JP2003060946A - Frame photographing video camera apparatus with intermittent illumination - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a frame photographing video camera apparatus, having an intermittent illumination that comprises a combination of a high image quality version of a solid-state imaging device with an electronic shutter employed for supervisory or the like of a moving body, such as a vehicle and an intermittent illumination device to the illumination contrast of which a person being an object feels no sense of flickering. SOLUTION: The solid-state imaging device having the electronic shutter function, that senses the approach of a moving object, such as a vehicle, intermittently emits a visual light to the object, applies consecutive frame photographing to a plurality of static images, employs a solid-state imaging element with many pixels whose video read period per frame is long. The device is provided with an illumination unit, including a light emission controller for emitting light for a plurality of times including one emission synchronous with the electronic shutter within the video read period for one frame, and the illumination device comprises a plurality of white light emission diodes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state imaging device with an electronic shutter function, which is used for monitoring a moving body such as a vehicle, and has high image quality, and intermittent illumination that does not cause a human subject to feel a flicker of light and dark. The present invention relates to provision of a frame-shooting video camera device with intermittent illumination in combination with the device.

[0002]

2. Description of the Related Art As a traffic monitoring device on a road such as a highway or a toll road, a tollgate, or a vehicle number reading device, it is detected that a subject such as a vehicle is approaching an image pickup position, and a discontinuity is generated by a strobe or the like. A solid-state image pickup device with an electronic shutter function is used which irradiates visible light, accumulates electric charges in a solid-state image pickup device in synchronization with the irradiation period, and continuously reads out still images. Using this solid-state imaging device with an electronic shutter function, a vehicle moving at high speed is recorded as a clear still image without blurring, and the recorded image is enlarged and displayed to confirm the driver or vehicle number. Higher shutter speeds and higher image quality with solid-state imaging devices with many pixels are required, and there is a strong demand for their realization.

The higher the speed of the electronic shutter of the solid-state image pickup device, the shorter the charge accumulation time of the solid-state image pickup device, the lower the sensitivity of the solid-state image pickup device, and the stronger illumination is required. In addition, the strong discontinuous illumination light emitted in accordance with the electronic shutter may cause a person such as a driver to feel a flicker of light and darkness in the eyes depending on the irradiation interval and may hinder driving. Come out. However, in the conventional TV-rate solid-state imaging device, the vertical scanning period of one frame of image reading is 1/60 seconds or 1/50 seconds, so that the lighting device synchronizes with the electronic shutter once every frame and 60 times per second. The light is emitted intermittently or 50 times, and the discontinuous light of this cycle does not cause a driver or the like as a subject to feel flicker.

However, in order to meet the demand for higher image quality of the solid-state image pickup device with an electronic shutter, if a high-sensitivity, high-pixel-number solid-state image pickup device used in a recent still video camera is used, Since the vertical scanning cycle of the solid-state imaging device is 1/10 seconds to 1/20 seconds, the visible light irradiation synchronized with the electronic shutter once in one vertical scanning cycle is 10 to 20 times per second. Will be perceived as flicker in the eyes of.

As a high-quality solid-state image pickup device, a high-definition solid-state image pickup device having a high-sensitivity solid-state image pickup device with a large number of pixels has already been used in television broadcasting and the like. However, the high-definition camera device is expensive and large, and cannot be adopted at the present time for applications requiring a large number of camera devices such as a road traffic monitoring system. .

Even if the illumination light source is infrared strobe light, the infrared light cannot be perceived by human eyes, so that the problem of flicker can be solved, but in this case too, the infrared camera device is expensive and cannot be adopted. .

[0007]

In view of the above situation, a high-sensitivity solid-state image pickup device for a still camera having a large number of pixels is used to improve the image quality of the solid-state image pickup device.
Visible light is emitted multiple times within the frame image readout period (one vertical scanning period), one of which is synchronized with the electronic shutter to contribute to the capture of a still image, and the other time, dummy light emission is performed as the subject. It is possible to realize a low-priced video camera device with intermittent illumination, which prevents flicker from being felt in the eyes of other people.

