JP2000261715A - Image composite device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a picture equivalent to multiple exposure of a silver salt camera with a very simple operation at all times by setting an image pickup device to a consecutive shot state that photographs a picture for a prescribed exposure period and selecting pictures only having pixels of a prescribed level or over in the captured picture for composite pictures. SOLUTION: In an automatic multiple exposure mode, a picture captured by a CCD 1 is fed to a picture memory 4 via a YUV processor 3. Simultaneously the captured picture is also fed to a video encoder 6 for through-picture display. A CPU 8 discriminates whether or not a pixel with a discrimination level or over is in existence in the captured picture and uses the captured picture for an objective of a picture composite when only one pixel as above is in existence in the captured picture. The pictures selected as synthesis objects because the pictures include the pixel with the discrimination level are sequentially composited in the picture memory 4. When the automatic multiplex exposure mode is finished, the composite picture data are written in a recording medium 9 and stored therein.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image synthesizing apparatus which obtains the same effect by synthesizing an image obtained by continuously taking images at a constant exposure cycle in an electronic image pickup apparatus. It is about.

[0002]

2. Description of the Related Art Conventionally, as a photographing method of a silver halide camera, there is a method of performing multiple exposures on the same film to obtain a plurality of superimposed images. To perform multiple exposure, usually set the valve (the shutter is open for a long time exposure) with the front of the lens covered with a black screen, and then perform exposure only while removing the black screen in front of the lens. After the exposure is completed, the front of the lens is again covered with a black screen. By repeating this operation a plurality of times, a multi-exposure image can be obtained.

[0003] A digital camera is known as an electronic image pickup apparatus. In this digital camera, a recording mode and a reproduction mode can be set. In the recording mode, an image pickup device such as a CCD disposed behind the lens outputs a photoelectric conversion output for one screen at regular intervals. This photoelectric conversion output is sampled and held by a sample and hold circuit, converted into digital data by an A / D converter, color processed by a color processing circuit, and digital luminance and color difference multiplex signals (YUV data) and DMA ( Direct Memory Access) output to the controller. The DMA controller is YU of the color process circuit.
The V data output is written into a buffer inside the DMA controller once using the synchronization signal of the color process circuit, the memory write enable, and the clock output.
The data is DMA-transferred to the DRAM via the AMI / F.

After the DMA transfer of the YUV data to the DRAM is completed, the CPU transfers the YUV data to the DRAMI.
Read from DRAM via / F and write to VRAM via VRAM controller. Digital video encoder (hereinafter simply referred to as video encoder)
Periodically reads the YUV data from the VRAM via a VRAM controller, generates a video signal based on the data, and outputs the video signal to a display device. As a result, the display device displays an image based on the image information captured from the current CCD.

When the shutter key is operated at a timing at which recording and preservation is desired while the image is currently displayed on the display device, a signal is generated. Then CPU
After the DMA transfer of one screen of YUV data taken from the current CCD to the DRAM in response to this signal,
Immediately, the path from the CCD to the DRAM is stopped, and the state transits to the record storage state. In this recording and storage state, the CPU
One frame of YUV data written in the RAM is read out via the DRAM I / F for each of Y, Cb, and Cr components in units called a basic block of 8 × 8 pixels and written to the JPEG circuit. , JPE
The code data compressed by the G circuit is read from the JPEG circuit and written to a flash memory which is a nonvolatile memory. Then, with the compression processing of the YUV data for one frame and the end of writing all the compressed data to the flash memory, the CPU starts the path from the CCD to the DRAM again.

In the reproduction mode, the CPU sends a signal from the CCD to the DR.
The path to the AM is stopped, and in response to pressing of an image selection key or the like, the CPU reads out the code data of a specific one frame from the flash memory and writes it into the JPEG circuit,
One frame of YUV data is developed in a VRAM via a VRAM controller in units of 8 × 8 basic blocks obtained by performing a decompression process in a G circuit. Then, the video encoder generates a video signal based on one frame of YUV data developed in the VRAM, and displays the video signal on the display device.

The digital camera as described above can handle a photographed image as image data, so that an effect such as multiple exposure is realized by synthesizing a plurality of all images obtained by photographing a plurality of times. .

