RU2065723C1 - Device for examination of eye iris - Google Patents

Abstract

FIELD: medicine, particularly, ophthalmology. SUBSTANCE: device has illuminating and projecting systems, Dowe prism ensuring circular scanning through eye, and three optoelectronic converters with light filters, intended for color imaging. Image of iris is formed within one scanning by means of turning Dowe prism. EFFECT: reduced light irradiation of eye under test. 3 cl, 5 dwg

Description

 The invention relates to medicine and can be used in ophthalmology as a device for the study of the iris.

 Known analogues of the device, allowing to obtain images of the eye using light-to-signal converters with various laws of scanning the subject plane, in particular, the device for AS N 1491434, class 5 A 61 V 3/00, containing the illuminator, projection system and transmitting television receiver. A disadvantage of the known device is a rectangular raster formed by the transmitting television tube when scanning the eyes, which leads to the appearance of redundant information at the output of the device.

 Of the known devices closest in technical essence (prototype) to the claimed is an iridopupillograph as. N 1169606, CL 5 A 61 V 3/10, containing a illuminator, a projection optical system, a viewfinder, a scanning mirror, a photodetector, a Dove prism located along the optical axis and connected with a rotation mechanism.

 A disadvantage of the known device is the black and white image obtained at the output of the scanning device, as well as the electromechanical scanner used for scanning along the line.

 To form a color image, multiple eye scans are required. In addition, using an electromechanical scanner, it is impossible to achieve high scanning speeds. All this leads to excessive overexposure of the eye in the process of its study and ultimately affects the patient’s health.

 The disadvantages are eliminated in the device for the study of the iris of the eye, containing sequentially mounted on the optical axis of the illuminator and a condenser, a projection optical system made in the form of sequentially installed on the optical axis, counting from the patient’s eye, the first lens, Dove prism kinematically connected to the engine and the second lens, as well as a block of light filters, the first and second photoelectronic converters and a signal processing system. To achieve a positive effect, a target is inserted into the device, mounted between the illuminator and the condenser, while the condenser is optically connected through a translucent mirror to the first lens, which, in turn, is optically connected through the same translucent mirror to the Dove prism, and a third photoelectric converter is also introduced, which, together with the first and second photoelectronic converters, are optically coupled through the first, second and third filters with the second lens, the system being processed The signal circuit contains a clock generator, a control signal generator, an analog signal switch, an analog-to-digital converter, an OR element, and a frequency divider, the outputs of the photoelectronic converters being connected to the information inputs of the analog signal switch whose control inputs are combined with the first group of control inputs of the photoelectric converters and together with the second group of inputs of the photoelectronic converters are connected to the outputs of the control signal generator, the input of which is connected to the output of the clock generator, and the output is connected to the control input of the analog-to-digital converter and to the first input of the OR element, the output of the analog-to-digital converter is the information output of the device, and the input is connected to the output of the analog signal switch, one of the outputs of the second group of control signal generator through a frequency divider is connected to the second input of the OR element, the output of which is the clock output of the device and to the input of the motor.

 A linear photosensitive device with charge transfer was used as a photoelectric converter.

 The invention is illustrated by drawings. Figure 1 presents the General functional diagram of the device, figure 2 shows the location of the photosensitive linear devices in the image plane; figure 3 shows a diagram of a switch of analog signals; figure 4 shows an example of the construction of the Dove prism; figure 5 shows a variant of the law of image scanning.

 The composition of the device for the study of the iris of the eye, shown in figure 1, includes a clock generator 1, a generator 2 of the control signals, the first, second and third photosensitive devices 3, 4 and 5, respectively, the second lens 9, the element 10 for wrapping the image, the first lens 11, a translucent mirror 12, a condenser 13, a target 14, a lighting system 15, a driver 16 of an engine 17, a frequency divider 18, an analog signal switch 19, an analog-to-digital converter 20, an OR element 21.

 Clock generator 1, generator 2 of the control signals, driver 16, frequency divider 18 is made similarly to the corresponding blocks of the application N 4766494, by dec. from 11.21.90.

 As an analog-to-digital converter, the K1107PV1 chip (bKO.348.754TU) can be used.

 As a photoelectric converter, a linear photosensitive device with charge transfer K1200 TsL1 can be used (See. Press. Devices with charge transfer).

 As the motor 17, a stepper motor ШД 300/300, (ИЖЕО.522.314.001-01 ПС) with three-phase control can be used.

 As a switch of analog signals shown in figure 3 can be used multiplexer K561 KP1 (Shilo. Popular digital circuits.-M. Radio and communications. 1987).

 The Dove 10 prism includes rolling bearings 22, gear 23, and the prism 24 itself.

 The lighting system 15 illuminates the target 14, which is a dark spot in the center of the bright field, the image of which is focused through the condenser 13, a translucent mirror 12 and the lens 11, into the pupil of the eye. At the same time, the lighting system provides illumination of the studied iris. The image of the studied shell through the lens 11, reflected from the translucent mirror 12, falls on the prism Dove 10, the rotation of which using a stepper motor 17 achieves a circular scan of the image. The image from the output of prism 10 Dove through the lens 9 and the filters 6, 7 and 8 provide illumination of photosensitive devices with a charge mixture of 3, 4 and 5, respectively.

 When applying clock pulses t from the output of generator 1 to the input of generator 2 of control signals, the latter generates pulses RL, FL, BL of information shift from the accumulation registers to the transport registers of linear photosensitive devices 3, 4, and 5, respectively, and pulses PL1, PL2, and PL3 shift information in the transport registers to the outputs VA-R, VA-G, VA-B of linear photosensitive devices with charge coupling 3, 4 and 5, respectively. Moreover, the control signal generator 2 generates the indicated pulses in accordance with the time diagram given in the article by Koshlakov et al. A linear photosensitive circuit with charge coupling K1200 TsL1. Electronic Industry, N 7, 1982, S. 7-9.