[0008]

Means for Solving the Problems The present invention has solved the above problems by the following means. (1) In a solid-state imaging device with an electronic shutter function that detects the approach of a moving subject such as a vehicle and intermittently irradiates the subject with visible light to continuously take a plurality of still images In addition to using a solid-state image sensor having a large number of pixels with a long image read cycle, an illumination device is provided that includes a light emission control device that emits light a plurality of times including one time synchronized with an electronic shutter within the image read cycle of one frame. A frame-shooting video camera device with intermittent illumination. (2) The lighting device includes a plurality of white light emitting diodes, and includes a light emission control device that emits light a plurality of times, including one time synchronized with an electronic shutter, within one frame of an image reading period. A frame-shooting video camera device with intermittent illumination according to the item (1). (3) The light emission control device uses the horizontal synchronization signal as a reference,
An address counter that outputs a vertical synchronization signal that determines a cycle of reading one frame of video and an electronic shutter control signal that determines a charge accumulation time of the image sensor, and the number of times the solid-state imaging device emits light during one frame of video reading A light emission pitch setting circuit that is arbitrarily set, and a latch that stores and holds an exposure time corresponding to an electronic shutter control signal of the solid-state imaging device with an electronic shutter, and outputs a light emission signal synchronized with the electronic shutter control signal to an adder A circuit, a dummy light emitting circuit for generating a plurality of dummy light emitting signals other than the light emitting signal synchronized with the electronic shutter control signal, a light emitting signal synchronized with the electronic shutter control signal output from the latch circuit, and a dummy light emitting circuit And an adder for adding the output dummy light emission signal to the lighting device. DOO intermittent illuminated lapse video camera apparatus according to claim 1 or 2, characterized in.

[0009]

Embodiments of the present invention will be described with reference to examples. 1 is a block diagram showing an outline of an embodiment of the present invention, FIG. 2 is a block diagram of a light emission control device, FIG. 3 is a waveform diagram of each part of the light emission control device of FIG. 2, and FIG. 4 is an explanatory diagram of flicker suppression.

The present invention, like the embodiment shown in FIG. 1, includes a solid-state image pickup device 1 with an electronic shutter function provided at a position overlooking a road surface such as a highway, and a plurality of white light emitting diodes which blink intermittently. And a sensor 3 installed on a road surface, a shoulder, etc. for confirming passage of a subject 5 such as a vehicle, and a signal from the sensor 3 for capturing an image of the solid-state imaging camera device 1 and emission of light of the illumination device 2. In a traffic monitoring system or the like configured with a control device 4 that performs control such as starting and stopping after a predetermined time, the solid-state imaging camera device 1 has a high sensitivity with a long reading period (vertical scanning period) of one image frame. By using a solid-state image sensor having a large number of pixels and having a function of blinking the lighting device 2 a plurality of times within a period of reading one frame of video, a driver or the like who is a subject can receive a function. Take intermittent lighted frame does not feel Kka to realize a video camera device.

In the following, a case will be described as an example where the solid-state image pickup device 1 with the electronic shutter function uses a high-quality solid-state image pickup device having more than 1.3 million pixels that outputs a video signal of 12 frames per second. Generally, the electronic shutter of a solid-state imaging device is
It operates only once within one frame of image reading period, that is, every 1/12 second. Therefore, when the high-speed shutter is used, as shown in FIG. 4A, the operating time (for example, 1/1000 second) 11 of the electronic shutter becomes extremely shorter than the 1-frame reading time. When the visible light is emitted in accordance with the electronic shutter actuation time 11, a short intense visible light is projected into the eyes of a driver or the like as a subject every 1/12 second, and flicker is felt. As one method for solving this problem, it can be considered to increase the number of times the lighting device emits light to a number at which flicker is not felt. For example, as shown in FIG. 4B, if the light is emitted four times including the electronic shutter actuation time 11 within one frame period, the light emission is 48 times per second, which is a frequency that does not cause flicker to human eyes. . However, the three times of light emission other than the electronic shutter actuation time 11 is the dummy light emission time 12 that is not involved in the imaging.

