JPH0787407A - Device and method for detecting false signal of ccd sensor - Google Patents

Abstract

PURPOSE:To detect a false signal with a simple configuration without the use of a specific object whose image is to be picked up independently of the shape of an image pickup body. CONSTITUTION:A coating 4 is provided to the surface of part of prescribed light emitting elements 3b in a light receiving element 3 providing an output of a picture element signal from a CCD sensor 1 and used to block the arrival of an incident light into the CCD sensor 1 to the prescribed light receiving elements 3b. Thus, an output of a picture element signal due to an incident light into the prescribed light receiving elements 3b is avoided and a false signal due to charges overflowed from light receiving elements 3a without the coating 4 is provided as an output. The presence of production of the false signal is recognized by detecting the presence of an output signal from the specific light receiving elements 3b subject to coating processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detection device and a detection method for generating a false signal (blooming) due to overflow of charges from a register due to an excessive input to a CCD sensor, and more particularly to an a priori method for detecting the shape of an object. The present invention relates to a false signal detection method that does not require information.

[0002]

2. Description of the Related Art Conventionally, CCD (Charge Coupled Devic)
e) In imaging using a sensor, many methods for suppressing blooming have been proposed in order to improve image quality.

As a method of suppressing the occurrence of blooming,
There is a method of detecting a false signal due to blooming and correcting the false signal. An important point in this method is to accurately detect a false signal in the signal. In one example of the conventional method, a false output is detected by capturing an image of an object whose shape is known in advance and comparing and analyzing the captured image based on the accumulated data. For example, the actual exploitation 61-
In the method described in Japanese Patent No. 179877, the light source and CC
A bar-shaped object is placed between the D sensor and the width of the CCD sensor output of the part blocked by the object is narrower than the actual size of the object, and the output level is not 0, so that false output is generated. I am trying to detect it.

[0004]

However, in the above-mentioned detection method of occurrence of false output in the conventional example, it is necessary that the shape of the object to be imaged is known in advance. A comparison process with the formed shape is required. Further, there is a problem that a light source and a rod-shaped object that partially blocks the light source are required.

The present invention provides a false signal detection device and a detection method for a CCD sensor, which does not require a specific object or the like with a simple structure or method and can detect a false signal regardless of the shape of an imaged object. To aim.

[0006]

In order to achieve such an object, the detection device of the first invention is a CCD in which the surface of a part of predetermined light receiving elements among the light receiving elements for outputting pixel signals is coated. It has a sensor and a signal detecting means for detecting a pixel signal from the light receiving element, and the signal detecting means detects the output of the pixel signal from a predetermined light receiving element of the CCD sensor, and thus is not covered. It is characterized in that a false signal due to electric charges overflowing from the light receiving element is detected.

Further, the detection method of the second invention receives an image signal output from a CCD sensor in which a part of the light receiving elements is provided with a coating, and a part of the received image signal having the coating is provided. Select the output signal of the light receiving element, detect the presence or absence of the image signal in the selected output signal, and by the detection result,
It is characterized in that a false signal in the image signal output from the CCD sensor is detected.

[0008]

According to the detecting device of the first aspect of the present invention, a part of the predetermined light receiving element has a coating on the surface thereof, and the coating prevents the incident light from reaching the predetermined light receiving element. Since the output of the pixel signal sensitive to the incident light is eliminated and the false signal due to the electric charge overflowing from the uncoated light receiving element is output from the predetermined light receiving element, Output only occurs if an overflow occurs.

Further, according to the detection method of the second invention, the image signal output from the CCD sensor in which a part of the light receiving elements is provided with the coating is received, and the part of the received image signal subjected to the coating processing. Since the output signal of the light receiving element is selected and the presence or absence of the image signal of the selected output signal is detected, it is possible to determine whether or not a false signal is generated in the image signal output from the CCD sensor based on the detection result. .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A CCD according to the present invention will now be described with reference to the accompanying drawings.
Embodiments of the sensor false signal detection device and detection method will be described in detail. Referring to FIG. 1, an embodiment of a CCD sensor applied to the false signal detection method of the present invention is shown, and FIG. 3 shows an example of a circuit of a detection device for detecting the occurrence of false output of the CCD sensor. ing. Hereinafter, the configuration of the present invention will be described in detail based on the embodiments shown in the drawings.

