CN100465754C - Exposure control system and method of image sensing device - Google Patents

Abstract

The present invention relates to an exposure control system and method for an image sensing device, which includes an image sensing device, an illumination device, a control device and a light separation device. The image sensing device has a plurality of light sensing pixels arranged in a two-dimensional matrix. When exposure is performed, exposure is performed in a sub-region of the plurality of light sensing pixels. The illumination device generates a flash as a light source during exposure. The light separation device filters out light other than the flash. The control device sequentially turns on each pixel column in the sub-region. When each pixel column in the sub-region is in an exposure state, the control device drives the illumination device to generate the flash.

Description

Exposure control system and method for image sensing device

technical field

The present invention relates to the technical field of image sensing, in particular to an exposure control system and method of an image sensing device.

Background technique

When using an image sensor, a shutter is often installed in front of it to control the exposure amount and exposure time of the image sensor. The shutter can be divided into a mechanical shutter and an electronic shutter. Under the requirements of small size, light weight and low price, the electronic shutter has become a commonly used shutter for general image sensing devices.

The electronic shutter means that the exposure time is controlled by the electronic signal in the image sensing device and the entire exposure time and process. Existing complementary metal oxide semiconductor (CMOS) image sensing devices handle reset, exposure and reading of the image sensing device in a row-by-row manner. As shown in FIG. 1, to expose a row of pixels, the row of pixels is first reset. In order to make the exposure time of each column the same, the reset of successive columns is carried out at a certain speed. Then turn on/off the electronic shutters of each row sequentially, so that each row is exposed in sequence. This row-by-row way of opening/closing the electronic shutter is called a rolling electronic shutter.

In this exposure mode, an illuminating device needs to be turned on during the exposure process of all rows, so as to provide the required light source during the exposure process. Due to the long exposure time, the lighting device cannot use a high-power light source to prevent the lighting device from being burned. That is to say, the illuminating device consumes a relatively small current, such as 150 mA, during the time T3 to T4. Although the lighting device consumes a relatively small current, the overall power consumption is considerable due to the long exposure time. In order to reduce power consumption, the brightness of the lighting device is usually reduced. However, this will cause the distance between the illuminating device and the surface of the object to be closer, so the angle cannot be effectively increased, or the opening time of the electronic shutter of each column of the CMOS image sensing device is prolonged in order to achieve sufficient illumination, but the exposure time is long , It is easy to form blurred images. If the time is to be shortened, the photosensitive area of the CMOS image sensing device needs to be enlarged to obtain enough light.

In order to avoid the above problems, in the U.S. Patent Publication No. US 2003/0007088 A1, multiple flashes are used in the exposure process of the image sensing device, so that each pixel column of the image sensing device receives the same exposure on average quantity. As shown in FIG. 2, the first flash affects columns 0-11, but not columns 12-31. The second flash will affect columns 12-23, but not columns 24-31, nor columns 0-11. Although for each pixel row from row 0 to row 31, there is only one flash light during exposure, so each pixel row receives the same exposure amount. However, during time T1 to T2, if the target object is moving, the image will be broken. Therefore, there are still many deficiencies in the exposure control system and method of the existing image sensing device, which need to be improved.

Contents of the invention

The object of the present invention is to provide an exposure control system and method for an image sensing device, so as to avoid the problem of uneven exposure of each pixel row during exposure in the prior art, and at the same time increase the quality of captured images.

In order to solve the above technical problems, the present invention provides an exposure control system of an image sensing device, which mainly includes an image sensing device, an illumination device, a control device and a light separation device. The image sensing device has a plurality of light-sensing pixels arranged in a two-dimensional matrix, and when exposed to light, it is exposed in a sub-region of the plurality of light-sensing pixels, and each pixel column in the sub-region has an exposureable state The illuminating device generates a flash as a light source during exposure; the control device is coupled to the image sensing device and the illuminating device to control the exposure timing of the image sensing device and the timing of the light source generated by the illuminating device; the light separation device is coupled to The image sensing device is to reduce the interference of light other than the illumination, and only allow the illumination to be transmitted to the image sensing device; wherein, the control device sequentially turns on each pixel column in the sub-area, when the sub-area When each pixel column in the area is in the exposureable state, the control device drives the illuminating device to generate the flash, and controls the flash period of the flash.

