JP2005103007A - Device, method and program for image processing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device, a method and a program for image processing for easily and speedily adjusting two kinds of variable parameter, the quantity of parallel movement and the gradient of a gradation converting characteristic curve. <P>SOLUTION: The quantity of gradual variation Δs of the parameter of the quantity of parallel movement s in selecting a button is Δo/al or Δo/a2 based on the gradient a1 or a2 of the gradation converting characteristic curve a or b, and the variation range Δo of values of output pixels. Accordingly, the value of output pixel is changed always by the constant variation range Δo whenever a button is selected, and an operator can select the brightness and the photographic density of an image as the operator likes by selecting a button to change the brightness or the density always by a constant value. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image processing apparatus, an image processing method, and a program for performing gradation conversion of image information using a gradation conversion characteristic curve.

  In recent years, with rapid progress of radiographic image acquisition devices represented by CR (Computed Radiography), radiographic images are acquired as digital image information, and an operator outputs the image information to a high-definition monitor or an imager. Interpretation or diagnosis is increasing.

  Here, when the image information is output to a high-definition monitor or an imager or the like, gradation conversion is performed using an image processing apparatus, and gradation is made suitable for interpretation or diagnosis. In this gradation conversion, a gradation conversion characteristic curve having the parallel movement amount and the inclination as variable parameters is used (for example, see Patent Document 1).

The operator adjusts the variable parameter of the gradation conversion characteristic curve for each piece of image information based on the difference in the imaging conditions of the image information or the difference in the imaging region, and performs output. In order to save the labor of adjustment, variable parameters are automatically calculated based on statistical information of image information (see, for example, Patent Document 2).
JP-A-9-16762, (first page, FIG. 1) JP-A-63-031641 (pages 3-4, Fig. 2)

  However, according to the above-described background art, much labor and time are required to adjust the variable parameter that repeats trial and error. That is, for each piece of image information, an imaging region and a region of interest are determined, and a variable parameter suitable for this is searched. Further, even when the adjustment is performed automatically, there has been a need for further fine adjustment when the image information is read or diagnosed.

  In particular, when adjusting the variable parameters, the operator needs to simultaneously optimize two variable parameters such as the amount of translation and the inclination corresponding to the brightness, density, and contrast while referring to the display image. The adjustment work is difficult and requires experience and skill.

  For these reasons, it is important how to realize an image processing apparatus, an image processing method, and a program that easily and quickly adjust two variable parameters, that is, a translation amount and a slope of a gradation conversion characteristic curve.

  The present invention has been made in order to solve the above-described problems caused by the background art, and an image processing apparatus that easily and quickly adjusts two variable parameters such as a parallel movement amount and a slope of a gradation conversion characteristic curve, An object is to provide an image processing method and program.

  In order to solve the above-described problems and achieve the object, an image processing apparatus according to claim 1 includes an input unit for inputting image information and a parallel movement of an input pixel value included in the image information. Image processing means for performing gradation conversion using a gradation conversion characteristic curve having the amount and inclination as variable parameters, processing condition adjusting means for performing adjustment by changing the value of the variable parameter, and the gradation converted Output means for outputting image information consisting of output pixel values, wherein the processing condition adjustment means is configured to input the same when the variable parameter is a parallel movement amount. Adjustment amount determining means is provided for setting a change width of the parallel movement amount for each operation so that an output change of the output pixel value for each change is constant.

  In the first aspect of the present invention, when the processing condition adjustment unit is the adjustment amount determination unit and the variable parameter is the parallel movement amount, the processing condition adjustment unit calculates the change amount of the parallel movement amount for the same input operation designating the change. Because the output change of the output pixel value for each change is set to be constant, the output change of the output pixel value for each input operation is constant preferable for the operator regardless of the gradient of the gradation conversion characteristic curve. Change.

  In the image processing apparatus according to the second aspect of the present invention, the adjustment amount determination unit may calculate a change width for each same input operation that specifies the change when the variable parameter is an inclination. It is characterized by a value obtained by multiplying the slope of the tone conversion characteristic curve by a certain ratio.

  According to the second aspect of the present invention, the width of change for each input operation that designates a change is a constant ratio corresponding to the slope of the gradation conversion characteristic curve.