FIG. 1 shows an example of the structure of a CCD sensor 1 used in the method of the present invention. The figure (a) is
The light receiving surface of the light receiving element 3 that constitutes the CCD sensor 1 is shown, and the light receiving element 3 is composed of, for example, a unit photodiode. Further, FIG. 1B is an enlarged conceptual view of a specific portion of FIG. As shown in FIG. 1 (b), this CCD sensor 1 has a predetermined width 1 of the light receiving element 3.
A coating 4 is applied to the surface of the light receiving elements 3b in the row, and the light incident on these light receiving elements 3b is blocked by the coating 4 and does not reach the light receiving elements 3b. This coating 4
The light-receiving element 3b provided with and the other light-receiving element 3a are different only in the presence or absence of the coating 4, and the other configurations are the same.

The basic structure of the CCD sensor 1 is the same as the conventional one, as described above. For example, the CCD sensor 1 used in the embodiment is an image pickup device using crystalline silicon. The CCD sensor 1 converts the intensity of light incident on the light receiving portion of the device into an electric signal and stores the electric signal in the form of electric charge, and transmits a signal based on the accumulated electric charge amount to an adjacent element one after another by a bucket relay method. A method of amplifying the entire signal with an amplifier and outputting it is adopted.

FIG. 2 shows an equivalent circuit of the light receiving element 3 of the CCD sensor 1. The CCD sensor 1 has a photo diode PD and MOS transistors Q1 and Q2 as elements constituting one pixel. Photo diode PD
Current changes according to the amount of incident light 6,
The MOS transistors Q1 and Q2 are used as switches to output the amount of incident light as a charge amount.

In a predetermined horizontal row of the light receiving element 3b of the embodiment, a coating 4 is formed on the surface of the light receiving element 3b so that the incident light 6 does not enter the semiconductor element Q1. The coating 4 may be formed in the manufacturing process of the CCD sensor 1 by, for example, not exposing the silicon oxide film on the surface so that the silicon oxide film is not removed during etching. Incident light 6 is incident on the CCD sensor 1 in the other light receiving element 3a from which the oxide film has been removed, but the incident light 6 is not incident only on the light receiving element 3b where the silicon oxide film remains. Therefore, the semiconductor element Q1 that constitutes the light receiving element 3b in the predetermined one horizontal row does not operate, the charge is not accumulated in the capacitor C, and the output signal VEn thereof should be 0V.

The signal processing circuit 2 shown in FIG. 3 is a circuit for inspecting the presence or absence (whether or not less than a predetermined value) of the output signal VEn of a predetermined one column of the above-mentioned pixel arrangement and outputting the inspection result. is there. Although not shown, the signal processing circuit 2 detects a storage circuit for storing the address number of the CCD sensor 1 provided with the coating 4 and whether or not the voltage level of the output signal from the CCD sensor 1 is below a predetermined value. It has a circuit and an output circuit which outputs a detection result.

The false output which is the detection target in this embodiment is mainly generated by blooming. Blooming
This is a well-known phenomenon that a large amount of electric charge is generated when strong light is incident on the screen, the generated electric charge amount exceeds the capacity of the capacitor C, and excess electric charge overflows to surrounding pixels. When blooming occurs, a phenomenon occurs in which pixels above and below or around the occurrence location are expressed in white over a wide range.

The relationship between the occurrence of blooming and the output signal is conceptually shown in FIG. Figure 4 (a)
Shows the output of each pixel when the input is not too large, assuming that a strong light 6 having a small circular shape is incident for the sake of easy understanding. In the case of this example, the pixel signal with the covering 4 is not output.