The present invention also provides an exposure control system of an image sensing device, which mainly includes an image sensing device, a lighting device, a control device and a light separation device. The image sensing device has a plurality of light-sensing pixels arranged in a two-dimensional matrix, and when exposed, it is exposed in a sub-region of the plurality of light-sensing pixels, and each pixel column in the sub-region has an exposureable state ; the lighting device generates a flash as a light source during exposure; the control device is coupled to the image sensing device and the lighting device to control the exposure timing of the image sensing device and the timing of the light source generated by the lighting device; the light separation device consists of a Composed of a top cover and a base, the image sensing device, lighting device and control device are fixed in the light blocking device to reduce the interference of light other than the lighting and allow the lighting to be transmitted to the image sensor device; wherein the control device sequentially turns on each pixel row in the sub-region, and when each pixel row in the sub-region is in the exposing state, the control device drives the illuminating device to generate the flash, And control the flash period of that flash.

The present invention further provides an exposure control method for an image sensing device, which is to expose an image sensing device, the image sensing device has a plurality of photosensitive pixels arranged in a two-dimensional matrix, and when exposing, it is exposed on the In a sub-area of a plurality of light-sensing pixels, the image sensing device is provided with a light separation device to reduce the interference of light other than a flash, and the method includes the following steps: a resetting step, simultaneously for the sub-area Each pixel row in the sub-area is reset to allow each pixel row to enter an initial state; an activation exposure step is activated to sequentially activate each pixel row in the sub-region to enter an exposure state; an illumination step is used to generate The flash is used as a light source for exposure; a processing step is to sequentially sample each pixel row in the sub-region to obtain an exposure image of an object; wherein, when each pixel row in the sub-region is exposed The flash is generated in the state, and the flash period of the flash is controlled.

The present invention further provides an exposure control method for an image sensing device, which is to expose an image sensing device, the image sensing device has a plurality of photosensitive pixels arranged in a two-dimensional matrix, and when exposing, the exposure is performed on the In a sub-area of a plurality of light-sensing pixels, the image sensing device is provided with a light separation device to reduce the interference of light other than a flash, and the method includes the following steps: a resetting step, simultaneously for the sub-area Each pixel column in the sub-area is reset to allow each pixel column to enter an initial state; an activation exposure step is activated to simultaneously activate each pixel column in the sub-region to enter an exposure state; an illumination step is used to generate the Flash, as a light source during exposure; a processing step, sequentially sampling each pixel row in the sub-region to obtain an exposure image of an object; wherein, when each pixel row in the sub-region is in the exposure state When the flash is generated, and the flash period of the flash is controlled.

Description of drawings

FIG. 1 is a schematic diagram of conventional exposure using a rolling electronic shutter.

FIG. 2 is a schematic diagram of conventional exposure using multiple flashes.

FIG. 3 is a block diagram of an embodiment of an exposure control system with an image sensing device according to the present invention.

FIG. 4 is a schematic diagram of an exposure control method with an image sensing device of the present invention.

FIG. 5 is a schematic diagram of another embodiment of the exposure control method of the present invention.

FIG. 6 is a schematic diagram of another embodiment of the exposure control method of the present invention.

FIG. 7 is an exploded perspective view of another embodiment of an exposure control system with an image sensing device according to the present invention.

Description of figure number

Image sensing device 310 Convex mirror group 320

Lighting device 330 Control device 340

light divider 350 object 360

Image sensing device 710 Convex mirror group 720

Lighting device 730 Control device 740

Light Barrier 750 Extension Arm 770

Circuit board 760 Cover 751

Base 752

Detailed ways

3 is a block diagram of an embodiment of an exposure control system with an image sensing device according to the present invention. The system mainly includes an image sensing device 310, a convex mirror group 320, an illuminating device 330, a control device 340 and a light Separator 350 .

