JP3327614B2 - Imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus for photographing an object by dividing the object into a plurality of regions and synthesizing a video signal in each region to obtain a high-definition image or a panoramic image.

[0002]

2. Description of the Related Art A so-called image synthesizing camera that divides a subject into a plurality of regions, synthesizes video signals obtained by photographing the respective divided regions, and creates a high-definition image or a panoramic image has been conventionally known. FIG. 4 is a block diagram showing a configuration of a conventional image synthesizing camera as this type of imaging apparatus, and FIG.
FIG. 5 is a diagram illustrating an example of dividing a subject when taking a picture with the image combining camera. The image synthesizing camera shown in FIG. 4 includes an optical lens 1, an image sensor 2, a sample and hold circuit 3, a signal processing circuit 4, an A / D converter 5, a memory controller 7, a DSP 8, a D / A converter 9, and a recording circuit 10. A recording medium 11 such as a magnetic disk is connected in this order, and a memory 6 is connected to the memory controller 7. Further, a synchronizing signal generating circuit 12 and a system controller 13 to which a colorimetric sensor 14 is connected are provided, and the synchronizing signal generating circuit 12 synchronizes the operation of each unit such as a sample hold pulse and a clamp pulse. A clock is output and supplied to each unit. Also, the system controller 13
Calculates a white balance correction value and a luminance correction value based on the color temperature of external light detected by the colorimetric sensor 14 and controls the overall operation of the image synthesis camera.

In photographing, as shown in FIG. 5, the subject is divided into nine regions, i.e., regions I to IX, and taking into account that the main part of the subject is often located at the center of the photographing frame. Are set as, for example, region V, region IV, region VI, region II, region VIII, region I, region III, region VII, and region IX. First, an area V is photographed by pointing the optical lens 1 of FIG. 4 toward the area V of the object, an optical image of the area V of the object is formed on the imaging surface of the image sensor 2, and the optical image is photoelectrically converted. The imaging device 2 outputs an electric signal corresponding to the region V of the subject. The electric signal is input to the sample hold circuit 3, which outputs a video signal corresponding to the region V of the subject.

The video signal is input to a signal processing circuit 4, and the signal processing circuit 4 responds to the video signal by a command signal from a system controller 13 in response to the color temperature of external light input from a colorimetric sensor 14. , White balance (WB) correction is performed, and further, luminance correction and γ conversion are performed. The video signal subjected to the white balance correction, the luminance correction, and the γ conversion in this manner is AD-converted into a digital signal by the AD converter 5 and input to the memory controller 7. Then, the data is stored in a predetermined area of the memory 6 by the memory controller 7.

[0005] Then, the optical lens 1 is pointed at the region IV of the subject, and the region IV is photographed.
The video signal corresponding to the region IV of the subject is subjected to white balance correction, luminance correction, and γ conversion, A / D converted, and stored in a predetermined region of the memory 6. In the same way,
The video signals of the subjects corresponding to the respective regions are sequentially stored in the memory 6 in the order of VI, region II, region VIII, region I, region III, region VII, and region IX. The video signal is stored in the memory 6.

When the storage of the video signal of each area of the subject in the memory 6 is completed in this way, the video signal of the entire subject is obtained based on the video signal corresponding to each area by a command signal from the memory controller 7. Are synthesized, and the synthesized video signal is output from the memory controller 7,
The digital signal is processed by the DSP 8 into a predetermined format. The video signal subjected to the signal processing in this manner is DA-converted into an analog signal by the DA converter 9, converted into a predetermined format by the recording processing circuit 10, and recorded on the recording medium 11.

In this conventional image synthesizing camera, it is desirable that the AE (automatic exposure) level and the white balance level of the video signal corresponding to each area are all the same. The correction value of each area after the area VI is set according to the level.