  An image processing apparatus according to a third aspect of the invention is characterized in that the processing condition adjustment means includes an adjustment input means for performing the input operation.

  In the invention according to the third aspect, the input operation is performed by the adjustment input means.

  The image processing apparatus according to claim 4 is characterized in that the adjustment amount determination means obtains a plurality of movement candidate points of the variable parameter value based on statistical information of the input pixel value. To do.

  In the invention according to the fourth aspect, the adjustment of the value of the variable parameter is simplified.

  The image processing apparatus according to the invention described in claim 5 is characterized in that the adjustment input means includes a changing means for changing the value of the variable parameter to the movement candidate point.

  In the invention according to claim 5, the adjustment input means changes the value of the variable parameter to the movement candidate point by the changing means.

  In the image processing apparatus according to the sixth aspect of the present invention, the processing condition adjustment unit calculates an adjustment range of the variable parameter value based on the statistical information of the input pixel value, and sets the adjustment range. Adjustment value limiting means is provided for invalidating the input when the value of the deviating variable parameter is input.

  In the sixth aspect of the present invention, the processing condition adjusting unit calculates the adjustment range of the variable parameter value based on the statistical information of the input pixel value by the adjustment range limiting unit, and sets the variable parameter out of the adjustment range. When a value is input, this input is invalidated.

The image processing apparatus according to claim 7 is characterized in that the adjustment input unit makes a change width of a variable parameter value variable for each of the same input operations.
It is characterized by that.

  According to the seventh aspect of the present invention, the input operation in the vicinity of the target adjustment value is quickly and precisely performed.

  The image processing apparatus according to an eighth aspect of the invention is characterized in that the processing condition adjusting means includes display means for displaying image information including the output pixel values.

  In the eighth aspect of the invention, the display unit displays the image information including the output pixel value.

  An image processing method according to claim 9 includes an input step of inputting image information, and a gradation conversion characteristic in which an input pixel value included in the image information has a parallel movement amount and an inclination as variable parameters. An image processing step for gradation conversion using a curve, a processing condition adjustment step for adjusting by changing the value of the variable parameter, and an output step for outputting image information composed of the output pixel values subjected to the gradation conversion And when the variable parameter is a parallel movement amount, the processing condition adjustment step includes a change width of the parallel movement amount for each identical input operation that specifies the change, An adjustment amount determining step for setting the output change of the output pixel value for each change to be constant is provided.

  In the invention according to claim 9, in the processing condition adjustment step, when the variable parameter is the parallel movement amount in the adjustment amount determination step, the change amount of the parallel movement amount for each identical input operation that specifies the change is calculated. The output change of the output pixel value for each change is set to be constant.

  Further, in the image processing method according to claim 10, when the adjustment amount determination step is performed when the variable parameter is an inclination, a change width for each same input operation designating the change is calculated. It is characterized by a value obtained by multiplying the slope of the tone conversion characteristic curve by a certain ratio.

  According to the tenth aspect of the present invention, the width of change for each input operation that designates a change is a constant ratio corresponding to the slope of the gradation conversion characteristic curve.

  The image processing method according to the invention described in claim 11 is characterized in that the processing condition adjustment step includes an adjustment input step for performing the input operation.

  In the invention according to claim 11, the processing condition adjustment step performs an input operation by the adjustment input step.

  The image processing method according to claim 12 is characterized in that the adjustment amount determining step obtains a plurality of movement candidate points of the variable parameter value based on statistical information of the input pixel value. To do.

  In the invention of the twelfth aspect, the adjustment of the value of the variable parameter is simplified.

  The image processing method according to the invention described in claim 13 is characterized in that the adjustment input step includes a change step of changing the value of the variable parameter to the movement candidate point.

  In the invention described in claim 13, the adjustment input step changes the value of the variable parameter to the movement candidate point by the changing step.

  In the image processing method according to the fourteenth aspect of the present invention, the processing condition adjustment step calculates an adjustment range of the variable parameter value based on the statistical information of the input pixel value, and sets the adjustment range. An adjustment range limiting step of invalidating the input when the deviating variable parameter value is input is provided.