The image sensing device 310 is a complementary metal oxide semiconductor (CMOS) image sensing device. It has a plurality of photosensitive pixels arranged in a two-dimensional matrix. The CMOS image sensing device may have 640×480, 659×494, 752×480 and other various numbers of photosensitive pixels. To meet different applications, the size of the active region of the CMOS image sensing device can be set. For example, the working area of a 640X480 CMOS image sensing device is set as 320X240. In this embodiment, exposure is performed in a sub-area of the plurality of photosensitive pixels, and the size of the sub-area can be 320×240 or 96×96 or the entire area.

The illuminating device 330 generates a flash as a light source when the image sensing device 310 is exposed. The illuminating device 330 can be a non-thermal light source. These non-thermal light sources include laser light sources and light emitting diodes (LEDs). The illuminating device 330 can also be infrared.

The convex mirror group 320 includes a convex mirror and an aperture. One side of the convex mirror group 320 is in a state corresponding to the CMOS image sensing device 310, so as to gather light and enhance the light entering the image sensing device 310. . The convex mirror is made of transparent material, and the transparent material is glass or transparent plastic. When the flash light generated by the illuminating device 330 is reflected by an object 360, the reflected light is more focused by the convex lens group 320, and then transmitted to the image sensing device 310 for imaging. The aperture can be adjusted to be smaller when the brightness of the light is high. For greater depth of field and easier focusing.

When the illuminating device 330 uses a laser light source, since the brightness of the light generated by the laser light source is relatively high, the depth of field can be increased, and focusing is easier.

The light separation device 350 is disposed at a position corresponding to the CMOS image sensing device 310 to reduce the interference of light other than the flash light generated by the illuminating device 330 , so that the flash light is transmitted to the image sensing device 310 . When the illuminating device 330 is an infrared ray, the light separating device 350 is an infrared filter device (IR filter) or a blocking device for external light.

The control device 340 is coupled to the image sensing device 310 and the lighting device 330 to control the exposure timing of the image sensing device 310 and the timing of the light source generation by the lighting device 330 . When exposing, the control device 340 drives the illuminating device 330 during the exposure time to generate the flash and control the flash period of the flash, so that the flash passes through the reflected light of an object 360 (object) to the light in the sub-region. Sensing pixels have the same light sensing effect. The control device 330 can dynamically adjust the duration of the flash and the brightness of the flash to optimize image quality and light energy consumption.

Fig. 4 is a schematic diagram of the exposure method of the present invention. Wherein, the exposure time of column 0 is changed from T1 to T2 to T1 to T4, and the exposure end time (T4) of column 0 is after the exposure start time (T3) of column n−1. That is, during time T3 to T4, the shutters in column 0 to column n−1 are all open. However, due to the optical separation device 350, column 0 is also less likely to generate noise during time T1 to T4. The illuminating device 330 generates a flash at time T5 to T6. Due to the short exposure time, the illuminating device can use a high-power light source, so that columns 0 to n−1 can be evenly exposed to light. Due to the short exposure time and high-power light source, the light generated by the lighting device 330 has a flash-like effect.

Fig. 5 is another schematic diagram of the exposure method of the present invention. At time T0, the control device 340 generates a reset signal to reset the pixel rows in the sub-region of the image sensing device 310, so that each pixel row enters an initial state. At time T1, each pixel column is exposed. Since the light separation device 350 only allows the flash light to be transmitted to the image sensing device 310 , even ambient light cannot enter the image sensing device 310 . The control device 340 drives the illuminating device 330 to generate a flash light before the end of row 0 exposure ( T2 ), as a light source for the image sensing device 310 to expose. The lighting device 330 generates a flash that consumes a relatively large current, such as a flash with a current of 300mA, at time T4 and T5. However, due to the short exposure time, the overall power consumption can be less than that of the prior art. At time T2, the control device 340 sequentially generates a sampling signal to sample data from row 0 to row n−1.

Fig. 6 is another schematic diagram of the exposure method of the present invention. It is mainly similar to the exposure method in FIG. 5 . Only after the time T2, the control device 340 increases the clock of the image sensing device 310 to speed up data sampling for columns 0 to n−1.

