JPH03135173A - Electronic still camera - Google Patents

Abstract

PURPOSE:To obtain a picture at the moment when a shutter is operated by transferring the information of a memory storing the newest picture information to a data compression device when a difference of sets of picture information in two buffer memories exceeds a threshold level. CONSTITUTION:A picture signal outputted from a photoelectric conversion element 13 applying photoelectric conversion to a picture for each pattern is stored alternately in buffer memories 81, 82 by the control of a microcomputer 7 as the digital signal. When the processor 7 detects it that the difference of the signals stored in the memories 81, 82 exceeds a threshold level, the processor 7 transfers the picture information from the memory 81 or 82 storing the newest picture information to a data compression device 9 via a data bus 6. When the object between the two patterns starts movement, since the picture is recorded on a memory pack P, the picture at the moment when a shutter is operated is obtained.

Description

[Detailed Description of the Invention] [Summary] In an electronic still camera that shoots and records still images,
This system is designed to obtain an image at the moment when the subject starts moving.The movement of the subject is detected by the difference between two consecutive images, and when the movement of the subject is detected, the newer of the two images is displayed. Now records images.

[Industrial application field]

The present invention relates to electronic still cameras that take and record still images, particularly digital electronic still cameras.

[Conventional technology]

Such an electronic still camera is known, for example, from Japanese Patent Application Laid-Open No. 62-26
No. 9581 describes a digital electronic still camera in which analog image information obtained from an imaging element is digitized, data is compressed, and then recording is performed.

There are times when you want to take a picture of the moment when an insect starts to move using an electronic still camera like the one mentioned above or a regular camera, but in order to take such a picture, the photographer needs to judge by himself when to press the shutter. .

[Problem to be solved by the invention]

The object of the present invention is to obtain an electronic still camera that detects the movement of a subject and automatically operates the shutter when, for example, an insect takes flight or starts moving, thereby obtaining an image at that moment. It is something.

[Means to solve the problem]

Two image memos: an imaging device V that photoelectrically converts images screen by screen, and an image memo that alternately stores image information of consecutive screens output from this imaging device at predetermined time intervals! J
M+, M2, and an image comparator Cv that detects a difference between data of corresponding pixels of image information stored in these two image memories, and the difference detected by this image comparator is set to a predetermined threshold value. The electronic still camera is designed to record the last stored image information in the memory when the above occurs.

Regarding the detection of the above-mentioned difference, the difference can be detected for pixels in a predetermined range of the screen.

[For production]

FIG. 1 is a block diagram showing the principle of the present invention, in which image information from an imaging device V is switched by a switch Si, and image information for one screen is alternately stored in a first image memory MI and a second image memory M2. Accumulate in. Note that it is desirable to configure the switching interval so that it can be changed as appropriate depending on the subject to be photographed.

These image memos 'JM1. The image information stored in M2- is compared by an image comparator Cv, and the difference d between corresponding pixels of the image information stored in the image memories M, . . . M2 is output. When detecting this difference d,
For example, the difference between all the pixels in the image stored in the image memory MI and the pixels in the corresponding image memory pack may be calculated, but in other embodiments, the image memory M,
, it is possible to compare a part of the image information stored in M2, and if this comparison part is selected in a specific area in the center of the screen, insects etc. located in this area can be compared. You can capture the moment when the object moves.

The difference comparator Cd compares the above difference value d with a preset threshold, and if d≧, it can be determined that there has been a change in the image, that is, the subject has moved, so the latest image information is This image information is recorded from the stored image memory M1 or M2 into a memory pack P exchangeably stored in the electronic still camera body via a switch So.

As a result, an image obtained when the amount of movement of the subject between two consecutive screens exceeds a predetermined value, that is, when the subject starts moving, can be recorded in the memory pack.

〔Example〕

FIG. 2 is a block diagram showing an embodiment of an electronic still camera according to the present invention, which includes an optical system including a lens 11, a shutter 12, etc., and a photoelectric conversion element such as a CCD that photoelectrically converts an image projected by this optical system. The shutter 1 □ is controlled by a system control circuit 2 to scan the photoelectric conversion element 13 one screen at a time.
The photoelectric conversion element 13 is controlled by the output from the system control circuit 2 via the drive circuit 3 to output image information for each screen.

