JPH0650906B2 - Electronic imager - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electronic image pickup apparatus (hereinafter referred to as an electronic camera), and more particularly to improvement of exposure amount evaluation means.

[Prior Art] Generally, as an exposure amount evaluation unit used in an electronic camera, an average photometric system for evaluating the average exposure amount of the entire imaged screen is used. Therefore, the average exposure amount of the entire screen could be evaluated, but the exposure amount of each part in the screen could not be evaluated. However, in actual imaging, even if the exposure amount of the entire screen is appropriate, the exposure amount of each portion is relatively incorrect. Therefore, if the exposure amount is determined by the average photometric evaluation unit, an image quality defective portion due to overexposure or underexposure occurs on the imaged screen. In particular, when these image quality defective parts are important parts of the subject, the problem is great. As described above, the exposure amount evaluation means of the average photometry method has a drawback that it is impossible to evaluate the two-dimensional exposure amount focusing on each part of the imaged screen.

In an electronic camera with an electronic viewfinder, the video signal output from the image pickup device is monitored by the electronic viewfinder so that the two-dimensional image quality can be evaluated. However, since only the overexposed area and the underexposed area are not clearly specified and displayed, there is a problem in that it takes time to confirm them.

[Purpose] An object of the present invention is to be able to two-dimensionally evaluate and clearly recognize whether or not the exposure amount of the imaging target screen is appropriate, without being affected by noise in the output video signal from the imaging means. In addition, the evaluation target area can be specified as a desired area on the screen, and therefore, an electronic imaging device capable of appropriately taking measures for obtaining a high-quality image based on the evaluation result is provided. Especially.

〔Overview〕

In order to achieve the above object, the electronic image pickup apparatus of the present invention sets the image output of the electronic image pickup apparatus main body and the image pickup device in the main body to either one or both of the saturation level vicinity and the black level vicinity thereof. A binarization circuit that performs a binarization process using a value as a threshold level, and a video signal level takes an abnormal value for each predetermined unit area consisting of a plurality of pixels when a binarized signal is obtained by this binarization process. In order to eliminate the influence of noise in the above video output, by recognizing the ratio of pixels closing the unit area and treating this unit area as an area not having an abnormal value when this ratio is less than or equal to a predetermined value. , A noise killer circuit, and a binarizing means including both circuits, a binarizing signal obtained by the binarizing means to be a binarized video signal, and the binarized video signal. No two It is characterized by comprising a metering means for metering the appearance degree of area represented by either.

〔Example〕

FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention. The optical image from the subject 1 is an image pickup lens 2, a diaphragm 3,
Imaging device 6 through half mirror 4 and shutter 5.
It is incident on the light receiving surface of and forms an image. A part of the optical image of the subject is formed on the focus glass 7 by the half mirror 4.
The optical image formed on the focus glass 7 is visible through the penta prism 8 and the eyepiece lens 9. An electronic image is displayed on the display device 10 as will be described later, and this electronic image is projected by the half mirror 11 on the optical axis connecting the focus glass 7 and the pentaprism 8. . Therefore, the electronic image is also visible through the pentaprism 8 and the eyepiece lens 9. The display device 10 is composed of a scanning type two-dimensional solid-state display element such as a liquid crystal or a light emitting diode.

2 and 3 are a front view and a side view showing the structure of the shutter 5.

As shown in FIGS. 2 and 3, the shutter 5 is a rotary shutter in which the shutter speed is variable by controlling the phases of the two discs with slits 12 and 13.
That is, the two discs 12 and 13 are arranged so that the two servomotors 14 and 1 are opposed to each other so that the centers of rotation are coaxial.
5 is attached to each shaft. One disk 12
Is provided with three slits A, B, and C divided by 90 degrees. The other disc 13 has two slits a and b
It is provided in 80 degree division. The discs 12 and 13 are rotated and supported at 1800 PRM when the image pickup device 6 is driven at a field frequency of 60 Hz. Therefore, shutter exposure can be performed on the image pickup device 6 every 1/60 sec.

On the other hand, the servomotors 14 and 15 are subjected to phase servo so that the slit positions of them are constant. Then, by controlling the phase shift of the phase servo by a shutter control signal based on photometric information described later, the slit widths W1 and W2 can be changed to continuously and steplessly adjust the shutter width. .

