JPH02105682A - Image pickup lens - Google Patents

Abstract

PURPOSE:To automatically exchange aberration correction data even when a lens is exchanged by providing a memory to store the aberration correction data in a lens main body, and performing registration correction by reading out the correction data stored in the lens main body at need. CONSTITUTION:Data to correct aberration generated at an optical part 4 is held corresponding to the characteristic and the position of the lens in an aberration correction data memory 2. A lens parameter detection circuit 3 detects the parameter of an image pickup state, and takes out the aberration correction data corresponding to the parameter from the memory 2. The correction data is transmitted to the microcomputer 15 of the camera main body via a transmission path 21. The microcomputer 15 computes the registration correction signals of a red color image pickup tube 6 and a blue color image pickup tube 8 by using transmitted correction data. In such a way, an operator can be released from complicated work such as to exchange the correction data, and registration defect can be completely eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photographic lens used in a photographic device such as a television camera, and more particularly to a photographic lens that performs registration correction according to lens aberration.

[Conventional technology]

Japan Broadcasting Corporation (NHK) as the next generation television system
advocates a high-definition television system.

The high-definition television system uses 1,125 scanning lines, more than double the current system, and aims to provide images with high definition and a sense of realism. Therefore, television cameras used in high-definition television systems are required to have higher resolution characteristics than ever before.

Registration (image overlay) errors are one of the factors that reduce the resolution characteristics of television cameras.
Reducing this registration error leads to higher resolution.

For high-definition television cameras that perform registration correction, references (1) ``Development of color camera for high-definition television; Takaran et al. 1 Hitachi Review V
o 1.67, Nn5. PP5l-54, 1985", and in the current system, Reference (2) "Real-time correction of dynamic registration deviation: right side and others, Technical Report of the Television Society, published on May 24, 1980"
There are things listed in. The purpose of both is to perform registration correction and obtain high-resolution television images.

FIG. 3 is a block diagram of the registration correction section of the television camera described in the above document. The main purpose of this registration correction section is to remove registration errors caused by lateral chromatic aberration of the lens, so it has the configuration described below.

That is, it is composed of an optical section 4, an imaging lens 30 consisting of a lens parameter detection circuit 31, and a camera head body 48.

The camera head body 48 includes a color separation prism 47 that separates an incident image into red, green, and blue. Field image tubes 35, 36, 37 that convert each color image into an electrical signal. Image tube 35, 36, 37 deflection circuit 38, 39, 40° preamplifier 41, 42, 43
and a microcomputer 32 for performing registration correction; and a memory 49 for correction data. Correction signal generation circuit 33. Main deflection waveform generation circuit 34. Addition circuit 44.45
It consists of

The aberration of the imaging lens 30 varies depending on conditions such as the lens aperture value, zoom ratio, and subject distance. Therefore, the lens parameter detection circuit 31 detects the lens parameter (aperture value F
, zoom ratio 2. Detects the object distance L) and outputs lens parameter information to the microcomputer 32. The microcomputer 32 reads aberration correction data corresponding to the lens parameters from the memory 49 and calculates a signal for correcting registration errors.

A correction signal generation circuit 35 controlled by a microcomputer 32 generates a correction signal, and this correction signal is applied to the deflection 4.1 of the main deflection signal generation circuit 34 and the addition circuit 44.4.
5 and applied to the deflection circuit 38.39.

As shown in Figure 3, the above camera stores the aberration correction data of the lens in a read-only memory installed inside the camera body.
ROM) 49 and used for aberration correction.

[Problem to be solved by the invention]

When shooting television images, it is necessary to change the shooting lens in order to change the angle of view for shooting.

For example, a telescope lens with a long focal length is used for outdoor photography, and a wide-angle lens with a short focal length is used for studio photography. Therefore, if the aberration correction data is stored in the camera body instead of the lens body as in the conventional technology, the contents of the memory must be rewritten each time the lens is replaced. A person must perform the troublesome task of replacing this memory.

An object of the present invention is to eliminate the above-mentioned inconvenience, and to automatically exchange aberration correction data even when changing lenses.
Another object of the present invention is to provide a photographing lens for a television camera whose contents can be updated.

(Means for Solving 111g) In order to solve the above problem, the present invention adopts a method of incorporating a memory in the lens body for storing aberration correction data corresponding to the lens.

[Effect]

Aberration correction data is stored in the memory provided in the lens body.This correction data memory stores correction data calculated from the results of measuring the amount of aberration of the lens in advance. The stored correction data is read out to the microcomputer in the camera body to perform registration correction as necessary. With this configuration, when the lens is replaced, the correction data is also changed at the same time as the lens is replaced.

Registration correction can always be performed using aberration correction data corresponding to the lens.

〔Example〕 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an imaging lens element according to the present invention.

