JPS6346888A - Image pickup device - Google Patents

Abstract

PURPOSE:To always correctly adjust a color temperature without being affected by the spectral transmittance of a lens, by dividing a part of the luminous flux whose image is formed on an image pickup element and processing the output of the image pickup element in accordance with the color temperature of this divided luminous flux. CONSTITUTION:A part of the luminous flux made incident on an image pickup element 8 from a photographic lens 1 is separated by a quick return mirror 2 and is led to an eyepiece lens 13 through a pentagonal prism 12. The light passing the central semitransparent mirror part of the mirror 2 is led toward a mirror 4 by a prism 3. The image of the reflected light is formed on a color temperature measuring sensor 7 through an image forming lens 6. The light emitted from the photographic lens 1 is made incident on the image pickup element 8, and output signals R, G, and B are inputted to an amplifying part 10, and the degrees of amplification to signals R, G, and B are changed in accordance with the color temperature outputted from the sensor 7. Chrominance signals outputted from the amplifier 10 are modulated by a recording process circuit 15 and pass a recording amplifier 17 and are recorded on a sheet 20 by a head 19.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an imaging device, and particularly to a color temperature adjustment device for an imaging device.

<Conventional technology> Conventionally, the color temperature adjustment of video cameras, etc. was carried out by what is called external measurement, in which a lighting window was installed to capture light from areas other than the lens, and the color temperature of the light captured from there was detected. The main thing that has been done is to make adjustments.

<Problems to be solved by the invention> However, in this method, the range used for color temperature detection does not match the angle of view actually photographed, so if the degree of mismatch is large, it is difficult to adjust the color temperature correctly. In addition, there are drawbacks such as when changing lenses, the spectral transmittance of the lenses will affect the effect, so even if the same subject is photographed, the hue will differ depending on the lens.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an imaging device that solves these problems and can always perform appropriate color temperature adjustment regardless of the angle of view at which images are taken.

Further, it is an object of the present invention to provide an imaging device that can always perform appropriate color temperature adjustment without being affected by the spectral transmittance of a lens.

Means for Solving the Problems> In order to solve the above-mentioned problems, the present invention provides an imaging optical system for forming an image of a light beam from an object onto an image sensor, a means for dividing the light beam of the optical system, and a means for dividing the light beam of the optical system. A means for receiving a part of the luminous flux divided by the means and detecting the color temperature of the luminous flux from the subject, and a means for processing the output of the image sensor according to the color temperature detected by the means. .

<Operation> A portion of the light beam that is imaged on the image sensor is divided, and the output of the image sensor is processed according to the color temperature of the divided light beam.

<Examples> Examples of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a photographing lens, and its exit pupil position is shown as 5, tentatively and traditionally. Reference numeral 2 denotes a quick return mirror, which separates a part of the luminous flux incident on the image sensor 8 and guides it to the pentaprism section 12 and the eyepiece section 13. 3 is a prism provided on the back surface of the quick return mirror 2, and reflects the light that passes through the center of the quick return mirror 2 toward the mirror 4. 6 is a prism that reflects the light reflected by the mirror 4. An imaging lens that forms an image on the color temperature measurement sensor 7, 7 is the color temperature measurement sensor. 8 is the image pickup element, and a color filter is provided on the element 8. The element 8 outputs signals corresponding to each of R, G, and B of the incident light. ゛9 is a drive system for changing the imaging position of the imaging lens 6, and the driving system The image lens 6 is moved. Reference numeral 10 denotes an amplifying section that amplifies the output corresponding to each color of R, G, and B output from the image sensor 8;
The degree of amplification changes depending on the output of the color temperature measuring sensor 7. That is, for example, if it is detected that the color temperature is low, the amplification degree of the output corresponding to B color is increased (and if it is detected that the color temperature is high, the amplification degree of the output corresponding to R color is increased). 11 is a control circuit that reads information on the exit pupil position from the photographic lens 1 and drives the drive system 9.

12 is a pentaprism, and 13 is an eyepiece lens that forms an image of the light beam reflected by the prism 12.

15 is a recording process circuit that modulates the signal amplified by the amplifier unit IO and converts it into a signal that can be recorded on the magnetic sheet 20; 17 is a recording amplifier that amplifies the output of the recording process circuit 15; A recording head, 20 is the magnetic sheet, and 22 is a motor for rotating the magnetic sheet 20.

Next, the operation of the embodiment of the present invention configured as above will be explained.

As shown in FIG. 1, the light beam that has passed through the photographic lens 1 is reflected by a prism 3 provided on the back side of a quick return mirror 2 having a transmitting portion in the center, and is routed to an optical path other than the optical path A to the image sensor 8. Divide into B. The light flux on the optical path B is focused on the color temperature measuring sensor 7 by the imaging lens 6 driven by the drive system 9.
It is driven by the control circuit 11 based on the exit pupil position information transmitted from the @shadow lens 1 so that the image is formed upward.