When slits A and a overlap, slit B
Since b and b always overlap, exposure can be performed every 1/60 seconds. Therefore, it becomes suitable for the feed recording mode in the electronic camera.

When the phases of the disks 12 and 13 are shifted from the position shown in the drawing by about 90 degrees in the clockwise direction in FIG.
And overlap. At this time, since the slits A and B of the disc 12 overlap the light-shielding portion of the disc 13, only the slit C works effectively. Therefore, in this case, exposure can be performed every 1/30 seconds. Therefore, it becomes suitable for the frame recording mode in the electronic camera.

Description will be returned to FIG. A main control circuit 20 shown at the lower end of the figure controls the entire apparatus. The main control circuit 20 includes an automatic / manual selection switch 21, an image confirmation switch 22, a recording switch 23, a reproduction switch 24, an aperture value setting device 25,
A shutter speed setting device 26, a display changeover switch 27, a display brightness adjusting device 28 and the like are provided.

Thus, the main control circuit 20 performs the normal program automatic exposure recording control when the automatic / manual select switch 21 is set to the automatic side. That is, based on the output signal from the external photometry circuit (not shown) or the photometry signal from the average photometry circuit 30, each time the recording switch 23 is pressed, the aperture control circuit 31 and the shutter speed control circuit 3 are pressed.
2, image pickup device drive circuit 33, recording switch circuit 3
4, a control signal is output to the recording / reproducing circuit 35 to record an image. In this case, as described above, the optical image picked up by the image pickup device 6 is converted into an electric signal and amplified by the preamplifier 36, then becomes a predetermined video signal in the visualization circuit 37, and the normally closed side 38 b of the changeover switch 38. , Through the recording switch 34 to the recording / reproducing section 35. Then, the image is recorded in the memory built in the recording / reproducing unit 35.

Further, the main control circuit 20 has an automatic / manual select switch 21.
When the mode is switched to the manual side, the set values of the aperture value setting device 25 and the shutter speed setting device 26 are read, the aperture control circuit 31 and the shutter speed control circuit 32 are operated, and the aperture 3 is set each time the recording switch 23 is pressed. The same recording is performed by controlling the aperture value and the shutter speed of the shutter 5.

On the other hand, when a TV program is created by playing back images captured by a TV camera and joining many screens with many bad signals, and joining only screens with few bad signals, press the play switch 24 to record and play. The section 35 and the reproduction switch circuit 39 are activated to read the video signal recorded in the memory. The read-out reproduction video signal is read by the control signal from the main control circuit 20 to the normally open side 3
Instead of the raw signal from the visualization circuit 37, it is supplied to a binarization circuit, etc., which will be described later, via the changeover switch 38 which has been switched to 8a.

If you want to evaluate the image quality without recording the image,
The image confirmation switch 22 may be pressed. That is, each time the switch 22 is pressed, the imaged image is evaluated as follows. For simplification, the case where the automatic / manual select switch 21 is set to the manual side and the changeover switch 38 is changed to the normally closed side will be described. When the image confirmation switch 22 is pressed, the imaging device 6 is operated under the conditions of the diaphragm and shutter speed based on the manually set values.
The optical image formed above is read once as an electric signal by the operation of the imaging device drive circuit 33, and the preamplifier 3
The signal is amplified in 6 and then converted into a predetermined video signal in the imaging circuit 37. Here, for the sake of simplification, an NTSC standard composite video signal will be described. This composite video signal is output to the changeover switch 3
8, the first comparator 41 and the second comparator 42 of the binarizing circuit 40, the video signal synthesizing circuit 5
0, output to the average photometry circuit 30. The composite video signal S1 applied to the first comparator 41 has a white level setting value VS set to be slightly lower than the saturation level V1 of the video signal.
Is converted into a binarized signal having a logical value "1" for portions exceeding this and a logical value "0" for portions not exceeding this. Similarly, the composite video signal S1 applied to the second comparator 42 is based on the black level set value VD that is set slightly higher than the black level V2 of the video signal, and the portion below this is the logical value "1", It is converted into a binarized signal having a logical value "0" in the portion that does not fall below. Then, these binarized signals are applied to the respective input terminals of the AND gates 43 and 44. The synchronizing signal from the synchronizing signal generating circuit 60 is applied to the other input terminals of the AND gates 43 and 44. Thus, each binarized signal has the blanking interval portion removed. The binarized signal S from which the blanking period is removed
2 and S3 are further connected to the OR gate 45 through the signals S2 and S.
3 becomes an OR output and becomes a binarized image quality defect signal S4.

