JPH02113786A - Electronic still camera - Google Patents

Abstract

PURPOSE:To give a flow photographing effect to a series of still images by outputting an image signal integrated between frames. CONSTITUTION:A between-frame integrating circuit 84 is composed of two subtracters 70 and 72 and a multiplier 76, image data are integrated between successive plural frames thereby, and the integrated image data are outputted to an output 78. The image data outputted to the output 78 are integrated between frames, and they are stored also in a frame memory 30. Consequently, when the image data of plural frames are successively outputted from a signal processing part 22, the image data to appear to the output 78 are made into the image data in which the influences of past plural frames are integrated. Thus, the flow photographing effect can be given to the still images to be successively photographed.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an electronic still camera, and more particularly to an electronic still camera having a continuous shooting function.

BACKGROUND ART Taking a digital electronic still camera as an example, this is a photographing device that photographs a field using a solid-state imaging device such as a COD and stores an image signal representing the field in a memory in the form of digital data. The memory often takes the form of a memory card equipped with a RAM such as a semiconductor memory. In this case, data compression such as orthogonal transform encoding and quantization is often performed in order to efficiently use the memory storage area.

Conventionally, digital electronic still camera systems that record and play back image signals have been unable to maintain a long image signal retention time in COD, and to avoid an increase in storage space due to the large amount of image data. The signal is compressed into data, but the compression process is complicated and takes time, so an image memory is provided to store the image signal. For example, the data compression/expansion method disclosed in Take Kaishu 61-147692 requires an image memory at +iij for two-dimensional discrete cosine transformation, as shown in FIG. This image memory usually contains C
An image signal generated at the optimum charge accumulation time of OD is input. Therefore, if charge storage continues for a longer time than this, there is a risk that the signal envelope 'rff (S/N) ratio will decrease due to the effects of thermal noise and dark current of the element.

One of the characteristics of electronic still cameras is that they are capable of high-speed continuous shooting. In continuous shooting, there is a demand for the so-called "panning shot" effect, which produces an afterimage effect in moving parts of a series of still images taken at short time intervals. In systems, it has been difficult to provide such a visual effect of panning shots due to the limited charge accumulation time in solid-state imaging devices such as dual arrays. A series of static J that eliminates shortcomings
An object of the present invention is to provide an electronic still camera that can change a panning effect to two images.

DISCLOSURE OF THE INVENTION According to the present invention, an electric still force that photographs a field and outputs an image signal representing the field is configured to photograph the field and form an image signal of a frame representing the field. an imaging means;
an output means for outputting an image signal; a temporary storage means for temporarily accumulating the image signal outputted from the output means in frame units; the output means includes a frame-to-frame integration step for performing inter-frame integration by taking the difference between the image signal obtained by the image signal and the image signal of the frame formed by the imaging means and subtracting this difference from the former image signal; , an image signal subjected to inter-frame integration is output.Description of Embodiments Next, embodiments of the digital electronic still camera according to the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 1, the embodiment of the digital electronic still camera has an imaging device 10, which photographs an object scene and sends an image signal representing it in the form of digital data to a memory card or the like. This is a photographing device that stores image signals in a storage medium. The imaging device IO is, for example, C
A solid-state imaging device such as a CD is applied to the 43rd camera, and the imaging lens 14 photographs the field, and color image signals representing the field are converted into red (R), green (G), and blue (B) signals, for example. This is an imaging device that outputs at its output 16 in the form of a color component signal. This color component signal is output in a rask scanning format similar to a TV signal. Other functional units necessary for photographing, such as an exposure mechanism and a focusing mechanism, are not directly related to the understanding of the present invention, and therefore their explanation will be omitted.

The output 16 of the imaging device 10 is connected to an analog/digital converter (ADC) +8, and the converter 18 converts the input analog image signal into corresponding digital data and outputs it to its output 20. This is a signal conversion circuit. This digital data is encoded into, for example, 8 pints for each of the color component signals RGB.The digital data output 20 is connected to a signal processing section 22.

In this embodiment, the signal processing unit 22 subjects the image data to pre-processing such as white balance adjustment and gradation correction, and luminance and color difference processing that converts color component signal data into a luminance signal and a two-phase color difference signal, Signal processing is performed to output this to its output 24. The signal processing unit 22 may perform blocking processing to divide the screen area represented by the image data into a plurality of predetermined blocks.

The output 24 of the signal processing section 22 is sent to two subtracters 70 and 7.
connected to one input of 2. The image signal output from the imaging device 10 is in the form of a normal rask scan sequential signal. The subtracter 70 is connected to the output of the other person's cuff 4 or the multiplier 76 and receives the output 24 of the processing section 22.
This is a functional unit that sequentially subtracts the image data of the output cuff 4 of the east unit 76 pixel-by-pixel from the image data output from the output cuff 8, and outputs the result to the output cuff 8. Similarly, the subtracter 72 has the other input 31 connected to the data readout output of the frame memory 30, and subtracts the image data of the output 31 of the frame J memory 30 from the image data of the output 24 of the signal processing section 22 in pixel correspondence. This is a subtraction circuit that outputs the result to an output 80.