[0008]

However, in such a conventional silver halide camera, in order to perform multiple exposure, a bulb (a shutter is in an open state and a long-time exposure state is required) with the front of the lens covered with a black screen or the like. ), And the operation of removing and covering the black screen in front of the lens is repeated several times to obtain a multi-exposure image. It is a CCD to set the camera to a bulb (exposed for a long time because the shutter is open).
The image was superimposed on top, which was difficult due to the discharge of electric charge. Further, after photographing a plurality of times, the operation of synthesizing all the photographed images is very complicated and time-consuming.

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and sets an image pickup apparatus in a continuous shooting state in which an image is continuously taken at a fixed exposure cycle, and a pixel having a certain level or more in a captured image. An object of the present invention is to provide an image synthesizing apparatus capable of obtaining an image equivalent to the multiple exposure of a silver halide camera by a very simple operation since an image to be synthesized is composed of only existing images.

[0010]

In order to solve the above-mentioned problems, the invention according to claim 1 comprises an image pickup means for picking up an object,
An image capturing apparatus having a recording unit for recording a subject image generated by the image capturing unit; a generating unit configured to perform exposure at regular intervals and generate image data of the subject image based on a signal generated by the image capturing unit; Detecting means for detecting the level of each pixel of the image data generated by the generating means; determining means for determining, by the detecting means, image data in which pixels having a predetermined level or higher are detected as an image to be synthesized; And combining means for sequentially combining the determined image data.

As described above, according to the first aspect of the present invention, the imaging apparatus is set to a continuous shooting state in which an image is continuously taken at a constant exposure cycle, and the level of each pixel in the captured image is detected. Since only the images having the above-mentioned pixels are determined and sequentially synthesized, it is possible to obtain an image equivalent to the multiple exposure of the silver halide camera by a very simple operation.

According to a second aspect of the present invention, in the combining means, an image is combined by adding the level of each corresponding pixel.

As described above, according to the second aspect of the present invention, it is possible to obtain a composite image by performing simple level addition on the level of each pixel.

The invention according to claim 3 is characterized in that the combining means compares the level of each corresponding pixel, selects the larger one, and combines the images.

As described above, according to the third aspect of the present invention, it is possible to obtain a composite image by comparing a level of each pixel and selecting a higher pixel level. Further, the invention according to claim 4 is characterized in that the detecting means includes a determining means for determining the image data detected when the average value of the levels of all the detected pixels is equal to or higher than a predetermined level as an image to be synthesized. And

As described above, according to the invention, when the average value of the levels of all the pixels detected by the detecting means is equal to or higher than a predetermined level, the image can be determined to be an image to be synthesized. Become.

According to a fifth aspect of the present invention, the detection means includes a determination means for determining, when a predetermined number or more of pixels having a predetermined level or more are detected, the detected image data as an image to be synthesized. It is characterized by:

As described above, according to the fifth aspect of the present invention, when the number of pixels detected by the detecting means is equal to or higher than a predetermined level and equal to or higher than a predetermined number, the image can be determined to be an image to be synthesized.

According to a sixth aspect of the present invention, in the synthesizing means, when the level of each corresponding pixel is equal to or less than a predetermined level, the images are synthesized with an average value of the pixels.
When one of the levels of the corresponding pixels is equal to or higher than a predetermined level, the image is synthesized by adding the levels of the corresponding pixels.

As described above, according to the present invention, when the level of each pixel is equal to or lower than the predetermined level, the images are synthesized with the average value of the respective pixels, and the level of each corresponding pixel is calculated. If either one is equal to or higher than a predetermined level, the image is synthesized by adding the level of each corresponding pixel, so that repeated image synthesis can prevent a dark part of the image from becoming bright and have a high contrast. A composite image can be obtained.

According to a seventh aspect of the present invention, when the level of each corresponding pixel is equal to or less than a predetermined level, the synthesizing means selects the smaller one to synthesize an image, and the level of the corresponding pixel is selected. When either one of them is equal to or higher than a predetermined level, a level is added for each corresponding pixel to synthesize an image.

As described above, according to the present invention, when the level of each pixel is equal to or less than the predetermined level, the smaller one is selected and the image is synthesized, and one of the levels of the corresponding pixel is selected. If the level is equal to or higher than a predetermined level, the image is synthesized by adding the level of each corresponding pixel, so that repeated image synthesis can prevent a dark part of the image from becoming bright, and obtain a high-contrast synthesized image. It becomes possible.

The image data generated by the generating means may be composed of RGB components, and the pixel level detected by the detecting means may be a value obtained by adding the RGB values. Yes, the synthesizing means synthesizes an image by adding RGB for each corresponding pixel for each component.

