JP2008212266A - Masking device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce an effect of jaggies on a masking boundary by a simple constitution and a high-speed processing in an image masking process. <P>SOLUTION: This masking device executes a first masking process on an analog image signal from an image pickup device in the both sides of an image signal section S1 and defines the image signal of the first masking area M1 as a pedestal level L1. This masking device executes a second masking process on the image signal processed by the first masking process on each pixel in the both sides of the image signal where the first mask area M1 is defined as the pedestal level L1 and inside one pedestal of the first masking area M1, and defines the pixel corresponding to the second masking area M1 as a prescribed gray level L2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an apparatus for performing an electronic mask process on an image signal, and an electronic endoscope apparatus using the apparatus.

An optical mask area that is physically shielded from light is provided at the peripheral edge of the image sensor, and electronic mask processing is further performed on the image signal output from this area. Further, in an electronic endoscope or the like, for example, an electronic mask process is performed on a peripheral region that is not in focus with respect to an image signal output from an imaging region surrounded by an optical mask region (Patent Literature). 1).
JP 2003-325444 A

  However, since the conventional electronic mask processing is performed by binary processing of whether a certain pixel is masked or not, if a straight line oblique to a curve or a horizontal line is used for the mask region boundary, There is a problem that jaggy is generated in these parts and the appearance is bad.

  An object of the present invention is to reduce the influence of jaggies at a mask boundary in a mask processing of an image by a simple configuration and high-speed processing.

  The mask processing apparatus of the present invention is a mask processing apparatus that performs mask processing on an image signal from an image sensor, and forms a first mask region having a first density that is relatively dark with respect to the image signal. Mask processing means, and second mask processing means for forming a second mask region with a relatively thin second density of pixels in a predetermined number of pixels adjacent to the periphery of the first mask region. It is characterized by.

  The first mask area includes an oblique boundary line portion with respect to the horizontal line, and the second mask area is provided adjacent to the boundary line portion. The predetermined number of pixels adjacent to the periphery of the first mask region that constitutes the second mask region is preferably one pixel. The first density is, for example, the black level of the image signal, and the second density is a predetermined gray level. The first mask area is an area surrounding the peripheral edge of the image, and the second mask area is an area along the inner peripheral edge of the first mask area.

  The electronic endoscope apparatus according to the present invention is characterized in that mask processing is performed on an image photographed by the electronic endoscope using the mask processing apparatus.

  As described above, according to the present invention, in image mask processing, the influence of jaggy on the mask boundary can be reduced by a simple configuration and high-speed processing.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram schematically showing a configuration of an electronic endoscope system according to an embodiment of the present invention.

  The electronic endoscope system 10 is photographed by an electronic scope 11 inserted into a lumen, a processor unit 12 that supplies illumination light to the electronic scope 11 and processes an image signal from the electronic scope 11, and the electronic scope 11. It is mainly comprised from the monitor 13 which displays the endoscopic image which was made.

  As is well known, the electronic scope 11 includes a flexible tubular insertion portion 14 and an operation portion 15 to which the insertion portion 14 is coupled and held by an operator to perform various operations. The operation unit 15 is detachably attached to the processor unit 12 via a flexible tube and a connector, and is electrically and optically connected to the processor unit 12.

  An image sensor 16 such as a CCD is provided at the distal end of the insertion unit 14, and an image signal from the image sensor 16 is converted into a digital signal via a signal processing circuit 17 provided in the operation unit 15, and the processor unit 12. Is output. In the processor unit 12, predetermined signal processing known in the art is performed on the image signal, converted into a video signal of a predetermined standard, for example, and output to the monitor 13.

  The operation unit 15 is provided with a mask circuit 18 using an FPGA or the like, and the mask circuit 18 stores or generates predetermined mask data. The mask signal from the mask circuit 18 is sent to the signal processing circuit 17 and is superimposed on the image signal from the image sensor 16, whereby electronic mask processing is performed. In this embodiment, as will be described later, two types of mask data (first and second mask data) are used and output from the mask circuit 18 to the signal processing circuit 17.

  As is conventionally known, the electronic scope 11 is provided with a light guide (not shown), one end of which is connected to a light source provided in the processor unit 12, and light from the light source is inserted through the light guide. The light is irradiated from the tip of the portion 14 into the lumen. The image sensor 16 is driven and controlled by an image sensor drive circuit (not shown) provided in the operation unit 15. In the present embodiment, the image sensor drive circuit is a part of the signal processing circuit 17 for convenience. It is drawn as.

  FIG. 2 schematically shows an example of an image displayed on the screen 13 </ b> A of the monitor 13 after the mask processing of the present embodiment is performed. A first mask region M1 is formed by the first mask data at the peripheral portion of the screen 13A, and a second mask region M2 is formed by the second mask data inside the first mask region. In the first mask area, the pixels in that area are set to a black level (first density), and in the second mask area, the pixels in that area are set to a gray level (second density) that is lighter (brighter) than the black level. Is done.

  Although the second mask region M2 is exaggerated in FIG. 2, the second mask region M2 is made up of pixels that are, for example, one pixel inside along the inner peripheral edge of the first mask region M1. In the present embodiment, the four corners of the first and second mask regions M1 and M2 are arcuate curves.

  FIG. 3 shows an enlarged view of the upper left corner of the first and second mask regions M1 and M2 that are arcuate curves. As shown in the drawing, the first mask region M1 is a black level mask, and jaggy occurs in a curved portion (even if it is an oblique straight line). The second mask region M2 is a gray level mask, and is formed, for example, for one pixel from the boundary of the first mask region M1 to the inside in the horizontal direction as shown in the drawing. That is, the second mask region M2 is formed by setting one pixel adjacent to the left and right inner boundary pixels of the first mask region M1 in each horizontal line to a gray level in drawing on the screen 13A by horizontal scanning.

