JP2730528B2 - Imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus for outputting a digital image obtained by scanning an object with a polygon mirror or an oscillating scanning mirror.
In particular, the present invention relates to an imaging device that performs spatial stabilization on an output image.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram showing an example of the configuration of a conventional imaging device which is not fixed to a platform.

In this conventional example, as shown in FIG. 4, an imaging mechanism 110 for obtaining a video signal, an imaging mechanism driving section 170 for outputting a signal for driving the imaging mechanism 110, and an imaging mechanism 1
Rate sensor 120 for detecting 10 horizontal angular velocities
And an A / D converter 130 that samples the video signal obtained by the imaging mechanism 110 and converts it into digital video data.
A spatial stabilization unit 190 for generating a signal for selecting video data based on the angular velocity detected by the rate sensor 120, and an output from the A / D conversion unit 130 based on the signal output from the spatial stabilization unit 190 An image data selection unit 140 for selecting digital video data to be processed and a frame memory 160 for temporarily storing the video data selected by the image data selection unit 140.

In the imaging apparatus configured as described above, the digital image data obtained by the A / D conversion in the A / D converter 130 is not fixed to the platform on which the spatial stabilization has been performed. The image is moved / selected to correct the amount of movement of the image, thereby achieving spatial stabilization of the output image.

[0005]

However, in the above-described conventional imaging apparatus, since the correction of the video data in the movement of the image is performed in units of pixels of the digital video data, spatial stabilization is performed. In the image obtained by the above, there is a possibility that disturbance occurs in the width of one pixel.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the conventional technology, and has as its object to provide an image pickup apparatus capable of obtaining a spatially stabilized image without image disturbance. And

[0007]

In order to achieve the above object, the present invention provides an image pickup apparatus which scans an object to be imaged, and outputs a video signal of the object after spatial stabilization. An imaging mechanism that acquires a video signal from an imaging target, outputs and outputs a plurality of predetermined timing signals, a rate sensor that detects a horizontal angular velocity of the imaging mechanism, and samples the video signal. An A / D converter for converting the image signal into digital image data; a moving amount of the image signal generated by the scanning from the image signal and the timing signal output from the imaging mechanism and the angular velocity detected by the rate sensor; A horizontal scanning direction space stabilizing unit for outputting a sampling clock for determining the sampling timing, and an image output from the horizontal scanning space stabilizing unit. The A / D based on the amount of movement of the No.
A video data selection unit for moving and selecting digital video data output from the conversion unit.

Further, the space stabilizing section in the horizontal scanning direction includes:
A sampling clock phase shift circuit that generates a plurality of clock signals based on a timing signal output from the imaging mechanism; and a movement amount of the video signal based on an angular velocity from the rate sensor, and the calculated movement amount. Of the sampling clock signal that determines the timing of the sampling based on the value below the decimal point,
An image moving angle calculation circuit that outputs a value of the moving amount with the decimal part truncated, wherein the video data selecting unit is configured to output the digital image based on the value of the moving amount with the decimal part truncated. A gate signal generation circuit for generating a timing for selecting data; and a video data selection circuit for moving and selecting the digital video data at the timing generated in the gate signal generation circuit.

Further, the sampling clock signal is
It is a value for correcting a phase shift caused by the movement amount.

Further, when the number of digits after the decimal point in the moving amount is m, the plurality of clock signals are ^{m m}
Each phase is shifted.

(Operation) In the present invention constructed as described above, when the imaging mechanism scans the object to be imaged, the video signal is shifted due to the horizontal movement of the imaging mechanism. The section calculates the moving amount of the video signal caused by the horizontal movement of the imaging mechanism, samples the video signal in the A / D converter at a timing based on the calculated moving amount, and then calculates the moving amount. The movement and selection of the video signal are performed based on the.

As described above, since the sampling timing of the video signal is changed more finely than one pixel in accordance with the moving amount of the video signal, the spatial stabilization of the video image more minutely than one pixel unit is performed. Will be

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the imaging apparatus according to the present invention.

In this embodiment, as shown in FIG. 1, a reflecting mirror 80 which is fixed only in the vertical direction and stabilizes a space, scans an object to be imaged, and photoelectrically converts light from the object through the reflecting mirror 80. The imaging mechanism 10 obtains and outputs a video signal and outputs a plurality of predetermined timing signals, an imaging mechanism driving unit 70 that outputs a signal for driving the imaging mechanism 10, A rate sensor 20 for detecting an angular velocity in a horizontal direction, an A / D converter 30 for sampling a video signal obtained by the imaging mechanism 10 and converting the video signal into digital video data, and a sample of a video signal in the A / D converter 30 A clock for determining the timing of the conversion, and a signal for selecting the video data based on the angular velocity detected by the rate sensor 20. A video data selection unit 40 for selecting digital video data output from the A / D conversion unit 30, and a frame memory 60 for temporarily storing the video data selected by the video data selection unit 40. ing.

