JP4654876B2 - Foreign object detection system - Google Patents

Description

  The present invention relates to a foreign object detection system that performs foreign object detection of an image sensor.

If foreign matter such as dust adheres to the front surface of the image sensor incorporated in the camera, the shadow of the foreign matter is reflected in the photographed image, and good photographing cannot be performed. In order to prompt the user of the camera to remove foreign matter, foreign matter detection of the image sensor is performed by the following method. That is, an image is captured by illuminating the imaging device substantially uniformly, and the luminance value of each pixel of the image is compared with a predetermined threshold value. And the part of brightness | luminance lower than a threshold value is made into the adhesion location of a foreign material (for example, refer patent document 1). Further, a proposal has been made that a threshold value relating to the size of the low-luminance portion is determined in advance, and only a portion larger than the threshold value is set as a foreign matter adhesion portion.
JP 2002-300455 A

  However, in the foreign matter detection system described above, the threshold setting, which is a criterion for determining whether or not a foreign matter is attached, is not changed (that is, a constant threshold value is always used). It was not limited. For example, if the resolution of the image is high, extremely fine foreign matter will be conspicuous. Therefore, if a threshold value is set according to such a case, even in the case of a low-resolution image, extremely fine foreign matter is detected wastefully. It will end up.

  An object of the present invention is to provide a foreign matter detection system that can appropriately detect foreign matter of an image sensor in accordance with image processing of a captured image.

Foreign object detection system of the present invention is a system that performs foreign object detection of the image pickup device of the camera,
A determination unit that determines the type of image processing for converting an image corresponding to the output signal output from the image sensor into a captured image for recording, and the image sensor attached to the front surface of the image sensor based on the output of the image sensor A detection unit that detects a foreign object, and a setting unit that sets sensitivity when the detection unit detects the foreign object according to the type of the image processing determined by the determination unit .

The image processing preferably includes any one selected from image reduction processing, information compression processing, noise reduction processing, gain-up processing, contour enhancement processing, and gradation correction processing.
The image processing is preferably image processing selected according to a shooting mode.
Further, the setting unit, when the image processing is intended to reduce the impact of the foreign object with respect to the captured image, it is preferable to set lower than the predetermined reference the sensitivity.
The setting unit preferably sets the sensitivity higher than a predetermined reference when the image processing emphasizes the influence of the foreign matter on the captured image .

The foreign object detection system of the present invention is a system that performs foreign object detection of the image sensor of a camera that performs predetermined image processing on the output of the image sensor to generate a captured image, and based on the output of the image sensor, A detection unit that detects foreign matter attached to the front surface of the imaging element; and a setting unit that sets sensitivity when the detection unit detects the foreign matter according to the type of image processing. When a plurality of types of image processing are performed on a single output of the image sensor related to the generation of the captured image, the sensitivity corresponding to the type of each image processing is combined and set.
The foreign matter detection system of the present invention is a system that detects foreign matter of the image sensor of a camera that generates a captured image based on the output of the image sensor, and is installed on the front surface of the image sensor based on the output of the image sensor. A detection unit that detects attached foreign matter, and a setting unit that sets sensitivity when the detection unit detects the foreign matter according to the number of pixels of the output of the imaging device used for generating the captured image. Is.

The foreign object detection system of the present invention is a system that performs foreign object detection of the image sensor of a camera that performs predetermined image processing on the output of the image sensor to generate a captured image, and based on the output of the image sensor, The detection unit detects the foreign matter according to the detection unit that detects the foreign matter attached to the front surface of the imaging device, the number of output pixels of the imaging device used to generate the captured image, and the type of the image processing. And a setting unit for setting the sensitivity at the time of performing.

In addition, the detection unit detects the foreign object candidate with higher sensitivity than the sensitivity set by the setting unit from the output of the imaging element, and then detects the foreign object candidate with the sensitivity set by the setting unit . It is preferable to detect the foreign matter.
In addition, it is preferable to further include a display unit that displays the foreign object detected with the sensitivity set by the setting unit and displays the candidate for the foreign object in a form different from the foreign object.