This lens consists of an optical part for forming an optical image; 4° aberration correction data memory; 2. It consists of a lens parameter detection circuit 3. The optical section 4 has the same function as a normal lens, and forms an input optical image on the light receiving surface of the image sensor. The feature of this lens is that the aberration correction data memory 2 is built into the lens body. This aberration correction data memory 2 holds data for correcting aberrations generated in the optical section 4.

The contents of this correction data are information on chromatic aberration of magnification as described in Reference 2, and are, for example, coefficients of an approximate polynomial used for correction (hereinafter, these coefficients are simply referred to as correction data). Lens aberrations are determined by lens parameters (
For example, since it changes depending on the zoom ratio, aperture value F, and subject distance L, the correction data is based on these parameters (F, L, Z).
) It is best to organize and memorize them.

The gist of the present invention is to hold aberration correction data in the data memory 2 and use this data to perform aberration correction, and this data must correspond to the characteristics and position of the lens.

FIG. 2 shows a block diagram of a television camera using this imaging lens. Note that in FIG. 2, camera circuits that are not directly related to registration correction are omitted.

This television camera is composed of an imaging lens 1 and a camera head body 5 shown in FIG. The camera head body 5 includes a color separation prism 23 that separates an incident optical image into three primary colors of red, green, and blue. Image pickup tubes 6, 7, which convert input images into electrical signals;
8, Deflection circuit 9゜10.11, Preamplifier 12, 13,
14. Microcomputer 15, correction waveform generation circuit 1
It consists of a 6° main deflection signal generation circuit 17, adder circuits 18 and 19, and a process circuit 20. Each color image separated by the color separation prism 23 is transferred to an image pickup tube 6° for red and an image pickup tube 7 for green. The image pickup tube 8 for blue color converts it into an electrical signal. Signals from these image pickup tubes are amplified by a preamplifier, input to a process circuit, converted into a television signal, and output as a video signal.

The lens parameter detection circuit 3 detects parameters (Z, F, L) of the photographing state and retrieves aberration correction data corresponding to these parameters from the memory 2. This correction data is transmitted to the microcomputer 15 of the camera body through the transmission line 21.

The microcomputer 15 calculates registration correction signals for the red image pickup tube 6 and the blue image pickup tube 8 using the transmitted correction data. These correction signals are added to the correction waveform generation circuit 16 and converted into a form that can be superimposed on the deflection signal of the image pickup tube. The main deflection signal generation circuit 17 generates a deflection signal. These deflection signals and correction signals are added by addition circuits 18 and 19 and applied to deflection circuits 9 and 10 of the image pickup tube.

Note that only the main deflection signal is applied to the deflection circuit 10 of the green image pickup tube 7. This is because the correction operation is performed using the green signal as a reference.

Registration correction can be realized through the operations described above. This configuration differs greatly from the conventional registration correction method described with reference to FIG. 3 in that the correction data is stored in the lens rather than in the camera body.

With the above-described configuration, when the lens is replaced, the memory for correction data is also automatically replaced6, thereby freeing the operator from the troublesome work of exchanging correction data. In addition, registration defects caused by not updating the correction data can be completely eliminated by replacing only the lens.

FIG. 4 and FIG. 5 are diagrams showing modifications of FIG. 1 and FIG. 2, respectively. The difference between the embodiments of the imaging lens shown in FIG. 1 and FIG. 4 is that lens parameter information is also output in addition to correction data.

Furthermore, the difference between the television cameras of the embodiments shown in FIG. 5 and FIG.
s Msa + ory) and a lens exchange monitoring circuit 26.

The flowchart representing the operating procedure of the camera in Figure 5 is shown in Figure 6.
As shown in the figure. In this camera, after the power is turned on, the camera starts initial adjustments such as white balance and black balance. This initial gll? ! After the period ends, the data in the correction data memory 2' in the lens is transferred to the rewritable memory 25 in the main body of the camera head 5'. The correction data stored in the memory 25 is used in subsequent registration corrections. Once the correction data has been transferred, the camera enters shooting mode. Registration correction in the photographing mode is performed using data in the memory 25, and the correction operation may be the same as that of the television camera shown in FIG.

Furthermore, in the television camera of the embodiment shown in Fig. 5, it is possible to determine whether or not the imaging lens needs to be replaced during normal shooting conditions, and when the lens is replaced, correction data corresponding to the replaced lens can be rewritten in the camera body. The data is transferred to the memory 25. Then return to shooting mode. This retransfer of data at the time of lens exchange is performed using the lens exchange monitoring circuit 26 and the microcomputer 15'. The lens exchange monitoring circuit 26 monitors the presence or absence of lens exchange, and when the lens is exchanged, issues a command to the microcomputer 15' to transfer the data in the read-only memory 2' of the lens to the rewritable memory 25 of the camera body. to be forwarded to. This operation allows the correction data to be automatically updated when the lens is replaced.

Other embodiments are shown in FIGS. 7 and 8.

In the embodiment shown in FIG. 7, the configuration is such that the imaging lens 50 and the camera body 53 can mutually transfer data. The information sent by the microcomputer 54 is
For example, it is a synchronization signal that informs the current scanning position of the image pickup tube. In this configuration.