The output 8 of the subtracter 70 is connected to the data input of the frame memory 30. In this embodiment, the frame memory 30 is a temporary storage device having a storage capacity capable of storing one frame of image data. The frame memory 30 realizes a delay function that delays image data by the time interval of continuous shooting.

The output of subtractor 72 is connected to the input of multiplier 76. The multiplier 7G is a multiplication function unit that multiplies the value of the human power 80 by a coefficient α and outputs the result to the output cuff 4.

The value of this coefficient α may be fixed to the multiplier 7G or may be variable. In this embodiment, the multiplier 76 has a control terminal 82 that receives a mode signal, and the coefficient α is controlled in response to the mode signal. The mode signal 82 is a signal that specifies whether or not to obtain a so-called panning effect in the double shooting mode. Control according to human power 8
2 is input. The multiplier 76 sets the daily coefficient α to 0 when the mode signal 82 does not indicate the panning effect, and sets the coefficient α to a predetermined value greater than 0 and less than 1 when the mode signal 82 indicates the panning effect. Set to .

As will be seen later, these two subtractors 70 and 7
2 and the multiplier 76 constitute an interframe integration circuit 84, which integrates image data between a plurality of successive frames and outputs the integrated image data to the output cuff 8. The image data output to the output cuff 8 is
Interframe integration has been performed, and this is also stored in the frame memory 30. Therefore, when a plurality of consecutive frames of image data are output one after another from the signal processing section 22, the image data appearing on the output cuff 8 becomes image data in which the influences of a plurality of past frames are integrated.

The image data output from the output cuff 8 is subjected to orthogonal transform encoding and sacrificialization such as two-dimensional discrete cosine transform, and is stored in an image data storage medium such as a memory card as compressed image data. be done. When such data compression is performed, blocking processing may be performed at any location on the image data path, such as in the signal processing unit 22, for example. For example, in a system in which the signal processing unit 22 performs broncization of image data, the interframe integration circuit 84 is configured to perform block-based difference calculations instead of pixel-based difference keying as described above. Good too.

In the case of normal shooting such as single shot mode, the mode signal 48 does not specify the panning effect, so the multiplier 76 has a coefficient α.
The value "0" is set as "0". Therefore, the value "0" is sent to the subtractor 70 from the output cuff 4! J-Can be obtained. When instructed to photograph, the imaging device 10 photographs the scene,
One frame of image signal representing the scene is output.

This image signal is output from the imaging device 10 to an analog-to-digital converter 18, where it is converted into a corresponding digital converter. This image data is processed by the signal processing unit 2.
2 is subjected to preprocessing and luminance color difference processing, and 1 subtracter 70
The image data is then output from the output cuff 8 as digital image data. At this time, "0" is input to the other input cap of the subtractor 70, and therefore the output cap 8 of the subtractor 70 is inputted with "0".
The signal from the other input 24 appears as is.

When the panning effect is designated by the mode signal 48 in the snapshot mode, a predetermined value of coefficient α is set in the multiplier 78. In the continuous shooting mode, I'i, the storage contents of the frame memory 30 are cleared to the initial state regarding the shooting of the first frame of quick shooting. Therefore, the image data of the first frame is sent to the signal processing unit in the same way as described in -1-.
The signal from the output 24 of 2 appears as it is at the device cuff 8. At the same time, this image data is also written to the frame memory 30 from the output cuff 8.

In the snapshot mode, the imaging device 10 is driven to continuously photograph the scene. At its output 16, image signals of a series of frames are outputted one after another. Therefore,
The image data from the t52nd frame onwards is subjected to interframe integration by the interframe integration circuit 84 and output from the output cuff 8.

To explain in more detail, the subtracter 72
The current frame image data inputted to the input 24 is sequentially received from the frame memory 30, and image data of corresponding pixels in the previous frame is read out from the frame memory 30 in synchronization with this. The subtracter 72 takes the difference between the two and outputs the difference as an output 80.
is input to the multiplier 78.

The multiplier 76 multiplies this difference by a coefficient α and inputs the result from the output cuff 4 to another subtractor 70 . As a result, the difference between the frame currently photographed by the imaging device 10 and the immediately previous frame is obtained by decreasing the difference by the coefficient α corresponding to each pixel.

The subtracter 70 subtracts this difference from the signal of the corresponding pixel of the current frame and outputs it to the output cuff 8. Therefore, the image data 7o that appears in output cuff 8 includes the effect of subtracting the difference from the previous frame by the coefficient α from the current frame, and so-called "tailing" appears for moving pictures. . In other words, a panning effect is provided.

