SU1150604A1 - Device for automatic lens focusing - Google Patents

Abstract

DEVICE FOR AUTOMATIC FOCUSING OF LENS, containing a lens connected with a drive, an image shift unit associated with an autonomous drive and transmitting a television tube, as well as a video amplifier, a scanner unit, the first key, the second key, a decoder, a comparison circuit, peak detector, high-frequency filter, recorder, the output of the comparison circuit is connected to the input of the lens drive, the output of the transmitting television tube is connected to the input of the high-frequency filter through a video amplifier the output of the scanner unit is connected to the first input of the transmitting television tube, characterized in that, in order to increase the focusing accuracy in wide ranges of brightness and contrast of the subject, the generator, the first, second, third and quarter waiting T-ultivibrators, the counter- divider, two-phase converter, log (iv: .at., additional key, first and second memory blocks, automatic using adjustment unit and a beam splitter located on the optical axis between the lens and the node shift The image and the deflecting part of the beams are on the recorder, while the generator output is connected to the input of the scanner unit, the separator counter input, the first input of the decoder and the third waiting multivibrator output connected to the second input of the decoder through the fourth waiting multivibrator, the second output of the scanner is connected with the third input of the decoder through connected in series the first vO and the second waiting multivibrators, the output of the Ultra high frequency is connected to the first input of the additional key via a single full-wave sequencer and a logarithm in series, the first output of the decoder is connected to the second input of an additional key, the output connected to the first input of the peak detector, the SP output of which is connected to the first i inputs of the first and second keys, the second and third outputs of the decoder are connected to the second inputs of the first and second keys, respectively, whose outputs are connected to the corresponding inputs of the first and second memory blocks, the outputs connected to the corresponding inputs of the circuit in this case, the bit outputs of the counter divider are connected to the corresponding inputs of the decoder, the fourth output of which is connected to the second input of the peak detector, the fifth output of the decoder is connected to the input of the autonomous drive, output.video

Description

The pit is connected to the second input of the transmitting television tube through the automatic gain control unit, the transmitting television tube is accomplished with an accumulation of charge.

and the image shift unit is made in the form of a vibrating mirror located during optical rays between the beam splitter and the transmitting television tube.

The invention relates to an optoelectronic system designed to enable automatic focusing of lenses, and can be used in devices that require a sharp sharp image of an object to be acquired automatically.

A device for automatic focusing of lenses is known, which contains a focusable lens arranged successively in the course of the rays, a beam splitter, a fiber-optic washer with a stepped entrance end and a dissector t J The areas of the input end of the fiber-optic washer are symmetrical with respect to the plane of the photographic material. Thus, the dissector scans the pre-focal and post-focal image of the subject. The main drawback of this device is that the dissector scans the pre-focal and after-focus images of different parts of the object, which in the case of arbitrary configurations and contrast lenses leads to significant errors in the focusing of the lens. The disadvantages of this device should also include a small range of riches of the subject in which Otto turns out to be operational.

The closest in technical essence to the invention is an automatic lens focusing device comprising a focused lens, lens drive, image shift unit in the form of glass plates of different thickness, assembled in one frame and rotating relative to a common center of symmetry with a certain frequency, image shift unit drive , transmitting television tube, video amplifier, block development, first key, second

key, image shift node position decoder, comparison circuit, peak detector, high frequency filter and recorder, the output of the comparison circuit is connected to the drive input of the focused lens, the output of the transmitting television tube is connected to the input of the high frequency filter via a video amplifier, and the output of the scanner unit is connected the input of the transmitting television tube. The principle of operation of the device is based on a differential comparison of the degree of sharpness equidistant from the image plane of an object formed by a focused lens. As an image sharpness analyzer, a transmitting television tube is used, which converts the illumination on its photocathode into an alternating electrical signal processed by an electronic circuit that isolates the signal to control the lens drive in accordance with the magnitude and defocus sign 2.