[0008]

In the above-mentioned conventional image synthesizing camera, a colorimetric sensor for measuring the color temperature of external light is required for white balance correction. There is a problem that the increase in the number of cameras and the miniaturization of the whole camera are hindered. In this case, it is conceivable to adopt a TTL method in which white balance adjustment is performed by using the output of the image sensor without using a colorimetric sensor. However, white balance adjustment is performed for each shooting of each area, and each area is adjusted. The white balance state varies between the regions due to the video signal. In order to prevent this, for example, it is conceivable that a control value of the white balance in the first region V is obtained, and thereafter, the control value is fixed and used. However, in this case, the control value of the white balance greatly depends on the color of the flower occupying most of the region V, and the control corresponding to the color temperature of the outer color is not performed correctly. In the case of FIG. 5, if the color of the flower is red, it is determined that the outer color is a low color temperature light source,
The correction will be made blue more than necessary.

The same applies to the luminance correction for performing the AE adjustment. For example, if a low-luminance object occupies a large portion in the first photographed area V, the influence is affected by the influence of the low-luminance object as a whole. Exposure is considerably overexposed.

The present invention has been made in view of the current state of signal processing in an image pickup apparatus of this kind as described above. An object of the present invention is to provide an imaging device capable of performing an appropriate correction process on a synthesized video signal without being affected by saturation or luminance of a specific area when synthesizing a video signal to create a synthesized video. .

[0011]

In order to achieve the above object, the present invention provides an image pickup means for dividing a subject into a plurality of regions for photographing, and a video signal of each of the regions output from the image pickup means. In an imaging apparatus comprising: storage means for storing; and synthesizing means for creating a synthesized video signal by synthesizing the video signals of the respective stored areas, at least two of the plurality of shot areas The image processing apparatus further includes a correction unit that corrects the composite video signal based on image characteristics of the video signal.

[0012]

With the above arrangement, the subject is photographed for each of the plurality of regions by the imaging means, and the image signals of each of the photographed regions are stored in the storage means. Then, the synthesizing means synthesizes the video signals in each area to create a synthesized video signal, and the correcting means appropriately corrects the synthesized video signal based on the image characteristics of all the video signals in the area. And a high quality photographed image is obtained.

[0013]

[First Embodiment] FIG. 1 is a block diagram showing the structure of the first embodiment. This first embodiment is the same as that of FIG.
In the configuration of the conventional image synthesizing camera described with reference to, the signal processing circuit 4 is removed, and the DSP 14 that performs signal processing including white balance correction, luminance correction, and γ conversion is replaced with the memory controller 7 and the DA in place of the DSP 8. The output terminal of the sample hold circuit 3 is connected to the system controller 13 via the integrator 15 between the converter 9 and the converter 9. The configuration of the other parts of the first embodiment is the same as that of the conventional image synthesizing camera described above.
In FIG. 1, elements corresponding to those in FIG. 4 are denoted by the same reference numerals.

Next, the operation of the first embodiment will be described. In the following description, as shown in FIG.
Area IX is divided into nine areas, and the main part of the subject is shot frame F
In consideration of the fact that there are many cases in the center of the
It is assumed that the region is set as I, region I, region III, region VII, and region IX.

First, the optical lens 1 is directed to the region V,
A video signal corresponding to the light image of the region V of the subject formed on the imaging surface of the imaging device 2 by the optical lens 1 is output from the sample-and-hold circuit 3 as an RGB signal, and AD-converted by the AD converter 5. The data is input to the memory controller 7 and stored in a predetermined area of the memory 6 according to a command from the memory controller 7. At the same time, the RGB signals are input to the integrator 15, and integration of the RGB signals is performed on the region V. Hereinafter, in the same manner, the video signals corresponding to the respective regions of the subject are sequentially set as the RGB signals in the order of the region IV, the region VI, the region II, the region VIII, the region I, the region III, the region VII, and the region IX. Is output from the A / D converter 5, the A / D converted by the A / D converter 5, and input to the memory controller 7,
The RGB signals are stored in a predetermined area of the memory 6 according to a command from the memory controller 7, and at the same time, the RGB signals are input to the integrator 15, and integration of the RGB signals is performed for each area.

