Imaging device and imaging method

Abstract

[Problem] To provide an imaging device and an imaging method with which it is possible to easily switch a double-speed setting without changing a clock and simplify a structure. [Solution] Provided are an imaging device that supports N-times faster imaging and an imaging method therefor, wherein an exposure control unit 7 causes a sensor 2 to be exposed in an exposure period in which exposure is performed at an M-fold speed equal to or less than the numerical value N of an N-fold speed for the video inputted from a lens. The exposure control unit 7 further exercises control by an exposure control signal so that a pixel signal is outputted in the same output period as the N-fold speed after the end of the exposure period and a given period after the end of the output period that corresponds to the numerical value M of an M-fold speed is made a disable period in which no pixel signals are outputted. A video rate conversion unit 5 outputs M frames of the M-fold speed video signal at the same timing as the N-fold speed.

Description

Imaging device and imaging method

[0001] The present invention relates to an imaging device that is applicable to a camera and is capable of high-speed imaging, and more particularly to an imaging device and imaging method that can easily switch between double-speed settings without changing the clock.

[0002] [Prior Art] Conventionally, broadcast cameras use SDI (Serial Digital Interface) for output, and the output format is basically 1 / 59.94 (frame rate: 59.94 fps) or 1 / 50 (50 fps), and the same applies to the clocks for sensor drive and video processing.

[0003] On the other hand, there are broadcast cameras that have high-speed functions that support Nx speed imaging. In such broadcast cameras (high-speed imaging devices), the SDI output is the same as 1x speed, at 1 / 59.94 or 1 / 50, but in order to drive the sensor and process the video at higher speeds, the clock of the main imaging circuit is set to Nx speed, and rate conversion processing is performed to match the SDI before output.

[0004] [Related Art] Related prior art includes Japanese Patent Laid-Open No. 2024-046934 entitled "Imaging Apparatus" (Patent Document 1). Patent Document 1 describes an imaging apparatus that can obtain a more natural video output by interpolation even when the frame rate is reduced due to slow shutter shooting.

[0005] JP 2024-046934 A

[0006] However, in conventional high-speed imaging devices, when imaging at N-times speed, the clock for driving the sensor and the clock for acquiring data must be dedicated to N-times speed, which is inconvenient and complicates the configuration, as the clock must be changed when changing the value of N. Furthermore, because the output format is the same as that for 1-times speed even during high-speed imaging, a different clock must be switched in the rate conversion unit according to the speed value before output, which is inconvenient and complicates the configuration.

[0007] Furthermore, Patent Document 1 does not describe a configuration in which the exposure control unit exposes the sensor at M times the speed, which is smaller than the maximum speed, to output pixel signals, and after the output period ends, controls the sensor to perform an invalid period in which pixel signals are not output for a certain period corresponding to the value of the number M.

[0008] The present invention has been made in view of the above circumstances, and has as its object to provide an imaging device and imaging method that can easily switch the speed setting without changing the clock and can simplify the configuration.

[0009] The present invention, which solves the problems of the above-described conventional example, provides an imaging device compatible with N-times speed imaging, comprising: a sensor that exposes an image input from a lens at M-times speed, which is equal to or less than the numerical value N of the N-times speed, and outputs pixel signals in an output period the same as the N-times speed; a rate control unit that outputs a rate control signal corresponding to the numerical value M of the M-times speed; and an exposure control unit that outputs an exposure control signal that sets an exposure period for exposing the sensor at M-times speed based on the rate control signal, causes the sensor to start outputting pixel signals after the exposure period has ended, and controls the sensor to be an invalid period in which no pixel signals are output after the output period has ended, for a certain period corresponding to the value of the numerical value M. The image processing device has a sensor receiving unit that converts pixel signals output from the sensor into a digital video format and outputs the converted signals as M-times-speed video signals, a video processing unit that performs video processing on the M-times-speed video signals output from the sensor receiving unit, a frame storage memory that stores M frames of the M-times-speed video signals, where M is the number of frames, a video rate conversion unit that stores M frames of the M-times-speed video signals output from the video processing unit in the frame storage memory and outputs M frames of the video signals from the frame storage memory at the same timing as the N-times-speed video signals, and a signal output unit that outputs the video signals from the video rate conversion unit.

