JP2007104158A - Electronic camera with shutter open/close time corrector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic camera having a mechanical shutter in which the luminance on the image forming plane can be kept in a range of appropriate value by correcting troubles in mechanical open/close operation based on aging or wear of the shutter. <P>SOLUTION: The electronic camera includes a mechanical shutter open/close time corrector consisting of a lens system, a mechanical shutter having single or a plurality of apertures opened/closed by an actuator, a means for measuring the open/close time of the single or a plurality of apertures in the mechanical shutter, an image sensor for taking in an image as an imaging signal through the lens system, a control means for operating image data obtained from the image sensor based on the measured time data and correcting the quantity of light entering from the opening, and a means for creating and storing the open time decision data of the mechanical shutter and creating mechanical shutter open time decision data used for correction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electronic camera having a shutter, and more particularly to an apparatus for controlling the luminance of image data obtained by correcting variations in luminance on an imaging plane based on a mechanical opening / closing operation of the shutter, The present invention relates to an electronic camera including a shutter opening / closing time correction device that measures, calculates, and corrects an exposure time at each point on an imaging plane.

2. Description of the Related Art Conventionally, an electronic camera configured to include an electronic shutter function and a shutter function having, for example, three openings for controlling the charge accumulation time of an image sensor imaging device is known. An example of such an electronic camera is disclosed in Patent Document 1. This electronic camera uses a shutter drive pulse application timing to detect a deviation from a specified exposure time that occurs due to variations in mechanical delay between the application of a shutter drive pulse instructing the opening operation of the shutter and the actual opening of the shutter. This is configured to be corrected by the adjustment.
JP 2000-278612 A

  In a first example of a specific correction device according to Patent Document 1, an image sensor is provided that accumulates charges corresponding to incident light, converts the accumulated charges into an electrical signal, and outputs the electrical signal. The incident light path to the image sensor is a mechanical shutter. While the mechanical shutter is controlled to open, the image sensor accumulation control means is used to start the charge accumulation of the image sensor, and the mechanical shutter closing control is started to start the mechanical shutter closing control. Until the mechanical shutter is closed, an electric signal amount corresponding to the amount of electric charge accumulated in the image sensor is acquired as a correlated parameter indicating a response delay of the mechanical shutter.

  The second example includes an image sensor that accumulates electric charges according to incident light, converts the accumulated electric charges into an electric signal, and outputs the electric signal. The incident optical path to the image sensor is controlled to be opened and closed by a mechanical shutter, whereby the mechanical shutter is While being controlled to open, the image sensor accumulation control means is used to start the charge accumulation of the image sensor, and the mechanical shutter close control is started after a lapse of a predetermined time. The amount of electric signal corresponding to the amount of electric charge accumulated in the image sensor is acquired until the closed state, the difference between the acquired electric signal amount and the reference electric signal amount is calculated, and the calculation result is calculated. A correlated parameter representing the response delay of the mechanical shutter is used.

  In the third example, in the second example described above, the reference electric signal amount is set to start the charge accumulation of the image sensor using the accumulation control means while the mechanical shutter is controlled to open, and for a predetermined time. When the charge accumulation of the image sensor is terminated after the elapse of time, the above-described charge is configured to be an electric signal amount corresponding to the charge amount accumulated in the image sensor.

In the above-described conventional electronic camera, although the mechanical mechanism of the mechanical shutter itself between the electronic cameras can be adjusted with high accuracy by adjusting the delay of the shutter mechanism until the mechanical shutter is actually opened, for example, the individual electronic cameras However, a deviation occurs in the opening / closing time of the opening of the mechanical shutter due to wear or the like based on the mechanical operation of the mechanical shutter itself, and the luminance change caused by this deviation cannot be corrected (adjusted). As a result, when there is a deviation in the opening / closing time of the mechanical shutter opening due to the use of an electronic camera, it is difficult to set the opening time of the opening to be the same as the initial value before the occurrence of wear, etc. Variations in brightness and the like due to the apertures make it difficult to accurately image the subject.
An object of the present invention is to measure opening / closing times of a plurality of openings of a mechanical shutter and correct captured image data based on the measurement data, thereby accurately converting luminance information of image data into luminance information of a subject over a long period of time. An object of the present invention is to provide an electronic camera including a mechanical shutter open / close time correction device that can be reproduced close to the camera.

