JPH08317147A - Line scanning camera - Google Patents

Abstract

PURPOSE: To obtain a high quality pickup image without a hand-shake by providing a shake detection means and an image pickup operation setting means. CONSTITUTION: A CPU 101 conducts initial setting for various control registers and initial adjustment of a control object. Furthermore, shake detection processing to optimize the operating condition is conducted in response to a degree of hand-shake. In the shake detection processing, an output of a shake sensor 53 is received and stored as a shake angle. Moreover, in the case of image pickup by a line sensor 11, the length of an exposure time for photoelectric conversion of an object image is set properly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line scanning camera for photographing an object with a line sensor (one-dimensional image pickup device).

[0002]

2. Description of the Related Art Generally, small video cameras and electronic still cameras are constructed so that an object image is converted into an electric signal by an area sensor (two-dimensional image pickup device).

Although the area sensor is suitable for reduction in size and weight, high resolution cannot be expected when using the area sensor. Therefore, conventionally, in order to perform high-resolution imaging, a line scanning camera in which a line sensor and a scanning mechanism such as a mirror rotating mechanism are combined has been proposed.
With a line sensor, the pixel density in the array direction is higher than that of the area sensor, and high-resolution imaging is possible by scanning this.

In this type of camera, operation control is performed in which the scanning speed is changed according to the brightness of the object so that the line sensor is not underexposed.
(Japanese Patent Publication No. 4-67836). That is, the scanning is delayed when the brightness of the subject is low. As a result, the image pickup time (line cycle) for one line becomes long, and it is possible to secure an appropriate exposure time in which the amount of incident light on the line sensor is necessary and sufficient.

[0005]

However, since the line scanning camera performs mechanical scanning, it takes a long time to photograph one screen (to photograph the entire subject image) as compared with the case of using an area sensor. Therefore, even when a still subject is photographed, the image is blurred (b
is likely to occur.

In particular, when the scanning speed is changed in order to secure an appropriate exposure time as described above, the time required for photographing one screen becomes longer as the brightness of the subject becomes lower, resulting in remarkable blurring. Will end up.

In a video camera using an area sensor, an angular velocity sensor or image processing means for recognizing a change in a photographed image detects a blur for each screen and shifts a read position of the area sensor according to the blur. As a result, blurring is reduced. However, such blur correction for each screen is meaningless in a line scanning camera.

The present invention has been made in view of the above problems, and an object thereof is to obtain a high-quality photographed image without blurring.

[0009]

According to a first aspect of the present invention, there is provided a camera, which is a line scanning type camera for picking up a two-dimensional object image by a line sensor and a scanning mechanism, and which is a signal indicating a blur amount of the object image. And a control means for optimizing the operation setting for capturing the subject image according to the amount of blur.

A line scanning camera according to the invention of claim 2 is
A photometric unit that outputs a signal indicating the subject brightness, and an imaging time for one line that is equal to or more than an appropriate value for the exposure of the line sensor within a range in which the required time for imaging the subject image does not exceed an allowable limit. Scanning control means for changing the operating speed of the scanning mechanism according to the subject brightness.

The line scanning camera according to the invention of claim 3 is
It has a variable resolution shooting mode for changing the setting of the number of lines as necessary so that the product of the image pickup time for one line and the number of lines does not exceed the allowable limit of the required time for picking up a subject image. .

[0012]

In order to obtain a photographed image without blurring, it is necessary to scan as fast as possible. However, in actuality, it is sufficient if the speed is equal to or higher than the minimum level where blurring is not noticeable. That is, the scanning speed may be set so that the required imaging time does not exceed the allowable limit.

The larger the blur amount, the lower the minimum limit of the scanning speed, and the shorter the permissible limit of the required imaging time. Therefore, the operation setting (scanning speed) of the scanning mechanism is changed to an optimum value according to the blur amount in order to perform imaging with a constant resolution (number of lines).

