SU1670664A1 - Device for video camera objective automatic focusing - Google Patents

Abstract

This invention relates to optoelectronic devices designed to realize automatic focusing of lenses. The purpose of the invention is to simplify the device and improve its performance. The device for automatic focusing of the lens contains a lens 1, mechanically connected with the drive of its movement, the first optical unit 4, the video camera 6, the high-pass filter 8, the full-wave rectifier 9, the amplifier 10, the recorder 27, four keys 11, 16, 13, 18 , two memory blocks 14, 19, two peak detectors 12, 17, differential amplifier 15. The first optical unit is designed so that, together with the lens, it is capable of forming two images of the subject, the plane of the best image on the photosensitive surface of the video camera tim which are arranged symmetrically with respect to this surface. The device also contains a high-frequency generator 25, a counter-decoder 26, a second optical unit 3, two mirrors 2, 5 mechanically connected with their movement drive, a control panel 23, a trigger 24 and a zero indicator 22. The second optical unit is designed so that together with the lens, an image of the subject, the plane of the best image of which coincides with the photosensitive surface of the camera. During operation, due to the movable mirrors 2, 5, the image is focused and recorded alternately. 5 il.

Description

The invention relates to optoelectronic devices intended for the implementation of automatic facies lensing, and can be used in special video and television cameras, where it is required to automatically obtain a sharp image of an object during the shooting process.

The aim of the invention is to simplify the device and improve its performance.

Figure 1 shows the block diagram of the device; Fig. 2 illustrates one possible embodiment of the device control panel; FIGS. 3a, b and c are waveforms on the first, fourth and fifth outputs of the counter-decoder, respectively; 4a, b, and c are the same, on the second, sixth, and seventh outlets; in fig.4g, on the fourth and fifth outlets; on fig.ba - the same, on the second output of the counter-decoder, on fig.Bb - on the third output; on figv - at the output of the trigger; Fig.5 g-on the output of the differential amplifier; in Fig. 5d, at the output of the control panel in the second mode of operation of the device.

1 shows a lens 1, a first mirror 2, a second optical unit 3, a first optical unit 4, a second mirror 5, a video camera 6, a photosensitive surface 7 of a video camera, a high-pass filter 8, a full-wave rectifier 9, an amplifier 10, the first key 11 , first peak detector 12, third key 13, first memory block 14, differential amplifier 15, second key 16, second peak detector 17, fourth key 18, second memory block 19, lens drive 20, mirror movement actuator 21, indicator 22 zero, control panel 23, trigger 24, high frequency th generator 25, counter-decoder 26, the recorder 27.

The first optical unit 4 can consist, for example, of a system of mirrors and beam splitters (not shown) and is intended to form, together with the lens 1 and mirrors 2 and 5, on the photosensitive surface 7 of the video camera 6 two images A and B (figure 1) of the subject The planes of the best images of which are located symmetrically with respect to the photosensitive surface 7 of the video camera 6, if the lens 1 is focused correctly. The analysis of these images is carried out to determine the magnitude and direction of the defocusing of the lens 1.

The second optical unit 3 can consist, for example, of a system of mirrors (not shown) and is intended to form together with the lens 1 on the photosensitive surface 7 of the video camera 6 a sharp image B (Fig. 1) of the subject if the lens is focused correctly. This image is recorded in recorder 27.

The high-pass filter 8, the full-wave rectifier 9 and the amplifier 10 serve to form a signal characterizing the sharpness of the images on the photosensitive surface 7 video camera 6.

The keys 11 and 16 are used to switch this signal with peak detectors 12 and 17, in which the maximum value of the high frequency components of the video signal received during scanning of images A and B, respectively, is stored.

Keys 13 and 18 are used to switch peak detectors 12 and 17 with blocks

0 14 and 19 of the memory, which stores the magnitude of the signal characterizing the sharpness of images A and B, respectively. Differential amplifier 15 compares these signals and controls drive 20, which is moving lens 1.

The console 23 of the angle is designed to set the selected mode of operation of the device. One of the possible embodiments of the control panel 23 is presented in FIG. 2.

The zero indicator 22 determines the point in time at which the output of the differential amplifier 15 becomes zero, i.e. when lens 1 turns out to be focused correctly. The output signal of the indicator 22 zero resets the trigger 24, the output of which controls the operation of the actuator 21 for moving the mirrors 2 and 5, the operation of the recorder 27, and is applied to

0 the second input of the counter-decoder 26.

High-frequency generator 25 and counter-decoder 26 are designed to generate signals that control the operation of keys 11, 13, 16 and 18, and to synchronize the horizontal and vertical scans of video camera 6 and the operation of drive 21 for moving mirrors 2 and 5 and recorder 27 with the work of the rest device blocks. The counter decoder 26 may consist of

0 counter-divider and schemes AND and OR (not shown).

The device works as follows.

The device has two modes of operation

5, which are set by the operator by switching the toggle switch A2 (FIG. 2) on the control panel 23.