[0010] In addition, in the above-mentioned imaging device of the present invention, the exposure control unit includes a time digital conversion circuit that outputs a time signal indicating a specific time from a clock, a time determination unit that uses the time signal to measure exposure times corresponding to multiple speed multiplication values ​​and generates exposure start and end timings for each speed multiplication value, and a selection circuit that selects and outputs the exposure start and end timings from the time determination unit based on a rate control signal.

[0011] In addition, in the imaging device of the present invention, the sensor performs exposure for a first time period from the start to the end of exposure based on an exposure control signal from an exposure control unit, outputs pixel signals exposed for a second time period after the first time period has elapsed to the sensor receiving unit, and does not output for a third time period after the second time period has elapsed until the start of the next exposure.

[0012] Also, in the imaging device of the present invention, the video rate conversion section treats the number of horizontal lines equal to the total number of horizontal lines arranged in the vertical direction×(N−M) / N as the number of invalid lines.

[0013] The present invention also provides an imaging method for an imaging device compatible with N-times speed imaging, in which an exposure control unit exposes a sensor for an exposure period of M-times speed, where N is the numerical value of N-times speed or less, and after the exposure period ends, causes the sensor to output pixel signals for an output period the same as the N-times speed, and after the output period ends, controls using an exposure control signal to set a certain period according to the value of M, the numerical value of M-times speed, as an invalid period in which pixel signals are not output, and a video rate conversion unit outputs M frames of M-times speed video signals at the same timing as the N-times speed.

[0014] According to the present invention, an imaging device compatible with N-times speed imaging includes a sensor that exposes an image input from a lens at M-times speed, which is equal to or less than the numerical value N of the N-times speed, and outputs a pixel signal in an output period the same as the N-times speed; a rate control unit that outputs a rate control signal corresponding to the numerical value M of the M-times speed; an exposure control unit that sets an exposure period for exposing the sensor at M-times speed based on the rate control signal, and outputs an exposure control signal that causes the sensor to start outputting pixel signals after the exposure period ends, and controls the sensor to be in an invalid period in which no pixel signals are output after the output period ends, corresponding to the value of the numerical value M; and a sensor that converts the pixel signal output from the sensor into a digital signal image format and outputs the digital signal as an M-times speed image signal. and a signal output unit that outputs the video signal from the video rate conversion unit. The imaging device has a sensor receiving unit, a video processing unit that performs video processing on the M-times speed video signal output from the sensor receiving unit, a frame storage memory that stores M frames of the M-times speed video signal, where M is the number of frames, a video rate conversion unit that stores M frames of the M-times speed video signal output from the video processing unit in the frame storage memory and outputs the M frames of the video signal from the frame storage memory at the same timing as the N-times speed, and a signal output unit that outputs the video signal from the video rate conversion unit. Therefore, by performing imaging and output with the sensor using the same clock as the maximum N-times speed, the speed value can be easily changed, which has the effect of simplifying the configuration.

[0015] Furthermore, according to the present invention, there is provided an imaging method in an imaging device compatible with N-times speed imaging, in which an exposure control unit exposes a sensor for an exposure period of M-times speed, where N is the numerical value of the N-times speed or less, and after the exposure period ends, outputs pixel signals for an output period the same as the N-times speed, and after the output period ends, controls by an exposure control signal so that a certain period according to the value of M-times speed is an invalid period in which pixel signals are not output, and a video rate conversion unit outputs M frames of M-times speed video signals at the same timing as the N-times speed.Therefore, by using the same clock as the maximum N-times speed to perform imaging and output with the sensor, the numerical value of the speed can be easily switched, which has the effect of simplifying the configuration of the imaging device.

[0016] FIG. 1 is an explanatory diagram showing the configuration of the imaging device; FIG. 2 is an explanatory diagram showing the configuration of an exposure control unit; FIG. 3 is an explanatory diagram showing the timing when imaging at Nx speed; FIG. 4 is an explanatory diagram showing the timing when imaging at 4x speed (N=4); FIG. 5 is an explanatory diagram showing the timing when imaging at 3x speed (N=4); FIG. 6 is a schematic explanatory diagram showing an image of a signal for each speed; FIG. 7 is an explanatory diagram showing the sequence when imaging at maximum speed (Nx speed); and FIG. 8 is an explanatory diagram showing the sequence when imaging at Mx speed (M<N).

