Image processing system

Abstract

To provide an image processing system that can improve contrast in a part to observe of an acquired X-ray image.SOLUTION: An image processing system generates an X-ray image by processing a read signal that is read from an image plate in which a radiography image is recorded. The image processing system processes a signal so that a change degree of density relating to part of a target region in accordance with an objective of observation relative to the whole output zone included in a read signal becomes larger than a change degree of density relating to a non-target region other than the target region.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] In particular, the present disclosure relates to image processing and an image processing device that processes a read signal read from an image plate on which an X-ray image is recorded to generate an X-ray image. [Background technology]

[0002] Conventionally, there is known a technique for reading an imaging plate (abbreviated as IP) on which a latent image is recorded by exposure to X-rays, and performing image processing of the X-ray image (see, for example, Patent Document 1). The reading device irradiates the imaging plate with laser light, detects photostimulated luminescence excited by the irradiation of the laser light, performs processes such as logarithmic conversion amplification and A / D conversion, and outputs a digital signal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-172362 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned conventional technology, the read signal obtained by detecting the photostimulated luminescence is subjected to processes such as logarithmic conversion, amplification, and A / D conversion. However, in the conventional technology, a dull image is generated depending on the purpose of the observation. A dull image is an image in which the contrast in the area to be observed is not clear and is vague (blurred).

[0005] The present disclosure describes an image processing system capable of improving the contrast of an area of ​​interest to be observed in an obtained X-ray image. [Means for solving the problem]

[0006] One aspect of the present disclosure is an image processing system that processes a read signal read from an image plate on which an X-ray image is recorded to generate an X-ray image, and performs signal processing so that, for the entire output range contained in the read signal, the degree of change in shading for a portion of a region of interest according to the purpose of observation is greater than the degree of change in shading for non-regions other than the region of interest.

[0007] According to this image processing system, the degree of change in shading is increased only in a portion of the target area according to the purpose of observation among the entire output range included in the read signal, thus improving the contrast of the area to be observed in the obtained X-ray image.

[0008] The image processing system may perform signal processing using logarithmic transformation, which makes it easier to see changes in shading even when the radiation intensity is low, for example. This makes it possible to obtain clinically useful X-ray images.

[0009] The image processing system may set the region of interest and the region of non-interest so that the dose intensity region corresponding to the region of interest is on the lower dose side than the dose intensity region corresponding to the region of non-interest. In this case, the contrast of the low dose side (region of interest) is emphasized at the expense of the contrast of the high dose side (region of non-interest). This allows high contrast to be achieved in regions with low dose intensity.

[0010] The image processing system may set the regions of interest and non-interest so that the dose intensity region corresponding to the region of interest is on the higher dose side than the dose intensity region corresponding to the non-interest region. In this case, the contrast of the high dose side (region of interest) is emphasized at the expense of the contrast of the low dose side (region of non-interest). This allows high contrast to be achieved in regions with high dose intensity.

[0011] The image processing system may set the region of interest and the region of non-interest such that the region of non-interest includes a first region of non-interest having a dose intensity range that is on the lower dose side than the dose intensity range corresponding to the region of interest, and a second region of non-interest having a dose intensity range that is on the higher dose side than the dose intensity range corresponding to the region of interest. In this case, the region of interest corresponding to a desired dose intensity range is set, and emphasis is placed on the contrast in the region of interest.

[0012] The image processing system may perform signal processing so that the non-attentional areas are displayed with a constant density by eliminating the degree of change in density in the non-attentional areas. In this case, the attentional areas and the non-attentional areas can be more clearly differentiated. The image parts corresponding to the non-attentional areas become images with uniform density and no contrast, while the image parts corresponding to the attentional areas become images with large density changes and clearer contrast.

[0013] The image processing system may perform signal processing on the analog signal before it is converted from analog to digital. If signal processing is performed on the digital signal, small differences in the output value may disappear. By performing signal processing on the area of ​​interest before (prior to) the analog to digital conversion, the differences in the analog signal can be reflected in the shading of the X-ray image.

[0014] Another aspect of the present disclosure is an image processing system that processes detection signals obtained by X-ray photography to generate an X-ray image, and performs signal processing so that, for the entire output range contained in the detection signal, the degree of change in shading for a portion of a region of interest corresponding to the purpose of observation is greater than the degree of change in shading for non-regions of interest other than the region of interest.

[0015] According to this image processing system, the degree of change in shading is increased only in a portion of the target area according to the purpose of observation among the entire output range included in the detection signal, thereby improving the contrast of the area to be observed in the obtained X-ray image. Effect of the Invention

[0016] According to some aspects of the present disclosure, it is possible to improve the contrast of a region to be observed in an obtained X-ray image. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of an image processing system according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a diagram showing a more specific configuration of the image processing system of FIG. [Diagram 3] FIG. 3 is a block diagram showing an example of the configuration of an image processing unit (image processing device). [Figure 4] FIG. 4 is a flow diagram of basic processing executed in the image processing system. [Diagram 5] FIG. 5 is a flow diagram showing an example of processing executed in the image processing system. [Figure 6] FIG. 6(a) is a diagram showing the characteristics of an analog signal, and FIG. 6(b) is a diagram showing the degree of change in output after signal processing. [Figure 7] FIG. 7(a) is a diagram showing the characteristics of an analog signal, and FIG. 7(b) is a diagram showing the degree of change in output after signal processing. [Figure 8] FIG. 8 shows an aluminum staircase phantom having a thickness of multiple steps. [Figure 9] 9(a) and 9(b) are diagrams showing the degree of change in shading when the signal processing of the present disclosure is not performed (no correction). [Figure 10] Figures 10(a) and 10(b) are figures showing the degree of change in shading when the area of ​​interest is set on the low-dose side (area with high X-ray absorption), and Figure 10(c) is a figure showing an example of an X-ray image in dental treatment in this case. [Figure 11] Figures 11(a) and 11(b) are figures showing the degree of change in shading when a region of interest is set on the high-dose side (region with low X-ray absorption), and Figure 11(c) is a figure showing an example of an X-ray image in dental treatment in this case. [Figure 12]FIG. 12(a) is a diagram showing the change in each step when no correction is performed, and FIG. 12(b) is a diagram showing the change in each step when correction is performed. [Figure 13] FIG. 13 is a block diagram showing another example of the configuration of the image processing unit (image processing device). [Figure 14] FIG. 14(a) is a diagram showing the characteristics of an analog signal, and FIG. 14(b) is a diagram showing the degree of change in output after signal processing in the configuration example of FIG. [Figure 15] FIG. 15 is a flow chart showing another example of the processing executed in the image processing system. [Figure 16] FIG. 16(a) is a diagram showing an example of an object, and FIG. 16(b) and FIG. 16(c) are diagrams showing examples of intensity detection. [Figure 17] 17(a) is a diagram showing the characteristics of an analog signal, and FIG. 17(b) is a diagram showing the degree of change in output after signal processing in the configuration example of FIG. [Figure 18] FIG. 18(a) is a diagram showing the characteristics of an analog signal, and FIG. 18(b) is a diagram showing the degree of change in output after signal processing in the configuration example of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated description will be omitted.