The mode of operation in which focusing occurs periodically with a period T (Fig. 56). Contacts b and from the toggle switch A2 are closed (figure 2). In this case, the signal (Fig. 56) from the third output of the counter-decoder 26 is fed to the first input of the trigger 24, which controls the operation of the actuator 21 for moving the mirrors 2 and 5 and sets them in a position in which the lens 1 together with the first optical unit 4 and mirrors 2 and 5 create on the photosensitive surface 7 of video camera 6 two images A and B (Fig. 1) of the subject. During line-by-line scanning, the electron beam of the transmitting TV tube (not shown) of video camera 6 successively passes the images A and B. In this case, when scanning the image A, the signal characterizing the sharpness of this image goes to the peak detector 12, and when scanning the image B - to the peak detector 17 Peak detectors 12 and 17 collect information about the sharpness of images A and B while scanning the entire television frame. Information is read from peak detectors 12 and 17 into blocks of 14 liters of 19 memory that occurs at the end of each television frame by triggering keys 13 and 18 (Fig. 4c). The signals on the fourth, fifth, sixth and seventh outputs of the counter-decoder 26 appear only when there is an enable signal (Fig. Bv) at the second input of the counter-decoder 26 only appear when there is an enable signal (fig.bv) on the second the input of the counter-decoder 26. Differential amplifier 15 produces a difference signal and controls the drive 20, by which the lens 1 is displaced to one side or the other along the optical axis depending on the polarity of the incoming signal. At the moment when the lens 1 is set to the correct focusing position, the output signal of the differential amplifier 15 (Fig. 5d) becomes zero. The zero indicator 22 generates a signal that resets the flip-flop 24. As a result, the output signal of the flip-flop 24 (FIG. BB) causes the actuator 21 to drive mirrors 2 and 5 out of the optical path of the beams. Through the lens 1 and the second optical unit 3 on the photosensitive surface 7 of the video camera 6, an image B (figure 1) of the subject is formed, which is recorded in the recorder 27, which can be used as a video recorder.

The mode of operation of the device in which the focus control is carried out at the command of the operator from the control panel 23. The toggle switch A2 closes the contacts a and c (figure 2). In this mode, when the operator presses the button B1 on the remote control 23

the latter generates a signal (fig. 5d), which puts the trigger 24 into a state in which mirrors 2 and 5 are driven by the drive 21 into the optical path of the rays. 5 The process of focusing, its completion and recording of the image in the recorder is the same as in the first mode. If the operator switches the dial A1 to a position where

0 pins a and b are closed, then the focusing process is carried out continuously, rather than periodically, as in the first mode with period 1 and not from switching on until operator B1 turns on at time points

5 T1 and T2. In this case, the registration of the image on the recorder 27 is impossible.

Timing diagrams of the operation of the device blocks are shown in FIG. 3-5.

FIG. Pros and 4e show signals on

0 to the first and second outputs of the counter-decoder 26, respectively, arriving at the first and second inputs of the video camera 6 and serving to synchronize the horizontal and vertical sweeps of the video camera 6 from the work of the remaining units of the device. The signal at the third output of the counter-decoder 26 (Fig. 56) is fed to the input of the control panel and is used in the first mode of the device for periodic focusing with a period T. Signals from the fourth and fifth outputs of the counter-decoder 26 (Fig. 36 and Zv) control the operation of keys 11 and 16, respectively, and provide a pass for signals characterizing the sharpness of images A and B (Fig. 1) to peak detectors 12 and 17, respectively, and only when scanning the central part of a television frame (Fig. 4d). the sixth The output of counter 0 of the decoder 26 (Fig. 46) is fed to the second inputs of the peak detectors 12 and 17 and is intended to zero them before scanning the next television frame. Signal at the seventh exit

5 of the counter-decoder 26 (Fig. 4b) controls the keys 13 and 18, which ensure the rewriting of the information about the sharpness of images A and B into memory blocks 14 and 19.

In the device, independent useful information occupies almost the entire field of the frame and, since one camera is used both to register the image in the recorder and to automate the focusing process, it means that

5 improves the performance of the device.

Claims (1)

Claims An apparatus for automatically focusing a camcorder lens, comprising lens, mechanically coupled to its drive, first optical unit, video camera, high-pass filter, full-wave rectifier, amplifier, recorder, four keys, two memory blocks, two peak detectors, differential amplifier, and the video camera output through the high-pass filter connected to the input of a full-wave rectifier, the output of the amplifier is connected to the first inputs of the first and second keys, the outputs connected to the first inputs of the first and second peak detectors, respectively, the outputs of the first and The second peak detectors are connected to the first inputs of the third and fourth keys, respectively., the outputs connected to the inputs of the first and second memory blocks, and the outputs of the first and second memory blocks are connected to the first and second inputs of the differential amplifier, the output connected to the input of the displacement drive of the lens, characterized in that, in order to simplify the device and improve its performance, a high-frequency generator, a decoder counter, a second optical unit, two mirrors, a fur canonically associated with the drive of their movement, the control panel, and the indicator zero trigger, the output of full-wave rectifier connected to the input of the amplifier, the output of the video camera is connected to the first input of the recorder, the output of the high-frequency generator is connected to the first input of the counter-decoder, the first and second outputs of which are connected to the first and second inputs of the video camera, respectively, the third output of the counter-decoder connected to the input of the control panel, the output which is connected to the first input of the trigger, the fourth and fifth outputs of the counter-decoder are connected to the second inputs of the first and second keys, respectively, the sixth output of the counter-decoder connected to the second inputs of the first and second peak detectors, the seventh output of the counter-decoder is connected to the second inputs of the third and fourth keys, the output of the differential amplifier is connected to the input of the zero indicator, the output connected to the second trigger input, the output of which is connected to the input of the first and second displacement actuator mirrors, the second input of the recorder and the second input of the counter-decoder, and the first mirror is located between the lens and the second optical unit and optically connected with the first optical unit, optically coupled to a second mirror located between the second optical unit and the video camera and optically coupled thereto. 5D1 Hs - ± -GB and with but / SA1 AT FIG. 2 (riel