Further, the detection unit detects, from the output of the image sensor, the foreign object candidate with a sensitivity higher than the sensitivity set by the setting unit, and then , based on the foreign object candidates, a plurality of settings set by the setting unit It is preferable to detect the foreign matter with each of different sensitivities.
In addition, it is preferable to further include a display unit that displays the foreign matter detected at the sensitivity set by the setting unit in a different form for each sensitivity and displays the candidate for the foreign matter in a form different from the foreign matter. .

The image sensor further includes an illumination unit that illuminates the image sensor, and the detection unit detects foreign matter attached to the front surface of the image sensor based on an output of the image sensor when illuminated by the illumination unit . Is preferred.

  According to the foreign matter detection system of the present invention, foreign matter detection of the image sensor can be appropriately performed according to the image.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Here, the camera system (10 to 30) shown in FIGS. 1A and 1B will be described as an example.
The camera system (10 to 30) includes a camera body 10, an interchangeable lens 20 that can be attached to and detached from the camera body 10, and a foreign object detection adapter 30. FIG. 1A shows a state at the time of photographing with the interchangeable lens 20 attached to the camera body 10. FIG. 1B shows a state where a foreign object detection adapter 30 is attached to the camera body 10 instead of the interchangeable lens 20.

  The overall control of the camera system (10-30) is performed by the control circuit 18 of the camera body 10. When the interchangeable lens 20 is attached to the camera body 10 (FIG. 1 (a)), the control circuit 18 of the camera body 10 communicates with the control circuit 22 of the interchangeable lens 20 via the communication contacts 1A and 2A. , Shooting operation is performed in conjunction. Further, when the foreign object detection adapter 30 is attached to the camera body 10 (FIG. 1B), the control circuit 18 of the camera body 10 communicates with the control circuit 33 of the foreign object detection adapter 30 via the communication contacts 1A and 3A. The foreign object detection operation is performed in conjunction.

In the camera system (10 to 30), when the interchangeable lens 20 is attached to the camera body 10 as shown in FIG. 1A, after the light from the subject passes through the optical system 21 of the interchangeable lens 20, It is guided into the camera body 10. The interchangeable lens 20 is attached to the camera body 10 by the mount 2B.
The light guided into the camera body 10 is incident on the screen 12 after being reflected by the quick return mirror 11 before photographing. At this time, a subject image is formed on the screen 12 by the optical system 21 of the interchangeable lens 20. The light transmitted through the screen 12 is reflected by the pentaprism 13 and is guided to the photographer's eye after passing through the eyepiece 14.

  On the other hand, at the time of shooting, the quick return mirror 11 of the camera body 10 is flipped up toward the screen 12, and the shutter 15 is opened at a predetermined exposure timing. At this time, the light guided into the camera body 10 goes straight as it is, passes through the optical low-pass filter 16, and enters the image sensor 17. The optical low-pass filter 16 is a member provided for preventing moire. The image sensor 17 is a CCD image sensor, a CMOS image sensor, or the like.

  Thus, at the time of shooting, light from the subject is guided to the image sensor 17, and a subject image is formed on the imaging surface of the image sensor 17 by the optical system 21 of the interchangeable lens 20. The output of the image sensor 17 is processed by the control circuit 18 of the camera body 10. The control circuit 18 performs predetermined image processing on the output of the image sensor 17 according to a preset shooting mode, and generates a shot image. This captured image is recorded in an image memory (not shown) and displayed on the display element 19. The display element 19 also displays information related to setting of various functions such as a shooting mode.

  Here, if foreign matter such as dust adheres to the front surface of the image sensor 17 (the surface of the optical low-pass filter 16), the shadow of the foreign matter may appear in the captured image. The degree of reflection (that is, the degree of influence of a foreign object on a captured image) is not uniform, and is considered to vary depending on the type of image processing related to generation of the captured image. Further, it is considered to depend on the number of readout pixels of the output of the image sensor 17.

