonomous, rigidly fixed and does not change during the operation of the device.

The device for obtaining a widescreen image has a power supply 12 and a glass cleaning unit 13.

The claimed device can significantly improve the quality characteristics of the resulting widescreen images by eliminating geometric distortions of the generated image. By replacing an expensive multifaceted mirror deflecting the laser beam in a vertical plane with a flat mirror, the manufacturing cost is reduced.

Claims (1)

A device for obtaining an image containing a video processor that controls the drivers of RGB RGB lasers, a flat mirror, characterized in that the non-linear distortions that occur during progressive drawing of the image in the vertical plane are eliminated by synchronizing the non-linear movement of the flat mirror with a step or galvanic motor, and distortions in the horizontal plane are eliminated by changing brightness and exposure time of pixels, depending on their position in the line.

Images