[0019] The basic configuration of an image processing system S of this embodiment will be described with reference to Fig. 1. The image processing system S is used, as an example, for X-ray photography in dental treatment. In dental treatment, an image plate 100 is placed in the oral cavity of a patient, and X-ray photography of the oral cavity is performed. An X-ray photographed image is recorded on the image plate 100. An image plate is sometimes called an imaging plate, and therefore may be referred to as an imaging plate.

[0020] As shown in FIG. 1, the image processing system S is a system that processes a read signal read from an image plate 100 (see FIG. 2) on which an X-ray image is recorded to generate an X-ray image. The image processing system S includes an IP excitation module 11, an image processing section 2, a main control section 20, an operation section (physical interface) 4, and a display section (display) 3. The IP excitation module 11 irradiates the image plate 100 with excitation light to scan the image plate 100 and detects photostimulated luminescence occurring in the image plate 100. The IP excitation module 11 has, for example, a photodiode array and an amplifier, and outputs a read signal of the X-ray image based on the obtained luminance information. A known configuration may be adopted as the IP excitation module 11. The IP excitation module 11 may be configured as a combination of a light source of excitation light and a scanner of photostimulated luminescence, and may be expressed as a light source-scanner 11. The main control section 20 has a CPU 20a and controls each section of the image processing system S. The operation unit 4 has operation buttons or a touch panel display, etc., and accepts operations by an operator. The operation unit 4 outputs a signal according to the input operation content to the main control unit 20. The image processing unit 2 has a CPU 2a, and is controlled by the main control unit 20 to perform various calculations related to image processing. The image processing unit 2 performs analog-to-digital conversion and synthesis processing, etc. on the read signal to generate an X-ray image. The main control unit 20 displays the X-ray image on the display unit 3. The image processing unit 2 may also function as the main control unit 20. The main control unit 20 may be configured as a circuit, and may be expressed as a main control circuit 20. The image processing unit 2 may be configured as a circuit, and may be expressed as a sub-image processing circuit 2.

[0021] The image processing system S may have the above-mentioned configuration integrated, or, for example, the IP excitation module 11 and a part of the image processing unit 2 may be integrated, and the other part of the image processing unit 2 and the display unit 3 may be integrated, and these may be communicatively connected by wiring or a network, etc. (see FIG. 2). In this case, the operation unit 4 may be provided in both. The image processing system S may be composed of a circuit. The image processing system S may be expressed as an image processing circuit S. Each component of the image processing system S may be integrated and built into, for example, a case or a housing. In that case, the image processing system S is configured as an "image processing device". In other words, the image processing system S may be expressed as an image processing device S. Next, a specific configuration example of the image processing system S will be described with reference to Fig. 2. In the following description, the image plate 100 will be abbreviated as IP100.

[0022] The image processing system S shown in FIG. 2 includes a first image processing device 10 and a second image processing device 30. The first image processing device 10 and the second image processing device 30 are connected by wiring or a network, etc., and can communicate with each other through input / output interfaces 25, 35. The first image processing device 10 has an IP excitation module 11, a first image processing unit 18 including a CPU 19, a main control unit 21 including a CPU 22, a display unit 23, an operation unit 24, and an input / output interface 25. The second image processing device 30 has a second image processing unit 28 including a CPU 29, a main control unit 31 including a CPU 32, a storage unit (memory) 36, a display unit (display) 33, an operation unit (physical interface) 34, and an input / output interface 35. The display unit 23 and the display unit 33 correspond to the display unit 3 in FIG. 1. The operation unit 24 and the operation unit 34 correspond to the operation unit 4 in FIG. 1.

[0023] The first image processing device 10 may be configured as a circuit and may be expressed as a first image processing circuit 10. The second image processing device 30 may be configured as a circuit and may be expressed as a second image processing circuit 30. The first image processing unit 18 may be configured as a circuit and may be expressed as a first sub-image processing circuit 18. The second image processing unit 28 may be configured as a circuit and may be expressed as a second sub-image processing circuit 28. The main control unit 21 may be configured as a circuit and may be expressed as a first main control circuit 21. The main control unit 31 may be configured as a circuit and may be expressed as a second main control circuit 31. The CPU 19 may be expressed as a first image processing processor 19. The CPU 22 may be expressed as a first main control processor 22. The CPU 29 may be expressed as a second image processing processor 29. The CPU 32 may be expressed as a second main control processor 32.

[0024] The IP excitation module 11 includes an IP receiving section 12 that receives the IP 100, an excitation light irradiating section (excitation light source) 14 that irradiates the IP 100 in the IP receiving section 12 with excitation light, and a light receiving section (light receiver) 16 that receives the light generated by the excitation light irradiating section 14. The light receiving section 16 outputs a read signal of the X-ray image to a first image processing section 18. The first image processing section 18 and the second image processing section 28 correspond to the image processing section 2 in FIG. 1. The first image processing section 18 and the second image processing section 28 execute a predetermined image processing step. The processing performed by the first image processing section 18 and the second image processing section 28 will be described later. The second image processing device 30 displays the X-ray image output from the second image processing section 28 on a display section 33 and outputs it to an external device 39.

[0025] A configuration example of the image processing unit 2 will be described with reference to FIG. 3. As shown in FIG. 3, the first image processing unit 18 of this embodiment has an analog-digital conversion unit 40 that performs analog-digital conversion on the read signal output from the IP excitation module 11. The first image processing unit 18 has the analog-digital conversion unit 40, and performs signal processing on the analog signal before analog-digital conversion. In particular, in this embodiment, the analog-digital conversion unit 40 sets some attention areas RV11, RP11 (R1) according to the purpose of observation, and non-attention areas RV2a, RP2a, RV2b, RP2b (R2) other than the attention area R1, for the entire output area included in the read signal (see FIG. 6(a)). The non-attention areas RV2a, RP2a are dose intensity areas that exist on the lower dose side than the dose intensity area corresponding to the attention area R1, and the non-attention areas RV2b, RP2b are dose intensity areas that exist on the higher dose side than the dose intensity area corresponding to the attention area R1. For example, among the non-attention areas, the first non-attention areas RV2a and RP2a, which have lower output values, can be determined to be represented by a uniform adjusted output value (e.g., white), and the second non-attention areas RV2b and RP2b, which have higher output values, can be determined to be represented by a uniform adjusted output value (e.g., black). For the attention area R1, a process for optimizing the contrast is performed (see FIG. 6(b)). The first non-attention area RP2a may be set to an offset value OF. According to such signal processing (image processing), it is possible to avoid unnecessary calculation burdens and to effectively use the limited number of bits in the calculation of the processor. In the graph, the elements on the vertical axis are represented by inserting the letter P, and the elements on the horizontal axis are represented by inserting the letter V. The analog-to-digital conversion unit 40 may be configured as a circuit, and may be represented as an analog-to-digital conversion circuit 40.

