JP3829393B2 - Signal amplification apparatus and set value adjustment method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a signal amplifying device that gives a predetermined set value and amplifies an input signal to a predetermined output signal based on the set value, and more particularly to adjustment of the given set value. More specifically, the present invention relates to adjustment of a gain or / and offset setting value of a signal amplification device.
[0002]
[Prior art]
Specify the gain In a signal amplifying device that gives a set value and amplifies an input signal to a predetermined output signal based on the set value, Specify the gain Given a set value Also The input signal may not be amplified according to a fixed value. Because of this, the desired gain Various methods have been proposed for adjusting the set value so as to amplify the input signal and obtain a stable output signal.
[0003]
One of them is an adjustment method described in Japanese Patent Publication No. 6-85564. The adjustment method described in Japanese Patent Publication No. 6-85564 is a predetermined method. Specify the gain Amplifies a specific input signal with the set value, compares whether the obtained output signal falls within the allowable range, updates the set value if it does not fall within the allowable range, and then re-enters the specific input signal with this set value. Amplify and Adjustment Is repeated until the output signal falls within the allowable range.
[0004]
[Problems to be solved by the invention]
The adjustment method described in the above publication has a drawback in that it takes time to make adjustments because the set value must be updated until the output signal falls within the allowable range.
[0005]
Therefore, an object of the present invention is to reduce the time for adjustment when adjusting the set value and to obtain a stable output signal with respect to the input signal.
[0006]
[Means for Solving the Problems]
The above problem can be solved by the following configuration.
[0007]
The invention described in claim 1 Specify the gain In a signal amplifying apparatus having an amplifying unit that amplifies an input signal to a predetermined output signal based on a set value, and a control unit that gives the set value to the amplifying unit and controls the amplifying unit, the control units are mutually connected A plurality of different set values are given to the amplifying unit, a plurality of output signals obtained by amplifying the predetermined input signal by the amplifying unit based on the plurality of set values are detected, and the plurality of set values, the predetermined value Based on the input signal and the plurality of output signals, a desired Gain is obtained A signal amplifying apparatus that determines a set value.
[0008]
Claims 3 The invention described in Specify the gain A plurality of setting values different from each other in a setting value adjusting method of a signal amplifying apparatus that gives a setting value and amplifies an input signal to a predetermined output signal based on the setting value Increase A plurality of set values, the predetermined input signals, and the plurality of output signals that are given to the width unit, and a predetermined input signal is amplified by the amplification unit based on the plurality of set values; Based on the output signal of the desired Gain is obtained A setting value adjusting method for a signal amplifying apparatus, wherein the setting value is determined.
[0009]
That is, the device according to claim 1 or the claim. 3 In the method described in the above, a plurality of set values given and output signals amplified by the set values are obtained, and a desired value is obtained based on the plurality of set values, the predetermined input signal, and the plurality of output signals. Gain is obtained Determine the setting value. In the conventional technique, since the allowable range is simply compared with the output signal, the setting value must be adjusted repeatedly. In the present invention, which setting value is used to obtain the desired setting value. You can ask how much you want to make it larger or how much you want to make it smaller. Gain is obtained The set value can be determined in a short time (usually, it can be determined once), and a stable output signal can be obtained.
[0013]
And claims 2 or 4 In the invention described in (1), the plurality of setting values to be assigned are the desired values. Specify the gain Setting value larger and smaller than setting value including Since there are at least two set values, Gain is obtained The set value can be determined accurately.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a functional block diagram of an amplifying device to which the present invention is applied. The amplifying device 1 is a device that gives a predetermined set value and amplifies an input signal to a predetermined output signal based on the set value, and has an amplifying means 10 and a control means 20, and in this embodiment, Further, reference signal generating means 30 is provided. The amplifying apparatus 1 converts image information obtained as an analog signal from an image sensor of an image reading device, in particular, radiation image information (input signal Vi) obtained as an analog signal from a photoelectric conversion device of a radiation image reading device into a CRT. A predetermined output signal Vo digitally converted for display or printout is obtained.