7 is an exploded perspective view of another embodiment of an exposure control system with an image sensing device according to the present invention. The system mainly includes an image sensing device 710, a convex mirror 720, an illuminating device 730, a control device 740, a The optical separation device 750 , an extension arm 770 and a circuit board 760 . The main difference from the embodiment in FIG. 3 is that the light separation device 750 is composed of an upper cover 751 and a base 752 . The circuit board 760 is fixedly installed in the above-mentioned optical separation device 750 , and the circuit board 760 is provided with a control device 740 . One side of the control device 740 has an extension arm 770 , and the extension arm 770 is provided with an illumination device 730 for providing illumination when the image sensing device 710 is exposed.

The image sensing device 710 , the convex mirror 720 , the lighting device 730 and the control device 740 are fixed in the light separating device 750 . The light outside the light separating device 750 is filtered, and only the light generated by the illuminating device 730 is transmitted to the image sensing device 710 . In this case, the illuminating device 730 may be a non-thermal light source. These non-thermal light sources include laser light sources and light emitting diodes. The illuminating device 730 can also be infrared or white light with multiple wavelengths.

Although the exposure method of the image sensing device ( 310 , 710 ) of the present invention is a row-by-row exposure method, it can also be a row-by-column exposure method. It can be easily accomplished by those familiar with the technology.

It can be seen from the above description that in the present invention, all the pixel rows in the sub-region are exposed to light at the same time, and the captured image quality is highly stable due to the short exposure time. Because within this short period of time, the moving distance of the object 360 is relatively small, so there will be no fragmentation in the captured image. The illuminating device 330 produces illumination in a form similar to flash illumination. Although the illumination brightness is high, because the exposure time is short, the overall average power consumption is lower than that of the prior art. At the same time, due to the high brightness of the light, the area of the photosensitive pixels of the image sensing device 310 can be small. Due to the high brightness of the illumination, the distance between the illumination device 330 and the object 360 can be increased, and thus the sensing angle of the image sensing device 310 can be increased. Moreover, compared with the prior art, the area of the photosensitive pixels of the sensing device 310 of the present invention can be smaller, and the cost can be further reduced.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications should also be It is regarded as the protection scope of the present invention.

Claims (29)

1. An exposure control system of an image sensing device, characterized in that the system comprises: An image sensing device, which has a plurality of photosensitive pixels arranged in a two-dimensional matrix, is exposed in a subregion of the plurality of photosensitive pixels when exposed, and each pixel column in the subregion has a Exposure status; A lighting device that produces a flash as a light source for exposure; A control device, coupled to the image sensing device and the lighting device, controls the exposure timing of the image sensing device and the timing of the light source generated by the lighting device; and a light separation device, coupled to the image sensing device, to reduce light interference other than the flash generated by the lighting device, so that the flash generated by the lighting device is transmitted to the image sensing device; Wherein, the control device sequentially turns on each pixel row in the sub-region, and when each pixel row in the sub-region is in the exposing state, the control device drives the illuminating device to generate the flash, and controls The flash period of the flash. 2. The system according to claim 1, further comprising: A convex mirror. One side of the convex mirror is corresponding to the image sensing device to focus the light entering the image sensing device. 3. The system according to claim 2, wherein the system further comprises: An aperture, the size of the aperture is adjusted according to the brightness of the exposure received by the image sensor. 4. The system of claim 1, wherein the image sensing device is a CMOS image sensing device. 5. The system according to claim 1, wherein the illuminating device is a laser light source device. 6. The system according to claim 1, wherein the illuminating device is a light emitting diode device. 7. The system according to claim 1, wherein the illuminating device is an infrared device. 8. The system according to claim 7, wherein the optical separation device is an infrared filter device. 9 . The system according to claim 1 , wherein the control device can dynamically adjust the flash period and brightness of the flash to optimize the image quality and energy consumption of the light. 10. The system according to claim 1, wherein the sub-region can be a part or all of the plurality of photosensitive pixels. 11. An exposure control system for an image sensing device, characterized in that the system comprises: An image sensing device, which has a plurality of photosensitive pixels arranged in a two-dimensional matrix, is exposed in a subregion of the plurality of photosensitive pixels when exposed, and each pixel column in the subregion has a Exposure status; A lighting device that produces a flash as a light source for exposure; A control device, coupled to the image sensing device and the lighting device, controls the exposure timing of the image sensing device and the timing of the light source generated by the lighting device; A light separation device is composed of an upper cover and a base. The image sensing device, lighting device and control device are fixed in the light separation device to reduce light other than the flash generated by the lighting device. interfere with the transmission of the light flashes generated by the lighting device to the image sensing device; Wherein, the control device sequentially turns on each pixel row in the sub-region, and when each pixel row in the sub-region is in the exposing state, the control device drives the illuminating device to generate the flash, and controls The flash period of the flash. 12. The system according to claim 11, further comprising: A convex mirror. One side of the convex mirror is corresponding to the image sensing device to focus the light entering the image sensing device. 13. The system according to claim 12, further comprising: An aperture, the size of the aperture is adjusted according to the brightness of the exposure received by the image sensor. 14. The system of claim 11, wherein the image sensing device is a CMOS image sensing device. 15. The system according to claim 11, wherein the illuminating device is a laser light source device. 16. The system of claim 11, wherein the illuminating device is a light emitting diode device. 17. The system of claim 11, wherein the illuminating device is an infrared device. 18. The system of claim 11, wherein the illuminating device is a white light generating device. 19. The system according to claim 11, wherein the control device can dynamically adjust the flash period and brightness of the flash to optimize the image quality and energy consumption of the light. 20. The system according to claim 11, wherein the sub-region can be a part or all of the plurality of photosensitive pixels. 21. An exposure control method for an image sensing device, which is to expose an image sensing device, the image sensing device has a plurality of photosensitive pixels arranged in a two-dimensional matrix, and when exposing, it is exposed on the plurality of photosensitive pixels In a sub-region of a light-sensing pixel, the image sensing device is provided with a light separation device to reduce the interference of light other than a flash, and it is characterized in that the method includes the following steps: a reset step, simultaneously resetting each pixel row in the sub-region, so that each pixel row enters an initial state; An activating exposure step, sequentially activating each pixel row in the sub-region to enter an exposure-capable state; an illuminating step for generating the flash as a light source for exposure; and A processing step, sequentially sampling each pixel row in the sub-region to obtain an exposure image of an object; Wherein, the flash is generated when each pixel column in the sub-area is in an exposed state, and the flash period of the flash is controlled. 22. The method of claim 21, wherein the image sensing device is a CMOS image sensing device. 23. The method according to claim 21, wherein the exposure method of the image sensing device is a row-by-row exposure method. 24. The method according to claim 21, wherein the exposure method of the image sensing device is a row-by-row exposure method. 25. An exposure control method for an image sensing device, which is to expose an image sensing device, the image sensing device has a plurality of photosensitive pixels arranged in a two-dimensional matrix, and when exposing, it is exposed on the plurality of photosensitive pixels. In a sub-region of the light-sensing pixel, the image sensing device is provided with a light separation device to reduce the interference of light other than a flash, and the method includes the following steps: a reset step, simultaneously resetting each pixel row in the sub-region, so that each pixel row enters an initial state; An activating exposure step, simultaneously activating each pixel column in the sub-region to enter an exposure-ready state; an illuminating step for generating the flash as a light source for exposure; and a processing step of sequentially sampling each pixel column in the sub-region to obtain an exposure image of an object; Wherein, the flash is generated when each pixel row in the sub-area is in the exposureable state, and the flash period of the flash is controlled. 26. The method according to claim 25, wherein the processing step further comprises: A timing increasing step is used to increase the timing of the image sensing device so as to reduce the sampling time of each pixel row in the sub-region. 27. The method of claim 25, wherein the image sensing device is a CMOS image sensing device. 28. The method according to claim 25, wherein the exposure method of the image sensing device is a row-by-row exposure method. 29. The method according to claim 25, wherein the exposure method of the image sensing device is a row-by-row exposure method.

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