KR20020055163A - Image sensor - Google Patents

Abstract

PURPOSE: An image sensor is provided to differently control a starting point of reading data inside of the image sensor, thereby outputting an image whose left and right sides are inverted or an image whose upper and lower sides are inverted and enabling a high speed transmission. CONSTITUTION: A control/external system interface(10) interfaces an external system. A pixel array(20) arrays pixels, and senses information on an externally-incoming image. A DAC(Digital-Analog Converter)(30) generates a reference voltage for comparing sensed voltages of each pixel, to change analog voltages of the pixels into digital voltages. A comparator(50) compares the sensed voltages outputted from the pixel array with the reference voltage. If the reference voltage is bigger than the sensed voltages, the comparator outputs a latch enable signal for writing a digital counter value outputted from the external system interface in a dual buffer(40). The dual buffer stores image signal values of the digitalized pixels by responding to the latch enable signal of the comparator.

Description

Image sensor {IMAGE SENSOR}

The present invention relates to an image sensor, and more particularly, to an image sensor capable of outputting an image inverted left and right or up and down without a separate external memory.

In general, an image sensor refers to a device that captures an image by using a property of a semiconductor that reacts to light. Part of each subject in the natural world has different electrical values at each pixel of the sensing device due to different brightness and wavelength of light, which makes the image sensor a level capable of signal processing. Is what it does.

In recent years, such image sensors have been applied to various security equipment, video conferencing cameras, digital still cameras, PC cameras, and next-generation personal mobile communication equipments having a function of transmitting video information.

As such, as the application range of the image sensor becomes wider, a specific application field requires an image in which the image captured by the image sensor is shifted from side to side or up and down. When taking a picture and storing it and then outputting the stored image, the output image is always displayed only in a certain direction by outputting data from the start point of a specific position of the pixel array unit. You cannot print it. As described above, in order to obtain an image in which the image has been changed up, down, left, or right in a conventional image sensor having a fixed starting point, an external memory must be provided with a separate memory, so that a separate memory must be provided. The cost increases.

The present invention has been made in order to solve the above problems, unlike the conventional fixed start point of the read image is controlled to the four corners of the pixel array portion as a starting point X-flip image that the left and right of the image is changed in the image sensor itself The object of the present invention is to provide an image sensor capable of obtaining a Y-flip image in which X and Y are reversed.

1 is a block diagram of an image sensor according to an embodiment of the present invention.

2A to 2D are conceptual views illustrating an order in which an image is read according to a position of a start point of reading a stored value in an image sensor according to an exemplary embodiment of the present invention.

* Description of the main parts of the drawing

10: control and external system interface unit 20: pixel array unit

30: DAC40: double buffer section

50: comparison unit 60: X-Y flip control unit

70: row decoder 80: column decoder

According to an aspect of the present invention, there is provided an image sensor comprising: control and external system interface means for controlling the overall operation of the image sensor and serving as an interface to an external system; A pixel array unit configured to sense the information about an image from the outside by arranging pixels arranged horizontally N and vertically M to maximize the response to light; Digital-to-analog converting means for generating a comparison reference voltage used for comparing the sensed analog voltage at each pixel of the pixel array to a digital voltage for processing in a digital system; Comparison means comprising N arrays of comparators for comparing the analog voltage output from the pixel array section and the comparison reference voltage output from the digital-analog conversion means; Double buffer means for storing digital values from the control and external system interface means, which are image signal values of the digitized pixels in response to the output of the comparator; A row address encoding signal and a column address that are output from the control and external system interface unit in response to a first flip signal for controlling the image to be output left and right and a second flip signal for controlling the image to be output up and down Control means for controlling to output an order of encoding signals; Row decoding means for decoding a modified row address encoding signal output from the control means and driving a corresponding row among the pixel array units; And column decoding means for decoding the modified column address encoding signal output from the control means to drive a corresponding column of the pixel array unit.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art may easily implement the technical idea of the present invention. do.

1 is a block diagram of an image sensor according to an embodiment of the present invention, and controls an overall operation of an image sensor using a finite state machine (FSM), and serves as an interface to an external system. Responsible control and external system interface unit 10, the pixel to detect the information about the image coming from the outside by arranging the pixel (N) horizontally and vertically M pixels made to maximize the response to light The array 20 reduces linearly with the clock, which is used to compare the analog voltage sensed at each pixel of the sensor with the voltage sensed at each pixel to convert it to a digital voltage for processing in a digital system. From the digital-to-analog converter (DAC, 30) for producing a reference voltage in the form of a ramp, the pixel array unit 20 By comparing the sensed voltage (sensing analog value) output with the comparison reference voltage (lamp voltage) output from the DAC 30, the digital output from the control and external system interface unit 10 while the comparison reference voltage is greater than the pixel voltage. A comparator 50 comprising an array of N comparators for outputting a latch enable signal for writing a counter value to the double buffer unit 40 described later, and to an output (a latch enable signal) of the comparator 50. And a double buffer unit 40 which stores the image signal value of the digitized pixel in response.

Also, the image sensor of the present invention outputs the row address encoding signal and the column address encoding signal outputted from the control and external system interface unit 10 in response to the X and Y flip signals, respectively. The XY flip controller 60 controls the output of the XY flip controller 60 so as to properly change the order of the signals, and decodes the modified row address encoding signal outputted from the XY flip controller 60 so that a corresponding row among the pixel array units 20 can be decoded. And a column decoder 80 which decodes the modified column address encoding signal output from the XY flip controller 60 to select the corresponding column of the pixel array unit 20. Include.

For reference, the control and external system interface unit 10 includes a configuration register that can be programmed for various internal operations, and controls the operation of the entire image sensor according to the programmed information. .