  For example, the foreign substance 40 as shown in FIG. 2A is attached so as to overlap a part of each pixel 7R, 7G, 7B of the image sensor 17. In this case, since the light incident on some pixels is blocked by the shadow of the foreign object 40, when the captured image is generated by reading all the pixels of the image sensor 17, the shadow of the foreign object 40 appears in the captured image. Although depending on the characteristics of the optical system 21 of the interchangeable lens 20, it is considered that the shadow of the foreign matter 40 appears if the size of the foreign matter 40 is larger than the pixel size (generally □ 10 μm or less). FIG. 2A illustrates a case where the RGB array of the pixels 7R, 7G, and 7B of the image sensor 17 is a Bayer array.

  On the other hand, after all the pixels of the image sensor 17 are read out, a plurality of adjacent pixels are combined to generate a photographic image with a specific number of pixels (that is, image reduction conversion processing is performed). The size of one pixel of the image becomes relatively large, and the influence of the foreign matter 40 on the one pixel is reduced. For example, a photographed image in which 16 pixels of the Bayer array are combined to form one pixel and the number of pixels is ¼ both vertically and horizontally is as shown in FIG. In this case, even in the pixel to which the foreign matter 40 is attached, no foreign matter is attached to 12 out of the 16 pixels before synthesis. For this reason, it is considered that the influence of the foreign matter 40 is greatly reduced and the reflection on the photographed image can be ignored.

  Furthermore, when not all pixels of the image sensor 17 are read but only some of the pixels are selectively read (that is, thinning-out reading is performed), the influence of the foreign matter 40 is greatly reduced, and the captured image is reflected. Can be ignored. For example, FIG. 2C shows a case where the remaining pixels are read out by skipping pixels for two columns both vertically and horizontally. In such a case, since the number of pixels used in the captured image decreases, the probability that the foreign object 40 exists on the pixel is greatly reduced, and it is considered that the reflection in the captured image can be ignored. Thinning readout is one of the driving methods of the image sensor 17 that is performed for speeding up.

  In addition to thinning-out reading, there is also a method of reading out by adding analog charges of a plurality of pixels inside the image sensor 17. Such readout by pixel addition is performed in order to improve the S / N when the intensity of incident light is weak. Also in this case, since the influence of the foreign object 40 on one pixel of the captured image is reduced, it is considered that the reflection of the foreign object on the captured image can be ignored. Note that the driving method (any pixel, thinning, or pixel addition) of the image sensor 17 is selected according to, for example, the shooting mode.

  Further, as image processing performed on the output of the image sensor 17, in addition to the above-described image reduction processing, information compression processing such as JPEG compression, noise reduction processing by image smoothing, gain-up processing, contour enhancement processing, floor There are various image processing such as tone correction processing. These image processes are executed until at least one is selected according to the shooting mode, for example, and a shot image is recorded in an image memory (not shown).

  Depending on the type of image processing involved in the generation of the captured image, the degree of influence of foreign matter on the captured image differs. Similar to the image reduction processing, the image processing for reducing the influence of the foreign matter on the captured image is information compression processing, noise reduction processing, and gain-up processing among the above examples. Conversely, there is also image processing that emphasizes the influence of foreign matter on a captured image, and the contour enhancement processing and gradation correction processing in the above example correspond to this.

In addition, these image processes include a calculation process that reduces (or emphasizes) the influence of a foreign substance in proportion to the degree of the deterioration accompanying image information deterioration. The degree of degradation of image information can be represented by the correlation between the output (RAW data) of the image sensor 17 and the final captured image (for recording) after image processing.
FIGS. 3A to 3C show how the influence of foreign matter is reduced by image processing, and FIGS. 4A and 4B show how the influence of foreign matter is emphasized. 3 and 4, the horizontal axis represents the pixel position, and the vertical axis represents the brightness. FIGS. 3A and 4A are both readout waveforms from the image sensor 17 (that is, waveforms before image processing). This read waveform includes a portion with low brightness due to the shadow of the foreign matter. The size S and density D of this part can characterize the degree of influence of foreign matter on the captured image.