[0026] The original output pattern versus dose, without the output adjustment process according to the present configuration, is called the original output pattern OR, and this original output pattern OR is shown by the original output pattern line ORL on the graph as shown in Fig. 6(a). The image processing unit 2 performs signal processing on the analog signal. The output pattern versus dose, which is adjusted after signal processing, is called the adjusted output pattern AJ, and this adjusted output pattern AJ is shown by the adjusted output pattern line AJL on the graph as shown in Fig. 6(b). In the original output pattern OR, the low dose region includes many areas where the output value changes little in response to a change in dose value, and the high dose region includes many areas where the output value changes sharply in response to a change in dose value.

[0027] Therefore, it is possible to perform signal processing so that the degree of change in the adjusted output pattern AJ is greater (steeper) in areas where the output value changes little in response to changes in dose value in the original output pattern OR, i.e., areas where the degree of change in shading is small.

[0028] More preferably, it is possible to perform signal processing so that the degree of change in the adjusted output pattern AJ is smaller (more gradual) in areas where the output value changes sharply in response to changes in dose value in the original output pattern OR, i.e., areas where the degree of change in shading is steep. Figure 6(b) shows an example of a linear adjustment pattern that has been subjected to such processing. The upper limit value RH and the lower limit value RL of the adjusted output pattern AJ can be appropriately determined, but the upper limit value RH and the lower limit value RL may also be adapted to the minimum and maximum values ​​of the attention region R1 in the original output pattern OR as shown in the figure.

[0029] In contrast to the adjustment pattern that is linear over the entire wide attention region R1 as shown in FIG. 6, it is possible to limit the attention region R1 and perform signal processing so that the degree of change in shading for non-attention regions is greater (steeper) than the degree of change in shading for non-attention regions. FIG. 7(b) shows an example of such adjustment processing. In FIG. 7, the range of attention regions RV12, RP12 (R1) is limited to a lower dose side region than the example of R1 shown in FIG. 6. The analog-to-digital conversion unit 40 performs signal processing so that the degree of change in shading for the attention region is greater (steeper) than the degree of change in shading for non-attention regions R2 (RV2c, RP2c, RV2d, RP2d). The degree of change in shading for non-attention regions is gentler than the degree of change in shading for attention regions. The upper limit value RH and the lower limit value RL of the adjusted output pattern AJ can be determined appropriately, but the upper limit value RH and the lower limit value RL may be set to the width between the upper limit value and the lower limit value of the adjusted output pattern AJ in Fig. 6 as shown in the figure. The adjustment process will be described in detail later.

[0030] The analog-to-digital conversion unit 40 includes a logarithmic converter 41 and a first analog-to-digital converter 42. The logarithmic converter 41 performs logarithmic conversion on the read signal. The signal processing for making the degree of change in shading between the target area and the non-target area steeper or gentler is performed before the analog-to-digital conversion by the analog-to-digital converter 42. The signal processing may be performed before or after the logarithmic conversion by the logarithmic converter 41.

[0031] The second image processing unit 28 includes a synthesis processing unit 50. The synthesis processing unit 50 receives the digital signal output from the first analog-digital converter 42, and outputs X-ray image data (data of the synthesis image P). The synthesis processing unit 50 may be configured as a circuit, and may be expressed as a synthesis processing circuit 50.

[0032] Next, referring to FIG. 4, the basic processing executed in the image processing system S will be described. As shown in FIG. 4, the image processing unit 2 (see FIG. 1) acquires scan image data (read signal) from the IP excitation module 11 (step S020). The image processing unit 2 generates and displays a default image (step S030). Then, the operation unit 4 is operated, and the main control unit 20 accepts the operation (step S040). The main control unit 20 reads out the processing (step S060). The image processing unit 2 executes image processing based on the acquired scan image data (step S070). The image processing unit 2 generates an X-ray image, and the main control unit 20 causes the display unit 3 to display the X-ray image (step S080). The main control unit 20 accepts other operations (step S090). If other operations are accepted, the main control unit 20 returns to the processing of step S060. The scanned image data may be stored in the storage unit 36, and the scanned image data may be acquired from the storage unit 36 ​​when returning to the processing of step 060. If no other operations have been received, the image processing unit 2 ends the series of processes (step S100). In the image processing system S shown in FIG. 2, the processing performed by the image processing unit 2 is performed by the first image processing unit 18 and / or the second image processing unit 28. In the image processing system S shown in FIG. 2, the processing performed by the main control unit 20 is performed by the main control unit 21 and / or the main control unit 31.

[0033] Here, with reference to FIG. 8, an important concept in the image processing system S according to the present disclosure, that is, differences in the X-ray penetration dose (dose intensity) according to the observation part of the object, will be described. As shown in FIG. 8, an aluminum staircase phantom AL simulating an object to be X-rayed (for example, a patient's teeth or oral cavity, etc.) can be provided. In the aluminum staircase phantom AL, for example, aluminum plates are stacked to form a staircase so that the thickness of the aluminum varies over 10 stages including zero aluminum. In the thick aluminum part, more X-rays are absorbed and a smaller X-ray penetration dose is obtained. In the thin aluminum part, less X-rays are absorbed and a larger X-ray penetration dose is obtained. In the aluminum staircase phantom AL, for example, a low-dose side region RA (high X-ray absorption region) and a high-dose side region RB (low X-ray absorption region) are assumed.

[0034] When the aluminum step phantom AL is X-rayed and processed as described with reference to FIG. 6 including logarithmic transformation, a tendency is obtained in which the dose intensity increases stepwise as the thickness decreases, for example, as shown in FIG. 9(a). If the thickness changes continuously, rather than stepwise, the dose intensity may change linearly with the thickness. Thus, in normal image processing (stepwise processing), brightness differences are generated uniformly across the entire output range. In this embodiment, brightness differences are generated only in the region of interest.

[0035] Characteristic and specific processing in the image processing system S of this embodiment will be described with reference to each figure from FIG. 5 onwards. The same parts as those in FIG. 4 will not be described. As shown in FIG. 5, the image processing unit 2 executes different processing depending on the contents of the operation input in step S040. The main control unit 20 judges what operation has been accepted in step S040 (step S050). The types of operations that can be accepted include a first designation and a second designation. The first designation is an operation in which, for example, periodontium, endodontic, or caries is designated as a part of the attention area according to the purpose of observation. The second designation is an operation in which, for example, anterior teeth or molars are designated as a part of the attention area according to the purpose of observation.