Hereinafter, the operation of the image sensor of the present invention configured as described above will be described in detail.

The overall operation of the image sensor is programmed via a programming interface such that the off-chip system directs the desired operation to the placement registers of the control and external system interface 10. Subsequently, the control and external system interface unit 10 sends the row address encoding signal to the XY flip control unit 60 according to the programmed information, and the XY flip control unit 60 encodes the row address in the proper order according to the X-flip signal. The signal is generated and the pixel array unit 20 is driven by the row decoder 70 to read the lines one by one. Subsequently, the analog voltage output from the pixel array unit 20 is compared with the ramp voltage from the digital / analog converter unit 30 in the comparing unit 50 through the operation, and the result of the comparison is compared with the double buffer unit 40. ). The data written to the double buffer unit 40 outputs the data of the memory stored in the position decoded by the column decoder 80 in accordance with the column address encoding signals in the proper order generated by the XY flip control unit 60 according to the Y-flip signal. Let's do it.

2A to 2D are conceptual views illustrating an order in which images are read according to a position of a start point of reading a stored value in an image sensor according to an embodiment of the present invention.

First, FIG. 2A shows the row address encoding signals 0, 1, 2, 3, ..., M-2, M- outputted from the control and external system interface unit 10 without X-flip or Y-flip. The order of 1) and the order of the column address encoding signals (0, 1, 2, 3, ..., N-2, N-1) are not changed in the XY flip controller 60 without changing the order of the row decoder 70 and the column decoder. Figure 80 shows the case where data is read starting from the bottom right and then up, which is the most common image reading order.

2B shows the row address encoding signals 0, 1, 2, 3,..., M-2 output from the control and external system interface unit 10 in an X-flip only state (that is, a state in which only the left and right sides of the image are changed). , The order of M-1 and the column address encoding signals (0, 1, 2, 3, ..., N-2, N-1) are exported from the XY flip control unit 60 as the order of the row address encoding signals. The column address encoding signals are N-1, N-2, N-3,... , 2, 1, 0 in order to send to the row decoder 70 and the column decoder 80 to control the data to be read starting from the bottom left to the top, showing the mirror image by changing the left and right You get the same image as you see.

2C shows the row address encoding signals 0, 1, 2, and 3 outputted from the control and external system interface unit 10 in a state where both the X-flip and the Y-flip are changed (both left and right of the image are changed). , ..., M-2, M-1, and column address encoding signals (0, 1, 2, 3, ..., N-2, N-1) in the XY flip control unit 60 row address encoding The order of signals is M-1, M-2, M-3,... , 2, 1, 0, and the column address encoding signals N-1, N-2, N-3,... In this case, the data is read from the top left and down by controlling the control to be sent to the row decoder 70 and the column decoder 80 in the order of 2, 1, and 0.

Fig. 2D shows the row address encoding signals 0, 1, 2, 3, ..., M-2, M output from the control and external system interface unit 10 in the state of Y-flip only (the image is changed up and down). The order of -1) and the column address encoding signals (0, 1, 2, 3, ..., N-2, N-1) are exported from the XY flip control unit 60 in the same order as the column address encoding signals. The encoding signals are M-1, M-2, M-3,... In this case, the data is read from the upper right side to the lower side by controlling the data to be sent to the row decoder 70 and the column decoder 80 in the order of 2, 1, and 0.

Although the technical idea of the present invention has been described in detail according to the above preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

According to the present invention made as described above, by controlling the starting point of reading the data inside the image sensor differently, the left and right reversed images (X-flip) or the upside down image (Y-flip) can be used without using an external memory. It can output, thereby reducing the time to control a separate memory to enable a high-speed transmission, there is an effect that can reduce the production cost.

Claims (5)

In the image sensor, Control and external system interface means for controlling the overall operation of the image sensor and serving as an interface to an external system; A pixel array unit configured to sense the information about an image from the outside by arranging pixels arranged horizontally N and vertically M to maximize the response to light; Digital-to-analog converting means for generating a comparison reference voltage used for comparing the sensed analog voltage at each pixel of the pixel array to a digital voltage for processing in a digital system; Comparison means comprising N arrays of comparators for comparing the analog voltage output from the pixel array section and the comparison reference voltage output from the digital-analog conversion means; Double buffer means for storing digital values from the control and external system interface means, which are image signal values of the digitized pixels in response to the output of the comparator; A row address encoding signal and a column address output from the control and external system interface unit in response to a first flip signal for controlling the image to be output left and right and a second flip signal for controlling the image to be output up and down Control means for controlling to output an order of encoding signals; Row decoding means for decoding a modified row address encoding signal output from the control means and driving a corresponding row among the pixel array units; And Column decoding means for decoding a modified column address encoding signal output from the control means to drive a corresponding column of the pixel array unit; Image sensor comprising a. The method of claim 1, wherein the control means, When the image is to be shifted left and right, the row address encoding signals are output in the input order in response to the first and second flip signals, and the column address encoding signals are output in the reverse order of the input order. sensor. The method of claim 1, wherein the control means, The image sensor outputs the row address encoding signal and the column address encoding signal in the order of input in response to the first and second flip signals when the image is to be output in a normal state without changing the image from left to right or up and down. . The method of claim 1, wherein the control means, When the image is to be output upside down, in response to the first and second flip signals, the row address encoding signals are output in the reverse order of the input order and the column address encoding signals are output in the input order. sensor. The method of claim 1, wherein the control means, And in response to the first and second flip signals, the row address encoding signal and the column address encoding signal in the reverse order of the input order in response to the first and second flip signals.