  When noise reduction processing is performed on the readout waveform (FIG. 3A), a waveform as shown in FIG. 3B is obtained. The noise reduction process is a process for suppressing the protruding pixel value. For this reason, the shadow (density D) of the foreign matter is suppressed together with the noise, and the influence of the foreign matter is reduced. As the application amount of the noise reduction process increases, the influence of foreign matter is greatly reduced. As a result, it is considered that the shadow of a certain amount of foreign matter is not noticeable.

  Further, when an image reduction process is performed such that two pixels are combined into one pixel on the waveform after the noise reduction process (FIG. 3B), a waveform as shown in FIG. 3C is obtained. The shadow of the foreign object is further thinned by combining with the surrounding pixels, and the difference (density D) from the surrounding image information is further reduced. As a result, it is considered that the shadow of the foreign substance having a small readout waveform almost disappears and the shadow of the medium-sized foreign substance becomes inconspicuous.

On the other hand, when a contour emphasis process is performed on the read waveform (FIG. 4A), a waveform as shown in FIG. 4B is obtained. Although the size S of the foreign object shadow does not change, the apparent density D is further enlarged, and the influence of the foreign object is emphasized.
As described above, when a foreign object adheres to the front surface of the image sensor 17, the number of read pixels of the output of the image sensor 17 (all pixels, thinning, or pixel addition) and image processing related to the generation of the captured image Depending on the type (any of image reduction processing, information compression processing, noise reduction processing, gain increase processing, contour enhancement processing, gradation correction processing, etc.), the influence of foreign matter on the captured image is reduced (or enhanced) In some cases, the shadow of a foreign object appears in the captured image.

In the camera system (10 to 30) of this embodiment, only when a shadow of a foreign object appears in the final photographed image (for recording), the camera user is prompted to remove the foreign object, and good shooting is performed. For this purpose, foreign matter detection of the image sensor 17 is performed by the following method.
When foreign matter is detected by the image sensor 17, a foreign matter detection adapter 30 is attached to the camera body 10 as shown in FIG. Attachment of the foreign object detection adapter 30 to the camera body 10 is performed by a mount 3B similar to the mount 2B of the interchangeable lens 20. In addition to the control circuit 33 described above, the foreign object detection adapter 30 is provided with an LED 31 and an LED driver 32.

When the foreign object detection adapter 30 is mounted, the control circuit 18 of the camera body 10 recognizes the foreign object detection adapter 30 through communication and prepares for the foreign object detection operation. That is, in step S1 of FIG. 5, the quick return mirror 11 of the camera body 10 is flipped up toward the screen 12 (mirror up) to be in an exposure enabled state.
Then, a lighting instruction for the LED 31 is issued to the control circuit 33 of the interchangeable lens 20 (step S2). The control circuit 33 drives the LED driver 32 in accordance with an instruction from the control circuit 18 of the camera body 10 and controls the lighting of the LED 31. The light emission amount of the LED 31 is substantially constant under a predetermined driving condition. When detecting foreign matter, the exposure value may always be set to a predetermined value, and the operation for setting the exposure condition for each photographing for detecting foreign matter can be omitted. For this reason, lighting control of the LED 31 is performed under a predetermined driving condition (current value).

  Next, the control circuit 18 of the camera body 10 starts the front curtain of the shutter 15 (step S3), and starts exposure to the image sensor 17. Since the external light is blocked by the attachment of the foreign object detection adapter 30, only the light from the LED 31 can be guided to the image sensor 17. At this time, the illumination light after passing through the optical low-pass filter 16 enters the image sensor 17 and is illuminated almost uniformly.

  In this state, the accumulation operation of the image sensor 17 is performed (step S4). When a predetermined exposure time has elapsed, the rear curtain of the shutter 15 is started (step S5), and the exposure to the image sensor 17 is terminated. Thereafter (step S6), the control circuit 18 issues an instruction to turn off the LED 31 to the control circuit 33 of the interchangeable lens 20. In response to this, the control circuit 33 controls the LED 31 to be turned off.

