JPH03136594A - Left/right inverter - Google Patents

Abstract

PURPOSE:To realize a rear projection projector without use of a mirror by rearranging digital signals outputted from an A/D converter through the use of a memory. CONSTITUTION:An R signal 1, a G signal 2 and a B signal 3 are converted respectively into digital data by A/D converters 4, 5, 6 and inversion processing circuits 7, 8, 9 have a memory respectively to rearrange the arrangement of digital data by an instruction from an up-down counter circuit 10. The digital data are converted into analog signals by D/A converters 12, 13, 14 to obtain RGB signals equal to the case of inverting the scanning direction. Since a picture whose left and right sides are inverted is projected on the rear side of the screen by connecting a left/right side inversion converter to a prestage of a general video projector, the normal picture scanned from the left to the right is obtained visually.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a horizontal inversion converter for horizontally inverting an image of a video projector or the like.

[Prior Art] Since the projection surface of a rear projection type projector is the back side of the screen, when an image is projected from the rear side by a projector that scans from left to right, the image will be left and right reversed from the viewing plane.

Therefore, in the past, a mirror was installed to reflect the image, thereby projecting a horizontally inverted image onto the back surface of the screen, and from the viewing surface, a normal image was obtained by scanning from left to right.

FIG. 6 is an optical system layout diagram of a conventional rear projection type projector. 56 is an ordinary cathode ray tube that scans from left to right. The image projected on the cathode ray tube 56 is horizontally reversed and reflected by the mirror 55, and is reflected on the screen 5.
Project from the back of 4. Since the viewing plane is opposite to the projection plane, a normal image scanning from left to right can be seen when viewed from the viewing plane.

[Problems to be Solved by the Invention] However, the conventional method has problems such as image distortion due to mechanical distortion of the mirror and mounting errors, and reduction in brightness due to the reflectance of the mirror being about 90%. Ta.

The present invention is intended to solve these problems, and its purpose is to realize a rear projection type projector without using a mirror by performing left-right inversion through signal processing.

[Means for Solving the Problems] The left/right inverting converter of the present invention includes: a) an A/D converter that converts RGB signals into digital signals; b) storing an array of digital signals output from the A/D converter in a memory. C) an up/down counter circuit that supplies control signals such as addressing signals to the memory included in the inversion processing circuit; d) an analog converting circuit for converting digital data output from the inversion processing circuit; It is characterized by having a D/A converter for converting into a signal.

【Example〕

Hereinafter, the present invention will be described in detail based on examples.

FIG. 1 is a block diagram of a left-right inverting converter according to the present invention. The R signal 1, G signal 2, and B signal 3 are each converted into digital data by an A/D converter 4.5.6.1 Inversion processing circuit 7.8.9 each has a memory, and an up/down counter circuit 10 By rearranging the arrangement of the digital data in accordance with the command from , and converting this digital data into an analog signal by the D/A converter 12, 13, 14, an RGB signal equivalent to that obtained when the scanning direction is reversed can be obtained.

FIG. 2 is a detailed circuit diagram of the inversion processing circuit.

FIG. 3 is a detailed timing diagram at each location in FIG. 2. The digital data digitized by the A/D converter 22 in FIG.
Enter. The RAM 26 stores digital data when the data write signal 29 is at high level. At this time,
The up/down counter 24 operates in the up mode, and uses its counter output as an address designation signal 38 to input the RAM 2.
6, digital data is written into the RAM 26 in order from the lower address. The written data is called out when the data call signal 30 is at high level. At this time, the up/down counter 24 operates in the down mode, and the counter output is sent to the addressing signal 3.
In order to supply it to the RAM 26 as 8, it is called from the RAM 26 in order from the upper address, that is, in the reverse order from the writing. 35 is the called digital data. The RAM 27 stores digital data when the data write signal 31 is at a high level.