When the integration of the entire region is completed by the integrator 15, an integrated value corresponding to the obtained entire photographed image is input to the system controller 13, and the system controller 13 calculates R based on the integrated value. A white balance correction value is calculated so that the integrated value of the signal, the G signal, and the B signal becomes 1: 1: 1, and a corresponding white balance control signal is input to the DSP 8. On the other hand, the memory controller 7 reads out the video signals corresponding to the respective regions of the subject from the memory 6 after outputting the white balance control signal, combines these video signals, and inputs them to the DSP 14.

The system controller 13 calculates 0.3R + 0.59G + 0.11B as a luminance signal based on the integrated value input from the integrator 15, and this signal level is compared with a preset reference value. A comparison is made to calculate a luminance correction amount, and the corresponding luminance control signal is DS
Input to P14.

Therefore, the DSP 14 performs white balance correction on the composite video signal input from the memory controller 7 by a white balance control signal from the system controller 13, and performs luminance correction by a luminance control signal. Further, predetermined signal processing such as γ conversion is performed. In this way, the video signal of the subject that has been subjected to various signal processing including white balance correction and luminance correction is input to the D / A converter 9 and is converted to an analog signal by D / A conversion. And recorded on the recording medium 11.

Thus, according to the first embodiment,
The system controller 13 calculates a white balance correction value and a luminance correction value based on an integrated value of a video signal corresponding to the entire region of the subject, and the DSP 8 corresponds to the white balance correction value and the luminance correction value. Based on the white balance control signal and the luminance control signal, white balance correction and luminance correction are performed on the composite video signal input from the memory controller 7. For this reason, even if there is a region where the saturation or luminance is significantly different from the others in the divided region of the subject, the effect is suppressed to the minimum, the appropriate white balance correction and luminance correction are always performed, and high quality It is possible to obtain a high-definition image or a panoramic image.

[Second Embodiment] In the second embodiment, the first
In the embodiment, the integrator is configured to integrate a video signal weighted for each area. FIG. 2 is a circuit diagram showing a configuration of an integrator 15A of the second embodiment. The non-inverting input terminal of the operational amplifier 16 is grounded, the capacitor 22 is connected between the inverting input terminal and the output terminal, and Is connected to a system controller 13. Further, between the output side of the sample hold circuit 3 and the inverting input terminal of the operational amplifier 16,
A series connection circuit of the resistor 21, the switch 18, and the resistor 20;
A series connection circuit of a switch 17 and a resistor 19 is connected in parallel with each other. The other parts of the configuration of the second embodiment are the same as those of the first embodiment already described, so that the illustration and description are omitted.

In the second embodiment, at the time of integrating the video signal of the region V where the probability of the existence of the object is highest, the switches 17 and 1 are controlled by a command signal from the system controller 13.
8, the gain of the integrator 15A is set to the maximum,
Next, the areas IV, VI, II,
At the time of integrating the video signal in the area VIII, the switch 18 is closed to set a moderate gain. Further, when integrating the video signals of the regions I, III, VII, and IX with a low probability of the existence of the subject, the switches 17 and 18 are opened to set the gain small. In this manner, an integrated value at a level corresponding to the existence probability of the subject is obtained from the integrator 15A. Other operations of the second embodiment are the same as those of the first embodiment already described. Note that the gain may be set to 0 according to shooting or the situation of the subject.

Thus, according to the second embodiment,
In addition to the effects obtained in the first embodiment, the integrator 15A
However, since the integral value corresponding to the existence probability of the subject is calculated in each region, the accuracy of the luminance correction is particularly improved.

[Third Embodiment] In the third embodiment, when a high chroma portion exists in a subject, the effect is reduced to perform white balance correction. FIG. 3 is a block diagram showing a configuration of a third embodiment. This third embodiment is different from the configuration of the conventional image synthesizing camera already described with reference to FIG.
And a system controller 13, a second memory 23 is newly connected, and between the signal processing circuit 4 and the DA converter 9, an inverse γ conversion circuit 24 is newly connected, and the memory controller 7 is connected.
A direct connection route is newly provided to the D / A converter 9. Since the configuration of the other parts of the third embodiment is the same as that of the conventional image synthesizing camera described with reference to FIG. 4, the components corresponding to FIG. 4 in FIG. is there.