  Next (step S <b> 7), the control circuit 18 of the camera body 10 reads all pixels from the image sensor 17. In the output of the image sensor 17, when a foreign object adheres to the front surface of the image sensor 17 (the surface of the optical low-pass filter 16), a portion with low brightness due to the shadow of the foreign object appears. Note that a series of processes related to imaging for foreign object detection (sweep of charges from accumulation → AD conversion → gain adjustment, etc.) may be prepared in advance. For example, the sensitivity with the least noise is preferable.

  When the control circuit 18 generates an image for detecting a foreign object (an image of a uniform luminance surface including a low-luminance portion due to the shadow of the foreign object) based on the output of the image sensor 17, the control circuit 18 performs the following steps S8 and S9. After setting the sensitivity for detecting foreign matter, the image for detecting foreign matter is processed according to the detection sensitivity (step S10), and the foreign matter attached to the front surface of the image sensor 17 is detected. Then, foreign matter information is generated and recorded, and an image of the foreign matter is displayed (step S11). The image processing algorithm for foreign object detection may be a general method such as binarization of an image.

The processes in steps S8 and S9 will be described.
In step S8, the shooting mode set in the camera body 10 is read. The photographing mode is a mode when photographing is performed with the interchangeable lens 20 attached to the camera body 10 instead of the foreign object detection adapter 30 (FIG. 1A). At the time of shooting, depending on the shooting mode, the number of read pixels of the output of the image sensor 17 (all pixels, thinning, or pixel addition) and the type of image processing (image reduction processing, information compression processing) related to generation of the shot image , Any one of noise reduction processing, gain-up processing, contour enhancement processing, gradation correction processing, etc.) is specified.

  When detecting the foreign matter of the image sensor 17, the detection sensitivity is set according to the photographing mode (that is, according to the number of read pixels of the image sensor 17 and the type of image processing) (step S9). . For example, in the case of a shooting mode that generates a high-definition shot image, the sensitivity is set so that an extremely fine foreign object 40 (FIG. 2 (a)) that is difficult to visually confirm can be detected without missing. In the case of a shooting mode that generates a coarse shot image as in 2 (b) and (c), it is desirable to set the sensitivity so that only a large foreign object can be detected while ignoring the extremely fine foreign object 40.

  The setting of detection sensitivity corresponds to the setting of a threshold value when binarizing a foreign object detection image. When this threshold is defined as a decrease from the bright level, if the threshold is set smaller than a predetermined reference, the detection sensitivity is set higher than the predetermined reference. On the contrary, if the threshold value is set larger than a predetermined standard, the detection sensitivity is set lower than the predetermined standard. The threshold reference is, for example, the average luminance of each pixel of the foreign object detection image.

  Further, when setting the detection sensitivity, in addition to the above-described threshold setting regarding the luminance value, the threshold setting regarding the size of the low-luminance portion included in the foreign object detection image is also performed. Also in this case, if the threshold is set smaller than a predetermined reference, the detection sensitivity is set higher than the predetermined reference. On the contrary, if the threshold value is set larger than a predetermined standard, the detection sensitivity is set lower than the predetermined standard.

  Regarding the number of readout pixels among the imaging modes read out in step S8, it is preferable to set the detection sensitivity higher than the reference in the case of the readout mode with all pixels (FIG. 2A). In the mode of reading by thinning or pixel addition (FIGS. 2B and 2C), it is preferable to set the detection sensitivity lower than the reference. Qualitatively, in the case of thinning readout, it is preferable to lower the detection sensitivity as the thinning rate is higher (the smaller the number of readout pixels). In the case of pixel addition, it is preferable to lower the detection sensitivity as the number of pixels to be added is increased (the number of readout pixels is smaller).

  Further, regarding the type of image processing in the shooting mode read out in step S8, in the case of image processing (such as noise reduction processing or image reduction processing in FIG. 3) that reduces the influence of foreign matter on the captured image, the detection sensitivity is used as a reference. It is preferable to set it lower. In addition, in the case of information compression processing and gain-up processing, it is preferable that the detection sensitivity is similarly set lower than the reference.