At this time, the up/down counter 24 operates in the up mode, and the counter output is supplied to the RAM 27 as the address designation signal 39, so that digital data is sequentially written into the RAM 27 from the lower address. The written data is called out when the data call signal 32 is at high level. At this time, the up/down counter 24 operates in the down mode and supplies the counter output to the RAM 27 as the address designation signal 39.
They are called in order from the upper address, that is, in the reverse order of writing.

By the above signal processing, 2H (IH=15.734KH,
) can perform inversion processing for LH, so in order to obtain continuous inversion data 33, switch 28 is switched at the timing of switch changeover signal 37, and call data 35.36
to synthesize. The inverted data 33 obtained in this way is
When the input signal 21 is converted into an analog signal by the /A converter 25, a signal 34 obtained by horizontally inverting the input signal 21 is obtained.

FIG. 4 is an example of system connection of a rear projection type projector using the left-right inversion converter of the present invention. - By connecting the horizontal inversion converter 43 to the front stage of the video projector 42, a horizontally inverted image is projected on the back of the screen, so a normal image scanning from left to right can be obtained from the viewing surface. .

FIG. 5 shows an example of system connections for a full-surface projection type projector.

A front projection type projector can be used as a front projection type if the system is configured as shown in FIG. 5, and can be used as a rear projection type if the system is configured as shown in FIG. 4. That is, if the horizontal inversion converter of the present invention is added, one projector can be used as a rear projection type, and if not added, one projector can be used as a full projection type.

[Effects of the Invention] As described above, since the left-right inversion converter of the present invention inverts the left and right image information through signal processing, it is possible to realize a rear projection type projector without using a mirror, which eliminates the problems that conventionally occurred. It is possible to eliminate image distortion and reduction in brightness due to the use of mirrors. In addition, as shown in Figures 4 and 5, by connecting or not connecting a left-right inversion converter, it is possible to easily realize front projection type and rear projection type with one front projection type projector, which is extremely effective. is large.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a left-right inversion converter according to the present invention. FIG. 2 is a circuit configuration diagram of the inversion processing circuit. FIG. 3 is a timing diagram at each location in FIG. 2. FIG. 4 is a diagram showing an example of system connection of a rear projection type projector using the left-right reversing converter of the present invention. FIG. 5 is a diagram showing an example of system connections for a front-surface projection type projector. FIG. 6 is an optical system layout diagram of a conventional rear projection type projector. 1...R signal 2...G signal 3...B signal 0 1 2 3 4 1 2 3 4 5 26 ・ 27 ・ 28 ・ 29 ・ A/D converter・A/D converter・A/D converter・Inversion processing circuit ・Inversion processing circuit ・Inversion processing circuit ・Up-down counter circuit ・Control signal D/A converter ・D/A converter ・D/A converter ・R signal ・A/D converter ・Inversion processing circuit ・Up-down counter Circuit D/A converter AM AM switch data write signal 30 ・ ・ 3 l ・ ・ 32 ・ ・ 33 ・ ・ 34 ・ ・ 35 ・ ・ 36 ・ ・ 37 ・ ・ 38 ・ ・ 39 ・ ・ 4 l ・ ・ 42 ・ ・ 43・ ・ 44 ・ ・ 48 ・ ・ 49 ・ ・ 50 ・ ・ 54 ・ ・ 55 ・ ・ 56 ・ ・ ・ Data call signal, data write signal, data call signal, inversion pig, inversion output signal, call data, call data, switch Switching signal, address designation signal, address designation signal, screen, front projection type projector - left/right reversal converter, eye representing viewing direction, screen, front projection type projector - eye representing viewing direction, screen, mirror, cathode ray tube 57・Eye or above indicating visual direction

Claims (1)

[Claims] (1)a) A/D that converts RGB signals to digital signals
converter; b) an inversion processing circuit that uses memory to rearrange the arrangement of digital signals output from the A/D converter; c) supplying a control signal such as an addressing signal to the memory included in the inversion processing circuit; d) a D/A converter that converts digital data output from the inversion processing circuit into an analog signal.