In order to solve the above problems, an electronic camera according to the present invention provides:
A lens system comprising an imaging lens and a lens drive circuit, an actuator, a mechanical shutter having one or more openings that are opened and closed by the actuator, and a time measurement circuit that measures the opening and closing times of the single or plural openings of the mechanical shutter. And a time measuring means comprising a time measuring sensor,
An image sensor that captures an image as an imaging signal via the lens system;
Control means for calculating the image data obtained by the image sensor based on the time data measured by the time measuring means and correcting the amount of light incident from the opening;
The imaging signal is A / D converted, mechanical shutter open time determination data is generated and recorded under the control of the control means, and mechanical shutter open time determination data generation means for correction is used. A shutter opening / closing time correction device that enables correction of the amount of light incident on the opening accompanying the above and controls the brightness of the image data of the image, and an electronic camera including the same correction method are configured.

  In the above electronic camera, the mechanical shutter is made of a disk-shaped material having one or a plurality of through holes, and an actuator is arranged at the center of the rotation axis, and the disk-shaped material is rotated to rotate the one or more through-holes. The light incident on the image sensor through the hole is controlled by the time measurement means while correcting the time width during which each through hole is opened, thereby controlling the brightness of the image data of the image image. is there.

  Changes in luminance due to deviations in the opening and closing times of the aperture with time by measuring the opening and closing times of one or more apertures of the mechanical shutter and correcting the brightness data at each point on the image as needed based on these data The luminance information of the captured image of the subject can be reproduced with high accuracy. Further, even if a mechanical error occurs in the mechanical shutter due to the use of the electronic camera, this can be easily calibrated by the above-described internal control, and the camera can be used with high reliability over a long period of time. Furthermore, it is easy to obtain high-resolution image data using only a mechanical shutter without using an electronic shutter.

FIG. 1 is a block diagram showing a basic configuration of an electronic camera provided with a shutter according to the present invention. In FIG. 1, 1 is an electronic camera, 2 is a lens system, 3 is a lens drive circuit, 4 is a mechanical shutter, 5 is an actuator, 6 is a CCD image pickup device that operates as an image sensor, 7 is a CCD drive circuit, 8 is an image pickup circuit, 9 is an A / D conversion circuit, 10 is a memory, 11 is a control means, 12 is an operation means, 13 is an external I / F, 14 is a time measurement means, 14a is a time measurement sensor, and 14b is a time measurement circuit.
The control means 11 can be constituted by a PC as a processing unit constituted by a CPU and a RAM memory. The operation means 12 is an input unit for giving control information to a PC as a processing unit, and can be configured by a keyboard or the like connected to the PC. The external I / F 13 is an interface that outputs captured video information as image data.

  In FIG. 1, an electronic camera 1 includes a lens system 2 that is set to a predetermined state by a lens driving circuit 3, a mechanical shutter 4 that is set to a predetermined state by an actuator 5, and a CCD image sensor 6 that is operated by a CCD driving circuit 7. An image pickup circuit 8 for processing a video signal picked up by the CCD image pickup device 6, an A / D conversion circuit 9 for A / D converting the video signal obtained by the image pickup circuit 8, a video signal, time measurement data, etc. Are provided with a memory 10 for storing various signals and the like, a control means 11 and the like. Here, the image pickup circuit 8, the A / D conversion circuit 9, and the memory 10 constitute a mechanical shutter release time determination data generation unit 16 that operates under the control of the control unit 11. Further, the mechanical shutter 4 is provided with a time measuring sensor 14a such as a photoelectric sensor as the time measuring means 14 and a time measuring circuit 14b, and a time described later measured by the time measuring circuit 14b is stored in the memory 10. . Further, the control unit 11 is constituted by, for example, a PC, and controls the lens driving circuit 3, the actuator 5, and the CCD driving circuit 7, and also controls the imaging circuit 8, the A / D conversion circuit 9, and the like. Further, for example, a shooting mode is set by an operation unit 12 to an input I / F (not shown) of the control unit 11, and an external I / F 13 is connected to the output side of the control unit 11.