  Qualitatively, in the case of image reduction processing, it is preferable to lower the detection sensitivity as the number of pixels after processing is smaller (image size is smaller). In the case of information compression processing, it is preferable to lower the detection sensitivity as the compression rate increases. In the case of noise reduction processing, it is preferable to lower the detection sensitivity as image information deterioration caused by noise removal increases. In the case of gain-up processing, it is preferable to lower the detection sensitivity as noise increases due to gain-up.

  In the case of image processing that emphasizes the influence of foreign matter on a captured image (such as the contour enhancement processing in FIG. 4), it is preferable to set the detection sensitivity higher than the reference. In addition, in the case of gradation correction processing, it is also preferable to set the detection sensitivity higher than the reference. Qualitatively, in the case of the contour enhancement process, it is preferable to increase the detection sensitivity as the contour of the foreign object is sharpened. In the case of gradation correction processing, it is preferable to increase the detection sensitivity as the contrast is increased by gradation correction.

  Furthermore, when a plurality of types of image processing are performed on one output of the image sensor 17 related to generation of a captured image (that is, output of the image sensor 17 related to generation of one captured image) (FIG. 3). (see (c)) is preferably set by combining detection sensitivity suitable for each type of image processing. The detection sensitivity synthesis is, for example, a process of numerically adding a difference between a detection sensitivity suitable for each type of image processing and a predetermined reference.

  In a combination of a plurality of image processings that reduce the influence of foreign matter, a lower detection sensitivity is set as a result of combining the detection sensitivities. In a combination of a plurality of image processings that emphasizes the influence of foreign matter, higher detection sensitivity is set as a result of combining detection sensitivity. In the combination of the image processing for reducing the influence of foreign matter and the image processing for emphasizing, the difference between the predetermined reference and the predetermined reference may be offset as a result of the synthesis of the detection sensitivity.

  As described above, in the foreign object detection system of the present embodiment, since the detection sensitivity is set according to the number of read pixels of the image sensor 17 at the time of shooting and the type of image processing, the image sensor 17 of each image is captured. Foreign object detection can be performed appropriately. Then, by prompting the camera user to remove foreign objects based on the detection results, there is no possibility of issuing warnings for foreign objects that are smaller than necessary (foreign objects that do not appear in the photographed image), and an optimal dust warning Can be done.

The detection sensitivity may be set according to only the number of readout pixels of the output of the image sensor 17 at the time of shooting, or may be set according to only the type of image processing. Further, the detection sensitivity may be set according to both the number of readout pixels and the type of image processing. In this case, foreign matter detection can be performed more appropriately.
Furthermore, in this embodiment, the imaging element 17 is illuminated by the LED 31 built in the foreign object detection adapter 30, and the foreign object is detected based on the output of the imaging element 17 at this time. Therefore, the foreign object can be detected efficiently. it can.

(Modification)
In the above-described embodiment, the detection sensitivity is set according to the number of readout pixels of the output of the image sensor 17 and / or the type of image processing at the time of shooting, and the foreign matter on the front surface of the image sensor 17 is set according to the detection sensitivity. Although detected, the present invention is not limited to such a one-step detection process. After detecting a foreign substance candidate with a higher sensitivity than the detection sensitivity set according to the number of read pixels and / or the type of image processing from the output of the image sensor 17, the number of read pixels and / or an image is detected from the foreign substance candidate. You may detect a foreign material with the detection sensitivity set according to the kind of process. By performing such a two-stage detection process, the low-luminance portion appearing in the foreign object detection image can be classified as a foreign object candidate and a foreign object. A low-luminance portion (foreign matter candidate) that has not been detected as a foreign matter is an extremely fine portion that is unlikely to appear in a captured image. As the sensitivity used in the first-stage detection process, it is preferable to use a sensitivity that is not affected by noise components caused by uneven photoelectric conversion in the image sensor 17 or uneven illumination by the LEDs 31.