In addition, when the required time for imaging at the highest speed possible due to the performance of the line sensor and the scanning mechanism exceeds the allowable limit, an operation of reducing the number of lines in order to shorten the required time for imaging. Settings are optimized.

[0015]

1 is a schematic diagram showing the configuration of an optical system of an electronic camera 1 of the present invention. The electronic camera 1 is a handy type line scanning type camera that uses a battery as a main power source, and includes a line sensor 11 including a CCD array, a line scanning mechanism 13, an image forming lens 17, an electric focus adjusting mechanism 78, and a finder. Equipped with 19. CCD
Instead of the array, another imaging device is used as the line sensor 11
Can also be used. Also, the finder 19
May be an optical type or a liquid crystal display (LC
It may be electronic using a display device such as D).

The line scanning mechanism 13 includes a scan mirror 1
4 and a scan motor 15 for rotating the same, and the rotation axis of the scan mirror 14 is parallel to the pixel array direction (main scanning direction) of the line sensor 11.
By the rotation of the scan mirror 14, the subject image is scanned in the direction (sub-scanning direction) orthogonal to the main scanning direction.

On the upper surface of the housing 10, a release button 63A which is a photographing instruction operating means and first and second mode switches 6 which are a photographing mode switching operating means.
5, 66 are provided. Further, the electronic camera 1 of the present embodiment incorporates a blur sensor (angular velocity sensor) 53 as means for detecting camera shake.

FIG. 2 is a functional block diagram of a main part of the electronic camera 1. The electronic camera 1 is controlled by the CPU 101 including a microprocessor unit. CPU1
To the input port of 01, various operation switches 61, 63 to 66 forming the operation system 60, and various sensors 51 to 54 forming the detection system 50 are connected. CPU
Reference numeral 101 controls the drive system 70 and the like according to input signals from these switches and sensors. For example, the CPU 101 detects the rotation angle position and the rotation speed of the scan motor 15 by the rotation sensor 54,
The scan motor driving circuit 75 is instructed to perform sub-scanning at an appropriate speed.

In the electronic camera 1, when the above-mentioned release button 63A is pressed, the first release switch 63 is turned on first. In response to the release switch 63 being turned on, automatic focus adjustment is performed based on the output of the distance measuring sensor 51. Then, when the release button 63A is further strongly pressed, the second release switch 64 is turned on. In response to the release switch 64 being turned on, line-sequential photographing by the line sensor 11 and the line scanning mechanism 13 is started.

The line sensor 11 has a line period (t
For each s), the photoelectric conversion information of each pixel for one line is simultaneously latched in synchronization with the shift gate signal given from the line sensor drive circuit 71, and is output to the A / D conversion unit 110 in the pixel arrangement order. The photoelectric conversion information indicates the total amount of incident light during the exposure time (t), that is, the integrated value of the illuminance of the light receiving surface of each pixel. The exposure time (t) is set based on the photometric result as described later.

The A / D converter 110 includes the line sensor 1
The photoelectric conversion signal S11 from 1 is subjected to processing such as shading correction and amplification, and the processed photoelectric conversion signal S11 is obtained.
11 is synchronized with the pixel clock and a predetermined number of bits (for example, 8
(Bit) pixel-based imaging data D1 is quantized.

The image pickup data D1 is temporarily stored in the frame buffer 120 capable of storing the image pickup data D1 for one screen. At that time, the image correction unit 1 performs processing such as correction of optical image distortion associated with the scanning of the rotating mirror method on the image pickup data D1 and filtering for improving image quality.
30 as required.

The captured image of the subject virtually drawn on the frame buffer 120 by storing the captured image data D1 is
After being compressed by the compression / expansion processing unit 150, the image memory 1 which is a secondary storage medium via the interface 145.
40, and is stored as shooting information of the subject captured by the electronic camera 1. Then, the image data is sent from the image memory 140 to the external device 8 through the interface 146 at a proper time. The external device 8 includes an image editing device such as a personal computer and an image reproducing device such as a display or a printer. At the time of outputting to the external device 8, data expansion is performed by the compression / expansion processing unit 150 as necessary.