[0017] An image pickup device (the present device) according to an embodiment of the present invention is an image pickup device compatible with N-times speed image pickup, and includes a sensor that exposes an image input from a lens at M-times speed, which is equal to or less than N, based on an exposure control signal, and outputs pixel signals in the same period as when image pickup is performed at N-times speed, a rate control unit that outputs a rate control signal corresponding to M, which is the numerical value M of the M-times speed, an exposure control unit that outputs an exposure control signal that sets an exposure period for exposing the sensor at M-times speed based on the rate control signal, and controls the sensor output to be disabled for a certain period corresponding to the value M after the exposure period ends, a sensor receiving unit that converts the pixel signal output from the sensor into a digital signal image format and outputs the converted signal as an M-times speed image signal, and a sensor receiving unit that outputs the converted signal as an M-times speed image signal. The image capturing apparatus includes a video processing unit that performs video processing on an M-times speed video signal output from a signal processing unit, a frame storage memory that stores M frames of the M-times speed video signal, a video rate conversion unit that stores M frames of the M-times speed video signal output from the image processing unit in the frame storage memory and outputs M frames of the M-times speed video signal from the frame storage memory at a specific timing, and a signal output unit that outputs the video signal from the video rate conversion unit, so that even when capturing images at an M-times speed that is smaller than the N-times speed, sensor drive and data capture processing can be performed using the same clock as the N-times speed, eliminating the need to change the clock, allowing for easy switching of speed settings and simplifying the configuration.

[0018] [Device: Figure 1] This device will be described with reference to Figure 1. Figure 1 is an explanatory diagram showing the configuration of this imaging device. This device is a high-speed imaging device and is used for applications such as surveillance cameras, industrial cameras, and broadcast cameras. Here, we will explain cameras with SDI video output (broadcast cameras and industrial cameras) as an example. This device is also compatible with N-times imaging, where N-times is referred to as the maximum speed (maximum video rate). This device achieves imaging, sensor output, and data capture at M-times speed, which is a speed value smaller than N-times speed, without changing the clock (using the N-times clock).

[0019] As shown in Figure 1, this device includes a lens 1, a sensor 2, a sensor receiving unit 3, a video processing unit 4, a video rate conversion unit 5, a signal output unit 6, an exposure control unit 7, a frame storage memory 8, and a rate control unit 9. The lens 1 adjusts the light input to the sensor 2 and is provided according to the angle of view and focal length. The iris (aperture) of the lens 1 can be controlled between fully open and fully closed.

[0020] Sensor 2 is an image sensor in which pixels made up of imaging elements such as CCDs or CMOS sensors that use light-sensitive elements such as photodiodes are arranged two-dimensionally, horizontally and vertically. Sensor 2 outputs light as an analog electrical signal. Each horizontal row is called a line, and multiple lines arranged vertically form a two-dimensional image sensor. Here, the number of lines arranged vertically is referred to as the number of lines.

[0021] Furthermore, the exposure period (timing of exposure start and end) of the sensor 2 is controlled by an exposure control signal, which will be described later. In particular, the sensor 2 of this device uses a global shutter system in which readout is performed simultaneously for all pixels, and the readout period is the same as the maximum N-times speed, i.e., it always outputs data for the same period as N-times speed. A feature of this device is that after the sensor 2 completes exposure for one frame and outputs sensor data for the same period as N-times speed, it does not output sensor data until the exposure period for the next frame ends. This operation will be described later.

[0022] The exposure control unit 7 is a characteristic feature of this device, and controls the on / off of the exposure period for the sensor 2 and the output. Here, the length of the exposure period (exposure time) varies depending on the speed factor, with the exposure time becoming longer as the speed factor decreases. On the other hand, the output from the sensor 2 is controlled so that it is output at the same rate and for the same period as the output at maximum speed, regardless of the speed factor. This allows the clock for the imaging process and readout process in the sensor 2 to be the same as the clock at maximum speed, even if the speed factor changes, making clock changes unnecessary.