FIG. 4 is a waveform diagram showing how the binarization is performed. As shown in FIG. 4, in the −horizontal scanning period H of the composite video signal S1, the portion exceeding VS has a logical value “1”, and the portion during blanking is removed to become the binarized signal S2. . Further, the portion below VD also has the logical value "1", and the blanking period portion is removed to become the binarized signal S3. The binarized image quality defect signal S4 is an OR output of the signals S2 and S3. In addition, S5 in FIG.
The binarized image quality defect signal S4 obtained as described above is passed through the area setting circuit 70 shown in FIG.
Is a binarized video signal for specifying a defective image quality portion, which is a signal obtained by adding the synchronizing signal from the synchronizing signal generating circuit 60 after being adjusted to a proper gain and being added to the synchronizing signal.

FIGS. 5A and 5B are examples of one screen of the binarized video signal S5 thus obtained. This example is an example of a subject P1 who is a person standing against the window at the back of the sunset as shown in FIG. 7A, and when the image confirmation switch 22 is pressed, as shown in FIG. The defective image area P2
It is shown that a binarized electron image P3 that clearly indicates is obtained. That is, the back faced part of the person's face is the under-exposed part, the sunset part is the over-exposed part, and these parts are the poor image quality part P2.

In this way, the distribution of the area itself where the exposure amount is inappropriate on the screen can be visually confirmed as a binarized image pattern through the display means. Therefore, the photographer can change the framing by changing the zoom ratio or the direction of the camera according to the result of the above confirmation,
Alternatively, an appropriate response can be taken by manually changing the exposure setting or correcting the exposure.

Here, the explanation is returned to FIG. 1 again. The binarized video signal S5 obtained by the video circuit 80 is the video signal synthesis circuit 5
Supplied to zero. The video signal synthesizing circuit 50 supplies only the binarized video signal S5 to the display device 10 by the selection of the display changeover switch 27, or the output of the above-mentioned visualization circuit 37, that is, before performing the binarization process. Only the video signal is supplied to the display device 10, or further, the binarized video signal S5 is converted into a composite image signal which is analogically superimposed on the video signal before the binarization processing, and this is supplied to the display device 10. . A display brightness adjusting circuit 51 is inserted between the video signal synthesizing circuit 50 and the display device 10 so that the brightness of the display device 10 can be adjusted by an instruction from the display brightness adjuster 28. Further, if the display device 10 is turned off as necessary, only the image by the optical finder can be seen.

By the way, the area setting circuit 70 selects a predetermined area pattern, for example, a pattern as shown in FIGS. 6 (a) and 7 (a)-(d).
1, an image quality check area designation signal generation circuit 72 for generating a signal designating an image quality check area according to the pattern selected by the area pattern selection circuit 71, and the binary value according to the designation signal from this circuit 72. It is composed of a gate circuit 73 for passing the converted signal.

As shown in FIG. 6A, the area pattern selection circuit 71
When a pattern is selected in which the area 76 in the central portion of the screen 75 is used as the image quality check area, the image quality check area designating signal generating circuit 72 outputs a horizontal line H1 to the video signal S1 as shown in FIG. 6 (b). In H7, signal "0",
A signal "1" having a width T is transmitted on the horizontal lines H2 to H6, and this is given to one input end of the gate circuit (AND) 73. The other input terminal of the gate circuit 73 is supplied with the output signal of the binarizing circuit 40, that is, the binarizing signal S4. Therefore, the binarized signal S4 is applied to the gate circuit 7 only during a period in which the gate circuit 73 receives the designation signal from the image quality check area designation signal generation circuit 72.
Pass 3. This passing signal is supplied to the above-mentioned visualization circuit 80 via the image logic circuit 74. Therefore, the specific region 76 of the binarized video signal described above becomes effective as the photometric information for image quality determination. The area pattern to be selected is an extremely small rectangular area in the center of the screen as shown in FIG. 7 (a), a rectangular area below the screen as shown in FIG. 7 (b), and a screen center as shown in FIG. 7 (c). Various areas such as a circular area, a triangular area at the center of the screen as shown in FIG.