The disadvantage of the device is the deterioration of the image quality formed by the lens, due to the presence of a plane-parallel plate installed in a convergent beam of rays, and also due to distortions introduced by the shear plate plates having different thickness (or equal thickness of different refractive indices). ). Thus, the known auto focus device analyzes different image quality even when the focusable lens is in the correct position during the focusing process. This leads to the appearance of a difficultly removable systematic error in focusing.

The purpose of the invention is to increase the focusing accuracy in a wide range of changes in brightness and contrast of the subject. This goal is achieved by the fact that, in an automatic lens focusing device comprising a lens mounted on a drive, an image shift unit associated with an autonomous drive and a television tube, as well as a video amplifier, a scanner unit, a first key, a second key, a decoder, a comparison circuit, a peak detector, a high-frequency filter and a recorder, the output of the comparison circuit is connected to the input of the lens drive, the output of the transmitting television tube is connected to the input of the high filter often You are through a video amplifier, and the output of the scanner is connected to the first input of the transmitting television tube, the generator, first, second, third and fourth standby multivibrators, counter divider, full-wave rectifier, logarithm, additional key, first and second memory blocks, automatic block are entered gain control and a beam splitter located on the optical axis between the object and the image shift unit and the deflecting part of the rays on the recorder, and the generator code connected to the input of the scanner unit To, the input of the divider counter, with the first input of the di-diffractor and the input of the third multivibrator waiting Frequency is connected to the first input of an additional key through a series floor loop connected in series and logarithm. The first code of the decoder is connected to the second input of an additional key, you are connected to the first input of the peak detector, the output of which is connected to the first inputs of the first and second keys, the second and third decoder codes are connected to the second inputs of the first and second keys, respectively, whose outputs connected to the corresponding inputs of the first and second blocks for remembering, the outputs connected to the corresponding inputs of the comparison circuit, while the discharge outputs of the counter-divider are connected to the corresponding inputs Dami decoder, a quarter output of which is connected to the second input of the peak detector, the fifth output of the decoder is connected to the input of an autonomous drive, the output of the video amplifier is connected to the second input of the transmitting television tube through the automatic gain control unit, the transmitting television tube is accumulated with charge, and the shift node The image is made in the form of a vibrating plane mirror, which is located during optical rays by a ray beam splitter and a television tube in front of it. FIG. t is a block diagram of an auto focus device; in fig. 2 - waveform at the generator output; in fig. 26 and .b the waveform at the bit outputs of the counter divider by four; in fig. 2i-form signal at the output of the 4th standby multivibrator; in fig. Figures 23, 2e, 2, 2J, and 2 also show the waveforms of the signals on the first, second, third, fourth, and fifth outputs of the decoder, respectively. Fig 3 shows the lower-case pulses arriving at the input of the waiting multivibrator; in fig. 35 - waveform at the output of the first-waiting multivibrator; in fig. Zv - waveform at the output of the second standby multivibrator. The automatic lens focusing device contains the following components and blocks: focusable lens t, mechanically connected to drive 2, beam splitter 3, forming an image of the object together with focusable lens 1 on the photosensitive surface of the recorder 4 (not shown); the image shift unit 5, which is a mirror, performs a reciprocating motion with the help of drive 6, while the drive 6 of image shift unit 5 can be performed as an electromagnetic mechanism or an electroacoustic converter, on a movable element of which a flat mirror is fixed: transmitting television tube 7, accumulated with charge accumulation; a video amplifier 8 designed to amplify a weak signal removed from the transmitting television tube 7 and receive a signal used in the automatic gain control unit 9 inserted into the device to expand the operating range of the subject; the high-frequency filter 10 connected to the video amplifier 8 and transmitting only the high-frequency component of the signal, which after the high-frequency filter 10 is switched on using a full-wave rectifier 11, is logulated to a log of $ 12, inputting the device to extend the range of the contrast change the objects to be surveyed, and is fed through an additional key 13 to the first input of the peak detector 14; The first key 15 and the second key 16 are designed for switching the code of the peak detector 14 with the inputs of the first block 17 and the second memory block 18, the outputs of which are connected to the corresponding inputs of the comparison circuit 19, the output signal of which controls the drive 2, the objective 1 which is in the process of fitting. along the optical axis. The device also contains a unit raverut 20, which includes two generators (not shown) of frame and line pulses, which provide frame and line scan in the transmitting television tube 7 when scanning the image, the first 21, second 22, third L and fourth 24 waiting for multivibrator cl A pulse generator 25, which is used in conjunction with the watch-divider 26 and the decoder 27 to synchronize the operation of all units of the device. Cha: Gen 25 is 50 Hz. For operation of the device, it is necessary to ensure that, at any position of the mirror of the shear unit 5, the reading of a transmission frame tube 7 of several frames. Since the transmitting television tube is made with an accumulation of charge, the first frame is used to accumulate the charge, and the second frame is used to read the image. Therefore, in the case of using a transmission television tube 7 with accumulation of charge, when analyzing the image quality throughout the frame, it is sufficient to apply a counter-divider 26 with a division factor of four. The pulse generator 25 is connected to the input of the scanner unit 20, to the first input of the decoder 27, to the input of the splitter counter 26, and through the third multivibrator 23 and the fourth waiting multivibrator 24, which are connected in series, to the second input of the decoder 27. Block 20 is also connected to the third the input of the decoder 27 sequentially through the first 21 and second 22 waiting multivibrators. The bit outputs of the counter-divider 26 are connected to the corresponding inputs of the decoder 27. The signal from the first output of the decoder 27 controls the operation of the additional key 13. The signals from the second and third outputs of the decoder 27 control the operation of the first key 15 and the second key 16, respectively. The signal taken from the fourth output of the decoder 27 provides a storage capacitor (not shown) of the peak detector 14. The signal taken from the fifth output. The driver 11 of the driver 27 controls the operation of the drive 6 of the image shift unit 5. The device works as follows. Lower pulses (Fig. 3a) from the scanner unit 20 start the first standby multivibrator 21. The falling edge of the output signal (Fig. 3-5) of the first standby multivibrator 21 starts the second wait multivibrator 22, the output signal (Fig. 38) of which goes to the third input of the deshifter 27. The time constants t, and f 2 of the first and second waiting multivibrators 21 and 22 are chosen so that their sum is less than the time interval between pulses, and constant on the time r, more than the length of the horizontal pulse. The output signal (Fig. Sv) of the second standby multivibrator 22 controls the operation of the decoder 27 in such a way that the signal (Fig. 2 (5) on the first output of the decoder 27, supplied to the input of the additional key 13, cuts from the video signal lower-case pulses. Similarly, the third 23 and fourth 24 standby multivibrators cutting frame pulses from the video signal. The signal (Fig. 2a) from the generator 25 is fed to the input of the counter-divider 26, the signals from the bit outputs of which are fed to the corresponding inputs of the decoder 27, Signal (Fig. 2i s n that you The decoder code 27 is equipped with a drive 6 that moves the image shift node 5 mirror in such a way that the transmitting television tube 7 scans the pre-focal and after-focus images of the subject for two frames each. Output signal (Fig. 2e} from the first output of the decoder 27 control The operation of the additional key 13 is such that it is open only during the scanning of the second frame at each Mirror Position of the image shift node 5. The output signals (Fig. 2e and 2g) from the second and third outputs of the decoder 27 control the operation of the first key t5 and the second key 16. The signal (Fig. 2c |) from the generator 25 arriving at the input of the scanner unit 20 synchronizes the operation of the drive 6 of the image shift and sweep node 5 in such a way that scanning of the first frame begins simultaneously with moving the mirror of the image shift node 5 from one extreme position to another. When scanning the first frame (for example, pre-focal image - Fig. 2), additional key 13 is closed and charge accumulates on the photosensitive surface of the transmitting television tube 7 At the end of the first frame, the output signal (Fig. 23) from the fourth output of the decoder 27 discharges the storage capacitor peak detector 14. When scanning the second frame, the additional key 13 is open except for the time intervals when the horizontal pulses are present (Fig. 23) and the maximum value of the high-frequency components is the signal is recorded by a peak detector 14. When scanning the next frame (already behind the focal image), the additional key 13 is closed and the first key 15 is open, which ensures the maximum high-frequency recording of the video signal to the first memory block 17. At the end of the scan, this same frame the accumulator capacitor of the peak detector 14 is discharged, then (when scanning the next frame) an additional key 13 is opened, and the maximum value of the low-frequency components of the video signal The bar (for the focal image) is recorded by the peak detector 14. During the next frame, the second key 16 is unlocked and the maximum value of the high-frequency components of the video signal (for the focal image) is recorded in the second storage unit 18. The output signal of the comparison circuit 19, which compares the maximum values of high-frequency the constituent signals for the prefocal and after-focus images stored in the first memory block 17 and the second memory block 18 are fed to the actuator 2, which moves the Lecture 1 in the process of focusing until the compared values become equal. This corresponds to the fact that the image of the object is focused on the photosensitive surface of the recorder 4, which can be used to transmit a television tube, photo or film, and other photosensitive materials. This automatic lens focusing device has a higher defocusing sensitivity than limestone and devices, it can work over a wider range of objects and a wider range of contrast of subjects. In addition, the ability to change the distance between image analysis planes ensures the operability of this device when using interchangeable lenses that have different defocusing curves.