[0036] When the first designation is accepted, the main controller 20 reads out the first processing (step S060-1). The image processor 2 executes image processing suitable for the first processing (step S070-1). In step S070-1, the image processor 2 sets the region of interest and the region of non-interest so that the dose intensity region corresponding to the region of interest is on the lower dose side than the dose intensity region corresponding to the region of non-interest. For example, the image processor 2 sets the region of interest to an area with an output of less than 60 shown in FIG. 9, that is, the low-dose side area RA (high X-ray absorption area) shown in FIG. 8 and FIG. 10. The image processor 2 sets the region of interest to an area with an output of 60 or more shown in FIG. 9, that is, an area other than the low-dose side area RA shown in FIG. 8 and FIG. 10. The image processor 2 may perform signal processing so that the region of non-interest is represented with a constant density by eliminating the degree of change in shading regarding the region of non-interest. That is, the image processor 2 may perform logarithmic conversion and analog-to-digital conversion only on the analog signal in the region of interest. The above image processing is executed, for example, by the analog-to-digital converter 40 of the first image processor 18. The image processor 2 generates an X-ray image suitable for the first processing, and the main controller 20 causes the display unit 3 to display the X-ray image (step S080-1). The main controller 20 accepts other operations (step S090-1). If other operations have been accepted, the main controller 20 returns to the judgment process of step S050.

[0037] When the first designation is accepted, as shown in FIG. 10(a), the first image processor 18 performs signal processing so that the degree of change in shading in the low-dose side region RA is greater than the degree of change in shading in the regions other than the low-dose side region RA (see FIG. 10(b)). In this signal processing, when the detected X-ray dose intensity is taken on the horizontal axis and the output (pixel value) is taken on the vertical axis, the degree of change in shading in the low-dose side region RA is steeper than the degree of change in shading in the regions other than the low-dose side region RA. In the high-dose side region, which is a non-interesting region, the output (pixel value) is represented by a constant density. As shown in FIG. 10(b), the high-dose side region, which is a non-interesting region, is represented by a uniform black color in the X-ray image. In this way, the dose intensity (value expressed in mGy) obtained as an analog signal is not equally divided by a limited number of bits (65,535 for 16 bits), but the dose intensity in the low-dose side region RA, which is the region of interest, is equally divided, so that the contrast resolution of the region to be observed is optimized according to the purpose of observation. For example, as shown in Fig. 10(c), this type of image processing is suitable for observing the cervical region Y, and although details of the high-dose side region such as the periodontal region become difficult to see, caries, etc. in the cervical region Y can be easily found.

[0038] When the second designation is accepted, the main controller 20 reads out the second processing (step S060-2). The image processor 2 executes image processing suitable for the second processing (step S070-2). In step S070-2, the image processor 2 sets the region of interest and the region of non-interest so that the dose intensity region corresponding to the region of interest is on the higher dose side than the dose intensity region corresponding to the region of non-interest. For example, the image processor 2 sets the region of interest to an area having an output of 40 or more as shown in FIG. 9, that is, the high dose side region RB (low X-ray absorption region) as shown in FIG. 8 and FIG. 10. The image processor 2 sets the region of non-interest to an area having an output of less than 40 as shown in FIG. 9, that is, a region other than the high dose side region RB as shown in FIG. 8 and FIG. 10. The image processor 2 may perform signal processing so that the region of non-interest is represented by a constant density by eliminating the degree of change in shading regarding the region of non-interest. That is, the image processor 2 may perform logarithmic conversion and analog-to-digital conversion only on the analog signal in the region of interest. The above image processing is executed, for example, by the analog-to-digital converter 40 of the first image processor 18. The image processor 2 generates an X-ray image suitable for the second processing, and the main controller 20 causes the display unit 3 to display the X-ray image (step S080-2). The main controller 20 accepts other operations (step S090-2). If other operations have been accepted, the main controller 20 returns to the judgment process of step S050.

[0039] When the second designation is accepted, as shown in FIG. 11(a), the first image processor 18 performs signal processing so that the degree of change in shading in the high-dose side region RB is greater than the degree of change in shading in the regions other than the high-dose side region RB (see FIG. 11(b)). In this signal processing, when the horizontal axis represents the detected X-ray dose intensity and the vertical axis represents the output (pixel value), the degree of change in shading in the high-dose side region RB is steeper than the degree of change in shading in the regions other than the high-dose side region RB. In the low-dose side region that is a non-interesting region, the output (pixel value) is represented by a constant density. As shown in FIG. 11(b), the low-dose side region that is a non-interesting region is represented by a uniform white color in the X-ray image. In this way, the dose intensity (value expressed in mGy) obtained as an analog signal is not equally divided by a limited number of bits (65,535 for 16 bits), but the dose intensity in the high-dose side region RB, which is the region of interest, is equally divided, so that the contrast resolution of the region to be observed is optimized according to the purpose of observation. For example, as shown in Fig. 11(c), this type of image processing is suitable for observation around the root apex Z, and although details in the low-dose side region such as the tooth neck region become difficult to see, apical lesions around the root apex Z can be easily found.

[0040] As described above, the degree of change in shading in the region of interest in the X-ray image becomes steeper due to the signal processing by the first image processor 18. This can be easily understood from the steep degree of change in shading as shown in Fig. 12(b) compared to the uniform degree of change in shading as shown in Fig. 12(a) using the aluminum staircase phantom AL as an example.

[0041] According to the image processing system S of this embodiment, the degree of change in shading becomes large only in a part of the target area according to the purpose of observation among the entire output range included in the read signal. Therefore, the contrast of the part to be observed in the obtained X-ray image is improved.

[0042] The image processing system S may perform signal processing using logarithmic transformation. Logarithmic transformation makes it easier to see changes in shading even when the intensity of the radiation is low, such as in the low-dose region RA. This makes it possible to obtain X-ray images that are easy to handle clinically.

[0043] As shown in Fig. 10(a), the region of interest and the region of non-interest can be set so that the dose intensity region corresponding to the region of interest is on the lower dose side than the dose intensity region corresponding to the region of non-interest. As shown in Fig. 10(b), the contrast of the low dose side (region of interest) is emphasized at the expense of the contrast of the high dose side (region of non-interest). This allows high contrast to be achieved in the region of low dose intensity. If the image processing system S is applied to dental treatment, it is effective for detecting caries in observing the cervical region Y, as shown in Fig. 10(c).

[0044] As shown in Fig. 11(a), the region of interest and the region of non-interest can be set so that the dose intensity region corresponding to the region of interest is on the higher dose side than the dose intensity region corresponding to the region of non-interest. As shown in Fig. 11(b), the contrast of the high dose side (region of interest) is emphasized at the expense of the contrast of the low dose side (region of non-interest). This allows high contrast to be achieved in the region of high dose intensity. If the image processing system S is applied to dental treatment, it is effective for detecting apical lesions in observing the apex Z, as shown in Fig. 11(c).

[0045] In addition, the image processing system S performs signal processing so that the degree of change in shading in non-attentional areas is eliminated and non-attentional areas are displayed with a constant density. This makes it possible to further enhance the contrast between attentional areas and non-attentional areas. The image parts corresponding to non-attentional areas become images with uniform color (density) and no contrast, while the image parts corresponding to attentional areas become images with large density changes and clearer contrast.