A light emission control device of the illumination device 2 will be described with reference to FIGS. As shown in FIG. 2, the address counter 6 generates a vertical synchronizing signal a and an electronic shutter control signal b as shown in FIG. 3 with reference to the input horizontal synchronizing signal g. The control signal b is supplied to necessary circuits in the light emission control device as well as the solid-state image pickup camera device with an electronic shutter function. Further, the light emission pitch setting circuit 7 generates a pitch pulse c, which determines a time interval corresponding to the number of times the lighting device 2 is caused to emit light within one vertical scanning period, by the clock from the address counter 6 and sends it to the latch circuit 8. The latch circuit 8 stores and holds the count value corresponding to the operation time of the electronic shutter control signal b from the address counter 6, and when the pitch pulse c synchronized with the electronic shutter control signal b is input, the electronic shutter control signal b When the imaging light emission signal d having the same operation time is output to the adder 10 and the pitch pulse c that is not synchronized with the electronic shutter control signal b is input, a dummy count value corresponding to the operation time of the electronic shutter control signal b is input. It outputs to the light emission signal generation circuit 9. The dummy light emission signal generation circuit 9 creates a dummy light emission signal e from the input signal from the latch circuit 8 and sends it to the adder 10. In the adder 10, the imaging light emission signal d synchronized with the electronic shutter control signal b output from the latch circuit 8,
The dummy light emission signal e output from the dummy light emission signal generation circuit is added to create the illumination device light emission signal f. Electronic shutter control signal b, dummy light emission signal e, pitch pulse c
Etc. must be synchronized with each other. Since this synchronization is based on the vertical synchronization signal a, the vertical synchronization signal a is added to each circuit that requires synchronization. The operation control of each circuit described above is performed by a CP (not shown).
Do by U.

The use of a plurality of white light emitting diodes in a lighting device is suitable for applications such as traffic monitoring because the light emitting diodes have a long life and are maintenance-free. It has a short rise time, is suitable for capturing a still image of a subject moving at high speed, and operates at low voltage and consumes less power.

[0014]

According to the present invention, the following operational effects are exhibited. (1) By performing intermittent light emission a plurality of times within the vertical scanning period, a solid-state image sensor having a large number of pixels with a long vertical scanning period can be provided in a vehicle or the like without causing a person as an object to feel a free car associated with intermittent illumination. A frame shooting video camera device with intermittent illumination for recording a still image of a moving body can be realized. (2) By using the above-mentioned solid-state imaging device having a large number of pixels, a high-sensitivity and high-quality monitoring frame shooting video camera device can be realized at a low price. (3) By using a white light emitting diode as a light source, it is possible to realize a lighting device that has a long life, operates at a low voltage, and consumes less power.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an outline of an embodiment of the present invention.

FIG. 2 is a block diagram of a signal generation circuit that controls light emission of a lighting device.

FIG. 3 is a waveform diagram of each part in FIG.

FIG. 4 is an explanatory diagram of flicker suppression.

[Explanation of symbols]

1: Solid-state imaging device with electronic shutter function 2: Lighting device 3: Sensor 4: Control device 5: Subject 6: Address counter 7: Light emission pitch setting circuit 8: Latch circuit 9: Dummy light emission signal generation circuit 10: Adder 11: Electronic shutter operation time 12: Dummy light emission time a: Vertical synchronization signal b: Electronic shutter control signal c: Pitch pulse d: Imaging light emission signal e: Dummy light emission signal f: Lighting device light emission signal g: Horizontal synchronization signal

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5C022 AA01 AB15 AB17 AC42 AC52                 5C054 AA05 CA04 CC03 CE16 CF03                       CH04 HA26

Claims (3)

[Claims] 1. Detecting the approach of a moving subject such as a vehicle,
In a solid-state imaging device with an electronic shutter function that intermittently irradiates the subject with visible light and successively takes a plurality of still images, a solid-state imaging device having a large number of pixels with a long image read cycle of one frame is used. In addition, a frame shooting video camera device with intermittent illumination is provided, which is provided with an illumination device that includes a light emission control device that emits light a plurality of times including one time synchronized with an electronic shutter within the image reading cycle of one frame. 2. The lighting device comprises a plurality of white light emitting diodes, and includes a light emission control device that emits light a plurality of times, including one time in synchronization with an electronic shutter, within an image reading cycle of one frame. A frame-shooting video camera device with intermittent illumination according to claim 1. 3. An address counter for outputting a vertical synchronizing signal, which determines a cycle for reading one frame of image based on a horizontal synchronizing signal, and an electronic shutter control signal, which determines a charge accumulation time of the image sensor, by the light emission control device. An emission pitch setting circuit that arbitrarily sets the number of times the solid-state imaging device emits light during an image read period of one frame, and stores and holds an exposure time corresponding to an electronic shutter control signal of the solid-state imaging device with an electronic shutter. A latch circuit for outputting a light emission signal synchronized with the electronic shutter control signal to an adder; a dummy light emission circuit for generating a plurality of dummy light emission signals other than the light emission signal synchronized with the electronic shutter control signal; The light emission signal synchronized with the output electronic shutter control signal and the dummy light emission circuit output from the dummy light emission circuit 3. An intermittent illumination frame shooting video camera device according to claim 1 or 2, further comprising: an adder that adds the optical signal and adds it to the lighting device.