[0023] The sensor receiver 3 converts the analog signals output from each imaging element of the sensor 2 into digital signals with a specified bit depth (color depth), and then converts them into video signals in a pre-specified video format for easy use in subsequent stages. Bit depth refers to the amount of data allocated to one pixel. The video processor 4 performs pre-processing and linear / non-linear video processing on the video signals output from the sensor receiver 3, and outputs video signals on a frame-by-frame basis.

[0024] The video rate conversion unit 5 temporarily writes the frame-by-frame video signal output from the video processing unit 4 to a frame storage memory 8, and also reads out and outputs the video signal stored in the frame storage memory 8 at a predetermined timing. Specifically, the video rate conversion unit 5 of this device stores the N-times speed video signal from the video processing unit 4 in groups of N frames in the frame storage memory 8, and outputs the N-times speed video signal for N frames stored in the frame storage memory 8 all at once at a predetermined timing. The predetermined timing is the same regardless of the speed value. Here, as will be described later, if the maximum speed is N, the video rate conversion unit 5 has N output units, and outputs one frame's worth of video data and up to N frames' worth of video data from each output unit simultaneously.

[0025] In this device, when the speed value is M which is smaller than N, the video rate conversion unit 5 stores the M-times speed video signal in a batch of M frames in the frame storage memory 8, and outputs the M-times speed video signal for M frames stored in the frame storage memory 8 all at once at a predetermined timing.

[0026] The signal output unit 6 outputs the video signal to SDI. At that time, the signal output unit 6 disables the video signal from a specific output unit of the video rate conversion unit 5 in accordance with a control signal from the rate control unit 9, and does not output it to the outside. This will also be described later. Specifically, for example, the signal output unit 6 stores in advance information about the output unit that should output the video signal according to the speed factor, and based on the control signal from the rate control unit 9, outputs the signal from the corresponding output unit, but does not output the signal from the other output units.

[0027] The frame storage memory 8 stores the video signal for the number of frames equal to the speed multiplier. For example, a 1x speed video signal is stored for one frame, a 2x speed video signal for two frames, and so on, with an Mx speed video signal for M frames and an Nx speed video signal for N frames. The frame storage memory 8 outputs the stored video signals all at once at a predetermined timing, regardless of the speed multiplier, i.e., regardless of the number of frames stored.

[0028] The rate control unit 9 is a characteristic part of this device, and sets a speed value for the exposure control unit 7, sensor receiving unit 3, video processing unit 4, video rate conversion unit 5, frame storage memory 8, and signal output unit 6.

[0029] [Configuration of Exposure Control Unit: Figure 2] The configuration of the exposure control unit 7 of this device will be described using Figure 2. Figure 2 is an explanatory diagram showing the configuration of the exposure control unit. As shown in Figure 2, the exposure control unit 7 includes a TDC (Time to Digital Converter) circuit 71, a time determination unit 72, selectors 73 and 74, and an RS-FF (Reset Set-Flip Flop) circuit 75.

[0030] The TDC circuit 71 receives a system clock, measures (counts) a specific time, and outputs a timing signal (time signal) indicating the specific time. The time determination unit 72 includes speed determination units 72 (single speed determination unit 72-1, double speed determination unit 72-2, ..., N-speed determination unit 72-n) that output signals indicating the start and end of an exposure period for each speed value.

[0031] Each speed determination unit 72 outputs an ST signal indicating the start of an exposure period and an ED signal indicating the end of the exposure period so that the exposure time (length of the exposure period) corresponds to the speed value, based on the time signal from the TDC circuit 71. Note that the time determination unit recited in the claims corresponds to a plurality of speed determination units 72.

[0032] The selector 73 inputs the ST signal from each speed determination unit 72, selects the ST signal of the speed determination unit 72 that corresponds to the speed value set by the rate control unit 9, and outputs it as a pulse signal to the S (set) terminal of the RS-FF circuit 75.

[0033] Similarly, the selector 74 inputs the ED signals from each speed determination unit 72, selects the ED signal of the speed determination unit 72 corresponding to the speed value set by the rate control unit 9, and outputs it as a pulse signal to the R (reset) terminal of the RS-FF circuit 75.

