JPS63304378A - Deciding method for lateral turning of image - Google Patents

Abstract

PURPOSE:To decide a normal or laterally turned position of an image by obtaining the characteristic values of image signal levels of belt-shaped areas extending in the vertical and horizontal directions from those image signals forming image information on a human body and comparing said characteristic values with each other. CONSTITUTION:A belt-shaped area 4 includes many peripheral areas 2 and a slight part of a human body 1. Therefore, the total synthetic value of the image signal levels is larger in the area 4 than an area 3 as long as the sizes of both areas 3 and 4 are approximately equal to each other. Then both total synthetic values are compared with each other and it is decided that the image 1 is set at a normal position as long as the area having the larger value is extended horizontally. While the laterally turned position of the image 1 is decided if said area is extended vertically.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for determining whether the orientation of an image constituted by image signals carrying image information of a human body is normal or overturned.

(Prior art) In an X-ray tomography device, an ultrasonic diagnostic device, etc., an image signal carrying image information of the human body is obtained, and various algorithms related to image processing are applied to this image signal, or this image signal is processed in an easy-to-see manner. Displaying information has been conventionally performed. The present applicant also uses radiation (X-rays,
α rays, β rays.

When irradiated with γ-rays, electron beams, ultraviolet rays, etc., a portion of this radiation energy is accumulated in the phosphor, and then when it is irradiated with excitation light such as visible light, the phosphor is exhausted according to the accumulated energy. Taking advantage of the fact that it emits light, radiation image information of the human body is partially recorded on a sheet of stimulable phosphor, and then this stimulable phosphor sheet is scanned with excitation light such as a laser beam to produce stimulated luminescence. Generate light, photoelectrically read this stimulated luminescent light to obtain an image signal, perform image processing on this image signal, and create a radiation image of the subject on a photographic light-sensitive material, etc. based on the image processed image signal. A radiation image information recording and reproducing device that outputs a visible image to a recording material such as a CRT or other display device has already been proposed (Japanese Patent Laid-Open No. 55-1242).
(No. 9, No. 5B-11395, etc.) Normally, in such devices, the relative positional relationship between the device and the human body is determined when photographing, and image processing is performed on the image signal, or this image is When displaying a signal, it was treated as if it had been photographed in the legal positional relationship mentioned above. In the above device proposed by the present applicant, for example, when recording (photographing) radiation image information of a human body's chest, neck, etc. on a stimulable phosphor sheet, the vertical direction of the sheet is usually the vertical direction of the human body. Even after the image signal is read from the sheet, the vertical direction of the sheet is treated as the vertical direction of the image in the image formed by the image signal.

However, in some cases, images may be taken with the sheet turned horizontally, that is, with the vertical direction of the sheet facing the left and right directions of the human body. In the image that is displayed, the vertical direction of the image is the horizontal direction of the human body.

(Problem to be Solved by the Invention) However, normally images are taken in a predetermined positional relationship as described above, and for example, image processing is not performed on the assumption that the vertical direction of the image is the vertical direction of the human body. Various algorithms are set or the output process is set to output the visible image in an easy-to-see manner in which the vertical direction of the visible image is the vertical direction of the human body, so if the vertical direction of the visible image is different from the above direction, for example, If the vertical direction is the left and right direction of the human body, input this information to the image processing means or image reproduction means to change the image processing algorithm, or change the vertical direction in the visible image so that it is the vertical direction of the human body. It is necessary to change the output process, and for that purpose, it is necessary to check whether the image is in the normal position (for example, the normal position is when the vertical direction of the image matches the vertical direction of the human body as described above). Alternatively, it is necessary to determine whether the position is a rollover position rotated by 90 degrees from the normal position.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an image rollover determination method that can determine whether an image is in a normal position or a rollover position.

(Means for Solving the Problems) In order to achieve the above object, the image rollover determination method according to the present invention is based on an image signal carrying image information of a human body, including the vicinity of the center of the image, in the vertical and horizontal directions, respectively. The present invention is characterized in that each characteristic value of the image signal level of a band-shaped area extending in the direction is determined, each of these characteristic values is compared, and based on the result, it is determined whether or not this image is overturned.

(Function) The human body is composed of various bones, muscles, and other organs, and the degree of transmission or reflection of radiation, ultrasound, etc. varies depending on the organ. For example, bones that normally extend along the vertical direction of the human body have a property that radiation is less likely to pass through them compared to other parts of the human body. Also,
Radiation that passes through the human body is weakened by the body compared to radiation that does not pass through the surrounding human body. Furthermore, since the human body is substantially left-right symmetrical, these images are often substantially left-right symmetrical (if the image is overturned, it is symmetrical on the road).

Therefore, in these cases, including near the center of the image,
When the characteristic values of the image signal levels of the strip-shaped areas extending in the vertical direction and the horizontal direction are determined, there are clear differences between the characteristic values, and based on this difference, it is possible to determine whether the image is in the normal position or rotated by 90 degrees from the normal position. It becomes possible to determine whether the vehicle is at a rollover position.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory diagram illustrating an embodiment in which the present invention is applied to a radiographic image centered on the neck of a human body obtained by the above-mentioned radiographic image recording and reproducing apparatus proposed by the present applicant using a total value as a characteristic value. It is a diagram. In this image, the human body image 1 is a portion where radiation is absorbed and weakened by the human body compared to the surrounding area 2. Therefore, if the image signal is formed so that the level of the image signal carrying image information is proportional to the dose of radiation applied to the stimulable phosphor sheet, the image signal level corresponding to the human body image 1 is: It is lower than the image signal level corresponding to the surrounding region 2.