In the third embodiment, the video signal from the sample and hold circuit 3
Temporary white balance correction is performed by a preset gain, and the video signal is further γ-converted, then AD-converted to a digital signal by the AD converter 5, and stored in the memory 6 and the memory 23 via the memory controller 7. You. In this case, in the memory 23, if the level difference between the signal of one pixel and the signal of one pixel before and one line before is less than or equal to the reference value X, it is determined that the subject is the same color and the storage is not performed. In the memory 23, when it is determined from the color difference signals RY and BY output from the DA converter 9 that the portion is a high-saturation portion, the reference value X is set to a large value, and the same subject is set. The video signal that has been subjected to signal processing is stored in a state where the probability of determination is high.

Then, in the system controller 13,
The video signal stored in the memory 23 is read out, a white balance correction value is calculated based on the integrated value obtained by the addition and integration processing, and a corresponding white balance control voltage is output. In this state, the memory controller 7
A video signal is read from the memory 6, and this video signal is
The signal is input to the D / A converter 9 in the same signal format as the output of the sample and hold circuit 3 without passing through the DSP 8, converted to an analog signal by D / A conversion, and input to the inverse γ circuit 24.

Then, the video signal is subjected to inverse γ conversion in the inverse γ circuit 24, input again to the signal processing circuit 4, subjected to white balance correction by the control voltage obtained as described above, and γ converted. Later, it is input to the AD converter 5. The video signal that has been AD-converted into a digital signal by the AD converter 5 is input to the DSP 8 via the memory controller 7, where the signal is processed into a predetermined format by the DSP 8, and
The recording medium 1 is converted from an analog signal to a digital signal by a converter 9 and converted into a predetermined format by a recording processing circuit 10.
1 is recorded.

As described above, according to the third embodiment, the memory 23 omits storing a part of the video signal of the high chroma portion of the subject, and the system controller 13
The video signal read out from the image is added and integrated, and the white balance correction is performed based on the obtained integrated value. Therefore, in addition to the effect obtained in the first embodiment, in particular, the influence of the high chroma portion of the subject is reduced. White balance correction is possible.

In each of the embodiments described above, the case where the subject is photographed in each area by changing the direction of the optical lens has been described. However, the present invention is limited to each of the above embodiments. Instead, it is also possible to provide a plurality of sets of photographing optical systems each having an optical lens and an image sensor corresponding to each region, and switch between these photographing optical systems to photograph a subject in each region.

[0029]

As described above, according to the present invention, an image pickup means for dividing a subject into a plurality of areas for photographing, and a storage means for storing video signals of the respective areas output from the image pickup means. And a synthesizing unit for synthesizing the video signal of each of the stored areas to generate a synthesized video signal. Since there is a correction means for correcting the composite video signal based on the image characteristics of the signal, the white balance correction and the luminance correction appropriate for the composite signal can be performed without being affected by the saturation or luminance of a specific area. And other correction processes.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration of a main part of a second embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration of a third exemplary embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a conventional image synthesis camera.

FIG. 5 is a diagram illustrating an example of dividing a subject.

[Explanation of symbols]

 Reference Signs List 1 optical lens (imaging means) 2 imaging element (imaging means) 6 memory (storage means) 7 memory controller 13 system controller (correction means) 15, 15A integrator (correction means) 23 memory (correction means) 24 inverse γ conversion circuit

Claims (3)

(57) [Claims] An imaging unit that divides a subject into a plurality of regions and shoots the image, a storage unit that stores a video signal of each of the regions output from the imaging unit, and a video signal of each of the stored regions. An image pickup apparatus comprising: a synthesizing unit that generates a synthesized video signal by synthesizing the video signal. The correction of the synthesized video signal is performed based on image characteristics of the video signal in at least two of the plurality of captured areas. An imaging apparatus, comprising: a correction unit that performs correction. 2. The imaging apparatus according to claim 1, wherein the correction unit performs white balance correction on the composite video signal. 3. The imaging apparatus according to claim 1, wherein the correction unit corrects a luminance level of the composite video signal.