[0034] The RS-FF circuit 75 outputs an exposure control signal to the sensor 2, and when a pulse is input to the S terminal, the exposure control signal goes high (H) to indicate the start of exposure, and when a pulse is input to the R terminal, the exposure control signal goes low (L) to indicate the end of exposure. The selection circuit described in the claims corresponds to a configuration combining the selectors 73, 74 and the RS-FF circuit 75.

[0035] [Timing during N-speed imaging: Figure 3] Next, the operation timing of the sensor 2 and the video rate conversion unit 5 during imaging at N-speed, which is the maximum speed, will be described using Figure 3. Figure 3 is an explanatory diagram showing the timing during imaging at N-speed. As shown in Figure 3, if the frame period at 1-speed defined by the 1-speed VD (Vertical Drive: vertical synchronization signal) is T1, the frame period at N-speed is T2 (T1 / N).

[0036] The exposure time of the sensor 2 is controlled by an exposure control signal (exposure control unit output) from the exposure control unit 7, and varies depending on the exposure time T1 per frame at 1x speed and the speed factor (video rate), and at Nx speed, it is T3, which is T1 / N minus the time it takes for the signal to rise and fall.

[0037] Then, when the exposure control signal falls, output of one frame's worth of pixel signals begins from sensor 2. The time T4 of output from sensor 2 is approximately equal to one frame period (T2) at Nx speed (T4 = T2). As a result, during Nx speed imaging, N frames' worth of pixel signals (sensor outputs 1 to N) are output in the same time as the 1x speed frame period T1, converted into video signals by video processing unit 4, and input to video rate conversion unit 5, and the N frames' worth of video signals are temporarily stored in frame storage memory 8.

[0038] Then, at a predetermined timing, the video rate conversion unit 5 reads out N frames of Nx speed video signals stored in the frame storage memory 8, and the N frames of video signals are output simultaneously from output unit (1) to output unit (N). The effective period (output period) T5 from each output unit is equal to T1, which is the frame period at 1x speed.

[0039] [Timing for 4x Speed ​​Imaging (N=4): FIG. 4 ] Next, the operational timing for 4x speed imaging when the maximum speed is 4 (N=4) will be described using FIG. 4 . FIG. 4 is an explanatory diagram showing the timing for 4x speed (maximum speed) imaging. FIG. 4 is equivalent to the diagram in FIG. 3 where N=4. As shown in FIG. 4 , if the frame period for 1x speed is T6, the frame period for 4x speed is T6 / 4. Furthermore, the exposure time based on the exposure control signal output from the exposure control unit 7 is T8, and the effective image period T9 of the sensor output is approximately equal to T7. The number of outputs from the video rate conversion unit 5 is four, and four frames of 4x speed video signals are output collectively from output units (1) to (4) at a predetermined timing during output period T10 (=T6).

[0040] [Timing for 3x Speed ​​Imaging (N=4): Figure 5] Next, the operational timing for 3x speed imaging when the maximum speed is 4 (N=4) will be described using Figure 5. Figure 5 is an explanatory diagram showing the timing for 3x speed (N=4) imaging. In conventional imaging devices, when the speed factor was changed, the clock for imaging and readout from the sensor 2 was changed according to the speed factor, but in this device, imaging at a lower speed is achieved using the same clock as at the maximum speed.

[0041] Figure 5 shows the timing for high-speed imaging at 3x speed using the device shown in Figure 4, which has a maximum 4x speed. As shown in Figure 5, the frame period at 1x speed is T6, as in Figure 4, and the frame period at 3x speed, T11, is T6 / 3, which is longer than the frame period at 4x speed, T7. The exposure period T12 of the exposure control signal is also longer than the exposure period T8 at 4x speed, but the image-valid period of the sensor output is T9, the same as at 4x speed. A feature of this device is the provision of an image-invalid period T13 until the exposure of the next frame is completed (output begins).

[0042] In other words, even if the speed is small, the image is output for the same period as the maximum speed, and the waiting time until the exposure of the next frame is completed is set as the video invalid period. Therefore, the length of the video invalid period varies depending on the maximum speed and the set speed. This makes it possible for this device to capture and read at a slower speed using the same clock as the maximum speed, making it easy to change the speed.