FIG. 2 shows the video data selecting section 4 shown in FIG.
FIG. 3 is a block diagram illustrating a configuration of a space stabilizing unit 50 in a horizontal scanning direction.

As shown in FIG. 2, a horizontal spatial stabilization circuit 50 includes a sampling clock phase shift circuit 51 for outputting a plurality of clock signals having different phases based on a timing signal output from the imaging mechanism 10; A sampling clock switching circuit 52 that switches a plurality of clock signals output from the sampling clock phase shift circuit 51, and a movement amount of a video image captured by the imaging mechanism 10 is calculated from the angular velocity detected by the rate sensor 20, The video data selection unit 40 includes a video movement angle calculation circuit 53 to be output.
Signal generation circuit 42 for generating timing for selecting video data based on the moving amount of video output from
And a video data selection circuit 41 for selecting digital video data output from the A / D conversion unit 30 at the timing generated by the gate signal generation circuit 42.

The output of the moving amount of the video from the video moving angle calculating circuit 53 is transmitted to the sampling clock switching circuit 52 by sending a value below the decimal point as a clock switching value to the A / A / A.
The value used for setting the sampling point in the D conversion unit 30 and rounded down to the decimal point is sent to the gate signal generation circuit 42 as a signal generation value, and the gate signal generation circuit 42
Is used to generate the timing for selecting the video data.

Further, in the gate signal generating circuit 42, when the moving amount of the image is sent from the image moving angle calculating circuit 53, the image data moved by the amount of the moving amount is transmitted by a predetermined number. Only continuously select signals are generated.

Hereinafter, the operation of the image pickup apparatus configured as described above will be described with reference to FIGS.

When a video signal is input to the imaging mechanism 10 which is spatially stabilized only in the vertical scanning direction via the reflecting mirror 80,
The video signal a having a shift in the horizontal scanning direction due to the influence of the angular velocity of the imaging mechanism 10 in the horizontal scanning direction is output from the A / D converter 3.
0, the timing signal h from the imaging mechanism 10 is sent to the horizontal scanning direction space stabilizing unit 50, and the rate signal d, which is information on the horizontal angular velocity of the imaging mechanism 10 detected by the rate sensor 20, is It is sent to the horizontal space stabilizer 50. Note that the imaging mechanism 10 is driven by a driving signal k from the imaging mechanism driving unit 70.

Next, in the video moving angle calculation circuit 53 in the horizontal scanning direction space stabilizing section 50, the horizontal moving amount of the video signal is calculated from the rate signal d as the number of pixels.

Here, the horizontal movement amount (= M) of the video signal per unit time is represented by T _{dl at} the start position of each horizontal scan, ω _H and one pixel per pixel in the horizontal scan direction. If the viewing angle in the horizontal scanning direction is Δη _H , it can be obtained by the following equation.

[0024]

(Equation 1) In the image moving angle calculation circuit 53, ω
_The rate signal d is input to _M , and the horizontal movement amount of the video is calculated each time horizontal scanning starts.

[0025] Based on Equation 1, when obtaining the time shift amount ΔT in the horizontal direction of the video signal generated in the horizontal scanning of a predetermined time (= the T _s),

[0026]

(Equation 2) Becomes

When the moving amount of the video signal in the horizontal direction is calculated by the video moving angle calculating circuit 53, the value obtained by rounding off the decimal portion of the calculated time moving amount ΔT is used as the signal generation value e as the gate signal generation circuit. The value after the decimal point is sent to the sampling clock switching circuit 52 as the clock switching value 5a.

On the other hand, in the sampling clock phase shift circuit 51) in the horizontal scanning direction space stabilizing section 50, a plurality of clock signals φ _{0 to} φ _k-1 are generated based on the timing signal h sent from the image pickup mechanism 10. Generated.

Here, a plurality of clock signals φ ₀ -φ
_{When the} number of digits after the decimal point in the video movement amount is m, _k-1 is shifted by 1/2 ^m .

When the clock switching value 5a is transmitted from the video movement angle calculation circuit 53 to the sampling clock switching circuit 52, a plurality of clock signals φ generated in the sampling clock phase shift circuit 51 based on the transmitted value are output. A sampling clock signal having a shift amount φ corresponding to the clock switching value 5a is selected from _{0 to} φ _k−1 and A
It is output to the / D converter 30 as a sampling clock signal f for determining sampling timing.

When the signal generation value e is sent from the video movement angle calculation circuit 53 to the gate signal generation circuit 42,
In the gate signal generation circuit 42, a video selection signal j for continuously selecting the video data shifted by the transmitted value by a predetermined number of pixels is generated and output to the video data selection circuit 41.