[0046] Furthermore, the image processing system S performs signal processing on the analog signal before it is converted from analog to digital. When signal processing is performed on a digital signal, small differences in the output value may disappear. By performing signal processing on the area of ​​interest before (prior to) the analog to digital conversion, small differences in the analog signal can be reflected in the shading of the X-ray image.

[0047] The configuration of the image processing unit may be different from that of the above embodiment. FIG. 13 is a block diagram showing another configuration example of the image processing unit. As shown in FIG. 13, a first image processing unit 18A having a distributor 17, a first analog-digital conversion unit 40A including a logarithmic converter 41A and a first analog-digital converter 42A, and a second analog-digital conversion unit 60 including a second analog-digital converter 62 may be applied. In that case, a second image processing unit 28A having a synthesis processing unit 50 including a logarithmic conversion processing unit 51 and a synthesis unit 53 may be applied. The logarithmic conversion processing unit 51 may be configured to process a signal from the second analog-digital converter 62 by digital calculation. The first image processing unit 18A and the second image processing unit 28A form an image processing unit 2A. The first analog-digital conversion unit 40A may be configured as a circuit, and may be expressed as a first analog-digital conversion circuit 40A. The second analog-digital conversion unit 60 may be configured as a circuit, and may be expressed as a second analog-digital conversion circuit 60. The logarithmic conversion processing unit 51 may be formed by a circuit, and may be expressed as a logarithmic conversion processing circuit 51. The synthesis unit 53 may be formed by a circuit, and may be expressed as a synthesis circuit 53.

[0048] In the image processing system S having the above configuration, the first analog-digital conversion unit 40A performs a first analog-digital conversion adapted to a signal range of relatively low dose intensity for the entire output range included in the read signal, and the second analog-digital conversion unit 60 performs a second analog-digital conversion adapted to a signal range of relatively high dose intensity. The first analog-digital conversion unit 40A includes a logarithmic converter 41A and performs a logarithmic conversion on the read signal. Since the degree of change in output is small relative to the degree of change in dose for a signal range of relatively low dose intensity, conversion is performed so that this degree is increased. This conversion is performed before the analog-digital conversion. The logarithmic converter 41A is an example of this configuration, and the degree of change in output may be increased by using an element such as an amplifier that converts the gain of the input signal without using the logarithmic converter 41A. Then, the synthesis processing unit 50 performs image processing to synthesize both converted signals. In this case, the correction value shown in FIG. 10(a) and the correction value shown in FIG. 11(a) are combined to perform image processing, and clear contrast can be obtained in both the low-dose side area RA and the high-dose side area RB. As shown in FIG. 14(a) and FIG. 14(b), analog-to-digital conversion and logarithmic conversion are performed for each of the first attention area R1a and the second attention area R1b, and an advantageous X-ray image can be obtained according to each signal area. The adjusted output pattern AJ shown in FIG. 14(b) has a constant density in the high-dose area. In this way, depending on the diagnostic purpose, it is also possible to mix parts with steep and gradual output changes in the attention area.

[0049] The signal processing executed by the image processing unit 2 will be described with reference to Figs. 13, 16(a) to 16(c), 17(a), 17(b), 18(a) and 18(b).

[0050] Assume that there is an object TOB whose thickness increases in an arithmetic progression from thin to thick, as shown in FIG. 16(a). The object TOB is made of a material such as aluminum, which transmits X-rays to a certain degree. When this object TOB is irradiated with X-rays, the X-rays are absorbed according to the thickness, and the amount of transmitted X-rays received by the X-ray detection element such as IP is small for irradiation of thick parts and large for irradiation of thin parts. If this intensity is detected without output adjustment, it will be as shown in FIG. 16(b). For example, the intensity detection may be detection of the output of the signal intensity received from the light receiving unit 16. FIG. 16(b) shows a graph in which the left side corresponds to a large thickness, i.e., a low dose, and the right side corresponds to a small thickness, i.e., a high dose, in the read signal. Such an original output pattern for the dose, without the processing of output adjustment by the present configuration described later, is called an original output pattern OR, and this original output pattern OR is shown by an original output pattern line ORL on the graph as shown in FIG. 16(b).

[0051] As can be seen by observing the original output pattern line ORL, the original output pattern OR includes many areas in which the degree of change in output value relative to a change in dose value is small in the low dose area, and many areas in which the degree of change in output value relative to a change in dose value is large in the high dose area. A region boundary BD (BVn, BPn) is set to divide the original output pattern OR into a low change region LSE, which is the region on the side where the degree of change in output value is small, and a high change region STE, which is the region on the side where the degree of change in output value is large. This boundary region may be set as a default, or may be variable by operation. The region boundary BD may be variably adjustable within the range of the variable region BDV. The low change region LSE and the high change region STE may be distinguished, for example, by the magnitude of the slope of the tangent line TG1 when the tangent line TG1 is defined to the original output pattern line ORL of the low change region LSE, and the magnitude of the slope of the tangent line TG2 when the tangent line TG1 is defined to the original output pattern line ORL of the high change region STE, for example, by whether it is smaller or larger than a reference ratio.

[0052] 16C, the low change region LSE and the high change region STE may overlap each other, that is, the high output side end of the low change region LSE may be higher than the low output side end of the high change region STE.

[0053] With reference to Figures 17(a) and 17(b), an application example based on the same idea as the embodiment shown in Figure 14 will be described. The only difference between Figures 17(a) and 17(b) and Figures 14(a) and 14(b) is that in Figure 17(b), there is a slight difference in the pattern of the second adjustment range A1b for the second output range R1b compared to Figure 14(b). The following ideas are common to Figures 17(a), 17(b) and Figures 14(a), 14(b). In the low-dose region, adjustments are made so that the change is steeper in the region where the degree of change in output value in response to a change in dose value is smaller. In the high dose region, adjustments are made so that the change is more gradual in the region where the degree of change in output value in response to a change in dose value is greater.

[0054] In order to optimize the degree of change in the original output pattern OR shown in Fig. 16(b), a first output region (first region of interest) R1a is set for the low change region LSE, and a second output region (second region of interest) R1b is set for the high change region STE, as shown in Fig. 17(a), and adjustment processing is performed for each as shown in Fig. 17(b). Note that the adjusted output pattern AJ related to the adjustment processing is shown by the adjusted output pattern line AJL on the graph as shown in Fig. 17(b). As an adjustment process, the first output range R1a (RV1a, RP1a) is adjusted to the first adjustment range A1a (AV1a, AP1a) so that the degree of change in the output value in the adjusted output pattern AJ is greater than the degree of change in the output value in the original output pattern OR, and the second output range R1b (RV1b, RP1b) is adjusted to the second adjustment range A1b (AV1b, AP1b) so that the degree of change in the output value in the adjusted output pattern AJ is smaller than the degree of change in the output value in the original output pattern OR. When the low change region LSE and the high change region STE shown in FIG. 16(c) partially overlap, the first adjustment range A1a and the second adjustment range A1b are adjusted to have continuity and consistency.