  Furthermore, when performing the two-stage detection process as described above, it is preferable to display a foreign object image as follows. A display example is shown in FIG. The screen 50 corresponds to the entire image sensor 17. As shown in FIG. 6A, the foreign object 51 detected with the sensitivity set according to the number of read pixels and / or the type of image processing is displayed on the screen 50, and a form (marker) different from the foreign object 51 is displayed. Thus, a foreign object candidate 52 is also displayed on the screen 50 at the same time. The positions of the foreign object 51 and the candidate 52 on the screen 50 correspond to the adhesion position on the front surface of the image sensor 17. In addition to the position information, the size information of the foreign object 51 and the candidate 52 may be displayed together.

  Displaying the foreign object 51 and the candidate 52 in different forms provides the following effects. Even if there is no problem with the current setting value, there is a possibility that a stricter image mode may be used together with a foreign object (such as RAW-JPEG), so it is meaningful to display information on the candidate 52 together with the foreign object 51. . Even when the foreign object 51 is not present, if there are many candidates 52, it can be determined that it is time to clean the front surface of the image sensor 17 (the surface of the optical low-pass filter 16).

  Incidentally, when the foreign object 51 and the candidate 52 are displayed in the same form, the result is as shown in FIG. When only the foreign object 51 is displayed, it is as shown in FIG. In the display example as shown in FIG. 6B, the foreign object 51 and the candidate 52 cannot be distinguished, and an appropriate dust warning cannot be performed. In the display example as shown in FIG. 6C, since the candidate 52 is not displayed, only the most important information (information of the foreign object 51) can be selected and displayed, and the foreign object becomes more sensitive than necessary. There is no. The display example as shown in FIG. 6C is also applicable to the above-described one-stage detection process.

  Further, after detecting a foreign substance candidate from the output of the image sensor 17, the foreign substance is detected from each of the plurality of different sensitivities set according to the number of read pixels and / or the type of image processing. Also good. By performing such multi-stage detection processing, the low-intensity part appearing in the foreign object detection image can be classified as a foreign object candidate and a foreign object, and the foreign object is classified according to the size and other levels. You can also For this reason, the information amount regarding the foreign material on the front surface of the image sensor 17 can be increased.

  In addition, when performing multi-stage detection processing, the display of the image of the foreign matter is, for example, as shown in FIG. 6D, the foreign matter 53 detected with high sensitivity, the foreign matter 54 detected with low sensitivity, It is preferable to display the candidate 55 in a different form. Thus, the visibility of the classification of the foreign matter 53, 54 is improved by displaying the foreign matter 53, 54 in a different form for each sensitivity set according to the number of read pixels and / or the type of image processing. be able to.

  Furthermore, in the above-described embodiment, the camera system (10 to 30) configured by the camera body 10, the interchangeable lens 20, and the foreign object detection adapter 30 has been described as an example, but the present invention is not limited to this. The foreign object detection adapter 30 may be omitted, and the LED and its driver may be provided in the interchangeable lens 20 or the camera body 10. In this case, when detecting the foreign matter, it is preferable to set the aperture (not shown) of the interchangeable lens 20 to be small so that the intensity of the illumination light from the LED 31 is larger than the intensity of the subject light.

  In addition, the present invention can be applied not only to an interchangeable lens type camera system but also to a camera system in which an optical system that forms a subject image at the time of shooting, a foreign matter detection LED, and a driver thereof are provided integrally with an imaging device. Also in this case, it is preferable to set the photographing optical system to have a small aperture so that the intensity of the illumination light from the LED is larger than the intensity of the subject light. Furthermore, the present invention can also be applied when the foreign object detection LED and its driver are omitted.

It is a figure which shows the structure of a camera system (10-30). It is a conceptual diagram which shows the relationship between the influence of the foreign material with respect to a picked-up image, and image processing. It is a figure which shows a mode that the influence of a foreign material is reduced by image processing. It is a figure which shows a mode that the influence of a foreign material is emphasized by image processing. It is a flowchart which shows the procedure of the foreign material detection operation | movement of this embodiment. It is a figure explaining the example of a display of a foreign material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Camera body; 16 Optical low-pass filter; 17 Image pick-up element 18, 22, 33 Control circuit; 19 Display element; 20 Interchangeable lens 30 Foreign object detection adapter; 31 LED; 32 LED driver 40, 51, 53, 54 Foreign object; 52,55 Foreign object candidates