Therefore, the average color temperature of the light transmitted through the photographic lens 1 is measured by the sensor 7.

On the other hand, the light beam reflected by the quick return mirror 2 can be observed through the pentaprism 12 and the eyepiece lens 13.

Furthermore, during photographing, the quick return mirror 2 is raised, and the light beam incident on the image sensor 8 is photoelectrically converted by the element, amplified by the amplifier circuit 10 with an amplification degree according to the color temperature measured by the sensor 7, and recorded. Process circuit 1
The signal is modulated by 5, amplified by a recording amplifier 17, and then recorded on a sheet 20 by a head 19.

Next, an electric circuit of an imaging apparatus having the optical system shown in FIG. 1, particularly a circuit for reading out information on the exit pupil position from the lens to the camera body side, will be explained with reference to FIGS. 2 to 1.

FIG. 2 is a block diagram of the photographic lens and the camera body for explaining a communication method between the photographic lens and the camera body in the embodiment shown in FIG. In the figure, 100 is a photographic lens, 200 is a camera body, C1 is a camera microcomputer, C2 is a main interface, C21 is a power output terminal, C22 is a data terminal, and C23
is the Beege terminal, and C24 is the GND terminal. C3
is the ROM in which the main microcomputer program is stored.
, C4 is a power supply unit, C5 is a disk drive unit that drives a disk for recording images provided in the camera body 200, and C6 is a colorimetric system. An amplifier circuit 10 for the image sensor 8 is provided.

C7 is a distance measuring system. Further, the photographing lens 100 is removably attached to the camera body 200. Ll is the lens microcomputer, L2 is the 1nons interface, L2] is the power terminal, L22 is the data terminal, L23
is a visual terminal, L24 is a GND terminal, L3 is a ROM 5L4 in which various information of the lens 100 (to be described later) and a submicrocomputer program are stored, an aperture drive system, L5 is a focus drive system, and L6 is a zoom drive system.

Next, various information about the lens 100 stored in the ROM L 3 of the photographic lens 100 will be explained using FIG. 3. In FIG. 3, from the camera 200 to the photographing lens]
Commands sent to 00 via data terminals C22 and L22, command codes, command contents, and shooting [
It shows the number of bytes of data sent from the NONS 100 and the type of data allocated to the bytes. Note that data marked with "-°" in the data content column indicates that the data is the same as the content shown in the content column.

The content read out by the command 1- shown in Te5tLoss indicates the transmittance of the photographing lens 100. Further, the contents read by the command shown as Te5t ID are data indicating the manufacturer, type 1, and function of the lens, and several bytes are appropriately allocated to each of them, and the data consists of 7 bytes in total.

Next, the content read out by the command shown as Te5t exit pupil position is the exit pupil position of the photographing lens 1, and in this embodiment, the reciprocal of the exit pupil position is taken.

Next, the commands and data shown in Figure 3 are sent to the camera body 2.
The order in which data is exchanged between 00 and lens 100 will be explained using FIGS. 4 and 5. FIG. 4 is a flowchart executed by the microcomputer C1 of the camera body 200, and FIG. 5 is a flowchart executed by the microcomputer L1 of the lens 100.

First, the operation of the camera body 200 starts, and from the step shown in FIG.
1 is executed and one of the commands shown in FIG. 3 is sent from the camera body 200 to the lens 100. on the other hand,
When the lens 100 starts operating, the flow starts from the step #θ shown in FIG. 5, and #1 is executed. The step shown in FIG. 5 #1 determines whether a command is sent from the camera body 200 to the lens 100, repeats the loop when no command is sent, and #1 when a command is sent. Proceed to 2. Therefore, when the operation of the camera body 2 is started and #1 in FIG. 4 is executed, the flow of the microcomputer L1 of the lens l receives the transmitted command and proceeds from #1 to #2 in FIG. . The lens 2 determines whether the received command is an executable command in #2 of FIG. 5, and if the command is executable, the process goes to #3 of FIG. Proceed to step 4.

Here, #3 in FIG. 5 is a step in which the command sent from the camera body 2 to the lens 1 is sent as is (return command) from the lens to the camera body 2.

After executing #3 in Figure 5, lens 1 executes the command (#5 in Figure 5) and then sends the data specified by the command to camera 2 (#5 in Figure 5). It progresses. Further, #4 in FIG. 5 is a step of transmitting data indicating a "command error" to the camera 2. #2 above
In other words, the flow of ~#5 is that if the command sent from the camera body 2 to the lens 1 is an executable command, the lens 1 sends the transmitted command as it is from the lens 1 to the camera body 2, and the camera This figure shows a flow in which if the command sent from the main body 2 to the lens 1 is not executable, the lens 1 sends a "command error" to the camera 2 indicating that the sent command is not executable. There is. In this state, as shown in FIG. 4, the camera body 2 is in a state to receive commands sent from one lens (as shown in #2 in FIG. 4).
The lens 1 receives and receives data transmitted from the lens 1 to the camera body 2 by executing the step #3 in FIG. 5 or #4 in FIG. 5 described above.