[0055] In Fig. 17, the second output range R1b is linearly processed over the entire range like the second adjustment range A1b, but as shown in Fig. 14(b), a uniform output value may be assigned to a part of the high dose side. The same is true for the first output range R1a, and a uniform output value may be assigned to a part of the low dose side. A uniform output value may be assigned to both a part of the low dose side of the first output range R1a and a part of the high dose side of the second output range R1b.

[0056] The image processor 2 sets a part of the attention area R1 (RV11, RP11) according to the purpose of observation for the whole output area included in the read signal, and a non-attention area R2 (RV2a+RV2b→RV2, RP2a+RP2b→RP2) other than the attention area R1 (see FIG. 17(a)). For example, it can be determined that the first non-attention area RV2a, RP2a with a lower output value among the non-attention areas R2 is represented by a uniform adjusted output value (for example, white), and the second non-attention area RV2b, RP2b with a higher output value is represented by a uniform adjusted output value (for example, black). An offset value OF may be assigned to the first non-attention area RP2a. The attention area R1 may be composed of a first output area R1a and a second output area R1b.

[0057] 17(b) shows an example of a linear adjustment pattern. The upper limit RH and lower limit RL of the adjusted output pattern AJ can be set appropriately, but may also be adapted to the width between the minimum and maximum values ​​of the attention region R1 in the original output pattern OR as shown in the figure.

[0058] This type of signal processing (image processing) can avoid the burden of unnecessary calculations and effectively use the limited number of bits available in the processor. Note that in the graph, the elements on the vertical axis are represented by inserting the letter P, and the elements on the horizontal axis are represented by inserting the letter V.

[0059] In contrast to the adjustment pattern that is linear over the entire wide attention region R1 as shown in FIG. 17, it is possible to limit the attention region R1 and perform signal processing so that the degree of change in shading in the attention region is greater (steeper) than the degree of change in shading in non-attention regions. FIG. 18(b) shows an example of such adjustment processing. In FIG. 18, the range of attention regions RV12, RP12 (R1) is limited to a higher dose side region than the example of R1 shown in FIG. 17. The analog-to-digital conversion unit 40 performs signal processing so that the degree of change in shading in the attention region is greater (steeper) than the degree of change in shading in non-attention regions. The degree of change in shading in non-attention regions is gentler than the degree of change in shading in the attention region. A gentle change includes cases where the degree of change is non-zero and cases where it is zero. The upper limit value RH and the lower limit value RL of the adjusted output pattern AJ can be set appropriately, but as shown in the figure, they may be set to match the upper limit value and the lower limit value of the adjusted output pattern AJ in Fig. 18. The adjustment process will be described in detail later.

[0060] The synthesis unit 53 synthesizes the digital signals that have been converted by the first analog-digital conversion unit 40A and the second analog-digital conversion unit 60, and generates a synthetic image P. The synthesis unit 53 inputs the digital signal from the first analog-digital converter 42A and the digital signal from the logarithmic conversion processing unit 51, and performs HDR (High Cynamic Range) synthesis.

[0061] As described above, in the image processing system S, the first analog-digital conversion unit 40A performs logarithmic conversion and first analog-digital conversion (first signal processing) for the entire output range included in the read signal, which is adapted to a signal range with a relatively low dose intensity. The second analog-digital conversion unit 60 performs second analog-digital conversion and logarithmic conversion (second signal processing) for a signal range with a relatively high dose intensity. In this way, the signal processing in the first analog-digital conversion unit 40A and the signal processing in the second analog-digital conversion unit 60 are different. Then, the synthesis processing unit 50A performs image processing to synthesize the signals after both conversions. In this case, the correction value shown in FIG. 10(a) and the correction value shown in FIG. 11(a) are combined to perform image processing, and clear contrast can be obtained in both the low dose side area RA and the high dose side area RB described above. As shown in Figures 17(a) and 17(b), analog-to-digital conversion and logarithmic conversion are performed for each of the first output range R1a and the second output range R1b, and advantageous X-ray images can be obtained according to each signal range.

[0062] According to the image processing system S of this embodiment, the first analog-digital conversion unit 40A performs first signal processing adapted to a first output range R1a (see FIG. 17(a)) having a relatively small output, and the second analog-digital conversion unit 60 performs second signal processing adapted to a second output range R1b (see FIG. 17(a)) having a relatively large output. The first signal processing converts signals corresponding to light colored parts in the X-ray image, and the second signal processing converts signals corresponding to dark colored parts in the X-ray image. By performing signal processing adapted to each output range and combining these, an X-ray image with good contrast can be obtained regardless of light and dark colored parts in the X-ray image.

[0063] Analog logarithmic conversion has several advantages. That is, with analog logarithmic conversion, data can be obtained in detail in the low-dose region. Also, when the data after logarithmic conversion is output as is, no digital noise occurs. In the image processing system S, the first analog-digital conversion unit 40A performs signal processing that is advantageous in the low-dose region. On the other hand, digital logarithmic conversion also has several advantages. That is, with digital logarithmic conversion, data can be obtained in detail in the high-dose region. Also, no electrical noise occurs. In the image processing system S, the second analog-digital conversion unit 60 performs signal processing that is advantageous in the high-dose region.

[0064] Furthermore, in the image processing system S, the first analog-to-digital converter 40A performs logarithmic conversion on the analog signal. When the first signal processing is performed on the digital signal, small differences in the output value may disappear. In particular, small differences in the output value are valuable information in light-colored areas. By performing signal processing on the first output range R1a before (prior to) the analog-to-digital conversion, the differences in the analog signal can be reflected in the shading in the X-ray image.

[0065] The first analog-digital conversion unit 40A performs signal processing so that the degree of change in shading for the first output region R1a is greater than the degree of change in shading for regions other than the first output region R1a, and the second analog-digital conversion unit 60 performs signal processing so that the degree of change in shading for the second output region R1b is greater than the degree of change in shading for regions other than the second output region R1b. Thus, the degree of change in shading becomes greater for each output region where the first and second signal processes are performed. As a result, the contrast is improved throughout the obtained X-ray image.

[0066] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, in the first signal processing, logarithmic conversion may be performed on the digital signal after analog-to-digital conversion. The second signal processing may include signal processing other than analog-to-digital conversion. In the above embodiment, the distributor 17 supplied the same read signal for the entire output range to each of the first analog-to-digital conversion unit 40A and the second analog-to-digital conversion unit 60. However, unlike this, the distributor 17 may supply a signal only in the first output range to the first analog-to-digital conversion unit 40A, and may supply a signal only in the second output range to the second analog-to-digital conversion unit 60. In other words, the distributor 17 may supply a read signal to each analog-to-digital conversion unit so as to distribute only a signal in an output range that can be advantageously signal-processed (adaptable) for each analog-to-digital conversion unit.