FIG. 4 (b) shows the output of each pixel when the input is excessive. The charge generated by photoelectric conversion in a pixel with excessive input overflows from one light receiving element and flows into another light receiving element, and when viewed on the screen, it seems that a tail is drawn upward along the vertical transfer register. To generate a fake image. In this example, the pixels with the coating 4 have an output, which produces a false image.

Blooming is the CCD sensor 1 of this embodiment.
When the above occurs, the signal processing circuit 2 detects a false output having the characteristic that occurs as the vertical stripes. Of the light receiving element 3 of the CCD sensor 1, a pixel at a known address is covered with a coating 4 so that the light 6 does not reach the output signal processing circuit 2.
Stores the address number of the pixel to which the coating 4 is applied, and the occurrence of false output can be detected by inspecting the presence or absence of the output from the CCD sensor 1 at the stored address. In this detection, it is not necessary to a priori know the shape of the imaged object. The signal processing circuit 2 detects the output of the CCD sensor 1 according to the procedure described above, and the detection of the false output makes it possible to perform an appropriate correction process for image reproduction.

Although the above-described embodiment is a preferred example of the present invention, the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention. For example, there are many different shapes of coatings applied to CCD sensors. One example is shown in FIG. The shape of the coating can be variously changed, such as diagonal, circular, and dotted, in addition to the box type shown in FIG.

[0021]

As is apparent from the above description, the false signal detection device for the CCD sensor of the first invention has a coating on the surface of a part of the predetermined light receiving elements, and this coating allows the incident light to be predetermined. To reach the light-receiving element, eliminate the output of the pixel signal from the predetermined light-receiving element, and output a false signal due to the electric charge overflowing from the uncoated light-receiving element. The presence / absence of blooming is detected by detecting the presence / absence of output from the light receiving element. Therefore, with a simple configuration, it is possible to know whether or not a false signal is generated regardless of the shape of the imaged object without requiring a specific imaged object.

Further, in the false signal detecting method of the second invention, the image signal output from the CCD sensor in which a part of the light receiving elements is provided with a coating is received, and a part of the received image signal subjected to the coating processing is received. The output signal of the light receiving element is selected, the presence or absence of the image signal of the selected output signal is detected, and the presence or absence of a false signal in the image signal output from the CCD sensor is determined based on the detection result. Therefore, with a simple method, it is possible to know whether or not a false signal is generated, regardless of the shape of the imaged object, without the need for the step of imaging a specific object.

[Brief description of drawings]

FIG. 1 is an example of a CCD sensor used in an apparatus according to the present invention, in which (a) is an overall view of the sensor and (b) is an enlarged view of a pixel arrangement at a predetermined position.

FIG. 2 is a circuit diagram showing an example of an equivalent circuit of a light receiving element of one pixel of the CCD sensor of FIG.

FIG. 3 is a block diagram showing an embodiment of a false signal detection device of the present invention.

4 is a diagram showing an output of an image signal of a light receiving element of the CCD sensor of FIG.

FIG. 5 shows another embodiment of the CCD sensor used in the device according to the present invention.

[Explanation of symbols]

 1 CCD sensor 3 Light receiving element 4 Coating

Claims (2)

[Claims] 1. A light receiving element for outputting a pixel signal, comprising: a CCD sensor in which a surface of a part of a predetermined light receiving element is covered; and a signal detecting means for detecting a pixel signal from the light receiving element. The signal detecting means may detect a false signal due to electric charges overflowing from the uncoated light receiving element by detecting an output of a pixel signal from the predetermined light receiving element of the CCD sensor. Characteristic CCD signal false signal detection device. 2. An image signal output from a CCD sensor having a coating provided on a part of the light receiving elements, and an output signal of a part of the light receiving elements having the coating is selected from the received image signals. Then, the presence or absence of the image signal in the selected output signal is detected, and a false signal in the image signal output from the CCD sensor is detected based on the detection result.
False signal detection method for CD sensor.