By performing the binarized image processing and the area setting processing as described above, the photographer can see the image quality information in the desired area on the electronic viewfinder as a two-dimensional image every time the photographer presses the image confirmation switch 22. It is possible to quickly and accurately determine the shooting conditions. By performing such a two-dimensional image quality evaluation, it is possible to deal with a special imaging condition that cannot be dealt with by the above-described average photometry circuit. Especially, since the latitude of video system is narrower than that of film system, such two-dimensional image quality evaluation is effective.

Next, an example in which the above-described two-dimensional image quality evaluation method by the image signal processing system is further developed and automated will be described. In other words, it is a means for adding the operability equivalent to the present fully automatic exposure single-lens reflex camera with shutter speed priority or aperture priority. Aperture value setting device 25 is "automatic""F1.4""F2"
The setting "F16" can be performed, and the shutter speed setting device 26 is set to "auto""1/60""1/1".
25 "..." 1/1000 "can be set. Then set the aperture setting device 25 to "automatic",
If the shutter speed setting device 26 is set to a value other than "automatic",
The shutter speed priority mode is set. Conversely, when the shutter speed setting device 26 is set to "automatic" and the aperture value setting device 25 is set to a value other than "automatic", the aperture priority mode is set.

When the screen confirmation switch 22 is set to the continuous side, the shutter speed automatically changes continuously in the aperture priority mode, and conversely, the aperture value automatically changes continuously in the shutter speed priority mode. The video signal corresponding to the change step of is sent to the binarization circuit 40. The output of the binarization circuit 40, that is, the image quality defect signal S4 is the area setting circuit 7
In the image logic circuit 74 provided at the output terminal of 0, in order to remove the influence of noise in the image output of the image pickup device 6, the noise killer circuit described below is applied to perform noise removal processing and sampled pixels. It is divided into and subjected to logical processing. As this logical processing, for example, a unit area, which is a unit to be evaluated by combining pixels into 2 × 2 or 3 × 3, is assumed, and for each unit area, there are only one or two defective pixels. A noise killer circuit for ignoring is disregarded, and processing such as invalidating an image quality defect signal in a minute area is performed. That is, this noise killer circuit recognizes the ratio of pixels having an abnormal value in the video signal level for each unit area as described above, and when this ratio is below a predetermined value, the unit area has an abnormal value. The effect of noise during the video output is removed by treating it as not. A binarizing unit is configured to include both the binarizing circuit and the noise killer circuit. Regarding the defective pixel remaining as a result of the above logical processing, this is regarded as an abnormal pixel, and the degree thereof is calculated by the abnormal pixel integration circuit (or abnormal pixel counter) 91. That is, this metric value is the degree of appearance of a region (for example, this corresponds to a high-brightness portion of the image which is equal to or higher than the saturation level) of the binarized video signal represented by either 1 or 0, or binary such as H or L. It represents the frequency of appearance. The image logic circuit 74 having the above functions constitutes the weighing means of the present invention.
The above-described processing is automatically performed by the measuring means for a plurality of different exposure amounts, and the result is evaluated by the minimum value detection circuit 92, and the exposure condition that minimizes the pixels is determined. The main control circuit 20 outputs the exposure condition of each step, that is, the shutter speed and the aperture value to the minimum value detection circuit 92.

FIG. 8 specifically shows the above-mentioned contents. Cases A and B are different for two subjects and different ambient conditions at the time of shooting.
This is an example evaluated by the shutter speed priority method. Case A
Then, when the shutter speed is 1/250 seconds, the best condition is the diaphragm 4. In case B, the best condition is not obtained when the shutter speed is 1/250 sec, and the best condition is obtained when the shutter speed is 1/60 sec and the aperture is 3.5. In this example, the shutter speed is prioritized, but the aperture may be prioritized or a slightly programmed simple form may be used. Since the above-mentioned automated image quality evaluation processing can be electrically performed in almost real time, if the system is operated in a mode compatible with the NTSC standard television system, 60 conditions per second can be checked. If the diaphragm or shutter is mechanical, the operating conditions are limited and the processing conditions per second are reduced, but if it becomes possible to use a physical shutter without mechanical operating parts, a physical diaphragm, etc. It is possible to check 60 conditions per second.