[0043] Then, three frames of triple-speed video signals are stored in the frame storage memory 8, the number of outputs from the video rate conversion unit 5 becomes three, and three frames of video signals are output all at once from output units (1) to (3) at the predetermined timing equivalent to that at quadruple speed, during output period T10 (=T6). The output signal from output unit (4) becomes invalid, and no output is made from signal output unit 6.

[0044] [Image of Signals at Each Speed: Figure 6] Next, the image of signals at each speed will be described using Figure 6. Figure 6 is a schematic explanatory diagram showing the image of signals at each speed. Here, the maximum speed is set to 4x, and signals at 4x speed are compared with signals at lower speeds of 3x, 2x, and 1x. (a) shows the image of signals at 4x speed imaging, (b) at 3x speed imaging, (c) at 2x speed imaging, and (d) at 1x speed imaging. Note that imaging at a rate lower than the maximum speed is sometimes referred to as slow shutter imaging.

[0045] Normally, video is processed by processing horizontal pixels for each vertical line, so it can be expressed as the product of the number of horizontal pixels Pall and the number of lines arranged in the vertical direction Lall. Here, the number of horizontal pixels Pall can be divided into an effective pixel period Pa and an ineffective pixel period Pi (Pall = Pa + Pi), and the values ​​of Pa and Pi are constant regardless of the video rate (video speed factor).

[0046] On the other hand, the breakdown of the number of vertical lines Lall into valid and invalid portions varies depending on the video rate. For example, as shown in Figure 6(a), during 4x speed imaging, which is equal to the maximum speed, four frames of valid data are input to the sensor receiving unit 3 per unit time, and the number of lines Lf4 from the input of valid data to the valid data of the next frame matches the number of lines La per frame. In other words, the breakdown of the number of vertical lines Lall during 4x speed imaging is Lall = 4 x Lf4 = 4 x La. As described above, the four frames of video data shown in (a) are stored in the frame storage memory 8 and output all at once at a predetermined timing.

[0047] 6(b), when high-speed shooting is performed at 3x speed when the maximum speed is 4x, the number of lines Lf3 from when valid data is input to the valid data of the next frame can be divided into the number of lines La per frame and the number of invalid lines Li(3). That is, Lf3 = La + Li(3), Lall = 3 x Lf3. Three frames of valid video data are stored in the frame storage memory 8, and the three frames of video data are output all at once from the frame storage memory 8 at the same timing as at 4x speed.

[0048] 6(c), when high-speed shooting is performed at double speed, the number of lines Lf2 from when valid data is input until the valid data of the next frame is divided into the number of lines La per frame and the number of invalid lines Li(2), as follows: Lf2 = La + Li(2), Lall = 2 × Lf2. Furthermore, when shooting at 1x speed, as shown in (d), Lf1 = La + Li(1).

[0049] In this way, this device uses the same clock as at maximum speed, outputs the sensor for the same period as at maximum speed, and sets the remaining period as an invalid video period, making it possible to set various speeds without changing the clock.

[0050] The image in Figure 6 will be explained using time. If the readout time per pixel is Tx, the image valid period T9 shown as T9 in Figure 5 (when capturing at 3x speed) is expressed as the product of Tx, the number of horizontal pixels, and the number of lines per frame, La. T9 = Tx x Pall x La

[0051] 5 is expressed by multiplying Tx by the number of horizontal pixels and the number of invalid lines Li(3): T13=Tx×Pall×Li(3)

[0052] Here, the calculation of the number of invalid lines will be described. When the maximum rate is Nmax, the set rate is N, and the number of lines per frame is La, the number of invalid lines Li(N) is calculated by the following formula (1).

[0053] ...Equation (1)

[0054] As is clear from Figure 6 and equation (1), the greater the difference between the maximum speed and the set speed, the greater the number of invalid lines Li(N) and the longer the video invalid period. The third time period in the claims corresponds to the video invalid period. By providing a video invalid period, this device can stabilize the video clock and the number of horizontal pixels, thereby simplifying the device configuration. The number of invalid lines may be calculated, for example, by the rate control unit 9, and notified to each unit to specify the vertical valid area.