Next, the camera body 2 is attached to the lens l as shown in FIG. 4 #3.
It is determined whether the data sent from the camera body 2 to the camera body 2 matches the command sent to the lens 1 in FIG. 4 #1. If they match, the camera body 2 receives the next transmitted data and performs the operation corresponding to the data, as shown in #4 in Figure 4, and the flow ends; however, if they do not match, The flow moves from #3 in FIG. 4 to #5, and in #3 in FIG. 4, it is determined whether the data transmitted from the lens 1 to the camera 2 is data indicating a "command error."

When the data sent there is determined to be a "command error", the flow returns to #1 in FIG. 4 and the same command is selected. Also, if "command error" is not determined in #5 of Figure 4, the command sent from camera 2 to lens I may have been sent to lens 1 by mistake, or lens 1
Either the data sent from the camera 2 to the camera 2 was incorrectly transmitted to the camera 2, but in any case, it is an error on the transmission path, so the flow stops there.

Through the above procedure, data on the exit pupil position of the photographic lens 100 and other data are transferred from the photographic lens 100 to the camera body 2.
00, and the drive system shown in FIG. 1 is driven according to the read exit pupil position, and the imaging lens 6 is moved so that the exit pupil of the photographing lens forms an image on the sensor 7. , color temperature adjustment is performed appropriately.

In this embodiment, a prism is provided on the back of the quick return mirror as a means for dividing a part of the light flux of the imaging optical system that focuses the light flux from the subject onto the image sensor. Alternatively, a method of providing a reflective surface within the finder, on the shutter surface, on the image surface, etc., as is done in normal TTL, may be used. Further, although the imaging lens 6 is used as a focusing means for forming an image of the exit pupil plane of the photographic lens onto the color temperature measurement sensor, optical components other than the lens or the sensor itself may be moved. Further, for exit pupil imaging, an optical member other than a lens having an equivalent imaging function (for example, a plane pattern such as a zone plate, a concave mirror, etc.) may be used. Furthermore, a so-called barrier pull power lens may be used as a means for focusing the lens.

As explained above, according to this embodiment, a part of the luminous flux incident through the photographic lens 1 is divided, and the color temperature of the divided luminous flux is measured to perform color temperature adjustment. Color temperature adjustment can be performed without being affected by the angle of view of the photographic lens and without being affected by the spectral characteristics of the lens.

Furthermore, according to this embodiment, since the exit pupil of the photographing lens is controlled to form an image on the sensor that measures the color temperature of the light flux incident through the photographic lens 1, the light beam incident through the photographic lens is It is possible to measure the color temperature of the average luminous flux.
Color temperature can be adjusted accurately.

Furthermore, according to this embodiment, as in the case called external measurement, the window-like part provided outside the lens for measuring color temperature is not exposed to the outside of the camera, so it is possible to accidentally block the window. It is also possible to eliminate the disadvantage that color temperature adjustment cannot be performed properly as a result.

<Effects of the Invention> As explained above, according to the present invention, it is possible to always perform appropriate color temperature adjustment without being affected by the angle of view of the photographing lens or by the spectral characteristics of the lens.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of an embodiment of the present invention, Fig. 2 is a block diagram showing the electric circuit of the imaging device shown in Fig. 1, and Fig. 3 is a block diagram showing the electric circuit of the imaging device shown in Fig. 1. FIG. 4 is a flowchart 1 executed by the microcomputer C1 of the camera body, and FIG. 5 is a flowchart executed by the microcomputer L1 of the lens. ■ is a photographic lens, 2 is a quick return mirror, 3 is a prism, 4 is a mirror, 5 is an exit pupil of the photographic lens, 6 is an imaging lens, 7 is a color temperature measurement sensor, 8 is an image sensor,
9 is a drive system for focusing the imaging lens 6, 10 is an amplification section, and 11 is a control circuit. Nagisa? same

Claims (2)

[Claims] (1) An imaging optical system that forms an image of the luminous flux from the subject on an image sensor, a means for dividing the luminous flux of the optical system, and a part of the luminous flux divided by the means, and a part of the luminous flux from the subject. An imaging device comprising: means for detecting color temperature; and means for processing the output of the image sensor according to the color temperature detected by the means. (2) The imaging device according to claim 1, wherein the means for detecting the color temperature is provided at an exit pupil position of the imaging optical system.