When the image memory 140 is constructed using a removable storage medium such as a memory card, the image memory 140 is removed from the electronic camera 1 and the external device 8 is used.
By attaching the image pickup data D1 to the external device 8
Can be transferred to.

The operation of the electronic camera 1 will be described in more detail below with reference to the flowchart. First, the electronic camera 1
Table 1 shows the symbols, names, and meanings of the various operation set values and measured values related to the control of 1. “*” In Table 1 indicates that the value is a variable that changes according to the shooting conditions. In addition,
In the following description and drawings, the operation set value or the measured value may be represented only by the symbol.

[0026]

[Table 1]

[Control Contents of First Embodiment] FIG. 3 shows a CPU 1
It is a flow chart which shows a rough operation of 01. When the battery is installed and the control power is turned on, the CPU 10
1 performs initial setting (# 1) of various control registers and the like and initial adjustment of control target (# 2), and waits for switch operation.

When the main switch 61 is operated,
That is, when there is a change in the state of the main switch 61, if the main switch 61 is in the ON state and is in the starting state, the OFF operation process for cutting off the supply of the drive current to the controlled object is performed. An ON operation process of supplying a drive current is performed (# 3 to 6).

When the mode switches 65 and 66 are operated, a mode switching process for setting the photographing mode according to the switch state after the operation is performed (# 7 and 8). For example, when the mode switch 65 is operated in a state in which a landscape mode suitable for shooting a landscape or a person is set, the shooting mode is switched from the landscape mode to the document mode suitable for shooting a document. When the mode switch 65 is operated again, the photographing mode is switched from the document mode to the landscape mode. Then, when the release button 63A is pressed to turn on the first release switch 63, the release process including the operation peculiar to the present invention is performed (# 9, 10).

FIG. 4 is a flow chart of the release process, and FIG. 5 is a flow chart of the blur detection process. In the release processing, the output of the distance measuring sensor 51 is fetched and the focus adjusting mechanism 78 is controlled according to the distance measuring result (# 11). Then, the output of the photometric sensor 52 indicating the brightness of the subject is captured as the photometric value L (# 12). At this time, the photometric value L
Depending on the situation, the aperture adjustment and the necessity setting for turning on the auxiliary light source may be set.

Subsequently, blurring detection processing for optimizing the operating conditions according to the degree of camera shake is performed (# 13). The blur detection process is a process of capturing and storing the output of the blur sensor 53 as the blur angle θx as shown in FIG. 5 (#
31, 32).

When the second release switch 64 is turned on (# 14), a photographing process for converting a subject image into image data D1 is performed (# 16). If the release switch 64 is in the off state and the first release switch 63 is subsequently in the on state, distance measurement, photometry, and blur detection are repeated.

FIG. 6 is a flow chart showing the first example of the photographing process of FIG. 4, and FIG. 7 is a graph showing the characteristics of scanning control. In the photographing process, first, it is checked whether or not the value of the photometric value L is larger than the reference photometric value L0 (# 61).

Here, the reference photometric value L0 will be described. When capturing an image with the line sensor 11, it is necessary to properly set the length of the exposure time t for photoelectric conversion of the subject image. The appropriate value of the exposure time t is shorter as the subject brightness is higher as shown in FIG. 7 (B). Further, in the line sensor 11, it takes a certain time (transfer time ts0) determined by the driving frequency and the number of pixels in one line to send out the photoelectric conversion information for one line. That is,
The line cycle ts cannot be shorter than the transfer time ts0 (ts ≧ ts0). The reference photometric value L0 is a photometric value L such that the appropriate value of the exposure time t matches the transfer time ts0.
Is.