Here, when comparing the respective total values of the image signal levels of each band-shaped area 3.4, it is found that the band-shaped area 3 contains many human body images 1,
The surrounding region 2 is only slightly included, while the strip region 4
contains a large amount of the surrounding area 2, and the human body image 1 contains only a small portion, so if each band-shaped area 3.4 has approximately the same area (number of pixels), each sum of the image signal level Regarding the values, the total value corresponding to band-shaped area 4 is larger than the total value corresponding to band-shaped area 3. Therefore, by comparing each total value, if the area corresponding to the larger value is an area extending in the horizontal direction, this image is in the normal position, and the area corresponding to the larger value is an area extending in the vertical direction. If
This image can be determined to be in a rollover position.

When the total value is used as the characteristic value as described above, it is preferable that the area of each band-shaped region extending vertically and horizontally be approximately equal, but even if the area differs depending on the part of the human body being photographed, This does not apply if the above magnitude relationship is stable.

FIG. 2 is an explanatory diagram illustrating an embodiment in which the present invention is applied to a radiographic image of a human chest. In this embodiment, the average value is used as the characteristic value of the image signal level extending in the vertical and horizontal directions. is used. The mediastinum 5, which extends vertically in the center, has many bones with low radiolucency. On the other hand, the lung field 6 has a higher radiotransmittance than the mediastinum 5 on average. Therefore, if the image signal is formed so that the amount of radiation transmitted through the human body is proportional to the image signal level, the image signal level of the mediastinum 5 is lower on average than the image signal level of the lung field 6. Therefore, the average value of the image signal level of the band-shaped region 8 which relatively has a large portion in the lung field 6 and a small portion in the mediastinum 5 is as follows. It is larger than the average value of the image signal level in area 7. Therefore, in this example as well, if the above average value for the strip-shaped area extending in the horizontal direction is larger than the above-mentioned average value for the strip-shaped area extending in the vertical direction, this image is in the normal position; When the average value of the vertically extending strip area is larger, it can be determined that the vehicle is in a rollover position.

The width of the strip area 7.8 shown in FIG. 2 is narrower than that of the strip area 3.4 shown in FIG. The difference between the two average values may be set in advance so as to be the most stable and large, depending on the relative size of the average value and the photographed body part.

In addition, when the average value is adopted as the characteristic value, the area of each strip-shaped region extending vertically and horizontally may be different, and the area of each strip-shaped region extending vertically and horizontally may be different, and the area of each strip-shaped region is All you have to do is determine the area.

The characteristic values that can be adopted in the present invention are not limited to the total value and average value described in the above embodiments. Any characteristic value may be used as long as it can extract characteristic values from the image signals of the above two band-shaped regions and stably determine whether or not the image is overturning based on the extracted characteristic values. .

Furthermore, the present invention is not limited to the parts described in the above embodiments, but can be applied to all parts where it is possible to stably determine whether or not an image has rolled over based on the characteristic values of the image signal levels of the two band-shaped regions. can do. Further, the application of the present invention is not limited to radiographic images, but may also be radiographic reflection images or images obtained by irradiating the human body with ultrasound, and it does not matter by what means the image signal of the human body was obtained. It doesn't matter.

(Effects of the Invention) The method for determining rollover of an image according to the present invention calculates each characteristic value of the image signal level of a strip-shaped region that includes the vicinity of the center of the image and extends in the vertical and horizontal directions, and compares each characteristic value. Based on the results, it is determined whether the image is in the normal position or in the overturned position, so depending on the part of the human body being photographed, the relative size of the photographed screen and the part of the human body being photographed, etc. By setting the width of each band-shaped area in advance and setting in advance which is the normal position and which is the rollover position based on the results of comparing each of the above characteristic values, it is possible to easily and accurately adjust the width accordingly. It can be determined whether the image is in the normal position or in the overturned position.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram illustrating an embodiment in which the present invention is applied to a radiographic image of the neck, and FIG. 2 is an explanatory diagram illustrating an embodiment in which the present invention is applied to a radiographic image of the chest. 1... Image of human body 2... Surrounding area 3, 4.
7.8... Band-shaped region 5... Mediastinum 6... Lung field Figure 1 Figure 2

Claims (3)

[Claims] (1) From an image signal carrying image information of a human body, obtain each characteristic value of the image signal level of a band-shaped region including the vicinity of the center of this image and extending in the vertical and horizontal directions, and compare the two characteristic values, A method for determining rollover of an image, comprising determining whether or not the image has rolled over based on the result. (2) The image horizontal determination method according to claim 1, wherein the characteristic value is a total value, and the determination is made based on which value of each total value is larger. (3) The image rollover determination method according to claim 1, wherein the characteristic value is an average value, and the determination is made based on which of the average values is larger.