Claims (13)

A system that performs foreign object detection of the image pickup device of the camera,
A determination unit that determines a type of image processing for converting an image corresponding to an output signal output from the image sensor into a captured image for recording;
Based on the output of the image sensor, a detection unit that detects foreign matter attached to the front surface of the image sensor;
A foreign object detection system, comprising: a setting unit that sets sensitivity when the detection unit detects the foreign object according to the type of image processing determined by the determination unit . The foreign object detection system according to claim 1,
The foreign object detection system , wherein the image processing includes any one selected from image reduction processing, information compression processing, noise reduction processing, gain-up processing, contour enhancement processing, and gradation correction processing . The foreign object detection system according to claim 1,
The foreign object detection system , wherein the image processing is image processing selected according to a photographing mode . The foreign object detection system according to any one of claims 1 to 3,
The said setting part sets the said sensitivity lower than the predetermined reference | standard , when the said image processing reduces the influence of the said foreign material with respect to the said picked-up image . The foreign material detection system characterized by the above-mentioned . The foreign object detection system according to any one of claims 1 to 3,
The foreign substance detection system , wherein the setting unit sets the sensitivity higher than a predetermined reference when the image processing emphasizes the influence of the foreign substance on the captured image . A system for detecting foreign matter of the image sensor of a camera that performs predetermined image processing on an output of the image sensor to generate a captured image,
Based on the output of the image sensor, a detection unit that detects foreign matter attached to the front surface of the image sensor;
In accordance with the type of the image processing, a setting unit that sets sensitivity when the detection unit detects the foreign matter ,
The setting unit synthesizes and sets the sensitivity according to each type of image processing when a plurality of types of image processing are performed on a single output of the image sensor related to generation of the captured image. Foreign matter detection system characterized by that. A system for detecting foreign matter of the image sensor of a camera that generates a captured image based on an output of the image sensor,
Based on the output of the image sensor, a detection unit that detects foreign matter attached to the front surface of the image sensor;
A foreign matter detection system , comprising: a setting unit that sets sensitivity when the detection unit detects the foreign matter according to the number of pixels output from the imaging element used for generating the captured image . A system for detecting foreign matter of the image sensor of a camera that performs predetermined image processing on an output of the image sensor to generate a captured image,
Based on the output of the image sensor, a detection unit that detects foreign matter attached to the front surface of the image sensor;
A setting unit configured to set a sensitivity when the detection unit detects the foreign object according to the number of pixels output from the imaging element used for generating the captured image and the type of the image processing. A featured foreign matter detection system. The foreign object detection system according to any one of claims 1 to 8 ,
The detecting unit from the output of the imaging device, after detecting the candidates of the foreign substance with high sensitivity than the sensitivity set by the setting unit, from the candidate of the foreign matter, the foreign substance with a sensitivity that is set by the setting unit Foreign matter detection system characterized by detecting The foreign object detection system according to claim 9 ,
A foreign object detection system, further comprising a display unit that displays the foreign object detected with the sensitivity set by the setting unit and displays the candidate for the foreign object in a form different from the foreign object. The foreign object detection system according to any one of claims 1 to 10,
The detection unit detects, from the output of the imaging element, the foreign object candidate with higher sensitivity than the sensitivity set by the setting unit, and then detects a plurality of different sensitivities set by the setting unit from the foreign object candidate. A foreign matter detection system , wherein each of the foreign matter is detected . The foreign object detection system according to claim 11,
The apparatus further includes a display unit that displays the foreign object detected at the sensitivity set by the setting unit in a different form for each sensitivity and displays the candidate for the foreign object in a form different from the foreign object.
Foreign matter detection system characterized by that. The foreign object detection system according to any one of claims 1 to 12,
An illumination unit that illuminates the image sensor;
The detection unit detects foreign matter adhering to the front surface of the imaging device based on an output of the imaging device when illuminated by the illumination unit.
Foreign matter detection system characterized by that.

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