  According to the fourteenth aspect of the present invention, in the processing condition adjustment step, the adjustment range limiting step calculates the adjustment range of the variable parameter value based on the statistical information of the input pixel value, and the variable parameter deviating from the adjustment range. When the value of is input, this input is invalidated.

  The image processing method according to the invention described in claim 15 is characterized in that the adjustment input step makes a change width of a variable parameter value variable for each of the same input operations.

  According to the fifteenth aspect of the present invention, the input operation in the vicinity of the target adjustment value is quickly and precisely performed.

  The image processing method according to claim 16 is characterized in that the processing condition adjustment step includes a display step of displaying image information composed of the output pixel values.

  In the invention of the sixteenth aspect, the display means displays the image information composed of the output pixel values.

  A program according to the invention described in claim 17 causes a computer to execute the method described in claims 9-16.

  In the invention described in claim 17, the method described in claims 9 to 16 is executed by a computer by a program.

  As described above, according to the first aspect of the present invention, regardless of the gradient of the gradation conversion characteristic curve, the output change of the output pixel value for each input operation becomes a constant change preferable for the operator, and the image information is stored. It is possible to improve the operability easily and quickly with the desired brightness or density.

  According to the second aspect of the present invention, the change width for each same input operation becomes a constant ratio according to the gradient of the gradation conversion characteristic curve which is preferable for the operator, and the image information can be easily and quickly liked. Therefore, the operability can be improved.

  According to the third aspect of the present invention, an input operation can be performed by the adjustment input means.

  According to the invention described in claim 4, the adjustment of the value of the variable parameter can be simplified and performed quickly.

  According to the invention described in claim 5, the adjustment input means can change the value of the variable parameter to the movement candidate point by the changing means, and can easily adjust the value.

  According to the sixth aspect of the present invention, it is possible to quickly adjust the value of the variable parameter without departing from the adjustment range.

  According to the seventh aspect of the invention, the operator can perform the input operation near the target adjustment value more quickly and precisely.

  According to the eighth aspect of the invention, the display means allows the operator to see the image information and make an appropriate adjustment.

  According to the ninth aspect of the invention, regardless of the gradient of the gradation conversion characteristic curve, the output change of the output pixel value for each input operation becomes a constant change preferable for the operator, and the image information can be easily and quickly. The operability can be improved by setting the brightness or density to the desired level.

  According to the tenth aspect of the present invention, the change width for each same input operation is a constant ratio according to the gradient of the gradation conversion characteristic curve which is preferable for the operator, and the image information can be easily and quickly liked. Therefore, the operability can be improved.

  According to the eleventh aspect, an input operation can be performed by the adjustment input step.

  According to the invention described in claim 12, the adjustment of the value of the variable parameter can be simplified and performed quickly.

  According to the invention described in claim 13, in the adjustment input step, the variable parameter value can be changed to the movement candidate point by the changing step, and the adjustment can be easily adjusted.

  According to the fourteenth aspect of the present invention, the value of the variable parameter can be adjusted quickly without departing from the adjustment range.

  According to the fifteenth aspect of the present invention, the operator can further quickly and precisely perform an input operation near the target adjustment value.

  According to the sixteenth aspect of the present invention, the operator can make an appropriate adjustment by viewing the image information through the display step.

  According to the invention described in claim 17, the method described in claims 9 to 16 can be executed by a computer by a program.

DETAILED DESCRIPTION Exemplary embodiments of an image processing apparatus, an image processing method, and a program according to the present invention will be described below with reference to the accompanying drawings. Note that the present invention is not limited thereby.
(Embodiment 1)
First, the overall configuration of equipment including the image processing apparatus 1 according to the first embodiment will be described. FIG. 2 is a block diagram showing the overall configuration. This overall configuration includes a radiation image acquisition device 2, an image processing device 1, and an image output device 3. The radiological image acquisition apparatus 2 is an apparatus that acquires image information of a subject using a ray, such as CR. The image processing apparatus 1 is an apparatus that performs image processing such as gradation processing on image information acquired from the radiation image acquisition apparatus 2 via a communication line. The image output device 3 is, for example, a high-definition monitor, an imager, or the like, and is a device that outputs image information of the image processing device 1 subjected to image processing in a monitor display or a film state that can be interpreted by an operator.