As described above, according to the present embodiment, there is no drawback of the conventional video image pickup system, and the multifunctional image pickup can be achieved, which is impossible with the film system, as described below.

(1) The image quality can be determined as a two-dimensional image without the ambiguity of the image that the conventional average photometry method has.

(2) Image quality can be displayed with a 1: 1 corresponding positional relationship with the actual image.

(3) Automation is implemented so as to satisfy the above (1) and (2).

(4) In addition to the condition setting at the time of recording, the image quality of an already recorded image can be evaluated.

(5) The optical image and the electronic image can be made to correspond to each other at a ratio of 1: 1.

(6) It is possible to sufficiently check the deterioration factor of the image quality, which becomes unclear due to the conventional FM recording method or modulation method at the time of recording, before recording, and prevent the occurrence of color skipping.

(7) Either the optical finder or the electronic finder can be selectively used.

Next, a second embodiment of the present invention for further improving the photometric accuracy will be described. In FIG. 1 described above, the binarization levels VS and VD are commonly used as a circuit for both imaging and reproduction. V in FIG.
Since S and VD can be set as appropriate levels for the evaluation of the reproduction image quality, the idea of FIG. 1 can be used for the evaluation of the reproduction image quality. However, at the time of imaging or recording, the circuit of FIG. 1 is not very accurate. The reason is that the imaging circuit 37 shown in FIG. 1 includes a gamma correction circuit, a knee circuit, a clipping circuit, etc. for changing the output of the image pickup device 6 as process circuits. Therefore, if the output of the image pickup circuit 37 is binarized and used as it is in this state, the image quality of the image output distorted by the action of the process circuit is evaluated. Therefore, at the time of recording, it is preferable that the binarization circuit 40 be in the preceding stage of the process circuit.

This will be specifically described below with reference to FIGS. 9 and 10. 9th
The figure shows the preamplifier 3 with respect to the amount of light incident on the imaging device 6.
6 is a diagram showing the relationship between the signal output of 6 and the signal output of the process circuit described above. FIG. In FIG. 9, the amount of light incident on the image pickup device 6 corresponding to the optimum white level is 100%, and the signal output of the preamplifier 36 at that time is I _o = 0.
It is assumed that the reference output is 7V. Assuming that the gamma characteristic of the image pickup device 6 is γ = 1, the signal output of the preamplifier 36 increases in proportion to the amount of incident light, as indicated by the solid line K in FIG. Saturation at 3 I _o or higher is due to clipping at the clip level by the preamplifier 36. When the signal output of the preamplifier 36 enters the process circuit as an input, the output of the process circuit becomes an output as shown by a broken line M in FIG. That is, the amount of incident light is 0
For 100%, the gamma correction circuit works and γ = 0.
The inclination is corrected to 45. In addition, the amount of incident light is 100 to 200.
In the region of%, the output of the knee circuit is extremely small due to the function of the knee circuit. When the light amount is 200 to 300%, the output m2 of a constant voltage is suppressed by the clip circuit. Therefore, the output of the process circuit does not directly transmit the photometric information of the image pickup device 6.

Therefore, in the present embodiment, as shown in FIG.
Is provided in parallel with the process circuit at the output end of the preamplifier 36 to improve the image quality evaluation accuracy during image pickup or recording. The binarization level VS in this case is
As shown in FIG. 9, the voltage E1 corresponding to the incident light amount of 100 to 150% is set. The binarization level VD is set to the voltage E2 corresponding to the incident light amount of 0 to 10%.