By the way, in the case of YES in step # 61 of FIG. 6, that is, L> L0 (in principle, L ≧ L0 may be satisfied).
In this case, since the appropriate value of the exposure time t is shorter than the transfer time ts0, the line period ts is set to the lower limit value of the transfer time ts.
It can be set to 0.

Therefore, the shortest scan time T0 is set as the scan time T which is the image pickup time for one screen, and the maximum rotation speed ω0 is set as the rotation speed ω of the scan mirror 14 (# 62). Then, an appropriate exposure time t (t <ts0 in this case) according to the photometric value L is obtained and set as a photoelectric conversion end timing condition during the line period ts (# 63). In this embodiment, a data ROM in which the photometric value L and the appropriate value of the exposure time t are associated with each other is provided, and the exposure time t is obtained in the look-up table format. Further, the transfer time ts0 is set as the line cycle ts (# 64).

Then, a scanning process, which will be described later, for driving the line sensor 11 and the line scanning mechanism 13 is performed under the previously set operation condition (# 65). As described above, when the photometric result is L> L0, the scanning at the maximum speed that is most advantageous for preventing blurring is performed.

On the other hand, in the case of NO in step # 61, that is, in the case of L ≦ L0, the appropriate value of the exposure time t is equal to or longer than the transfer time ts0, and therefore the scanning at the maximum speed is performed in order to avoid excess or deficiency of exposure. I can't do it. For this reason, a scan optimization process for changing the operation setting according to the degree of camera shake is performed (# 66), and then the process proceeds to step # 65 to photograph the subject.

FIG. 8 is a flowchart of the scanning process of FIG. In the scanning process, first, the scan mirror 1
4 is rotated at the rotation speed ω (# 71). If the rotation is stable, the line sensor 11 is driven to perform line sequential scanning with a cycle ts (# 72). When the scanning of the predetermined number of lines R is completed, the scan mirror 14 is stopped (# 73).
After that, image processing is performed as necessary as described above (# 74), and the captured data is stored in the image memory 140 (# 75). When the photographing of the subject is completed in such a procedure, the processing of the CPU 101 returns to the main routine of FIG. 3, and the electronic camera 1 enters the standby state.

FIG. 9 is a flowchart of the scan optimization process of FIG. 6, and FIG. 10 is a flowchart of the T _LIM calculation process of FIG. First, an appropriate exposure time t (t ≧ ts0 in this case) according to the photometric value L is obtained (# 101).
Then, the scan time T is calculated using the obtained exposure time t as the line cycle ts (# 102). Scan time T
Is the product of the line period ts and the number of lines R (T = t
s × R).

Next, the allowable scan time T _LIM in consideration of camera shake is calculated (# 103). Here, the allowable scan time T _LIM is the longest scan time T within which the blurring of the captured image is within a practically allowable range, and becomes shorter as the degree of camera shake increases.

In this embodiment, the amount of positional deviation of the line sensor 11 with respect to the subject image being exposed does not exceed the line width, that is, the amount of camera shake (angle) during exposure does not exceed the mirror rotation angle for one line. Thus, the allowable scan time T _LIM is set. This is because if the amount of positional deviation exceeds the line width, the information of the line to be imaged is completely lost.

The amount of camera shake during exposure is θx × t (= θx × t
s), and the mirror rotation angle for one line is θ0 / R. Therefore, the allowable scan time T _LIM is set so as to satisfy the expression (1).

Θx × ts = θ0 / R (1) Since the line period ts is T / R (that is, T _LIM / R), the allowable scan time T _LIM is expressed by the equation (2).

T _LIM = θ0 / θx (2) The calculation process of T _LIM in step # 103 in FIG.
As shown in FIG. 10, the average value of θx captured before the start of scanning is calculated, and T is calculated by the equation (2) based on the average value.
_This is processing for calculating _LIM (# 1031, 1032).
It should be noted that θ0 (scan angle) is set to a value corresponding to a change in the focal length of image formation due to attachment of a zoom lens or lens exchange. Generally, the blur becomes more remarkable as the focal length increases. However, .theta.0 decreases the larger the focal length, since T _LIM becomes shorter accordingly, no increase in blurring occurs. That is, the scanning condition suitable for the focal length is automatically set.