As described above, according to the eighth aspect of the present invention, even for a color image in which each pixel is composed of three types of RGB, each pixel level obtained by adding each RGB value is detected, and each pixel level is detected. RGB can be added for each component to synthesize an image, and an image equivalent to multiple exposure shooting by a silver halide camera can be obtained.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of the present apparatus. In the recording mode, the image captured by the CCD 1 is transferred to the YUV processor 3 by the CCD controller 2 which controls the CCD.
Sent to The image data subjected to the color process processing by the YUV processor 3 is sent to the image memory 4 via the memory controller 5. At the same time, the image data captured for displaying a through image is also sent to the video encoder 6, which generates a video signal based on the image data sent from the memory controller 5 and outputs the video signal to the video output unit 7. . The key processing unit 10 processes a key input.

Here, if the automatic multiple exposure mode is set, the CPU 8 determines whether or not there is a pixel higher than the judgment level in the captured image, and if any such pixel exists, Make the captured image a target for image synthesis. As described above, the images to be combined due to the presence of the pixel at or above the determination level are sequentially combined in the image memory 4. When the automatic multiple exposure mode ends, the synthesized image data is written and stored in the recording medium 9. Since a pixel having a certain level or more is determined from the captured image and image synthesis is performed, a synthesized image can be easily obtained.

FIG. 2 shows the timing of exposing the CCD 1 of this apparatus, transferring the captured image, and determining the image to be combined. Exposure of the CCD 1 and image transfer to the image memory 4 are performed based on the frame pulse F output every frame period. In the present embodiment, it is set so that one image is obtained with an exposure time for four frames. Upon completion of the exposure for four frame times, the image transfer from the CCD 1 to the image memory 4 is immediately performed. Among images transferred every four frames, an image including pixels at or above the image synthesis determination level is a target to be synthesized. Since not all images are combined but only necessary images are selected and combined, efficient image combining can be performed without complexity. Further, the exposure time is fixed to a period of four frames, but the exposure time is not limited to four frames.

FIG. 3 shows a method of judging an image to be synthesized as to whether or not a pixel having a certain level or more exists in the image fetched from the CCD 1. For simplicity, each pixel is monochrome and has a level of 0 to 255 (8 bits). The level of each pixel is equivalent to the brightness or shading of the pixel. The captured image 11 is 4-13
Pixels of the following level. Judgment level is 10
Since it is set to 0 and the image 11 does not have any pixels with a level of 100 or more, the image 11 is an image that is not an object of image synthesis. The captured image 12 is 2
156 pixels. Image 12
Has five pixels of level 100 or higher. Therefore, since one or more pixels of level 100 or more exist, the image 1
2 is a target of image composition.

As another discrimination method, the discrimination may be made based on the average value of the levels of all the pixels in the image, or by the number of pixels such as the number of pixels having a certain level or more in the image. Is also good. Further, as described above, in FIG. 3, a monochrome image (when each pixel has one type of level) has been described as an example, but a similar image is obtained for a color image in which each pixel is composed of three types of RGB. Can be used. In this case, each pixel level for determining an image to be combined uses a value obtained by adding three values of RGB for each pixel, and in combining images, the values of each of the RGB are assigned to two corresponding pixels. The RGB values after combination may be obtained by separately adding.

FIG. 4 shows an image synthesizing method. A method for obtaining a composite image by simple addition of levels will be described. The image 13 is an image that has been subjected to image composition and is stored in the image memory 4 in advance, and the image 14 is an image that has been newly subjected to image composition. The corresponding pixels of the image 13 and the image 14 are sequentially added to obtain a composite image. For example, at the upper left pixel, image 13 has level 11 and the corresponding upper left pixel of image 14 has level 8. When these are added, level 19 is obtained as in the upper left pixel of the image 15.
become. Similarly, looking at the pixel on the right, the level is 9 in the image 13 and the level 7 in the image 14, so that the level is 16 as shown in the image 15. When the same process is repeated for each pixel, an image 15 synthesized from the images 13 and 14 is obtained.

In the case where the pixel level does not exist in FIG. 4 but the pixel level becomes 255 or more as a result of the addition, the pixel of the image 13 is at the level 181 and the pixel level of the image 14 is at 177, and the addition result is 258. In this case, the part 3 of 255 or more as a result of the addition is trimmed to 255. As described above, by determining an image to be synthesized, image synthesis can be performed by simple pixel-level addition. Further, as a method of synthesizing the images, the levels of the corresponding pixels in the two images to be synthesized may be compared, and the level of the larger pixel may be selected.