[0020]
The signal amplifying unit 10 is a unit that amplifies the input signal Vi and outputs an output signal Vo based on a set value given from the control unit 20 to be described later. The amplifying unit 11 and the A / D converting unit 12 are connected to each other. Have. More specifically, the amplifying unit 11 amplifies the input signal Vi based on the given set values (gain G and offset O in the present embodiment) and outputs an amplified signal Va. In the following description, it is assumed that amplification at this time is performed based on Va = G × (Vi + O) unless otherwise specified. Then, the A / D converter 12 converts the amplified signal Va (analog signal) into a digital signal and outputs it as an output signal Vo to a CRT, printer, computer, etc. (not shown) in the subsequent stage.
[0021]
In this embodiment, the amplification signal Va is obtained based on Va = G × (Vi + O). However, the present invention is not limited to this, and any one of gain G and offset O may be used as a set value. Also, a logarithm or exponent may be taken for the input signal Vi and / or the output signal Vo. In the present embodiment, the A / D conversion unit 12 performs the A / D conversion after the amplification by the amplification unit 11. However, the present invention is not limited to this, and the amplified signal Va is output without performing the A / D conversion. You may do it.
[0022]
In such a signal amplifying apparatus 1, the desired gain In order to obtain the output signal Vo obtained by amplifying the input signal Vi, it is necessary to adjust the set value. In particular, when outputting image information obtained from a radiographic image reading apparatus to a CRT or the like, an output signal Vo to be obtained differs depending on an imaged part (eg, chest, abdomen) or a diagnostic part (eg, lung, bone, etc.). . That is, in the radiation image reading apparatus, for example, even if output from density 0 (zero) to density 4 is possible, it may be necessary to make a more detailed diagnosis of the range from density 1 to density 2 depending on the site. At this time, the input signal Vi is amplified based on the set values of the gain G and the offset O, and the density 1 is output as the output signal Vo = 0 and the density 2 is output as the digital signal of the output signal Vo = 4095 (A / D conversion is 212). In the case of conversion to bits), it is possible to make a more detailed diagnosis of density 1 to density 2. Thus, when changing the output signal Vo depending on the part, the desired signal gain In order to amplify the input signal Vi in the same manner and obtain a stable output signal Vo, the set value needs to be adjusted.
[0023]
In addition, the signal output from the radiographic image reading apparatus (input signal Vi in this specification) changes variously due to individual differences in the radiographic image reading apparatus, environmental changes, and the like, but image information to be obtained (output in this specification) As the signal Vo), information that does not depend on individual device differences or environmental differences is required. For this reason, it is necessary to adjust the set value in order to obtain a stable output signal Vo (of course, changes according to the input signal Vi) regardless of differences between individual devices or environmental differences.
[0024]
In the present embodiment, a control means 20 and a reference signal generation means 30 are provided to adjust this set value.
[0025]
The reference signal generating means 30 is a means for generating a reference signal Vr, which is a known signal as a reference, and outputting the reference signal Vr to the amplifying unit 11 of the amplifying means 10. The reference signal Vr generated by the reference signal generating means 30 is output to the amplifying unit 11 through the same path as the path through which the input signal Vi is input to the amplifying unit 11. Further, the reference signal Vr generated by the reference signal generating means 30 is generated by alternately controlling a plurality of (at least two) signals different from each other when the gain G is adjusted, and the offset O is adjusted. In this case, at least one signal is generated by being controlled by the control means 20. The reference signal Vr generated from the reference signal generating means 30 is also output to the control means 20 as will be described later.
[0026]
In the present embodiment, the reference signal generating means 30 is provided to generate the reference signal, and the output of the reference signal is made accurate. However, an image serving as a reference by an image reading device (radiation image reading device) or the like. And the signal may be used as the reference signal Vr.
[0027]
The control means 20 is constituted by a CPU or the like, and is a means for controlling the amplification means 10, the reference signal generation means 30, and the like and adjusting a desired set value. In FIG. 1, the inside of the control means 20 is shown divided into functional blocks, but this may be configured by software or hardware.
[0028]
The inside of the control means 20 will be described. The control means 20 includes a granting unit 21, a detection unit 22, a first calculation unit 23, a second calculation unit 24, a determination unit 25, and the like. The assigning unit 21 assigns a set value to the amplifying unit of the amplifying unit 10. At the time of adjusting the set value, a plurality of (at least two) set values different from each other are alternately given as the set values given by the assigning unit 21. In particular, the plurality of setting values can be accurately adjusted by setting at least two setting values, that is, a setting value larger than a desired setting value and a setting value smaller than the desired setting value. That is, when the gain G is adjusted as a set value, a gain larger than a desired gain and a smaller gain are alternately applied (at this time, the offset O is the same). Similarly, when adjusting the offset O as a set value, an offset larger than a desired offset and an offset smaller than the desired offset are alternately applied (at this time, the gain G is the same).
[0029]
The detection unit 22 detects the output signal Vo amplified and A / D converted by the amplification means 10. The detection unit 22 samples and detects the output signal Vo after the reference signal Vr is generated from the reference signal generation unit 30, that is, after a predetermined time has elapsed after the reference signal Vr is input to the amplification unit 10. By configuring, it is a period during which the output signal Vo is unstable (a period (region) from when the reference signal Vr is input until a predetermined time elapses). This predetermined time is a stable and / or amplifying unit of the input signal Vi. 11), a stable output signal Vo can be obtained. In addition, the detection unit 22 may obtain the output signal Vo by one sampling. However, by detecting (for example, an average value) based on the output signal Vo obtained by sampling a plurality of times, the detection unit 22 can be affected by noise and the like. Regardless of this, it can be detected accurately and accurately.
[0030]
The first calculation unit 23 calculates an actual set value based on the input signal Vi (reference signal Vr generated from the reference signal generation unit 30) input to the amplification unit 10 and the output signal Vo detected by the detection unit 22. It is a calculation part which calculates. That is, the first calculation unit 23 is based on the reference signal Vr generated from the reference signal generating means 30 and the set values (G, O) given to the reference signal Vr by the applying unit 21 by the amplifying unit 11. Based on the output signal Vo amplified and A / D converted by the A / D converter 12, an actual set value is calculated.
[0031]
More specifically, when the gain G is adjusted, at least two reference signals Vr that are different from each other based on predetermined set values (G, O) and the respective reference signals Vr detected by the detection unit 22 are used. The actual gain G ′ is calculated from the output signal Vo. On the other hand, when the offset O is adjusted, the actual offset is calculated from at least one reference signal Vr based on a predetermined set value (G, O) and the output signal Vo with respect to the reference signal Vr detected by the detector 22. O 'is calculated. In the first calculation unit 23, when the gain G is adjusted, two different reference signals Vr and output signal Vo are used. When the offset O is adjusted, one reference signal Vr and output signal Vo are actually used. Set value (gain or offset) can be calculated, but the actual set value may be calculated from the reference signal Vr and the output signal Vo more than that, respectively. The calculation can be performed with higher accuracy.
[0032]
The second computing unit 24 is configured to provide the assigned setting value and the actual setting value based on the plurality of assigned setting values different from each other by the assigning unit 21 and the plurality of actual setting values calculated by the first computing unit 23. It is a calculating part which calculates the relationship. That is, the second calculation unit 24 differs from the predetermined set value given from the grant unit 21 to the amplification unit 11 and the actual set value calculated by the first calculation unit 23 based on the set value at least different from each other. The relationship between the assigned setting value and the actual setting value is calculated with two predetermined setting values.
[0033]
The determination unit 25 determines a setting value corresponding to a desired setting value based on the relationship between the assigned setting value calculated by the second calculation unit 24 and the actual setting value. The set value corresponding to the desired set value is a set value for obtaining a predetermined output value for a predetermined input signal, or a desired value for the input when adjusting individual device differences. This is the setting value that can be obtained.
[0034]
Here, the operation of the present embodiment will be described with reference to FIGS. 2 and 4 are diagrams illustrating the relationship between the input signal and the output signal, and FIGS. 3 and 5 are diagrams illustrating the relationship between the assigned set value and the actual set value. 2 and 3 are diagrams for explaining gain adjustment, and FIGS. 4 and 5 are diagrams for explaining offset adjustment. In order to simplify the description, A / D conversion by the A / D converter 12 is omitted, and the output signal Vo = amplified signal Va is assumed.
[0035]
Now, a description will be given of a case where the setting value (desired setting value) desired to be set by the amplifying apparatus 1 is adjusted to the desired gain Gw and the desired offset Ow. The amplification by the amplification unit 11 is based on Vo = G × (Vi + O).
[0036]
First, the gain G is adjusted. In the adjustment of the gain G, a gain Ga smaller than a desired gain Gw and a predetermined offset Oa are applied from the applying unit 21 to the amplifying unit 11. In this case, the offset Oa may be an arbitrary value. When applied, the reference signal Vra is input as the input signal Vi from the reference signal generating means 30 to the amplifying means 10 under the control of the control means 20. The amplifying means 10 amplifies the reference signal based on the above equation and outputs the output signal Vo1. The output signal Vo1 is detected by the detection unit 22 after a predetermined time has elapsed since the reference signal Vra was input. Further, the reference signal generating means 30 inputs a reference signal Vrb different from the reference signal Vra to the amplifying means 10 under the control of the control means 20, and similarly, the output signal Vo2 is detected by the detection unit 22.
[0037]
On the other hand, a gain Gb (a value different from the gain Ga) greater than the desired gain Gw and a predetermined offset Oa are applied from the applying unit 21 to the amplifying unit 11. Similarly, the reference signal Vra is input to the amplification means 10, and the output signal Vo3 amplified based on the above equation is detected by the detection unit 22. Further, the reference signal Vrb is input to the amplifying means 10, and similarly, the output signal Vo4 is detected by the detection unit 22. The output signals Vo1 to Vo4 detected by the detection unit 22 may be stored in a storage unit such as a memory (not shown).
[0038]
Here, the first calculator 23 calculates the actual gain Ga ′ from the reference signals Vra and Vrb and the output signals Vo1 and Vo2 (see FIG. 2). This is Ga '= (Vo2-Vo1) / (Vrb-V ra ). Similarly, from the reference signals Vra and Vrb and the output signals Vo3 and Vo4, the actual gain Gb ′ is obtained as follows: Gb ′ = (Vo4−V51) / (Vrb−V ra ).
[0039]
In the present embodiment, the reference signals Vra and Vrb output from the reference signal generating means 30 are input to the first calculation unit 23. However, the reference signals Vra and Vrb are known in advance. If it is (known), it is not necessary to input it, and it may be stored in a memory (not shown) and the stored reference signals Vra and Vrb may be used. In the present embodiment, the actual gains Ga ′ and Gb ′ are calculated after all the output signals Vo1 to Vo4 are detected. However, the present invention is not limited to this, and the actual gain is detected after the output signals Vo1 and Vo2 are detected. The actual gain Gb ′ may be calculated after calculating Ga ′ and then detecting the output signals Vo3 and Vo4.
[0040]
Next, the relationship between the applied gain and the actual gain is determined from the plurality of applied gains Ga and Gb and the actual gains Ga ′ and Gb ′ obtained by the first calculation unit 23 via the amplification unit 10. Calculation is performed by the second calculation unit 24. That is, as shown in FIG. 3, the relationship between the applied gain indicated by the solid line and the actual gain is obtained. Here, the alternate long and short dash line in FIG. 3 indicates a case where the applied gain matches the actual gain. In this embodiment, this calculation obtains the relational expression (linear function) in FIG. More specifically, a relational expression G (Gw) of G (Gw) = (Gb−Ga) × (Gw−Ga ′) / (Gb′−Ga ′) + Ga is obtained. In this relational expression G (Gw), Gw is a desired gain, G (Gw) is a gain corresponding to the desired gain Gw, and is a gain applied to the amplifying means 10 in order to obtain the desired gain Gw.
[0041]
In the present embodiment, the relationship between the applied gain and the actual gain is calculated based on the two applied gains Ga and Gb and the two actual gains Ga ′ and Gb ′ in the second arithmetic unit 24. Although the calculation is not limited to this, the calculation may be performed with three or more, and in this case, the relationship between the applied gain and the actual gain can be calculated more accurately.
[0042]
Then, the gain corresponding to the desired gain is determined based on the relationship between the applied gain calculated by the second calculation unit 24 and the actual gain. As described above, even if a desired gain is applied to the amplifying means 10, the actual gain is different from the desired gain and is not amplified as the desired gain. Therefore, the gain corresponding to the desired gain is determined so that the actual gain becomes the desired gain. This is done by substituting the desired gain Gw into the above-described relational expression G (Gw) to determine the gain G (Gw) corresponding to the desired gain.
[0043]
The gain G (Gw) corresponding to the desired gain determined in this way is stored in a storage unit such as a memory (not shown) and is applied to the amplification unit 10 by the applying unit 21.
[0044]
Subsequently, the offset O is adjusted. The adjustment of the offset O is performed in the same manner as the adjustment of the gain G described above. That is, the gain G (Gw) corresponding to the desired gain Gw determined above and the offset Oa smaller than the desired offset Ow are applied from the applying unit 21 to the amplifying unit 11. When applied, the reference signal Vra is input as the input signal Vi from the reference signal generating means 30 to the amplifying means 10 under the control of the control means 20. The amplifying unit 10 amplifies the reference signal based on the above equation and outputs the output signal Vo5. The output signal Vo5 is detected by the detection unit 22 after a predetermined time has elapsed since the input signal Vra was input. A gain G (Gw) corresponding to a desired gain Gw and an offset Ob larger than the desired offset Ow (a value different from the offset Oa) are applied from the applying unit 21 to the amplifying unit 11. Similarly, the reference signal Vra is input to the amplification means 10, and the output signal Vo6 amplified based on the above equation is detected by the detection unit 22. The output signals Vo5 and Vo6 detected by the detection unit 22 may be stored in a storage unit such as a memory (not shown).
[0045]
Here, the first calculator 23 calculates an actual offset Oa ′ from the reference signal Vra and the output signal Vo5. This is calculated based on Oa ′ = V5−Vra × G (Gw). Similarly, from the reference signal Vra and the output signal Vo6, the actual offset Ob ′ is calculated based on Ob ′ = V6−Vra × G (Gw) (see FIG. 4).
[0046]
In the present embodiment, the actual offsets Oa ′ and Ob ′ are calculated after detecting all the output signals Vo5 and Vo6. However, the present invention is not limited to this, and the actual offset Oa ′ is detected after the output signal Vo5 is detected. After that, the actual offset Ob ′ may be calculated after detecting the output signal Vo6.
[0047]
Next, the relationship between the applied offset and the actual offset is calculated from the plurality of applied offsets Oa and Ob and the actual offsets Oa ′ and Ob ′ obtained by the first calculation unit 23 via the amplification unit 10. Calculation is performed by the second calculation unit 24. In the present embodiment, a relational expression O (Ow) of O (Ow) = (Ob−Oa) × (Ow−Oa ′) / (Ob′−Oa ′) + Oa is obtained (see FIG. 5). In this relational expression O (Ow), Ow is a desired offset, O (Ow) is an offset corresponding to the desired offset Ow, and is an offset to be given to the amplification means 10 in order to obtain the desired offset Ow.
[0048]
In the present embodiment, the relationship between the applied offset and the actual offset is calculated based on the two added offsets Oa and Ob and the two actual offsets Oa ′ and Ob ′ in the second arithmetic unit 24. Although the calculation is not limited to this, the calculation may be performed with three or more, and in this case, the relationship between the applied offset and the actual offset can be calculated more accurately.
[0049]
Then, an offset corresponding to a desired offset is determined based on the relationship between the applied offset calculated by the second calculator 24 and the actual offset. As described above, even if a desired offset is given to the amplifying means 10, the actual offset is different from the desired offset and is not amplified as the desired offset. Therefore, an offset corresponding to the desired offset is determined so that the actual offset becomes the desired offset. This is done by substituting Ow for a desired offset into the relational expression O (Ow) described above, thereby determining an offset O (Ow) corresponding to the desired offset.
[0050]
The offset O (Ow) corresponding to the desired offset determined in this way is stored in a storage unit such as a memory (not shown) and is applied to the amplification unit 10 by the applying unit 21.
[0051]
The gain G (Gw) corresponding to the desired gain and the offset O (Ow) corresponding to the desired offset determined as described above are added to the amplifying unit 10 by the applying unit 21, and the gain and Offset adjustment is completed.
[0052]
In the present embodiment, the adjustment of the set value (determination of the set value corresponding to the desired set value) is performed by calculating the actual set value and calculating the relationship between this and the assigned set value. Without adjustment, the set value may be adjusted (a set value corresponding to a desired set value is directly determined). In this case, a set value corresponding to a desired set value is directly determined (adjusted) based on a plurality of output signals, a plurality of assigned set values, and an input signal (reference signal). In this case, in FIG. 1, the first calculation unit 23 and the second calculation unit 24 are not provided, and the reference signal and the assigned set value are input to the determination unit 25.
[0053]
In the present embodiment, the set value is adjusted for the gain and the offset. However, the present invention is not limited to this, and only one of them may be used. Further, when the adjustment of the set value is performed for the gain and the offset, the gain is adjusted (determination of the gain corresponding to the desired gain) and then the offset is adjusted (corresponding to the desired offset) as in the present embodiment. However, the present invention is not limited to this, and the gain may be adjusted after adjusting the offset.
[0054]
When this embodiment is used for a radiographic image reading apparatus, the radiographic image reading apparatus has different desired set values (desired gain and desired offset) depending on an imaging region, a diagnostic region, and the like. For this reason, the adjustment described above is performed for each different desired setting value, and the setting value corresponding to the obtained desired setting value may be stored in a storage unit such as a memory. Then, based on the selection of an imaging menu such as an imaging region or a diagnostic region performed by the user on the operation panel of the radiographic image reading apparatus, the user reads out from the storage unit, and the adding unit 21 applies the read setting value to the amplification unit 10. You can do that.
[0055]
【The invention's effect】
Device according to claim 1 or claim 3 In the method described in the above, a plurality of set values given and output signals amplified by the set values are obtained, and a desired value is obtained based on the plurality of set values, the predetermined input signal, and the plurality of output signals. Gain is obtained Determine the setting value. In the conventional technique, since the allowable range is simply compared with the output signal, the setting value must be adjusted repeatedly. In the present invention, which setting value is used to obtain the desired setting value. You can ask how much you want to make it larger or how much you want to make it smaller. Gain is obtained The set value can be determined in a short time (usually, it can be determined once), and a stable output signal can be obtained.
[0057]
And claims 2 or 4 In the invention described in (1), since the plurality of setting values to be assigned are at least two setting values, a setting value larger than the desired setting value and a setting value smaller than the desired setting value, the setting value corresponding to the desired setting value is accurately set. Can be determined.
[Brief description of the drawings]
FIG. 1 is a functional block diagram of an amplification device to which the present invention is applied.
FIG. 2 is a diagram illustrating a relationship between an input signal and an output signal.
FIG. 3 is a diagram illustrating a relationship between an assigned set value (gain) and an actual set value.
FIG. 4 is a diagram illustrating a relationship between an input signal and an output signal.
FIG. 5 is a diagram illustrating a relationship between an assigned set value (offset) and an actual set value.
[Explanation of symbols]
1 Signal amplifier
10 Amplification means
11 Amplifier
12 A / D converter
20 Control means
21 Granting Department
22 Detector
23 First operation unit
24 2nd operation part
25 decision part
30 Reference signal generating means

Claims (4)

In a signal amplifying apparatus comprising: an amplifying unit that amplifies an input signal to a predetermined output signal based on a setting value that indicates a gain; and a control unit that applies the setting value to the amplifying unit and controls the amplifying unit.
The control means gives a plurality of different setting values to the amplification means,
Detecting a plurality of output signals in which a predetermined input signal is amplified by the amplifying means based on the plurality of set values;
A signal amplifying apparatus that determines a set value for obtaining a desired gain based on the plurality of set values, the predetermined input signal, and the plurality of output signals. 2. The signal amplifying apparatus according to claim 1, wherein the plurality of setting values are at least two setting values including a setting value larger than a setting value indicating a desired gain and a setting value smaller than the setting value. In a method for adjusting a set value of a signal amplifying apparatus that gives a set value indicating a gain and amplifies an input signal into a predetermined output signal based on the set value,
Applying a plurality of different set values to the amplification means,
Detecting a plurality of output signals in which a predetermined input signal is amplified by the amplifying means based on the plurality of set values;
A setting value adjusting method for a signal amplifying apparatus, wherein a setting value for obtaining a desired gain is determined based on the plurality of setting values, the predetermined input signal, and the plurality of output signals. The set value adjustment of the signal amplification device according to claim 3 , wherein the plurality of set values are at least two set values including a set value larger than a set value indicating a desired gain and a set value smaller than the set value. Method.

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