When the allowable scan time T _LIM corresponding to the degree of camera shake in the current photographing is obtained in step # 103 of FIG. 9, it is compared with the scan time T obtained from the viewpoint of proper exposure in step # 102 (# 104). .

Scan time T is allowable scan time T _LIM
If it does not exceed, there is substantially no effect of camera shake, so the rotational speed ω corresponding to the scan time T is calculated, and the result is set as the drive condition of the scan motor 15 (# 105). In this case, the line period ts increases or decreases according to the photometric value L as shown in FIG. Scan cycle T
Is the time R times the line period ts.

On the other hand, when the scan time T exceeds the allowable scan time T _LIM , the scan time T
_Replace the value of with the value of the allowable scan time T _LIM (# 1
06). Then, the line period ts and the exposure time t are obtained again, and the result is set as the driving condition of the line sensor 11 (# 107). After that, step # 105
To set the rotation speed ω. In this case, as shown in FIG. 7B, the line period ts is limited to T _LIM / R, which is shorter than the proper value of the exposure time t. For this reason, the photographed image becomes dark due to insufficient exposure, but it is a good image as a whole with no noticeable blurring.

[Details of Control of Second Embodiment] FIG. 11 is a flowchart showing a second example of the photographing process of FIG. FIG.
In the first example, first, it is checked whether the electronic camera 1 is fixed to a support such as a tripod (# 80). This check is performed, for example, by providing an appropriate sensor in the tripod mounting screw hole on the outer surface of the housing 10 and detecting the presence or absence of a screw.

When the camera is not fixed to a tripod or the like, that is, in the case of hand-held photography, the photometric value L is compared with the reference photometric value L0 as in the example of FIG. 6 (# 81), and according to the result, Operation settings for maximum speed scanning (# 82-8
4), or scan optimization processing (# 87). Then, the scan process (# 85) is performed thereafter. The content of the scan process is the same as the series of processes (# 71 to 75) in FIG. However, when recording the image (# 75), the resolution R (or R ') is also recorded as the photographing information as necessary.

On the other hand, when the camera is fixed to a tripod or the like, that is, in the case of fixed shooting, there is almost no fear of camera shake, so the maximum scan time T is the scan time T
_MAX is set, and the minimum rotation speed ω _MIN is set as the rotation speed ω of the scan mirror 14 (# 87). The line period ts is T _MAX / R. Then, an appropriate value of the exposure time t is obtained according to the photometric value L, and the result is set as the driving condition of the line sensor 11. However, at this time, the exposure time t is set so as not to exceed the line period ts.

FIG. 12 is a flow chart of the scan optimization process of FIG. 11, FIG. 13 is a flow chart of the resolution changing process of FIG. 12, and FIG. 14 is a graph showing the characteristics of the scan control corresponding to FIG.

In the scan optimization process of FIG. 12, the process of FIG.
Similar to the example, first, an appropriate exposure time t (t ≧ ts0 in this case) according to the photometric value L is obtained, and the scan time T is calculated with the obtained exposure time t as the line cycle ts (# 201). , 202).

Next, it is checked whether the exposure priority mode is set (# 203). The exposure priority mode is set or released in response to the operation of the mode switch 66. That is, the photographer can arbitrarily specify the exposure priority mode according to the purpose of photographing.

In the exposure priority mode, the rotational speed ω corresponding to the current scan cycle T calculated to secure the proper exposure time t is obtained (# 206), and FIG.
The process returns to the shooting processing routine. That is, in the exposure priority mode, scanning is performed at a speed that does not cause insufficient exposure regardless of the presence or absence of camera shake.

If it is not the exposure priority mode, the allowable scan time T _LIM in consideration of camera shake is calculated (# 204).
The processing content of this step # 204 is the same as the T _LIM calculation processing of FIG.