As shown in FIG. 10, the output of the image pickup device 6 is amplified by the preamplifier 36 and sent to the process circuit 100 and the binarization circuit 40 for giving a suitable display function to the monitor screen. The black level of the output of the preamplifier 36 is clamped by the clamp circuit 101 in order to stabilize the image quality. AGC of process circuit 100
When the amount of light incident on the image pickup device 6 is insufficient, the circuit 102 receives the output from the main control circuit 20, amplifies the signal voltage, and sends it to the gamma correction circuit 103. Gamma correction circuit 1
03 converts the input into a curve of γ = 0.45 and sends it to the knee circuit 104. The knee circuit 104 is a gamma correction circuit 103.
When the output is within a predetermined value, the input is set to the output m1 having a low slope as shown in FIG. Clip circuit 105
When the output m1 of the knee circuit 104 is a predetermined value or more, the output is clipped to the output m2 having a constant voltage value.
About 1 V is selected as the clip voltage.

On the other hand, the signal from the preamplifier 36, which has been subjected to the black level clamp processing as described above, is supplied to the binarization circuit 40 and is regarded as an image quality defective signal as in the above embodiment. The image quality defect signal is converted into a binarized video signal by the video conversion circuit 80 and output to the video signal synthesis circuit 50. The other input of the video signal synthesis circuit 50 is the process circuit 1 described above.
00 is a raw video input obtained by processing the output of 00 by the visualization circuit 106. The video signal synthesizing circuit 50 analog-adds the binarized video signal and the raw video signal to form a synthetic image, and outputs it to the display system 110 such as an electronic finder. Note that the binarized image quality defect signal is the pixel integration circuit 9 as in the previous embodiment.
1, also supplied to the minimum value detection circuit 92. Thus, information indicating the degree of image quality failure is supplied to the main control circuit 20.

As described above, in the present embodiment, the quality of the image quality is determined by using the output of the preamplifier 36 that is sufficiently reliable as the photometric information. Therefore, as compared with the first embodiment,
Image quality can be evaluated with higher accuracy. In the same way, in FIG. 10, the output of the preamplifier 36 is guided to the photometric circuit 30 as it is, and the shutter 5 or the diaphragm 3 is controlled.

Although an integrating circuit is usually used as the photometric circuit 30, it is also possible to perform photometry within a specific pattern area as shown in FIG. That is, a pattern signal is generated by the pattern generation circuit 201 that operates in response to a control signal from the main control circuit 20, and a timing signal designating a specific area is transmitted from the photometric control timing circuit 202 based on this pattern signal. Then, by applying this timing signal to the analog switch 203 and the integrating circuit 204, an average photometric signal of a specific region is obtained.

The present invention is not limited to the above embodiments. For example, as the electronic pixel display means, a toning filter may be provided on the entire surface of the display device 10 made of liquid crystal or the like to form a color contrast suitable for visual observation.

Also, the operation switches and modes should be given different types or names depending on the application of the present invention.

Also, as the circuit system, various system other than the above-mentioned embodiment can be applied.

As the recording / reproducing means, an optical disk, a magnetic disk,
The image memory such as a magnetic tape or a solid-state memory can be used.

Further, it is possible to construct various recording modes and reproduction modes by utilizing the function of the present invention.

Further, in the above-described embodiment, the case where the OR output of VS and VD is used as the defective image quality signal is shown, but it goes without saying that VS or VD may be used alone.

Further, in the above-described embodiment, two threshold levels VS and VD are shown as the threshold level for binarization, but the threshold levels are not limited to the above two, and for example, VS1, VS2 ..., VD1, V.
D2 ..., may be multivalued, or VS, VD
The value of may be variably set by an external volume on the control panel surface. By doing so, it is possible to evaluate the image quality with higher accuracy.

Further, in the above-described embodiment, the two disks 12 and 13 with slits are used as the shutter 5 in an overlapping manner.
Although the rotary shutter in which the shutter speed is made variable by controlling the phase of is described above, a film-running shutter of a front film and a rear film may be used. Further, in the above-mentioned embodiment, the case where the binarized video signal is displayed on the electronic finder of the apparatus main body is illustrated, but it is not always necessary to display it on the electronic finder, and the point is to obtain the binarized video signal. hand,
This may be made visible on another monitor or the like.

[Effect of the Invention] As described above, the present invention photoelectrically converts an optical image incident through the imaging lens of an electronic camera into an image signal by an imaging device, and binarizes the image signal by, for example, two comparators. In addition to the circuit, the video signal is converted into a binarized signal by the threshold level set in this binarization circuit,
An image forming circuit forms a binarized video signal for displaying an image corresponding to the binarized signal based on the binarized signal, and further includes, for example, a region pattern selection circuit and a gate circuit. It is characterized in that a specific portion of the binarized video signal is made effective as photometric information by the area setting means.