The image signal output from the imaging device 1 is subjected to gamma correction, white balance adjustment, etc. in a signal processing circuit 4, and the output of this signal processing circuit 4 is then converted from analog to digital by an AD converter 5 to generate digital image information. This digital image information is output from the data bus 6 to the first buffer memory 8 . and are alternately transferred and stored in the second buffer memory 8□.

The microprocessor 7 operates from the A/D converter 5 to the buffer memory 8 . ．． Also these buffer notes to 82! 18. ．． 8□ to data compressor 9, which will be described later.
In addition to controlling the transfer of image information to the first buffer memory 8. The image comparator shown in FIG. 1 which compares the image information stored in A comparison corresponding to the difference comparator Ck is performed.

As a result of such a comparison, if the microprocessor 7 detects that the difference between the two image information exceeds the threshold k as explained with reference to FIG. 1, the microprocessor 7 stores the latest image information. The image information from the separate memory 8I or 82 is transferred to the data bus 6.
The data is transferred to the data compressor 9 via the data compressor 9, and at the same time, a start signal for the drive device 10 is sent to the system control circuit 2.

This drive device 10 rotates a magnetic disk when the memory pack P detachably and replaceably housed and connected to the electronic still camera body C uses a rotating recording medium such as a magnetic floppy disk. The image information compressed by the data compressor 9 is recorded on this rotating magnetic disk. It goes without saying that a recording medium such as a RAM card can be used as the memory pack P.

FIG. 3 is a flowchart of an embodiment of the present invention, in which, for example, after specifying automatic photographing according to the present invention using a switch or the like, when the shirt button is pressed down to start the operation,
In step ■, the value of the image counter in the microprocessor 7 is set to "0", and in the next step ■, for example, the drive circuit 3
The image information from the imaging device 1 is read under the control of , and in the following step (2), "1" is added to the value of the above counter, and n
=1, and stores that this image information is the image information of the first image.

1ζ In step ■, check which image this image information relates to based on the value of the above counter,
If the image information is about an odd numbered image, step■
This image information is stored in the #1 buffer memory in step 2, and if the image information is about an even-numbered image, this image information is stored in the #2 buffer memory in step (3).

After this accumulation is completed, the value of the counter is checked in step (2) and it is n-1, which means that n≧2 is not satisfied. This time, n=2 at step (2), so this image information is stored in the #2 buffer memory according to the judgment at step (2). That is, the judgment in step (2) above is a process of checking the existence of image information to be compared.

This time, since n=2, we move from step ■ to step ■, and compare the data of each pixel of the image information stored in the #ll buffer memory with the data of each pixel of the image information stored in the #2 buffer memory. The difference d is determined in this step (2).

The value of this difference d is compared with a predetermined threshold value in step 2, and if d<k, there is little change in the image information stored in #1 buffer memory and #2 buffer memory, that is, the movement of the subject is small. Since there is no image or the image information is small, the process returns to step (2) to read the image information for the third image and store it in the #l buffer memory.

Therefore, the difference d found in the next step (2) is based on a comparison between the image data for the second image and the image data for the third image.

When it is determined in step ■ that the value of the difference d obtained in step ■ is d≧ due to the movement of the subject, the process moves to the next step @, and the image information stored in the #1 buffer memory, i.e. The newly accumulated image information is compressed by a data compressor and recorded in the memory pack P in the subsequent step 0, and the process is completed.

〔Effect of the invention〕

According to the present invention, it is possible to achieve the special effect of automatically recording an image at the moment the subject starts moving without relying on the photographer's skill or intuition, and also to When the movement of the subject is detected, erroneous recording due to movement of a subject other than the intended subject can be prevented by locating the intended subject within this range.

[Brief explanation of the drawing]

FIG. 1 is a principle diagram of the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is a flowchart showing an embodiment of the operation according to the present invention.

Claims (2)

[Claims] (1) Imaging device (V) that photoelectrically converts images screen by screen
, two image memories (M_1, M_2) that alternately store image information of consecutive screens output from this imaging device at predetermined time intervals, and the correspondence between the image information stored in these two image memories. and an image comparator (Cv) that detects the difference between pixel data, and when the difference detected by the image comparator exceeds a predetermined threshold, the last stored image information in the memory is An electronic still camera characterized by recording. (2) The electronic still camera according to claim 1, wherein the difference is detected for pixels in a predetermined range of the screen.