Correction data that changes depending on the position of the screen is stored in the memory 51 of the lens body 50, and based on the scanning position information from the microcomputer 54, correction data corresponding to the position can be obtained.

The correction data read from the memory 51 is sent to the microcomputer 54 of the camera body using the signal line 55. The microcomputer 54 controls the correction signal generation circuit and performs registration correction.

The embodiment shown in FIG. 8 is a modification of the embodiment shown in FIG. 2, but the difference is that a registration error detection circuit 65 is provided. As described above, the main cause of registration errors is the chromatic aberration of the lens, but registration errors also occur in the prism 23 used for color separation. Registration error detection circuit 65 in diagram fJ8
is for detecting errors occurring in this prism.

The registration error detection circuit 65 receives the input red,
Registration errors are detected from each of the green and blue video signals, and the results are sent to the microcomputer 62. The microcomputer 62 generates a registration correction signal using the above data and the lens correction data sent from the lens correction data memory 61.

According to this configuration, it is possible to remove registration errors caused by components other than the lens. Note that the correction data calculated by the microcomputer 62 is stored in the memory 63 in the camera head body and used for correction, but this data may also be transferred to the correction data memory 61 in the lens.

Another embodiment is shown in FIG. 9. The embodiment shown in FIG. 9 differs from other embodiments in that a microcomputer 71 is built into the lens body 72. This microcomputer 71 performs some of the functions of the microcomputer 15 built into the camera head body shown in FIG. For example, interpolation calculations, etc. Registration correction data for the lens 1 changes depending on parameters such as the lens aperture value, subject distance, and focal length, but a large capacity memory is required to hold correction data for all combinations of these parameters. This results in an increase in circuit scale, so interpolation calculations are performed.

The correction data memory 70 stores representative correction data measured in advance, and the microcomputer 71 calculates registration correction data for all lens parameters from the representative correction data by complementary 1111 operations. This calculation result is then sent to the camera body 74.

According to the above configuration, there is an effect that the memory capacity provided inside the lens can be reduced. In the embodiment shown in FIG. 9, the lens body and the camera head body have two microcomputers 71 and 73, but
This may be present only in the lens body; the Micro Convenience Tough 1 in the lens body performs all interpolation calculations,
The configuration may be such that the correction signal generation circuit 16 of the camera head is controlled based on the result.

The gist of the present invention is to provide the data necessary for registration correction in the lens body instead of the camera body.
As described above, data may be transferred in advance from the memory built into the lens body, or the correction data may be automatically updated when the lens is replaced. Further, the correction data of this memory and the 1ill+constant data of the registration error detection circuit may be used in combination.

In the explanation of the embodiment, the correction method of adding a registration correction signal to the (i-plane signal) of the image pickup tube has been mainly explained, but this registration correction method may be of any type. No matter what, it does not detract from the gist of the present invention.

Furthermore, it is clear that the present imaging lens is effective for registration correction not only for image pickup tube type cameras but also for television cameras using solid-state image sensors. It goes without saying that the present invention can also be applied to electronic still cameras and the like that use an imaging lens and an imaging element.

〔Effect of the invention〕

As described above, according to the present invention, in a television camera equipped with a registration correction function, it is possible to reliably obtain registration correction data even when changing lenses, and the excellent effect is that the best registration correction can always be performed. There is.

In addition, the operator can be relieved from the task of exchanging correction data, resulting in improved operability.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an imaging lens according to an embodiment of the present invention.
Figure 2 is a block diagram of a television camera using the imaging lens of the embodiment shown in Figure 1, Figure 3 is a block diagram of a conventional television camera that performs registration correction, and Figure 4 is a modification of Figure 1. FIG. 5 is a block diagram showing a modification of FIG. 2, FIG. 6 is a flowchart explaining the operation of the television camera shown in FIG. 5, and FIGS.
The figure is a block diagram showing another modification of the embodiment of FIG. 2. 1... Imaging lens, 2... Correction data memory, 3.
...Lens parameter detection circuit, 4...Optical section, 5.
...Camera head body, 6,7.8...Image tube, 9,
10° 11... Change circuit, 15... Microcomputer, 16... Correction signal generation circuit, 17... Main deflection signal generation circuit, 18.19... Addition circuit, 20...
・Process equivalent 4 Diagram ゛゛. Me Yuzu me brothel or next to the host N- Tairazu Me? figure

Claims (1)

[Claims] 1. A photographing lens of an imaging device that performs at least registration correction, wherein registration correction data corresponding to parameters of the lens such as a lens aperture value, focal length, and object distance is stored in the lens body. A photographic lens characterized by being provided with a storage means for holding data. 2. A photographic lens of an imaging device that performs at least registration correction, which includes means for detecting parameters such as the lens aperture value, focal length, and object distance, and holds registration correction data corresponding to the parameters of the lens. A photographic lens characterized by being provided with a storage means.