[0067] The image processing system of the present disclosure is not limited to a form that processes a read signal read from an image plate on which an X-ray image is recorded. The image processing system of the present disclosure may be an image processing system that processes a detection signal by X-ray photography to generate an X-ray image. The detection signal by X-ray photography is, for example, a detection signal output by a CCD or CMOS as an imaging element (semiconductor sensor). In this case, the image processing system may perform signal processing so that the degree of change in shading for a part of the attention area according to the purpose of observation is greater than the degree of change in shading for a non-attention area other than the attention area, for the entire output range included in the detection signal. The signal processing disclosed in the above embodiment may be applied to the detection signal output by the imaging element. Even in this case, the degree of change in shading is greater only for a part of the attention area according to the purpose of observation among the entire output range included in the detection signal. Therefore, the contrast of the part to be observed is improved in the obtained X-ray image.

[0068] 15, in step S040, the main control unit 20 may receive a first and a second operation (designation). In step S060, the main control unit 20 may read out a process that matches the combination of the first and second operations (designation). In this way, the image processing unit 2 may be configured to enable image processing according to multiple purposes.

[0069] The technical subject matter of the present disclosure can be expressed as the following technical subjects 1 to 9, with emphasis on the mechanical configuration. [Technical subject 1] An image processing circuit for generating an X-ray image by processing a read signal read from an image plate on which an X-ray photographed image is recorded, An image processing circuit that performs signal processing so that, for the entire output range contained in the read signal, the degree of change in shading for a portion of the attention area according to the purpose of observation is greater than the degree of change in shading for non-attention areas other than the attention area. [Technical subject 2] The image processing circuit described in technical subject 1 performs the signal processing by logarithmic transformation. [Technical subject 3] The image processing circuit described in technical subject 1 or 2 sets the area of ​​interest and the area of ​​non-interest so that the dose intensity range corresponding to the area of ​​interest is on the lower dose side than the dose intensity range corresponding to the area of ​​non-interest. [Technical subject 4] The image processing circuit described in technical subject 1 or 2 sets the area of ​​interest and the area of ​​non-interest so that the dose intensity area corresponding to the area of ​​interest is on the higher dose side than the dose intensity area corresponding to the area of ​​non-interest. [Technical subject 5] The image processing circuit described in technical subject 1 or 2 sets the area of ​​interest and the area of ​​non-interest so that the area of ​​non-interest includes a first area of ​​non-interest having a dose intensity range that is on the lower dose side than the dose intensity range corresponding to the area of ​​interest, and a second area of ​​non-interest having a dose intensity range that is on the higher dose side than the dose intensity range corresponding to the area of ​​interest. [Technical subject 6] The image processing circuit according to any one of technical subjects 1 to 5, which performs signal processing so that the non-target area is displayed with a constant density by eliminating the degree of change in shading regarding the non-target area. [Technical subject 7] The image processing circuit according to any one of technical subjects 1 to 6, wherein the signal processing is performed on an analog signal before being analog-to-digital converted. [Technical subject 8] An image processing circuit that processes a detection signal obtained by X-ray photography to generate an X-ray image, An image processing circuit that performs signal processing so that, for the entire output range contained in the detection signal, the degree of change in shading for a portion of the attention area according to the purpose of observation is greater than the degree of change in shading for non-attention areas other than the attention area. [Technical subject 9] An image processing device in which each component of the image processing circuit of any one of technical subjects 1 to 8 is integrated to form a single device.

[0070] In the conventional technology described in the above-mentioned Patent Document 1, the read signal obtained by detecting photostimulated luminescence is subjected to processes such as logarithmic conversion amplification and A / D conversion. In the obtained X-ray image, the color is usually light in areas where the X-ray dose intensity is low, and the color is dark in areas where the X-ray dose intensity is high. An X-ray image is composed of pixels with a variety of densities, from light to dark. However, in the conventional technology, there is a possibility that a dull image part will be generated at any dose intensity. A dull image part is an image part that does not have clear contrast and is vague (blurred).

[0071] The technical subject matter described below relates to an image processing system capable of obtaining an X-ray image with good contrast regardless of whether the X-ray image has light or dark colored areas. The technical subject matter relating to the system and signal processing described with reference to each of the drawings from FIG. 16(a) onwards can be expressed as the following technical subjects 1A to 6A, with emphasis on the mechanical configuration. [Technical subject 1A] An image processing system for generating an X-ray image by processing a read signal read from an image plate on which an X-ray image is recorded, by logarithmic transformation, comprising: The output range included in the read signal includes a predetermined first output range and a second output range having an output greater than that of the first output range, a first analog-to-digital conversion unit that performs first signal processing adapted to the first output range; a second analog-to-digital conversion unit that performs second signal processing different from the first signal processing adapted to the second output range; a synthesis unit that synthesizes digital signals that have been converted in the first analog-to-digital conversion unit and the second analog-to-digital conversion unit. [Technical subject 2A] The image processing system described in technical subject 1A, wherein the first analog-to-digital conversion unit performs the logarithmic conversion on an analog signal. [Technical subject 3A] the first analog-to-digital conversion unit performs signal processing so that a degree of change in shading relating to the first output region is greater than a degree of change in shading relating to a region other than the output region; The image processing system described in technical subject 1A or 2A, wherein the second analog-to-digital conversion unit performs signal processing so that the degree of change in shading regarding the second output area is greater than the degree of change in shading regarding areas other than the output area. [Technical subject 4A] An image processing system for generating an X-ray image by processing a detection signal obtained by X-ray photography using a logarithmic transformation, The output range included in the detection signal includes a predetermined first output range and a second output range having an output greater than the first output range, a first analog-to-digital conversion unit that performs first signal processing adapted to the first output range; a second analog-to-digital conversion unit that performs second signal processing different from the first signal processing adapted to the second output range; a synthesis unit that synthesizes digital signals that have been converted in the first analog-to-digital conversion unit and the second analog-to-digital conversion unit. [Technical subject 5A] An image processing system described in any of technical topics 1A to 4A, in which, in the read signal, a region in the low dose region where the degree of change in output value relative to a change in dose value is small is set as a low change region, and a region in the high dose region where the degree of change in output value relative to a change in dose value is set as a high change region, and the first output range is set for the low change region and the second output range is set for the high change region. [Technical subject 6A] An image processing device in which the components of the image processing system of any one of technical subjects 1A to 5A are integrated to form a single device.

[0072] According to the image processing system of technical subject 1A, the first analog-digital conversion unit performs first signal processing adapted to a first output range having a relatively small output, and the second analog-digital conversion unit performs second signal processing adapted to a second output range having a relatively large output. The first signal processing converts signals corresponding to light colored parts in the X-ray image, and the second signal processing converts signals corresponding to dark colored parts in the X-ray image. By performing signal processing adapted to each output range and combining these, an X-ray image with good contrast can be obtained regardless of light colored parts and dark colored parts in the X-ray image.