  In the present embodiment, since one inner pixel along the entire circumference of the first mask region M1 is defined as the second mask region M2, one horizontal line adjacent to the lower side of the upper side formed by the first mask region M1 One horizontal line adjacent to the upper side of the lower side is also set as the second mask region M2.

  FIG. 4 schematically shows the principle of mask processing in the present embodiment. FIG. 4A is an example of an analog image signal for one horizontal line input to the signal processing circuit 17 from the image sensor 16. In the present embodiment, the following processing is executed in the signal processing circuit 17 by timing control by the mask circuit 18 (see FIG. 1), for example. In FIG. 4A, the signal part S1 is a video signal part, the signal part S2 is a horizontal synchronizing signal part, and the signal part S3 is a color burst signal part. The signal level L1 is a pedestal level that determines the black level.

  FIG. 4B is an example of an analog image signal for one horizontal line obtained by performing a first mask process on the image signal of FIG. That is, the video signal in the hatched area (corresponding to both ends of the horizontal line) in FIG. 4B is set to the pedestal level L1 by the first mask processing. This is achieved by setting the interval corresponding to the shaded portion and the image signal level to the pedestal level L1 with respect to the image signal in FIG.

  FIG. 4C shows an example of an analog image signal for one horizontal line obtained by performing the second mask process of the present embodiment on the image signal subjected to the first mask process in FIG. It is. In FIG. 4C, the second mask process is performed on the video signal of, for example, one pixel on both sides inside the first mask area M1, which is at the pedestal level L1 in FIG. 4B. . In other words, the video signal in the shaded area is a signal of the gray level L2 (a predetermined level (for example, an intermediate value) between the pedestal level and the maximum value of the video signal). The second mask process is achieved by setting the image signal level in FIG. 4B to the gray level L2 in the section corresponding to the shaded area.

  As described above, according to the present embodiment, it is possible to make a jaggy such as a mask area angle inconspicuous while performing high-speed mask processing on an electronic endoscopic image with a simple configuration. In particular, in the present embodiment, mask processing that reduces jaggies at high speed with a simple configuration that only maintains the signal level at a predetermined interval and a predetermined level corresponding to the first and second mask regions in the analog signal is performed. Can be applied. Since such a circuit can be easily provided on the electronic scope side, by adopting the configuration of the present embodiment, it is possible to perform mask processing with reduced jaggy on the electronic scope side. As a result, it is not necessary to perform mask processing on the processor unit side where various electronic scopes are mounted, so the data for the processor unit to recognize the type of the electronic scope mounted and perform mask processing corresponding to this, etc. There is no need to hold.

  In the present embodiment, jaggies are generated only at the four corners of the mask area where the boundary line is an arcuate curve. Therefore, as shown in FIG. It is good also as a structure which provides M2 '.

  It should be noted that the present invention can be similarly applied to a jaggy occurrence location at the boundary of the mask region. In addition to the present embodiment in which the corner of the mask region is an arcuate curve, the present invention is also applied to a boundary including an oblique straight line. Is possible. In the present embodiment, mask processing is performed using a two-level mask. However, it is also possible to provide one or more light gray regions inside the second mask region.

  In this embodiment, the gray scale is used. However, the mask color is not limited to gray, and a plurality of levels of mask areas of specific colors such as blue may be provided.

  Further, in this embodiment, the analog signal is masked. However, after the image signal is converted to a digital signal, the second mask processing can be performed on the pixels inside the first mask region. It is. In the present embodiment, the second mask area is for one pixel, but it may be for one pixel or more.

It is a block diagram which shows the structure of the electronic endoscope system which is one Embodiment of this invention. It is an example of the mask image in this embodiment. FIG. 3 is an enlarged view of an upper left corner of the mask image of FIG. 2. It is a figure which shows the principle of the 1st and 2nd mask process performed with respect to an analog image signal. It is an enlarged view of the upper left corner part in the modification of a mask image.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electronic endoscope system 11 Electronic scope 12 Processor unit 13 Monitor 16 Image pick-up element 17 Signal processing circuit 18 Mask circuit M1 1st mask area | region M2 2nd mask area | region L1 Pedestal level L2 Gray level

Claims (6)

A mask processing apparatus that performs mask processing on an image signal from an image sensor,
First mask processing means for forming a first mask region having a first density relatively dark with respect to the image signal;
And a second mask processing means for forming a second mask region with a relatively thin second density of pixels in a predetermined number of pixels adjacent to the periphery of the first mask region. Processing equipment.   2. The mask processing apparatus according to claim 1, wherein the first mask region includes an oblique boundary line portion with respect to a horizontal line, and the second mask region is provided adjacent to the boundary line portion.   2. The mask processing apparatus according to claim 1, wherein the predetermined number of pixels adjacent to a periphery of the first mask region constituting the second mask region is one pixel.   The mask processing apparatus according to claim 1, wherein the first density is a black level of an image signal, and the second density is a predetermined gray level.   The said 1st mask area | region is an area | region surrounding the peripheral part of an image, The said 2nd mask area | region is an area | region along the inner peripheral part of the said 1st mask area | region, The said 1st mask area | region is a region | area. Mask processing device.   An electronic endoscope apparatus that performs mask processing on an image photographed by an electronic endoscope using the mask processing apparatus according to any one of claims 1 to 5.