  FIG. 3 is a functional block diagram showing the configuration of the image processing apparatus 1. This configuration can be configured using any of hardware, firmware, or software. The image processing apparatus 1 includes an input unit 10 for inputting image information, an image data storage unit 20, an image processing unit 30, a processing condition storage unit 40, a processing condition adjustment unit 50, an output data storage unit 60, and an output unit 70. .

  The input means 10 is an interface for inputting image information acquired by the radiation image acquisition apparatus 2, for example, image information having a 12-bit gradation of 0 to 4095, and the image data storage means 20 is the input image information. Is memorized and saved.

  The processing condition storage means 40 stores various parameters at the time of image processing, that is, image processing conditions, and in particular, shows the relationship between the input pixel value and the output pixel value used when gradation processing is performed. As a basic LUT in a lookup table (hereinafter referred to as LUT). The LUT is a one-dimensional array that holds an output pixel value with respect to an input pixel value, and performs input / output conversion at a high speed when the gradation conversion characteristic curve is expressed by a complicated mathematical expression. Further, the processing condition storage means 40 can prepare a plurality of basic LUTs and perform selection based on information on the imaging region or imaging direction.

  The image processing means 30 is an arithmetic unit having a function of performing gradation processing on image information, a function of reducing the number of pixels of image information, generating reduced image information, a function of generating a histogram of pixel values from image information, and the like. is there.

  The output data storage unit 60 stores the image information output from the image processing unit 30, and the output unit 70 is an interface that outputs the image information to the image output apparatus 3.

  The processing condition adjusting unit 50 is an adjusting unit that adjusts image processing conditions, and includes an adjustment input unit 51, an adjustment amount determining unit 52, an adjustment range limiting unit 53, and a display unit 54. The adjustment input means 51 is used to set various parameter values used by the operator for image processing, and is composed of input devices such as a mouse, a keyboard, and a touch pad.

  The adjustment amount determination unit 52 determines the adjustment amount from the various parameters input by the adjustment input unit 51. The adjustment range limiting unit 53 uses the parameter input from the adjustment input unit 51 to determine whether the adjustment amount determined by the adjustment amount determination unit 52 is within the adjustable range, and if it is outside the adjustable range. Then, take measures such as disabling the input parameters. The display means 54 is a display monitor that is configured by a CRT, an LCD, or the like and forms a GUI when an operator performs various parameter adjustment operations.

  Here, when the gradation processing is performed, the image processing unit 30 first reads out the image information stored in the image data storage unit 20 and samples it to generate reduced image information with a reduced number of images. To do. By generating the reduced image information, it is possible to increase the processing speed and reduce hardware resources. Various parameters as basic LUT and image processing conditions are read from the processing condition storage means 40, and gradation processing is performed on the generated reduced image information based on these information. The reduced image information and the image processing conditions subjected to the gradation processing are transmitted to the processing condition adjusting unit 50.

  The processing condition adjustment unit 50 displays the reduced image information on the display unit 54, and the operator adjusts the image processing condition such as changing the gradation conversion characteristic curve using the adjustment input unit 51 while referring to the display image. I do.

  Thereafter, the processing condition adjusting unit 50 transmits the adjusted image processing condition to the image processing unit 30, and the image processing unit 30 performs image processing based on the image processing condition, particularly gradation processing again. Then, the image processing unit 30 transmits the reduced image information subjected to the image processing again to the processing condition adjusting unit 50 and displays the reduced image information on the display unit 54.

  The operator repeats the adjustment of the image processing conditions using the adjustment input unit 51 and the reference of the reduced image redisplayed on the display unit 54, and acquires image processing conditions suitable for interpretation. Then, the operator instructs the end of adjustment from the adjustment input means 51, and the image processing means 30 reads the base image information stored in the image data storage means 20 based on this adjustment end instruction, and sets the processing conditions. Image processing is performed in accordance with the final image processing condition after adjustment acquired from the adjusting unit 50.

  Thereafter, the image processing means 30 stores the image information subjected to the image processing in the output data storage means 60, and further, via the output means 70, to the image output device 3 such as a laser imager or a high-definition monitor. Output.

  Here, the gradation conversion characteristic curve set in the basic LUT when the image processing means 30 performs gradation processing using the basic LUT will be described in detail. This gradation conversion characteristic curve is a function that determines an output pixel value with respect to an input pixel value. FIG. 5 shows an example of a curve that is the basis of the gradation conversion characteristic curve. The horizontal axis represents the input pixel value x, and the vertical axis represents the output pixel value y.

  This curve is a function such as a basic characteristic curve y = f (x) shown in FIG. 5, and a straight line region is expressed by y = a1 * x + b1 as shown in FIG. Here, as an adjustment parameter for obtaining a desired gradation conversion characteristic curve, a parallel movement amount s in which the parallel movement in the negative direction of the x axis with respect to the basic characteristic curve y = f (x) is a positive value. Then, the gradient g of the gradation conversion characteristic curve in which the gradient of the straight line portion is changed with reference to a predetermined output pixel value Os with respect to the basic characteristic curve y = f (x) is defined. By adjusting the parallel movement amount s and the inclination g, a gradation conversion characteristic curve whose shape is changed based on the basic characteristic curve y = f (x) is obtained.

Arbitrary gradation conversion characteristics determined by the above-described parallel movement amount s and inclination g, where Is is the input pixel value for the output pixel value Os of the basic characteristic curve y = f (x), which is the gradation conversion characteristic of the basic LUT. The curve is obtained by changing the independent variable x from the basic characteristic curve y = f (x) to the new variable x ′, that is,
x ′ = g / a1 * (x + s) + (1−g / a1) * Is
It is obtained by replacing with the expression shown in. The slope a1 is obtained from, for example, the slope between two points (I1, O1) and (I2, O2) on the reference characteristic curve y = f (x) across the output pixel value Os in FIG. When the variable x ′ does not become an integer value, the gradation conversion characteristic curve value can be obtained using the nearest integer value and can be refined by linear interpolation or the like.

  The image processing unit 30 acquires the basic characteristic curve y = f (x) included in the basic LUT from the processing condition storage unit 40, and the adjusted parallel movement amount s and inclination g from the processing condition adjustment unit 50. Obtain a new gradation conversion characteristic curve according to the above equation.

  Here, the display screen of the display means 54 that forms a GUI with the operator when adjusting the parallel movement amount s and the inclination g that determine the gradation conversion characteristic curve will be described in more detail.

  FIG. 4 shows an example of the display screen of the display means 54. In this display screen, reduced image information is displayed on the left side, buttons and sliders for inputting the values of various parameters that are image processing conditions on the left side, and a parameter value for adjustment as a guideline for adjustment. The display value determined by is displayed.

  The buttons and sliders arranged on the right side are roughly classified into two similar upper and lower buttons and slider groups. The button and slider group located in the upper right part is a button and slider group that controls the luminance or density of the pixel value, and the button and slider group located in the lower right part are the contrast between pixels, that is, the gradient of the gradation conversion characteristic curve. A group of buttons and sliders for controlling These buttons and sliders are set by an input device such as a mouse linked with a cursor on the screen, for example.

  Here, each time the button 201 of the button group for controlling the luminance or density is selected, the parallel movement amount s is changed stepwise by the change amount Δs, and the button 202 has a parallel movement amount s described later. A value closest to the set value is selected from a plurality of candidate values, and the slider 203 sets a parallel movement amount s corresponding to the pointer position on the slider 203.

  Each time the button 205 of the button group for controlling the inclination is selected once, the inclination g is changed stepwise by the change amount Δg, and the button 206 is selected from a plurality of candidate values of the inclination g described later. Then, the value closest to the set value is selected, and the slider 207 sets the inclination g corresponding to the pointer position on the slider 207.

  The buttons 204 and 208 change the stepwise parameter change amount per button and the parameter change amount due to the pointer position change of the slider.

  Next, the operation of the adjustment amount determination unit 52 according to the first embodiment will be described with reference to FIG. The adjustment amount determination means 52 sets the parallel movement amount Δs that changes stepwise every time the button 201 is selected so that the change amount of the output pixel value is constant regardless of the inclination.

  FIG. 1 shows how the gradation conversion characteristic curve changes each time the button 201 is selected. The gradation conversion characteristic curve has two linear portions where y = a1 * x + b1 and y = a2 * x + b2. This is illustrated in the case of a gradation conversion characteristic curve.

  Here, each time the button 201 is selected, the adjustment amount determination means 52 determines the changing parallel movement amount | Δs | by the following method. First, the adjustment amount determination unit 52 sets Δo as a change width of a preset output pixel value each time the button 201 is selected once. This change width Δo is set to a change width that does not give the operator a sense of incongruity.

  Then, the adjustment amount determining means 52 is | Δs | = Δo / a1 in the case of the gradation conversion characteristic curve a (y = f (x)) where the straight line portion is y = a1 * x + b1 shown in FIG. In the case of the gradation conversion characteristic curve b (y = g (x)) where the straight line portion is y = a2 * x + b2, | Δs | = Δo / a2. As a result, the output pixel value that changes each time the button 201 is selected becomes new gradation conversion characteristic curves a ′ and b ′ that become Δo regardless of the gradient of the gradation conversion characteristic curve.

  Here, when the left arrow button is selected from the two buttons 201 shown in FIG. 4, the parallel movement amount s is s = s−Δs, and when the right arrow button is selected, s = S + Δs. As a result, when the left arrow button is selected, the gradation conversion characteristic curve moves to the right, the output pixel value with respect to the input pixel value becomes low, and the image becomes dark. When the right arrow button is selected, the gradation conversion characteristic curve moves to the left, the output pixel value with respect to the input pixel value increases, and the image has higher brightness or density.

  Next, a case where the amount of change Δo of the output pixel value is made constant regardless of the inclination g when the adjustment amount determination unit 52 moves the pointer position on the slider 203 by a predetermined amount will be described. Here, the adjustment amount determination means 52 changes the change amount Δs of the parallel movement amount s of the gradation conversion characteristic curve when the pointer on the slider is moved by a predetermined amount, and the gradient g of the gradation conversion characteristic curve is changed. Every time, it adjusts according to the value of inclination g. This adjustment is performed by changing the range width in which the parallel movement amount s can be set corresponding to the operating range of the pointer on the slider 203.

  If the lower limit value and the upper limit value of the settable parallel movement amount s of the slider 203 at the time of adjustment are L1 and Lh, the pointer on the slider 203 can set a continuous value from L1 to Lh. The range width of the lower limit value Ll and the upper limit value Lh is changed to make the change amount Δo of the output pixel value constant when the pointer position changes by a predetermined amount regardless of the inclination g.

  The value of the parallel movement amount s corresponding to the pointer position on the slider 203 at the time of adjustment is defined as Vn. Here, when the gradient of the gradation conversion characteristic curve is 1, the lower limit value and the upper limit value of the settable parallel movement amount s are set as reference values Kl and Kh, and the gradation conversion characteristic is based on the Kl and Kh. The lower limit value Ll and the upper limit value Lh are adjusted according to the slope g of the curve. It is defined that Kl = −4000 and Kh = 4000.

  When the gradient g of the gradation conversion characteristic curve is changed by operating the buttons 205 and 206 and the slider 207, the pointer position on the slider 203 of the parallel movement amount s at the time of adjustment is positioned at the center on the slider 203. Similarly, the values of the lower limit value Ll and the upper limit value Lh are adjusted by the following equations.

Ll = Vn− (Kh−Kl) / g / 2, Lh = Vn + (Kh−Kl) / g / 2
As a result, the adjustment amount determination unit 52 makes the change amount Δo of the output pixel value constant when the pointer on the slider 203 is moved by a predetermined amount regardless of the gradient g of the gradation conversion characteristic curve.

  Next, there will be shown a case where the adjustment amount determining means 52 makes the gradient g of the gradation conversion characteristic curve a constant ratio regardless of the gradient each time the button 205 is selected once. Here, the adjustment amount determination means 52 uses the amount Δg that changes each time the button 205 is selected as the rate of change in the gradient g of the gradation conversion characteristic curve. Thereby, the change amount of the inclination g when the button 205 is selected once becomes g * Δg.