[0073] In the image processing system according to technical topic 2A, the first analog-digital conversion unit may perform logarithmic conversion on the analog signal. When the first signal processing is performed on the digital signal, small differences in the output value may disappear. In particular, small differences in the output value are valuable information in light-colored areas. By performing signal processing on the first output range before (prior to) the analog-digital conversion, the differences in the analog signal can be reflected in the shading in the X-ray image.

[0074] In the image processing system according to Technical Subject 3A, the first analog-digital conversion unit may perform signal processing so that the degree of change in shading in the first output region is greater than the degree of change in shading in the region other than the first output region, and the second analog-digital conversion unit may perform signal processing so that the degree of change in shading in the second output region is greater than the degree of change in shading in the region other than the second output region. In this case, the degree of change in shading becomes greater for each output region in which the first and second signal processes are performed. Thus, the contrast is improved throughout the obtained X-ray image.

[0075] According to the image processing system of Technical Topic 4A, the first analog-digital conversion unit performs first signal processing adapted to a first output range having a relatively small output, and the second analog-digital conversion unit performs second signal processing adapted to a second output range having a relatively large output. The first signal processing converts signals corresponding to light colored parts in the X-ray image, and the second signal processing converts signals corresponding to dark colored parts in the X-ray image. By performing signal processing adapted to each output range and combining these, an X-ray image with good contrast can be obtained regardless of light colored parts and dark colored parts in the X-ray image.

[0076] According to the image processing system of Technical Subject 5A, in the read signal, the region on the side where the degree of change in output value relative to the change in dose value is small in the low dose region is set as the low change region, and the region on the side where the degree of change in output value relative to the change in dose value is set as the high change region in the high dose region, and a first output range is set for the low change region and a second output range is set for the high change region. This makes it possible to average out the degree of change in output value and achieve appropriate distribution.

[0077] Technical subjects 1A to 5A relating to the system and signal processing described with reference to each of the drawings from FIG. 16(a) onwards can be expressed as the following technical subjects 1B to 6B when expressing with emphasis on the mechanical configuration. [Technical subject 1B] An image processing circuit for generating an X-ray image by processing a read signal read from an image plate on which an X-ray image is recorded, by logarithmic conversion, The output range included in the read signal includes a predetermined first output range and a second output range having an output greater than that of the first output range, a first analog-to-digital conversion circuit that performs first signal processing adapted to the first output range; a second analog-to-digital conversion circuit that performs a second signal processing different from the first signal processing adapted to the second output range; a synthesis circuit that synthesizes the digital signals that have been converted in the first analog-to-digital conversion circuit and the second analog-to-digital conversion circuit. [Technical subject 2B] The image processing circuit described in technical subject 1B, wherein the first analog-to-digital conversion circuit performs the logarithmic conversion on an analog signal. [Technical subject 3B] The image processing circuit described in Technical Subject 1B or 2B, wherein the first analog-digital conversion circuit performs signal processing so that the degree of change in shading regarding the first output area is greater than the degree of change in shading regarding areas other than the output area, and the second analog-digital conversion circuit performs signal processing so that the degree of change in shading regarding the second output area is greater than the degree of change in shading regarding areas other than the output area. [Technical subject 4B] An image processing circuit that processes a detection signal obtained by X-ray photography by logarithmic conversion to generate an X-ray image, The output range included in the detection signal includes a predetermined first output range and a second output range having an output greater than the first output range, a first analog-to-digital conversion circuit that performs first signal processing adapted to the first output range; a second analog-to-digital conversion circuit that performs a second signal processing different from the first signal processing adapted to the second output range; a synthesis circuit that synthesizes the digital signals that have been converted in the first analog-to-digital conversion circuit and the second analog-to-digital conversion circuit. [Technical subject 5B] An image processing circuit described in any one of technical topics 1B to 4B, in which in the read signal, a region in the low dose region where the degree of change in output value relative to a change in dose value is small is set as a low change region, and a region in the high dose region where the degree of change in output value relative to a change in dose value is set as a high change region, and the first output range is set for the low change region and the second output range is set for the high change region. [Technical subject 6B] Each image processing device in which the components of the image processing circuit of any one of technical subjects 1B to 5B are integrated to form a single device. [Explanation of symbols]

[0078] 2...image processing unit, 3...display unit, 4...operation unit, 10...first image processing device, 18...first image processing unit, 20...main control unit, 30...second image processing device, 28...second image processing unit, 50...synthesis processing unit, R1...area of ​​interest, R2...non-area of ​​interest, S...image processing system.

Claims

1. An image processing system for generating an X-ray image by processing a read signal read from an image plate on which an X-ray image is recorded, comprising: An operation unit that accepts operations by an operator is provided, a first designation designating a first region of interest within an entire output range included in the read signal, and a second designation designating a second region of interest, the second region of interest being a different dose intensity range from the first region of interest, within the entire output range included in the read signal, are received in the operation unit; when the first designation is accepted, signal processing is performed so that a degree of change in shading regarding the first attention area is greater than a degree of change in shading regarding a first non-attention area other than the first attention area; An image processing system that, when the second designation is accepted, performs signal processing so that the degree of change in shading relating to the second area of ​​interest is greater than the degree of change in shading relating to a second non-area of ​​interest other than the second area of ​​interest.

2. 2. The image processing system according to claim 1, wherein the signal processing is performed by logarithmic transformation.

3. 3. The image processing system according to claim 1, wherein signal processing is performed so that the degree of change in shading for the first non-attention area is eliminated and the first non-attention area is represented at a constant density, or signal processing is performed so that the degree of change in shading for the second non-attention area is eliminated and the second non-attention area is represented at a constant density.

4. 3. The image processing system according to claim 1, wherein signal processing is performed so that the degree of change in shading for the first non-attention area is eliminated and the first non-attention area is represented at a constant density, and signal processing is performed so that the degree of change in shading for the second non-attention area is eliminated and the second non-attention area is represented at a constant density.

5. 5. The image processing system according to claim 1, wherein the signal processing is performed on an analog signal before being analog-to-digital converted.

6. An image processing system for generating an X-ray image by processing a detection signal obtained by X-ray photography, An operation unit that accepts operations by an operator is provided, a first designation designating a first region of interest within an entire output range included in the detection signal, and a second designation designating a second region of interest, the second region of interest being a different dose intensity range from the first region of interest, within an entire output range included in the detection signal, are received by the operation unit; when the first designation is accepted, signal processing is performed so that a degree of change in shading regarding the first attention area is greater than a degree of change in shading regarding a first non-attention area other than the first attention area; An image processing system that, when the second designation is accepted, performs signal processing so that the degree of change in shading relating to the second area of ​​interest is greater than the degree of change in shading relating to a second non-area of ​​interest other than the second area of ​​interest.

Images