  FIG. 2 is a perspective view of the mechanical shutter 4 shown in FIG. In FIG. 2, 4a, 4b, and 4c are through-holes of the mechanical shutter 4, and 5a is a motor for the actuator 5 arranged at the center of the rotation shaft corresponding to the through-holes 4a, 4b, and 4c. Reference numeral 15 denotes a straight line indicating an optical path incident on the mechanical shutter 4, and indicates an optical path incident on the through hole 4a.

  In FIG. 2, the mechanical shutter 4 is formed in a disk shape having a plurality of (three in FIG. 2) through holes 4 a to 4 c and is disposed in an optical path between the lens system 2 and the CCD image pickup device 6. ing. The mechanical shutter 4 is rotated counterclockwise in the direction of the arrow ω in FIG. 2 by driving the motor 5a for the actuator 5, and blocks incident light at portions other than the through holes 4a to 4c, thereby exposing the CCD image pickup device 6. Is prohibited. The mechanical shutter 4 is not limited to a rotary disk. For example, you may comprise with the plate body which can be advanced / retracted with the other actuator of the cylinder structure corresponding to the incident optical path 15. FIG. Also, other types of through holes can be used as appropriate. Furthermore, the number of the through holes 4a to 4c of the disc type mechanical shutter 4 can be increased or decreased as appropriate. On the other hand, it is also possible to configure the mechanical shutter 4 with only a single through hole 4a. In this case, the positions of the through holes 4b and 4c are not drilled.

  In the time measuring means 14, when the mechanical shutter 4 is rotating, for example, the opening time of the through holes 4a to 4c arranged corresponding to the three primary colors of RGB is detected by the sensor 14a and processed by the time measuring circuit 14b. Thereby, the shutter opening time in each through-hole 4a-4c is measured. If the measurement data corresponding to the through holes 4a, 4b, and 4c are time T1, T2, and T3, the measurement data T1 to T3 are stored in the memory 10. The measurement times T1 to T3 stored in the memory 10 are read out to the control means 11, and the luminance of each of the three primary color components of the actual captured image is corrected (see later). When only the through-hole 4a is drilled and the luminance of the y signal is measured, if the measurement data corresponding to the through-hole 4a is time T1, this measurement data T1 is read out to the measuring means 11 and its luminance deviation Is corrected.

  FIG. 3 is a flowchart of a mechanical shutter opening time determination control process showing an operation example of the electronic camera shown in FIG. 1 configured according to the present invention. In FIG. 3, S101 is the start of processing, S101-1 is input of imaging data and clock measurement data, S102 is determination of whether clock measurement data is present, S103 is reading of data T1 to T3, S104 Is a coincidence determination by comparing the values of T1 to T3, S105 to S107 are respectively recorded with correction levels 0 to 2 corresponding to the degree of approximation, S108 is a determination of whether there is imaging data, S108-1 is imaging data Occurrence of an error due to the absence of an image, S109 is a step of reading imaging data / correction level, S110 is correction, S111 is output of corrected imaging data, and S112 is a step of executing the end of processing. Needless to say, when only the through-hole 4a exists, only the data T1 is determined.

Next, the operation along the process flow shown in FIG. 3 will be described.
When the power of the electronic camera 1 is turned on and the operation is started (S101), imaging data is input in S101-1, and clock measurement data is input at the same time. Subsequently, it is first determined whether or not there is time measurement data (S102). If YES in this determination (S102) step, the through holes 4a to 4c of the mechanical shutter 4 measured by the time measurement means 14 are determined. The measurement data T1 to T3 are read into the memory 10 (S103). Whether the read measurement data T1 to T3 are substantially the same as the initial value before the shutter is worn, is it a small difference within a preset range, or is a large difference beyond this range? It is determined whether or not (S104).