For example, as shown in FIG. 2A, if there is movement of a certain picture in the second frame following the first frame, and the difference obtained by the subtractor 72 is L, for example, if the coefficient α is 05, then As shown in FIG. 2B, this is subtracted to 1/2L by the multiplier 7 days and input to the subtracter 70. Assuming that there is no movement of the picture after the third frame, the influence in the second frame will further appear in the third frame and after by the coefficient 172. When the coefficient α is smaller than "1", this influence gradually attenuates as shown in the figure. In this way, a panning effect is imparted to a series of still IF images obtained in continuous shooting mode.

In this way, the image data subjected to frame 1 and inter-integration is output to the output cuff 8, and is also fed back to the frame memory 30, so that from the second frame onwards, the image data of multiple frames are continuously transmitted to the signal processing unit. 22, image data in which the influences of a plurality of past frames are accumulated is obtained at the output cuff 8.

The coefficient α of the multiplier 76 may be set to “1”. In this way, the portion that has changed in the current frame is completely subtracted from the current frame, so the image signal of the previous frame is output from the output cuff 8. Therefore, the output image is
Missing images are fixed to the top, first frame image. As will be seen, the closer the coefficient α is to rlJ, the greater the integral effect is. Furthermore, when the coefficient α is set to "0", the latest frame is always output as is, as described above.

FIG. 3 shows another embodiment of the present invention, which has a function of improving the S/N ratio by utilizing an interframe integration effect in addition to the panning effect. Because of this function, this embodiment uses the OR cable 1 and the control manual 82 of the multiplier 76.
80 and a comparator 92 are connected as shown, and the two series of mote signals are input to one input 84 of the OR gate 80. The output 80 of the subtracter 72 is connected to one input of the comparator 92, and a predetermined threshold value serving as a reference for comparison is manually input to the other input 9B. The comparator 82 is the subtracter 7
This is a circuit that compares the output 80 of No. 2 with a threshold 86 and, if the former is less than the latter, energizes its output 98. When the OR gate 90 energizes the control power 82 of the multiplier 76, the multiplier 76 sets the coefficient α to "0" as in the embodiment shown in FIG.
” to a predetermined value greater than ”.

This embodiment takes advantage of the fact that noise has no correlation between frames, and when the difference between successive frames is small, it is regarded as noise and the coefficient α is set to a predetermined value, thereby reducing the noise. I try to make it appear with less impact. That is, the subtractor 72 always takes the difference from the current frame to the previous frame, the comparator 82 compares this with the threshold value 86, and if the difference does not exceed the threshold value 96, the coefficient α of the multiplier 76 is set to a predetermined value. At 4, I'm nimble. This causes the inter-freight integration circuit 84 to perform the inter-frame integration operation as described above, thereby eliminating noise. When the panning mode signal is manually input to the input 94 of the OR gate 90, the control input 82 of the multiplier 76 is activated in the same way as in the previous embodiment, so that an integral calculation for one frame is performed, and the image data is It can give a hemming effect.

In this embodiment as well, the processing performed by the interframe integration circuit 84 does not necessarily have to be an integral calculation for each pixel.

For example, if the signal processing unit 22 is configured to block image data, the image data may be integrated between frames in blocks. Further, in each of the embodiments, the inter-frame integration is performed after converting the image signal into digital data, but the inter-frame integration may be performed in the form of an analog signal.

In this specification, for the convenience of explanation, the edict [frame jh
shall be used synonymously with

As described above, according to the present invention, a panning effect can be added to continuously shot still images using a simple configuration that utilizes interframe integration.
t-can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram showing an embodiment of a digital electronic still camera according to the present invention. FIGS. 2A and 2B are explanatory diagrams for explaining the panning effect in the embodiment shown in FIG. FIG. 2 is a functional block diagram similar to FIG. 1, showing another embodiment of the present invention. 1. Explanation of codes for essential parts 10...Imaging device 22, signal processing unit 30,...Frame memory? 0,72. , subtractor 13 multiplier, inter-frame integral circuit Patent applicant Fuji Photo Film Co., Ltd. Representative Person Address Takashi ΔF Takao Ohiba

Claims (1)

[Scope of Claims] An electronic still camera that photographs a field and outputs an image signal representing the field, wherein the camera photographs the field and outputs an image of a frame representing the field. an imaging means for forming a signal; an output means for outputting an image signal; a temporary storage means for temporarily accumulating the image signal outputted from the output means on a frame-by-frame basis; interframe integration, which performs interframe integration by reading out an image signal, taking the difference between the read out image signal and the image signal of the frame formed by the imaging means, and subtracting the difference from the former image signal; An electronic still camera comprising: means for outputting an image signal subjected to the inter-frame integration.