FIG. 5 is a flowchart showing the processing operation of the CPU. The CPU first counts the frame counter,
It is determined whether four frames of the exposure time have elapsed (S
1). If four frames have elapsed, the image data from the CCD 1 is transferred to the image memory 4 (S2). The image data taken into the image memory 4 is sent to the video encoder 6 for displaying a through image (S3). Next, FIG.
However, as described above, it is determined whether or not a pixel of the captured image has a pixel equal to or higher than the determination level (S4). As a result, if there is at least one pixel at or above the determination level,
The image is used as an image to be synthesized, and the images are added for each pixel as described with reference to FIG. 4 to synthesize the image, thereby creating an image for recording (S5). As described above, images are continuously taken at a fixed exposure cycle, and only images with pixels exceeding the discrimination level in the captured image are targeted for synthesis, so with a very simple operation even a digital camera can perform multiple exposure of silver halide photography. An equivalent image can be obtained. It is especially effective for shooting fireworks and celestial bodies (meteors).

FIG. 6 shows a method for obtaining a composite image having high contrast. In the simple addition of levels, which is the combination method shown in FIG. 4, simple addition is performed even for the level of a pixel having a low level. )) Gradually gets brighter. A constant reference level is also set for a low value of a pixel level. If the levels of the corresponding pixels in the two images to be combined are both equal to or less than a certain level, the average value of the levels of both pixels is used instead of simple addition Do the way you take.

A fixed reference level 16 is set. The level of the upper left pixel of the image 16 is 11, and the level of the upper left pixel of the corresponding image 17 is 8. Here, since both pixels are equal to or lower than the reference level 16, (11 + 8) /2=9.5, the fractional part is rounded down, the average value of both pixels is 9, and the level of the pixel of the synthesized image 18 is 9. . Similarly, since the pixels on the right side are also equal to or lower than the reference level 16 for both pixels, (9 + 7) / 2 = 8, the average value of both pixels is 8, and the level of the pixels of the synthesized image 18 is 8.
Also, at least one of the two pixels has a reference level 1
If it is 6 or more, simple addition is performed as shown in FIG. For the pixel in the second row from the top of the image 16 and the third column from the left, the pixel level is 167, and the corresponding pixel level of the image 17 is 5. Here, since one of the pixels is equal to or higher than the reference level 16, simple addition is performed, and the level of the pixel of the image 18 synthesized by 167 + 5 = 172 becomes 172.

By providing a constant reference level for the low pixel level and changing the synthesizing method, it is possible to prevent the dark portion of the image from becoming bright due to repeated synthesizing of the image. A high image can be obtained. In the above embodiment, if the levels of the corresponding pixels in the two images to be combined are both equal to or lower than a certain level, the average value of the levels of the two pixels is used. In the following case, a method of selecting the level of a pixel having a smaller level may be adopted.

[0036]

As described above, according to the first aspect of the present invention, the image pickup apparatus is set to continuously take an image at a constant exposure cycle, and the level of each pixel in the captured image is detected. Since only the images having the above pixels are determined and sequentially synthesized, an image equivalent to the multiple exposure shooting of the silver halide camera can be easily obtained, and fireworks, celestial bodies (meteors) and the like can be shot.

According to the second aspect of the present invention, the image can be synthesized by simply adding the level of each pixel of the image to be synthesized determined by the determining means.

According to the third aspect of the present invention, the level of each pixel of the image to be synthesized determined by the determining means is compared, and as a result of the comparison, the larger pixel level is selected to synthesize the image. Can be.

According to the fourth aspect of the present invention, when the average value of the levels of all the pixels of the image data detected by the detecting means is equal to or higher than a predetermined level, the image can be determined as an image to be synthesized. it can.

According to the fifth aspect of the present invention, when the pixel level of the image data detected by the detecting means is equal to or higher than a predetermined level and equal to or higher than a predetermined number, the image can be determined as an image to be combined. .

According to the present invention, when the level of each pixel of the image to be synthesized determined by the determining means is less than a predetermined level, the image is synthesized with an average value of the levels of the pixels. However, when either one is equal to or higher than a predetermined level, the image can be synthesized by simple addition, so that it is possible to prevent a dark part of the image from becoming bright due to repeated image synthesis, and to obtain a high-contrast synthesized image. Can be obtained.