  When the determination step (S104) is “substantially the same”, the correction level 0 is recorded in the memory 10 (S105), and when it is “small difference”, the correction level 1 is recorded in the memory 10 (S106). If “there is a large difference”, the correction level 2 is recorded in the memory 10 (S107). The weighted levels 0 to 1 are set in the order of correction level 0> correction level 1> correction level 2. When the correction level is set, it is determined whether there is imaging data (S108). If YES in this determination step (S108), both the imaging data and the correction level data are read (S109). Then, the imaging data is corrected based on the correction level (S110). If NO in the determination step (S108), the system is restarted due to an error. The correction data obtained by the determination is output as corrected imaging data (S111), and the series of operations is terminated (S112).

  The above-described control processing operation is performed according to the operation flow shown in FIG. 3 by the control means 11, the operation means 12, the external I / F 13, the time measurement means 14, and the mechanical shutter opening time determination data generation means 16 shown in FIG. Therefore, it is executed. Here, the video signal obtained by imaging is output to the external device through the external I / F 13.

  As described above, in the present invention, the determination (correction level: weighting) in step (S104) is not limited to three levels, and can be set to two levels or four or more levels. According to the present invention, when an electronic camera that cannot be equipped with an electronic shutter is required to have a high resolution, the mechanical shutter opening / closing time correction method provided by the present invention can be used to reduce the opening / closing time caused by mechanical shutter wear. It is possible to correct the deviation. Further, according to this method, it is possible to suppress the influence of unnecessary components caused by the deviation of the opening / closing time of the mechanical shutter 4. Furthermore, it is possible to calibrate the CCD image pickup device 6 using the opening times T1 to T3 of the mechanical shutter 4 (T1 when there is a single through-hole), and control and calibration of each part of the electronic camera. It is also possible to perform.

  The present invention can be applied to any electronic camera for business use or industrial use provided with a mechanical shutter. Further, in the conventional mechanical shutter, the light amount (brightness) unevenness in the shutter may occur due to change with time or wear. However, in the present invention, by executing determination control of the mechanical shutter opening time, the problem of uneven brightness due to aging and wear can be solved, so that it can be used for all electronic cameras in which such a defect is a problem. There is sex.

It is a block diagram which shows the basic composition of the electronic camera provided with the shutter concerning this invention. It is a perspective view of the shutter shown in FIG. It is a flowchart of the shutter open time determination control processing which shows an example of the operation example of the electronic camera shown in FIG. 1 comprised by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electronic camera 2 Lens system 3 Lens drive circuit 4 Mechanical shutter 4a, 4b, 4c Through-hole 5 Actuator 5a Motor 6 Image sensor (CCD imaging device)
7 CCD drive circuit 8 Imaging circuit 9 A / D conversion circuit 10 Memory 11 Control means 12 Operation means 13 External I / F
14 time measuring means 14a time measuring sensor 14b time measuring circuit 15 incident light path 16 mechanical shutter open time determination data generating means S101 to S112 processing steps

Claims (2)

A lens system comprising an imaging lens and a lens driving circuit;
A mechanical shutter having an actuator and having one or more openings that are opened and closed by the actuator;
A time measuring means comprising a time measuring circuit and a time measuring sensor for measuring the opening / closing time of one or more openings of the mechanical shutter, respectively;
An image sensor that captures an image as an imaging signal via the lens system;
Control means for calculating the image data obtained by the image sensor based on the time data measured by the time measurement means and correcting the amount of light incident from the opening;
The imaging signal is A / D converted, and the mechanical shutter opening time determination data is generated and recorded under the control of the control means, and the mechanical shutter opening time determination data generating means for the correction is comprised, and
An electronic camera provided with a shutter opening / closing time correcting device configured to control the luminance of image data of the image image by correcting the amount of light incident on the opening due to a change with time or wear. The electronic camera according to claim 1.
The mechanical shutter is made of a disk-shaped material having one or a plurality of through-holes, and an actuator is disposed at the center of the rotation shaft so that the disk-shaped material is rotated to form the one or more through-holes. The light incident on the image sensor is controlled by correcting the time width during which each through hole is opened by the measuring means, thereby controlling the brightness of the image data of the image image. Electronic camera.

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