[0055] [Operation of the Device: Figures 1 and 5] The operation of the characteristic parts of the device will be briefly described using Figures 1 and 5. In the device, the exposure control unit 7 controls the start / stop of exposure in the sensor 2 by turning the exposure control signal on / off (Hi / Low) based on the exposure time corresponding to the speed value set by the rate control unit 9. At the same time, when the sensor 2 completes exposure for one frame, it outputs sensor data for the same period as at maximum speed, and when the output ends, there is a video invalid period (T13 in the example of Figure 5) during which no sensor data is output until the exposure of the next frame is completed.

[0056] The video signal is input in frame units to the video rate conversion unit 5 via the sensor receiving unit 3 and the video processing unit 4. The video rate conversion unit 5 stores the same number of frames as the speed multiplier value set by the rate control unit 9 in the frame storage memory 8 and outputs them all at once to the signal output unit 6 at a predetermined timing. The signal output unit 6 selects an effective output unit of the video rate conversion unit 5 in accordance with the speed multiplier value set by the rate control unit 9 and outputs the video signal. In this way, the present device can perform imaging at different speed multipliers with simple processing, without changing the clock.

[0057] [Sequence for Imaging at Maximum Speed ​​(N-fold Speed): FIG. 7] Next, the sequence of the exposure control unit 7, sensor 2, and sensor receiving unit 3 when imaging at maximum speed will be described with reference to FIG. 7. FIG. 7 is an explanatory diagram showing the sequence when imaging at maximum speed (N-fold speed). As shown in FIG. 7, when the exposure control unit 7 sets the exposure control signal to Hi (S11), the sensor 2 starts exposure and enters the exposure state. Then, when the exposure control signal from the exposure control unit 7 goes Low (S12), the sensor 2 stops exposure. Next, the sensor 2 starts outputting sensor data to the sensor receiving unit 3 (S13) and enters the data output state.

[0058] Meanwhile, the exposure control unit 7 sets the exposure control signal for the next frame to Hi (S14), and the sensor 2 continues to output the sensor data for the previously exposed frame until output is complete (S15), while also performing exposure. When the exposure control signal goes Low (S16), the sensor 2 ends exposure and starts outputting sensor data (S17). Similarly, exposure and output of sensor data are performed in parallel as shown in steps S18 to S22.

[0059] As shown in Figure 7, when imaging at maximum speed, the exposure time and data output period are almost the same, and the sensor 2 outputs sensor data after exposure is complete. When output of one frame is complete, the exposure for the next frame is also complete, so the next output begins immediately. In this way, the sequence for imaging at maximum speed is performed.

[0060] [Sequence for Imaging at M-fold Speed ​​(M<N): FIG. 8] Next, a sequence for when the speed value is M, which is smaller than the maximum speed value N, will be described. FIG. 8 is an explanatory diagram showing the sequence for imaging at M-fold speed (M<N). As shown in FIG. 8, when the exposure control unit 7 sets the exposure control signal to Hi (S31), the sensor 2 starts exposure and enters the exposure state. Then, when the exposure control signal from the exposure control unit 7 goes Low (S32), the sensor 2 stops exposure. Here, the length of the exposure period (during exposure) is longer than when imaging at N-fold speed.

[0061] Then, the sensor 2 starts outputting sensor data to the sensor receiving unit 3 (S33) and enters data output. The period during which data is being output is the image valid period. Furthermore, when the exposure control signal becomes Hi (S34), the sensor 2 starts exposure of the next frame and enters exposure. In the output of the sensor 2, the time during which data is being output at M-times speed is the same as at N-times speed, so even when data output has ended (S35), the exposure of the next frame has not yet ended.

[0062] Then, when the exposure control signal goes Low (S36) and exposure ends, the sensor 2 starts outputting sensor data for the next frame (S37). That is, in the output of the sensor 2, the period from when data output ends in process S35 to when output of sensor data for the next frame starts in process S37 is the video invalid period. Output of sensor data starts when the exposure control signal goes Low. In this way, the sequence for imaging at Mx speed is performed.