When the sampling clock signal f is input to the A / D converter 30, the video signal a is sampled based on the sampling clock signal f and output as digital video data b.

Then, in the video data selection circuit 41, the digital video data b output from the A / D conversion section 30 is moved and selected based on the video selection signal j output from the gate signal generation circuit 42, and is selected. It is output to the frame memory 60 as the stabilized digital video c, and is written into the frame memory 60 by the frame memory write control signal i output from the gate generation circuit 42.

Here, in Equation 2, n is an integer and φ is 0
If it is a real number in the range of ≦ φ <2π,

[0035]

(Equation 3) Becomes

At this time, n corresponds to the number of moving pixels,
φ corresponds to the sampling clock phase.

Thereafter, the video data g in the frame memory 60 is output.

FIG. 3 is a diagram showing the number of pixels for correcting the image shift and the shift amount of the sampling clock.

As shown in FIG. 3, in the imaging apparatus according to the present embodiment, the moving amount ΔT of the video image obtained by Expression 2 is

[0040]

(Equation 4) Is set so as to satisfy
After that, the digital video data obtained by the sampling clock φ is moved and selected by n pixels, so that a more precise video movement correction than one pixel is possible,
It is possible to obtain video data with good spatial stabilization.

[0041]

As described above, according to the present invention, the moving amount of the video signal caused by the horizontal movement of the imaging mechanism is calculated, and the sampling of the video signal in the A / D converter is performed based on the calculated moving amount. A horizontal scanning direction space stabilizing unit for determining the timing is provided, and the sampling timing of the video signal is changed more finely than one pixel by adapting to the moving amount of the video signal. Can be stabilized.

As a result, it is possible to obtain a spatially stabilized image free from image disturbance.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an embodiment of an imaging apparatus according to the present invention.

FIG. 2 is a block diagram illustrating a configuration of a video data selection unit and a horizontal scanning direction space stabilization unit illustrated in FIG. 1;

FIG. 3 is a diagram showing the number of pixels and the amount of shift of a sampling clock for correcting image shift.

FIG. 4 is a block diagram illustrating a configuration example of a conventional imaging device that is not fixed to a platform.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 imaging mechanism 20 rate sensor 30 A / D converter 40 video data selector 41 video data selector 42 gate signal generation circuit 50 horizontal scanning direction space stabilization unit 51 sampling clock phase shift circuit 52 sampling clock switching circuit 53 video movement angle Calculation circuit 60 Frame memory 70 Imaging mechanism driving unit 80 Reflector 5a Clock switching value a Video signal b Digital video data c, g Space stabilized digital video d Rate signal e Signal generation value f Sampling clock signal h Timing signal i Frame memory writing Control signal j video selection signal k drive signal

Claims (4)

(57) [Claims] 1. An imaging apparatus that scans an imaging target and spatially stabilizes and outputs a video signal of the imaging target. The imaging device acquires a video signal from the imaging target, outputs the video signal, and outputs the video signal. An imaging mechanism that outputs a plurality of determined timing signals; a rate sensor that detects a horizontal angular velocity of the imaging mechanism; an A / D converter that samples the video signal and converts the video signal into digital video data; A horizontal signal for outputting a moving amount of the video signal generated by the scanning and a sampling clock for determining the sampling timing from the video signal and the timing signal output from the imaging mechanism and the angular velocity detected by the rate sensor; A scanning direction space stabilization unit; and an output from the A / D conversion unit based on a moving amount of a video signal output from the horizontal scanning space stabilization unit. Imaging apparatus characterized by having the video data selection unit for moving and selection of digital video data. 2. The imaging device according to claim 1, wherein the horizontal stabilizing unit in the horizontal scanning direction includes a sampling clock phase shift circuit that generates a plurality of clock signals based on a timing signal output from the imaging mechanism. Calculating a moving amount of the video signal based on the angular velocity from the rate sensor, and selecting a sampling clock signal that determines the timing of the sampling based on a value below the decimal point among the calculated moving amounts, An image moving angle calculation circuit that outputs a value of the moving amount with the decimal part truncated, wherein the video data selecting unit is configured to output the digital image based on the value of the moving amount with the decimal part truncated. A gate signal generation circuit for generating a timing for selecting data, and a timing generated in the gate signal generation circuit. An image data selecting circuit for moving and selecting the digital image data. 3. The imaging apparatus according to claim 2, wherein the sampling clock signal is a value for correcting a phase shift generated due to the movement amount. 4. The imaging device according to claim 2, wherein the plurality of clock signals are out of phase by 1/2 ^m when the number of digits after the decimal point in the moving amount is m. An imaging device characterized in that: