CN106375689A - High-speed flexible sampling image sensor and its sampling control method - Google Patents

Abstract

The invention relates to a high speed flexible sampling image sensor. A image feedback unit of the sensor receives image data output by a read circuit and positions a row pixel or a column pixel which needs to be secondary sampled or window-opened, and transmits a data choosing instruction to a coding logic unit; the coding logic unit codes according to the data choosing instruction; a row choosing decoder and a column choosing decoder respectively decode a row coding signal and a column coding signal output by the coding logic unit; and in the open window mode or the secondary sampling mode, the row choosing decoder controls a drive and control circuit according to the decoding result, chooses a relevant row pixel to conduct scanning, and the column choosing decoder controls the read circuit to choose relevant column pixel data to conduct reading. The high speed flexible sampling image sensor and the sampling control method thereof have the benefit of being high in the speed of reading valid data, high in controllability, high in open window efficiency, and no extra volume of the sensor is increased.

Description

High-speed flexible sampling image sensor and its sampling control method

technical field

The invention belongs to the technical field of image sensors, and in particular relates to a high-speed and flexible sampling image sensor capable of selecting a specific pixel area to work and a sampling control method thereof.

Background technique

CMOS image sensor is a photoelectric imaging device widely used in machine vision, target detection, security monitoring and medical detection. Due to its advantages of low cost and high integration, the image sensor chip can integrate more camera system functions, thereby reducing The peripheral circuit of the camera realizes the miniaturization of the camera volume and the diversification of functions.

In industrial detection, in order to achieve fast imaging and key target monitoring, the camera first performs sub-sampling mode. The principle is shown in Figure 1. After the sensor finds the target, it enters the window scanning mode, and only scans all pixels in a special area. The principle is as follows Figure 2 shows. In the sub-sampling mode, the image sensor only scans the fixed row and column pixels in the pixel according to the preset program, and captures the rough information image of the scene; All pixels are scanned to capture an accurate image of the subject. Since in these two scanning modes, the sensor only performs signal acquisition and processing on some pixels, so the reasonable allocation of driving and readout of pixels can effectively improve the frame rate of the image sensor.

In order to achieve the above functions, functional modules are generally added to the peripheral circuit of the camera, and the windowing function is realized from the additional functions of the system. Reading, to realize the half-opening of the sensor window, these control methods have disadvantages such as weak controllability of the sensor pixels, poor window opening efficiency, etc., and additional peripheral circuits increase the size of the camera and are not conducive to carrying.

Contents of the invention

The technical problem to be solved by the present invention is to provide a high-speed and flexible sampling image sensor with strong maneuverability and high window opening efficiency without additional increase in sensor volume.

In order to solve the above technical problems, the high-speed flexible sampling image sensor of the present invention includes a pixel array integrated on the image sensor chip, a drive control circuit, and a reading circuit; it is characterized in that it also includes a row selection decoder integrated on the image sensor chip , a column selection decoder, an image feedback unit and an encoding logic unit; wherein the image feedback unit and the encoding logic unit are composed of programmable logic circuits, and the image feedback unit receives the image data output by the reading circuit and locates the image that needs to be sub-sampled or windowed Row or column pixels, transfer the selection data instruction to the encoding logic unit; the encoding logic unit encodes according to the selection instruction; the row selection decoder and the column selection decoder respectively perform row encoding signal and column encoding signal output by the encoding logic unit Decoding, in the windowing mode or sub-sampling mode, the row selection decoder controls the drive control circuit according to the decoding result, selects the corresponding row of pixels for scanning, and at the same time, the column selection decoder controls the reading circuit to select the corresponding column pixel data for scanning. read.

Another technical problem to be solved by the present invention is to provide a sampling control method of the above-mentioned high-speed flexible sampling image sensor.

In order to solve the above-mentioned technical problems, the sampling control method of the high-speed flexible sampling image sensor of the present invention comprises the following steps:

Step 1. The image feedback unit receives and processes the image data output by the reading circuit, locates the row and column pixels of the sub-sampling area according to the processing results, and transmits the selection data instruction to the encoding logic unit; the encoding logic unit performs encoding according to the selection instruction , to obtain the row-encoded signal and the column-encoded signal in the sub-sampling mode;

Step 2, the row selection decoder decodes the row coding signal output by the coding logic unit to obtain the pixel row number to be scanned in each frame in the sub-sampling mode; the column selection decoder decodes the column coding signal output by the coding logic unit Decoding to obtain the pixel column number to be read in each frame in the sub-sampling mode;

Step 3, the row selection decoder controls the row selection switch in the driving control circuit according to the row number of pixels to be scanned in each frame obtained by decoding in step 2, and only exposes the pixels of the corresponding row in each frame; The column number of pixels to be read in each frame obtained by the code controls the column selection switch of the reading circuit, and only the pixel data of the corresponding column is read in each frame;

Step 4: The image feedback unit receives and processes the image data output by the reading circuit in the sub-sampling mode, locates the window area according to the processing result, and transmits the selection data instruction to the encoding logic unit; the encoding logic unit encodes according to the selection instruction, Obtain the row coding signal and the column coding signal under the windowing mode;

Step 5: The row selection decoder and the column selection decoder respectively decode the row coded signal and the column coded signal of the pixels in the windowed area output by the coding logic unit, and control the driving control circuit according to the decoding result, to open the window All row pixels in the area are scanned, and at the same time, the reading circuit is controlled to select all column pixels in the windowed area for data reading.

In said step 3, in the first frame, only the odd-numbered row pixels in the sub-sampling area are exposed, and the odd-numbered column pixel data in the sub-sampling area are read; in the second frame, only the even-numbered row pixels in the sub-sampling area are exposed, and the second Even-numbered column pixel data in the sampling area is read.

In said step 3, it is also possible to expose only the even-numbered row pixels in the sub-sampling area in the first frame, and read the even-numbered column pixel data in the sub-sampling area; in the second frame, only expose the odd-numbered row pixels in the sub-sampling area, Read the pixel data of odd-numbered columns in the sub-sampling area.

In said step 3, it is also possible to expose only the odd-numbered row pixels in the sub-sampling area in the first frame, and read the even-numbered column pixel data in the sub-sampling area; in the second frame, only expose the even-numbered row pixels in the sub-sampling area, Read the pixel data of odd-numbered columns in the sub-sampling area.

In the third step, it is also possible to expose only the pixels in the 3n+1 row of the sub-sampling area in the first frame, and read the pixel data in the 3n+1 column of the sub-sampling area; in the second frame, only the pixels in the sub-sampling area The pixels in the 3n+2 row are exposed, and the pixel data in the 3n+2 column of the sub-sampling area are read; in the third frame, only the pixels in the 3n+3 row of the sub-sampling area are exposed, and the pixels in the 3n+3 column of the sub-sampling area are exposed. Column pixel data is read, where n=0, 1, 2 . . . .

In the fourth step, the windowed area is one or more rectangles containing the target area.

The present invention combines the characteristics of high integration of CMOS image sensors, and integrates the sub-scanning function and the windowing function into the CMOS image sensor chip at the same time, and the row and column to be scanned can be flexibly selected through the sub-sampling mode, thereby obtaining a rough image of the object. Data information: After finding the target, read the data information of all rows and columns in the windowed area in the windowed scanning mode, so as to obtain the accurate data information of the object imaged, so that the camera has both high-speed and flexible scanning functions and volume miniaturization characteristic. The present invention can realize high frame rate of image sensor image acquisition and precise scanning of the region of interest, high effective data reading speed, strong controllability, high window opening efficiency, and does not additionally increase the volume of the sensor.

Description of drawings

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

FIG. 1 is a schematic diagram of a fast sub-sampling mode in the prior art.

Fig. 2 is a schematic diagram of a partial window opening mode in the prior art.

Fig. 3 is a schematic structural diagram of the high-speed flexible sampling image sensor of the present invention. FIG. 4 is a schematic diagram of a local circuit structure of the high-speed flexible sampling image sensor of the present invention.

FIG. 5 a is a schematic diagram of a normal row selection signal, and FIG. 5 b is a schematic diagram of a row selection signal after being intervened by a row selection decoder in Embodiment 1 of the present invention.

FIG. 6 is a schematic diagram of odd-even row-column exchange sampling in Embodiment 1 of the present invention.

FIG. 7 is a schematic diagram of window opening method 1.

Fig. 8a, Fig. 8b, Fig. 8c are schematic diagrams of window opening method 2.

FIG. 9 is a schematic diagram of window opening method 3.

detailed description

As shown in Figures 2 and 3, the image sensor chip is generally integrated with a pixel array, a clock circuit PLL, a timing generation circuit, a drive control circuit, a serial peripheral interface SPI, and a reading circuit. The high-speed flexible sampling image sensor of the present invention integrates a row selection decoder, a column selection decoder, an encoding logic unit and an image feedback unit on the image sensor chip; the input of the image feedback unit is connected with the reading circuit through a data channel, and the output It is connected with the input of the encoding logic unit, and the output of the encoding logic unit is connected with the input of the row selection decoder and the column selection decoder; the output of the row selection decoder and the column selection decoder are respectively connected with the drive control circuit and the reading circuit connection.

Example 1

The sampling control method of the high-speed flexible sampling image sensor of the present invention is specifically as follows:

As shown in Figure 5b and Figure 6, in the sub-sampling mode, the image feedback unit receives and processes the image data output by the reading circuit, locates the row or column pixels of the sub-sampling area according to the processing results, and passes the selection data instruction to An encoding logic unit; the encoding logic unit performs encoding according to the selection instruction, and obtains a row encoding signal and a column encoding signal in a sub-sampling mode.

The row selection decoder decodes the row encoding signal output by the encoding logic unit, controls the row selection switch in the drive control circuit according to the decoding result, and only turns on the odd row selection switch in the sub-sampling area in the first frame. The row pixels are exposed; at the same time, the column selection decoder decodes the column encoding signal output by the encoding logic unit, and according to the decoding result, only the odd column selection switch in the sub-sampling area of the reading circuit is turned on, and the odd-numbered and even-numbered rows are read. Column pixel data. Due to the odd/even point pixel sampling method, each frame only needs to collect a quarter of the original pixels in the sub-sampling area, so the frame rate of the image sensor can be increased by four times. In order to ensure that valid data is not missed, only even-numbered row and even-numbered column pixel data is read in the second frame. Through the processing of two frames of images before and after, determine the region of interest (window region) in the pixel array.

In this embodiment, it is also possible to read the pixel data of even rows and odd columns in the sub-sampling area in the first frame, read the pixel data of odd rows and even columns in the sub-sampling area in the second frame, or read the odd-numbered rows of the sub-sampling area in the first frame For pixel data of even columns, pixel data of even rows and odd columns in the sub-sampling area is read in the second frame, or pixel data of even rows and even columns of the sub-sampling area is read in the first frame, and odd-numbered rows and odd columns of the sub-sampling area are read in the second frame pixel data.

The subsampling area can be the entire pixel matrix or a part of the pixel matrix.

Example 2

The sampling control method of the high-speed flexible sampling image sensor of the present invention is specifically as follows:

As shown in Figure 5b and Figure 6, in the sub-sampling mode, the image feedback unit receives and processes the image data output by the reading circuit, locates the row or column pixels of the sub-sampling area according to the processing results, and passes the selection data instruction to An encoding logic unit; the encoding logic unit performs encoding according to the selection instruction, and obtains a row encoding signal and a column encoding signal in a sub-sampling mode.

The row selection decoder decodes the row encoding signal output by the encoding logic unit, controls the row selection switch in the driving control circuit according to the decoding result, and only turns on the row selection switch of the 3n+1th row in the sub-sampling area in the first frame , to expose the pixels in the 3n+1 row of the sub-sampling area; at the same time, the column selection decoder decodes the column encoding signal output by the encoding logic unit, and only connects the 3nth sub-sampling area in the reading circuit according to the decoding result +1 column selection switch, read the pixel data of the 3n+1 column in the sub-sampling area, only expose the pixels in the 3n+2 row of the sub-sampling area in the second frame, and perform the exposure on the pixel data of the 3n+2 column in the sub-sampling area Reading; in the third frame, only the pixels in the 3n+3th row of the sub-sampling area are exposed, and the pixel data in the 3n+3th column of the sub-sampling area is read, where n=0, 1, 2.... Because only one-ninth of the original pixels in the subsampled area are acquired per frame in this way, the frame rate of the image sensor can be increased by a factor of nine. The area of interest (window area) in the pixel array is determined through the processing of the three frames of images before and after.

The method of determining the window opening area is as follows.

Windowing method 1: As shown in Figure 7, according to the image data collected in the sub-sampling mode, the image feedback unit selects the square area containing the target as the windowing area

Window opening method 2: as shown in Figures 8a, 8b, and 8c, multiple windows are opened for multiple objects. According to the image data collected in the sub-sampling mode, the image feedback unit selects the square area containing the target as the window area.

Since the rows or columns of pixels occupied by multiple targets are discontinuous, the sensor can open multiple corresponding windows for multiple target objects in different rows or columns of pixels.

Windowing method 3: As shown in Figure 9, multiple overlapping objects open the largest window: According to the image data collected in the sub-sampling mode, the image feedback unit selects a rectangular area containing multiple objects as the windowing area.

Claims (7)

1. a kind of flexible sampled images sensor of high speed includes pel array, the drive control being integrated on image sensor chip Circuit, reading circuit；Characterized by further comprising the row being integrated on image sensor chip select decoder, column selection decoder, Image feedback unit and codimg logic unit；Wherein image feedback unit and codimg logic unit are by Programmable Logic Device group Become, image feedback unit receives the view data of reading circuit output and positions the row or column picture needing time sampling or windowing Element, passes to codimg logic unit selecting data command；Codimg logic unit is encoded according to selection instruction；Row translates code selectively Device, column selection decoder enter row decoding to the row encoded signal and row encoded signal of codimg logic unit output respectively, in windowing mould Under formula or secondary sampling configuration, row selects decoder according to decoding output control drive control circuit, selects corresponding line pixel to carry out Scanning, the reading circuit of column selection decoder control simultaneously selects respective column pixel data to be read out.

2. a kind of sampling control method of the flexible sampled images sensor of high speed as claimed in claim 1 is it is characterised in that bag Include following step:

Step one, image feedback unit receive the view data of reading circuit output and are processed, and are positioned according to result The row, column pixel of secondary sample area, and selection data command is passed to codimg logic unit；Codimg logic unit is according to selection Instruction is encoded, and obtains the row encoded signal under time sampling configuration and row encoded signal；

Step 2, row select the row encoded signal that decoder exports to codimg logic unit to enter row decoding, obtain under time sampling configuration Each frame pixel line number to be scanned；The row encoded signal that column selection decoder exports to codimg logic unit enters row decoding, obtains Each frame pixel row number to be read under secondary sampling configuration；

The pixel line number that step 3, row select each frame that decoder obtains according to step 2 decoding to be scanned controls drive control electricity Row choosing switch in road, is only exposed to the pixel of corresponding line in each frame；The each frame institute simultaneously being obtained according to step 2 decoding Pixel row number to be read controls reading circuit column selection switch, only the pixel data of respective column is read out in each frame；

Step 4, image feedback unit receive the view data that under time sampling configuration, reading circuit exports and are processed, according to Result positioning fenestration region, and selection data command is passed to codimg logic unit；Codimg logic unit is according to selection Instruction is encoded, and obtains the row encoded signal under windowing pattern and row encoded signal；

Step 5, row select decoder, the column selection decoder row coding respectively to the windowed regions pixel of codimg logic unit output Signal and row encoded signal enter row decoding, and according to decoding output control drive control circuit, to windowed regions all row pixel It is scanned, control reading circuit to select all row pixels of windowed regions to carry out digital independent simultaneously.

3. the sampling control method of the flexible sampled images sensor of high speed according to claim 2 is it is characterised in that described In step 3, only secondary sample area odd-line pixels are exposed in the first frame, to secondary sample area odd column pixel data It is read out；Only secondary sample area even rows are exposed in the second frame, to secondary sample area even column pixels data It is read out.

4. the sampling control method of the flexible sampled images sensor of high speed according to claim 2 is it is characterised in that described In step 3, only secondary sample area even rows are exposed in the first frame, to secondary sample area even column pixels data It is read out；Only secondary sample area odd-line pixels are exposed in the second frame, to secondary sample area odd column pixel data It is read out.

5. the sampling control method of the flexible sampled images sensor of high speed according to claim 2 is it is characterised in that described In step 3, only secondary sample area odd-line pixels are exposed in the first frame, to secondary sample area even column pixels data It is read out；Only secondary sample area even rows are exposed in the second frame, to secondary sample area odd column pixel data It is read out.

6. the sampling control method of the flexible sampled images sensor of high speed according to claim 2 is it is characterised in that described In step 3, only secondary sample area 3n+1 row pixel is exposed in the first frame, to secondary sample area 3n+1 row pixel Data is read out；Only secondary sample area 3n+2 row pixel is exposed in the second frame, secondary sample area 3n+2 is arranged Pixel data is read out；Only secondary sample area 3n+3 row pixel is exposed in the 3rd frame, to secondary sample area 3n+ 3 row pixel datas are read out, wherein n=0,1,2 ....

7. the sampling control method of the flexible sampled images sensor of high speed according to claim 2 is it is characterised in that described In step 4, windowed regions are one or more rectangle comprising target area.