When the allowable scan time T _LIM corresponding to the degree of camera shake is obtained, it is compared with the scan time T obtained from the viewpoint of proper exposure in step # 202 (# 20).
5). If the scan time T does not exceed the allowable scan time T _LIM , there is substantially no effect of camera shake. Therefore, the rotation speed ω corresponding to the scan time T is calculated, and the result is set as the drive condition of the scan motor 15. (# 10
5). In this case, the line cycle t as shown in FIG.
s increases or decreases according to the photometric value L. The scan cycle T is R times the line cycle ts.

On the other hand, when the scan time T exceeds the allowable scan time T _LIM , it is checked whether the document mode is set (# 207). This document mode is set in response to the operation of the mode switch 65 as described above.

In the document mode, it is required that there be no blurring and a predetermined resolution (standard line number R) in order to read characters. Therefore, the value of the scan time T is replaced with the value of the allowable scan time T _LIM (# 208). Then, the line period ts and the exposure time t corresponding to the scan time T are obtained again, and the result is set as the driving condition of the line sensor 11 (# 2).
09). After that, in step # 206, the scan time T
The rotation speed ω corresponding to (= T _LIM ) is set. In this case, the line period ts is limited to T _LIM / R, as shown by the chain line in FIG. 14B, and becomes shorter than the appropriate value of the exposure time t. Therefore, the photographed image becomes dark due to insufficient exposure, but becomes a high-resolution image in which blurring is not noticeable.

On the other hand, if the mode is not the document mode, that is, if the mode is the landscape mode, the resolution changing process (# 210) is performed, and then the process proceeds to step # 206 to set the rotation speed ω.

As shown in FIG. 13, in the resolution changing process, the number of lines R'which is smaller than the standard value is set as the number of lines R (# 2101), and the scan time T is the allowable scan time obtained in step # 204 of FIG. T _LIM is set (# 2102). Then, the line cycle ts (= T
_LIM / R ') is calculated (# 2103).

The line period ts thus obtained is compared with the proper exposure time t previously obtained (# 210
4) If t ≦ ts, the process directly returns to the routine of FIG. If t> ts, the value of t is replaced with the value of ts, and then the process returns (# 2105).

In any case, when the resolution changing process is executed, the scan time T is T as shown in FIG.
Limited to _LIM . However, as shown in FIG. 14 (B), the line cycle ts is prolonged from T _LIM / R by reducing the number of lines to T _LIM / R '. As a result, although the resolution is lowered, the range of photometric values where blurring is suppressed and exposure is appropriate is expanded. That is, in the landscape mode, exposure is given priority over resolution in terms of color reproduction.

When the value of the number R of lines is changed to R ', that fact is recorded as information for subsequent reproduction when the photographed image is stored in the scanning process. Of course, when the number of lines R is not changed, that fact may be recorded. If the proper exposure time t cannot be secured despite changing the number of lines R (No in step 2104 of FIG. 13), a warning may be issued to the photographer to stop scanning. It is also possible to issue a warning and then perform scanning with t = ts.

[Control Content of Third Embodiment] FIG. 15 is a flow chart showing a third example of the photographing processing of FIG. 4, and FIG. 16 is a graph showing the characteristics of scanning control corresponding to FIG.

In the photographing process of FIG. 15, first, the allowable scan time T _LIM according to the degree of camera shake is calculated (# 91). The content of this process is the same as the T _LIM calculation process of FIG.

Then, the value of the allowable scan time T _LIM is set as the value of the scan time T (# 92), and the line period ts is calculated and set as the operating condition (# 93). Further, as the exposure time t, an appropriate value corresponding to the photometric value L is set (# 94).

Then, the exposure time t is compared with the line period ts (# 95). If the exposure time t is equal to or less than the line cycle ts, the scanning process is performed under the same operating condition (# 97). If the exposure time t exceeds the line cycle ts, the resolution changing process (# 96) for reducing the number of lines is executed, and then the scanning process is performed.

The contents of the resolution changing process of step # 96 are the same as those of the routine of FIG. Also, step #
The content of the scan process of 97 is the same as that of the routine of FIG. However, when the captured image is stored, the resolution is also recorded if necessary.

In the example of FIG. 15, as shown in FIG.
The scan time T is limited to the allowable scan time T _LIM regardless of the photometric value L. On the other hand, the line period ts
Is set in two stages of T _LIM / R and T _LIM / R ′ according to the photometric value L so that the most appropriate exposure is possible.

[Control Content of Fourth Embodiment] FIG. 17 is a flow chart showing a fourth example of the photographing processing of FIG. 4, and FIG. 18 is a graph showing the characteristics of scanning control corresponding to FIG.

In the photographing process of FIG. 17, first, the allowable scan time T _LIM according to the degree of camera shake is calculated (# 301). The content of this process is the same as the T _LIM calculation process of FIG.

Subsequently, the allowable scan time T _LIM is compared with the shortest scan time T0 (# 302). Here, for example, the driving frequency of the line sensor 11 is low and the transfer time t
When s0 is relatively long, the shortest scan time T0 is the allowable scan time T _LIM when the degree of camera shake is large.
May exceed. If the drive frequency is low, the AD conversion and the memory can be composed of low-speed devices, and the cost of parts can be reduced.

In the case of T0> T _LIM as described above, the scan time T cannot be limited to T _LIM , so that blurring is noticeable in a captured image. Therefore, in the example of FIG. 17, when T0> T _LIM , R ′ is set as the number of lines R (# 303). That is, the resolution in the sub-scanning direction is reduced. As a result, the shortest scan time T0 is shortened as shown in FIG. 18A, so that the scan time T can be set to _TLIM or less even when the degree of camera shake is relatively large. In the example of FIG. 18A, when the value of the unit shake angle θx is equal to or smaller than θa, the standard line number R is set, and when it exceeds θa, the low resolution line number R ′ is set.

After changing the setting of the number of lines R as described above, the scan time T is calculated (# 304), and the obtained scan time T is compared with the previously obtained allowable scan time T _LIM (#). 305).

Even if the number of lines R is reduced, T> T
_In the case of _LIM, that is, when the value of the unit blurring angle θx exceeds θb in FIG. 18A, the blurring becomes conspicuous, and therefore a warning is issued by an LED or a warning sound (# 3
10) returns to the main routine (see FIGS. 3 and 4) without performing scanning.

When T ≦ T _LIM , ω corresponding to T
Is calculated (# 306), and t corresponding to the photometric value L is calculated (#
308), and ts is set to ts0 (# 308). And
Scan processing (# 309) is performed. The content of the scanning process is the same as the routine of FIG. However, when recording the captured image, the resolution is also recorded if necessary.

On the other hand, when the shortest scan time T0 for the standard number of lines R is less than or equal to T _LIM in step # 302, the magnitude relationship between the photometric value L and the reference photometric value L0 is determined as in the example of FIG. Then, operation setting for maximum speed scanning (# 311, 312, 307, 308) or scan optimization processing (# 313) is performed. The content of the process of step # 313 is the same as that of the routine of FIG. In this case, the scan time T is a time equal to or shorter than T _LIM as shown in FIG.

According to the above-described embodiment, it is possible to obtain a high-quality photographed image which is less affected by camera shake even though the line scanning type camera requires a relatively long time to photograph one screen.

In the above-described embodiment, the allowable scan time T considering only the hand shake (positional deviation) in the sub-scanning direction.
_LIM was calculated. This is because the positional deviation in the sub-scanning direction easily causes the loss of information. With respect to the main scanning direction, the imaging range of the line sensor 11 is set wider than the reading range, and the reading position is shifted by the amount of positional deviation, or a good image is obtained by using the reading position shift and image processing in combination. Obtainable. However, the allowable scan time T _LIM may be calculated in consideration of the positional deviation in the main scanning direction.

In the above embodiment, the allowable scan time T _LIM may be calculated based on the equation (3) instead of the equation (2). T _LIM = α × (θ0 / θx) (3) However, α is an arbitrary coefficient. Alternatively, α may be changed according to the distance measurement result. For example,
When a document is photographed, the characters in the photographed image become smaller as it is farther from the subject, and it becomes unreadable even if a slight hand shake occurs. That is, the farther from the subject, the greater the influence of camera shake. Therefore, α may be reduced as the shooting distance increases.

In the above embodiment, the blur sensor 5
Although the angular velocity sensor is provided as 3, an image having two screens may be taken by using an area sensor having a low resolution, and a relative position change with the subject may be detected by comparing the taken images of the two screens. In that case, the area sensor can also be used for the finder.

In the above embodiment, the line sensor 1
Line scanning may be realized by a mechanism for moving 1 in parallel. In addition, various changes can be made to the configuration of the electronic camera 1, the control content of the CPU 101, and the like.

[0084]

According to the present invention, it is possible to obtain a high-quality photographed image in which blurring is not noticeable.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of an optical system of an electronic camera of the present invention.

FIG. 2 is a functional block diagram of a main part of the electronic camera.

FIG. 3 is a flowchart showing a schematic operation of a CPU.

FIG. 4 is a flowchart of a release process.

FIG. 5 is a flowchart of blur detection processing.

FIG. 6 is a flowchart showing a first example of the shooting process of FIG.

FIG. 7 is a graph showing characteristics of scanning control.

FIG. 8 is a flowchart of the scan processing of FIG.

9 is a flowchart of a scan optimization process of FIG.

10 is a flowchart of a calculation process of T _{LIM in} FIG. 9.

FIG. 11 is a flowchart showing a second example of the shooting process of FIG.

12 is a flowchart of a scan optimization process of FIG.

13 is a flowchart of a resolution changing process of FIG.

FIG. 14 is a graph showing the characteristics of scanning control corresponding to FIG.

FIG. 15 is a flowchart showing a third example of the shooting process of FIG.

16 is a graph showing the characteristics of scanning control corresponding to FIG.

FIG. 17 is a flowchart showing a fourth example of the shooting process of FIG.

FIG. 18 is a graph showing characteristics of scanning control corresponding to FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Electronic camera (line scanning type camera) 11 Line sensor 13 Line scanning mechanism (scanning mechanism) 52 Photometric sensor (photometric means) 53 Blur sensor (blurring detection means) 101 CPU (control means, scanning control means) L Photometric value (subject Luminance) T Scan time (time required for imaging) T _LIM Allowable scan time (allowable limit) t Exposure time (appropriate value for exposure) ts Line cycle (imaging time for one line) ω Rotation speed (operating speed of scanning mechanism)

Claims (3)

[Claims] 1. A line scanning camera for picking up a two-dimensional image of a subject by a line sensor and a scanning mechanism, which comprises blur detection means for outputting a signal indicating the amount of blur of the subject image, And a control means for optimizing the operation setting for capturing the subject image. 2. A line scanning camera for picking up a two-dimensional image of a subject by a line sensor and a scanning mechanism, wherein photometric means for outputting a signal indicating the luminance of the subject, and a required time for picking up the subject image are allowed. Scanning control means for changing the operation speed of the scanning mechanism according to the subject brightness so that the imaging time for one line is equal to or more than the appropriate value of the exposure of the line sensor within a range not exceeding the limit; A line scanning camera characterized by being provided. 3. A line scanning camera for picking up a two-dimensional object image by a line sensor and a scanning mechanism, wherein the product of the image pickup time for one line and the number of lines exceeds an allowable limit of the required image pickup time. The line scanning camera is characterized in that it has a variable resolution photographing mode in which the setting of the number of lines is changed as necessary.