[0063] [Effects of the embodiment] According to the imaging device of the present invention, the imaging device is compatible with N-times speed imaging and includes a sensor 2 that exposes an image input from a lens at M-times speed, which is equal to or less than the numerical value of N, based on an exposure control signal, and outputs a pixel signal in the same period as when imaging at N-times speed; a rate control unit 9 that outputs a rate control signal corresponding to the numerical value M of the M-times speed; an exposure control unit 7 that outputs an exposure control signal that sets an exposure period for exposing the sensor 2 at M-times speed based on the rate control signal, and controls the sensor 2 output to be an invalid period for a certain period corresponding to the value of M after the exposure period has ended; a sensor receiving unit 3 that converts the pixel signal output from the sensor 2 into a digital signal video format and outputs it as an M-times speed video signal; a frame storage memory 8 that stores M frames of the M-times speed video signal output from the video processing unit 4 in the frame storage memory 8 and outputs M frames of the M-times speed video signal all at once from the frame storage memory 8 at a specific timing; and a signal output unit 6 that outputs the video signal from the video rate conversion unit 5. Even when capturing an image at M-times speed, which is a speed value smaller than N-times speed, the sensor drive and data capture process can be operated with the same clock as N-times speed, eliminating the need to change the clock, facilitating switching of speed settings, and resulting in an advantageous effect of simplifying the configuration.

[0064] The present invention is suitable for an imaging apparatus and an imaging method that can easily switch the speed setting without changing the clock.

[0065] DESCRIPTION OF SYMBOLS 1... lens, 2... sensor, 3... sensor receiving section, 4... image processing section, 5... image rate conversion section, 6... signal output section, 7... exposure control section, 8... frame storage memory, 9... rate control section, 71... TDC circuit, 72... time determination section, 73, 74... selectors, 75... RS-FF circuit

Claims

1. An imaging device compatible with N-times speed imaging, comprising: a sensor that exposes an image input from a lens at M-times speed, the M-times speed being equal to or less than the N-times speed value N, and outputs pixel signals over the same output period as the N-times speed; a rate control unit that outputs a rate control signal corresponding to the M-times speed value M; an exposure control unit that sets an exposure period for the sensor to expose at the M-times speed based on the rate control signal, and outputs an exposure control signal that causes the sensor to start outputting pixel signals after the exposure period ends, and controls the sensor to be in an invalid period for not outputting pixel signals for a certain period corresponding to the M-times speed value after the output period ends; a sensor receiving unit that converts the pixel signals output from the sensor into a digital signal video format and outputs the M-times speed video signals; a video processing unit that performs video processing on the M-times speed video signals output from the sensor receiving unit; and a frame storage memory that stores M frames of the M-times speed video signals, the number of frames being the M-times speed value. an image capture device comprising: a video rate conversion unit that stores the M frames of the M-times speed video signal output from the video processing unit in the frame storage memory, and outputs the M frames of the video signal from the frame storage memory at the same timing as the N-times speed; and a signal output unit that outputs the video signal from the video rate conversion unit.

2. An imaging device as described in claim 1, wherein the exposure control unit comprises: a time-to-digital conversion circuit that outputs a time signal indicating a specific time from a clock; a time determination unit that uses said time signal to measure exposure times corresponding to multiple speed values ​​and generates exposure start and end timings for each speed value; and a selection circuit that selects and outputs the exposure start and end timings from said time determination unit based on said rate control signal.

3. The imaging device of claim 1, wherein the sensor performs exposure for a first time period at M times the speed from the start to the end of exposure based on an exposure control signal from the exposure control unit, outputs the exposed pixel signal to the sensor receiving unit for a second time period after the first time period has elapsed, and does not output for a third time period after the second time period has elapsed until the start of the next exposure.

4. An imaging device according to claim 1, wherein the video rate conversion section treats the number of horizontal lines, which is the total number of horizontal lines arranged in the vertical direction x (the N - the M) / the N, as the number of invalid lines.

5. An imaging method for an imaging device compatible with N-times speed imaging, wherein an exposure control unit exposes a sensor to an image input from a lens for an exposure period at M-times speed, where M is less than or equal to the N-times speed, and after the exposure period ends, outputs pixel signals for an output period the same as the N-times speed, and controls using an exposure control signal to set a certain period after the output period according to the value of M-times speed as an invalid period during which pixel signals are not output, and a video rate conversion unit outputs M frames of the M-times speed video signals at the same timing as the N-times speed.

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