Signals VA-R, VA-G and VA-B are fed to the information inputs of the switch 19 analog signals. And under the influence of control signals PL1 and PL2 at the control inputs of the latter provide the passage of signals to the input VA. The signal from the output of the VA switch 19 of the analog signals is proportional to the amount of luminous flux incident on the photosensitive element of devices 3, 4, and 5 currently being polled, respectively. This signal is fed to the information input of the analog-to-digital Converter 20, the clock signal t. The analog-to-digital converter 20 is a parallel type converter, which for each pulse generates at the outputs VD _o -VD _{n-1 a} code corresponding to the value of the signal supplied to its information input VA.

The generator 2 of the control signals generates signals PL1, PL2, PL3, RL, FL, BL continuously, in a cycle, respectively, and the data at the inputs VD _o .VD _n-1 appear continuously. At the beginning of each scan cycle, a pulse is generated at the output of BL, which causes the switching of the frequency divider 18. At times when the signal at the BL / 2 output of the frequency divider 18, the signal is logical zero, the passage of clock pulses t to the clock output τ of the device through the OR element 21 is destroyed. By the presence of clock pulses t, an external (with respect to the claimed device) unit (not shown) receives data generated by the analog-to-digital converter 20 with the output VD _o -VD _n-1 .

At the time of switching the BL / 2 signal to a logical zero state, the engine driver 16 generates the next combination of control signals PM1, PM2, PM3 in accordance with the timing diagram of the control of the stepper motor, which causes the shaft of the stepper motor 17 to rotate one step, resulting in an element 10 image through a kinematic connection is rotated at an angle d (see figure 5). As a result of this rotation, the projection a _i b _{i of the} input window of the charge sensitive photosensitive device on the test object is rotated by 2 d angle. Moreover, depending on the location of the input window in a plane coinciding with the image plane relative to the line drawn from the optical axis to the center of the input windows (angle g 0) it is possible to implement the scanning law shown in Fig.5.

It should be noted that photosensitive charge-coupled devices 3, 4, and 5 operate in such a way that at the moment of information shift in transport registers, photosensitive cells accumulate charges that shift to the output during the next cycle of photosensitive devices 3, 4, and 5 with charge coupling. During operation of the device, even and odd work cycles are distinguished, identified by the state of the frequency divider 18. In even cycles of operation, when the signal value BL = 0, data VD _o -VD _n-1 is followed by signal t. At the beginning of even cycles, the next combination of phases is generated at the output of the driver 17 of the stepper motor. During this cycle, the transition process in the engine 17 system continues. The information accumulated in the photosensitive elements of charge devices 3, 4 and 5 during this cycle, in the next odd cycle, is not accompanied by t pulses, and therefore is ignored by an external device.

 In odd cycles, when the signal value is BL = 1, the image wrapping element 10 is at rest. The information accumulated in the photosensitive elements of devices 3, 4 and 5 with charge coupling during this cycle, in the next even cycle, is accompanied by pulses t, and therefore is perceived by an external device. This avoids the phenomenon of "blur" of the image, especially in cases where the angle of rotation d of the element 10 of the wrapping image is significant.

Due to this, that the analog signals VA-R, VA-G, VA-B from the outputs of the linear photosensitive devices 3, 4 and 5 are switched by a switch 19 to the input VA of the analog-to-digital converter 20, the signals at the outputs VD _o , VD _n-1 are obtained in the sequence: a red code, a blue code, a green code, etc., which allows moving a 10-by-180 element by moving, performing a full circular scan of the iris in three colors and obtaining a color image of it.

 This, in turn, in combination with the use of linear photosensitive devices with charge transfer, can significantly reduce the time and power of light exposure on the human eye, which is very important when creating medical equipment. YYY2 YYY4

Claims (3)

 1. A device for examining the iris of the eye, comprising a sequentially mounted illuminator and a capacitor on the optical axis, a projection optical system made in the form of sequentially mounted on the optical axis, counting from the patient’s eye, the first lens, Dove prism kinematically connected to the engine, and the second lens, as well as a block of light filters, the first and second photoelectronic converters and a signal processing system, characterized in that a target is inserted into the device, mounted between an amplifier and a condenser, the condenser being optically connected through a semitransparent mirror to the first lens, which, in turn, through the same translucent mirror, is optically connected to the Dove prism, and a third photoelectronic converter is also introduced, which, together with the first and second photoelectric converters, is optically connected through the first, second and third filters with the second lens, while the signal processing system contains a clock generator, a control signal generator, an analog switch x signals, an analog-to-digital converter, an OR element, and a frequency divider, and the outputs of the photoelectronic converters are connected to the information inputs of the analog signal switch, the control inputs of which are combined with the first group of control inputs of the photoelectric converters and, together with the second group of inputs of the photoelectric converters, are connected to the outputs of the control generator signals, the input of which is connected to the output of the clock generator, and the output is connected to the control input of analog-digital about the converter and to the first input of the OR element, the output of the analog-to-digital converter is the information output of the device, and the output is connected to the output of the analog signal switch, one of the outputs of the second group of the control signal generator is connected through the frequency divider to the second input of the OR element, the output of which is clocking device output, and to the engine input.  2. The device according to claim 1, characterized in that a linear photosensitive device with charge transfer is used as a photoelectric converter. 3. The device according to claims 1 and 2, characterized in that the location lines of the photosensitive elements of the first, second and third photoelectronic converters are located in the image plane at an angle of 120 ^{o to} each other.

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