According to the seventh aspect of the present invention, when the level of each pixel of the image to be synthesized determined by the determining means is less than a predetermined level, the level of the smaller pixel is selected and the image is selected. When one of the images is higher than a predetermined level, the image can be synthesized by simple addition. Therefore, it is possible to prevent a dark portion of the image from becoming bright due to repeated image synthesis, and to obtain a high-contrast image. Images can be obtained.

According to the eighth aspect of the present invention, even in a color image in which each pixel is composed of three types of RGB, each pixel level obtained by adding each value of RGB is detected.
Since the image is synthesized by adding the RGB of each pixel for each component, it is possible to easily obtain an image equivalent to the multiple exposure shooting of the silver halide camera.

[Brief description of the drawings]

FIG. 1 is a block diagram of the device of the present invention.

FIG. 2 is a diagram showing a timing of an automatic multiple exposure process.

FIG. 3 is a diagram illustrating a method of determining an image to be combined;

FIG. 4 is a diagram showing a method of synthesizing images.

FIG. 5 is a flowchart showing processing of a CPU.

FIG. 6 is a diagram showing a synthesizing method for obtaining a high-contrast image.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 CCD 2 CCD control part 3 YUV processor 4 Image memory 5 Memory controller 6 Video encoder 7 Video output part 8 CPU 9 Recording medium 10 Key processing part

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/91 G06F 15/66 450 5C065 9/04 H04N 5/91 J 5C076 F term (Reference) 5B057 AA11 BA02 BA30 CA01 CB12 CC02 CE08 CH11 DA16 DB02 DB06 DB08 5C022 AA13 AB17 AB19 AC00 AC52 AC69 5C024 AA01 BA01 CA00 CA24 DA04 FA01 GA11 HA12 HA18 HA24 HA27 5C052 AA17 DD02 GA02 GA03 GB06 GC00 GD09 GE04 GE06 GF00 KA30 KA30 GA08 5C065 AA03 BB48 CC01 DD02 GG21 GG26 GG32 5C076 AA19 BA02 BA03 BA04 BA07 BB13 BB32 CA02

Claims (8)

[Claims] 1. An image pickup apparatus comprising: an image pickup means for picking up an image of a subject; and a recording means for recording a subject image generated by the image pickup means. Generating means for generating image data of the subject image; detecting means for detecting the level of each pixel of the image data generated by the generating means; and detecting the image data in which pixels equal to or higher than a predetermined level are detected by the detecting means. An image synthesizing apparatus, comprising: a discriminating unit for discriminating an image to be combined; and a combining unit for sequentially combining image data determined by the discriminating unit. 2. An image synthesizing apparatus according to claim 1, wherein said synthesizing means synthesizes an image by adding levels of respective corresponding pixels. 3. The image synthesizing device according to claim 1, wherein said synthesizing means compares the level of each corresponding pixel and selects the larger one to synthesize an image. 4. The apparatus according to claim 1, wherein said detecting means includes a determining means for determining the image data detected when the average value of the levels of all the detected pixels is equal to or higher than a predetermined level as an image to be synthesized. The image synthesizing device according to the above. 5. The image processing apparatus according to claim 1, further comprising a determination unit configured to determine, when a predetermined number or more of pixels having a predetermined level or more are detected, a detected image data as an image to be combined. The image synthesizing device according to the above. 6. When the level of each corresponding pixel is equal to or lower than a predetermined level, the synthesizing unit synthesizes an image using an average value of the pixels, and one of the levels of the corresponding pixel is determined to be a predetermined level. 2. The image synthesizing apparatus according to claim 1, wherein when the level is equal to or higher than the level, an image is synthesized by adding the level of each corresponding pixel. 7. When the level of each corresponding pixel is equal to or lower than a predetermined level, the synthesizing unit selects the smaller one and synthesizes an image, and one of the levels of the corresponding pixel is equal to or higher than a predetermined level. 2. In the case of (1), an image is synthesized by adding the level of each corresponding pixel.
The image synthesizing device according to the above. 8. The image data generated by the generation means is composed of RGB components. Each pixel level detected by the detection means is a value obtained by adding each of the RGB values. 8. The image synthesizing apparatus according to claim 1, wherein the image synthesizing unit synthesizes an image by adding RGB corresponding to each pixel for each component.