Therefore, according to the present invention, the following operational effects can be expected.

a) It is possible to visually confirm, as a binarized image pattern, the distribution of the area itself where the exposure amount is inappropriate in the desired area on the screen through the display means. In other words, the two-dimensional image quality evaluation can be performed on a desired area in the screen.

b) Therefore, the photographer can change the zoom ratio or the direction of the camera according to the result of the above confirmation,
Appropriate measures can be taken by changing the framing or manually changing the exposure setting or exposure compensation.

c) The suitability of the exposure amount of the screen thus imaged can be evaluated quickly and accurately for each part of the screen,
Moreover, the area to be evaluated can be specified as a desired area on the screen, and it is possible to provide an electronic camera capable of accurately obtaining a high-quality image.

d) In particular, in the process of obtaining the binarized video pattern, a conversion process into a binarized signal is performed by applying a noise killer circuit for removing the influence of noise in the video output of the imaging device. The exposure of the image can be accurately evaluated without being affected by noise.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall construction of the first embodiment of the present invention, FIGS. 2 and 3 are front and side views showing the structure of a rotary shutter of the same embodiment, and FIG. 4 is the same. FIG. 5 (a) is a signal waveform diagram showing binarization of the embodiment.
FIG. 9B is a diagram showing a screen state due to a binarized image quality defect signal,
6 (a) and 6 (b) and FIGS. 7 (a) to 7 (d) are diagrams showing how the area is set by the area setting circuit, and FIG. 8 shows the number of abnormal pixels for each condition of aperture and shutter speed. FIG. 9 is a diagram showing the relationship, FIG. 9 is a diagram showing the relationship between the preamplifier output and the process circuit output with respect to the incident light amount, FIG. 10 is a block diagram showing the configuration of the second embodiment of the present invention, and FIG. 11 is the same embodiment. FIG. 8 is a block diagram showing a modification of the photometric circuit in FIG. 1 ... Subject, 2 ... Imaging lens, 3 ... Aperture, 4 ...
Half mirror, 5 ... Shutter, 6 ... Imaging device,
7 ... Focus glass, 8 ... Penta prism, 9 ... Eyepiece lens, 10 ... Display device, 11 ... Half mirror, 12, 13 ... Slit disk, 14, 15 ... Servo motor, 20 ... ... Main control circuit, 21 ... Automatic / manual select switch, 22 ... Image confirmation switch, 23 ...
... recording switch, 24 ... reproduction switch, 25 ... aperture value setting device, 26 ... shutter speed setting device, 27 ... display changeover switch, 28 ... display brightness adjusting device, 34 ... recording switch circuit, 39 ...... Playback switch circuit, 38 ...
... changeover switch, 40 ... binarization circuit, 41 ... first comparator, 42 ... second comparator, 43, 44 ... AND gate, 45 ... OR gate, 70 ... area setting circuit,
S1 ... Composite video signal, S2, S3 ... Binary signal, S
4 ... Binarized image quality defect signal, V1 ... White level set value,
VD ... Black level, VS ... White level setting value, VD ...
Black level setting value, P1 ... Subject, P2 ... Poor image quality portion, P3 ... Binarized electronic image.

Claims (1)

[Claims] 1. An electronic image pickup apparatus main body, and binarization processing is performed with a threshold value set to a value set to either or both of a saturation output level and a black level level of a video output of the image pickup device in the main body. The binarization circuit and the binarization process are performed to obtain a binarized signal. For each predetermined unit area consisting of a plurality of pixels, the ratio of the pixel having an abnormal video signal level to the unit area is confirmed. When this ratio is less than or equal to a predetermined value, the unit area is treated as an area that does not take an abnormal value and includes both circuits of the noise killer circuit for removing the influence of noise in the video output. The binarization means, the visualization means for converting the binarized signal obtained by the binarization means into a binarized video signal, and the appearance of a region represented by any one of the binary values of the binarized video signal. Fits electronic imaging apparatus characterized by comprising a metering means for metering.