Claims (1)

DEVICE FOR AUTOMATIC FOCUSING OF A LENS, containing a lens mounted along the drive, an image shift unit connected to an autonomous drive, and a transmitting television tube, as well as a video amplifier, a scan unit, a first key, a second key, a decoder, a comparison circuit, a peak detector , a high-pass filter, a recorder, wherein the output of the comparison circuit is connected to the input of the lens drive, the output of the transmitting television tube is connected to the input of the high-pass filter through a video amplifier, and the output of the scan unit is connected to the first input of the transmitting television tube, characterized in that, in order to increase the focusing accuracy in wide ranges of brightness and contrast of the subject, a generator, the first, second, third and fourth waiting multivibrators, a divider counter, and a half-wave are introduced into it rectifier, logarithm, additional key, first and second storage units, automatic gain control unit and a beam splitter located on the optical axis between the lens and the image shift unit I and the deflecting part of the beams to the registrar, while the generator output is connected to the input of the scan unit, the input of the divider counter, with the first input of the decoder and the input of the third standby multivibrator, the output connected to the second input of the decoder through the fourth standby multivibrator, the second output of the scan unit is connected to the third decoder input through connected in series the first 5 and second standby multivibrators, the output of the high-pass filter is connected to the first input of the additional key through the connected serial In particular, a two-half-wave rectifier and a χ rhymesmator, the first output of the decoder is connected to the second input of the additional key, the output connected to the first input of the peak detector, the output of which is connected to the first inputs of the first and second keys, ι --- the swarm and the third outputs of the decoder are connected to the second the inputs of the first and second keys, respectively, the outputs of which are connected to the corresponding inputs of the first and second blocks of the second-memory storage, outputs connected to the corresponding inputs of the comparison circuit, the output outputs of the divider divider are connected to the corresponding inputs of the decoder, the fourth output of which is connected to the second input of the peak detector, the fifth output of the decoder is connected to the input of the autonomous drive, the output of the video amplifier is connected to the second input of the transmitting television tube through the automatic gain control unit, the transmitting television tube made with the accumulation of charge, and the image shift unit is made in the form of a vibrating mirror located in the course of optical rays between the beam splitter and the front television receiver.