  When the left arrow button is selected from the two buttons 205 shown in FIG. 4, the newly set inclination g is g = g−g * Δg = g (1−Δg) and is directed to the right. When the arrow button is selected, the newly set inclination g is g = g + g * Δg = g (1 + Δg).

  As described above, in the first embodiment, the stepwise change amount Δs of the parameter of the parallel movement amount s when the button 201 is selected is expressed as the gradient g of the gradation conversion characteristic curve (the first embodiment). In this case, Δs = Δo / g from the change width Δo of the output pixel value and the change width Δo of the output pixel value. Therefore, every time the button 201 is selected, even when the gradient g of the gradation conversion characteristic curve is different. The output pixel value changes with a constant change width Δo, and the operator can easily make his / her preference by selecting the button 201 that always changes the brightness or density of the image by a constant brightness or density.

Further, in the first embodiment, the stepwise change amount Δg of the parameter of the inclination g when the button 205 is selected is set as a change ratio of the inclination g of the gradation conversion characteristic curve, and a newly set inclination is set. Since g is g = g (1 ± Δg), even when the gradient g of the gradation conversion characteristic curve is different, the gradient always changes at a constant change rate Δg each time the button 205 is selected. The selection of the button 205 that always changes the contrast of the image by a certain ratio can be easily set as desired.
(Embodiment 2)
By the way, in Embodiment 1 described above, when the button 201 is selected once, the stepwise change amount Δs of the parallel movement amount s is considered in consideration of the inclination g, so that the change width Δo of the output pixel value becomes constant. Thus, the operator has obtained a suitable tone conversion characteristic curve, but statistical information (for example, maximum signal value, minimum signal value, average value, histogram analysis value of input image information or image information of the region of interest). Etc.), a suitable gradation conversion characteristic curve can also be obtained. Therefore, the second embodiment shows a case where a plurality of movement candidate points are obtained based on statistical quantities from the histogram of the image information of the region of interest, and a suitable gradation conversion characteristic curve is determined. . As a method for determining a region of interest, for example, a method described in JP-A-5-7578 is known.

  Here, the hardware configuration according to the second embodiment is exactly the same as that shown in FIGS. 2 to 3, and the display means is exactly the same as the display means 54 shown in FIG. The detailed explanation is omitted. The gradation conversion characteristic curve is determined by two parameters of the parallel movement amount and the inclination. First, an example in which the parallel movement amount of the gradation conversion characteristic curve is determined from a histogram which is statistical information of image information. Show.

  The image processing means 30 generates a histogram of the region of interest from the generated reduced image information. This histogram shows a statistical distribution of pixel values included in the region of interest. An example of this histogram is shown inside the LUT in FIG. The horizontal axis represents pixel values, and the vertical axis represents the number of pixels in which each pixel value appears in the region of interest.

  Here, in the histogram of FIG. 6, the positions of the pixel values at which the cumulative frequency is 20%, 50%, and 80% from the lowest are indicated by symbols I20, I50, and I80, respectively. The image processing means 30 transmits the pixel value information of I20, I50 and I80 to the adjustment amount determining means 52 together with the image processing conditions. Statistical quantities such as the median value of the histogram and the most frequently used position can also be used.

  In FIG. 6, the output pixel value threshold value of the gradation conversion characteristic curve a, b or c is Ot, and the parallel movement amount s at which the output pixel value is Ot when the input pixel values are I20, I50 and I80. This shows a case where movement candidate points are used. The threshold value Ot is set approximately at the center of the output pixel value, and has a luminance or density that is easily visually perceived by the operator.

  Here, the adjustment amount determination unit 52 obtains the input pixel value It whose output pixel value is the threshold value Ot from the gradation conversion characteristic curve. When the operator presses the left arrow button of the two buttons 202 of the display means 54, the adjustment amount determination means 52 is greater than It from the pixel values of I20, I50, and I80. When the pixel value closest to It is selected as In and the right arrow button is pressed, the pixel value smaller than It and closest to It is selected as In from I20, I50 and I80.

  When the value of In is selected as I20, I50, or I80 when the button 202 is operated, the parallel movement amount s of the gradation conversion characteristic curve is updated as s = s + (It−In). To do. Thus, if the selected In value is, for example, a pixel value of I20, a pixel value with a cumulative frequency of 20% is converted to an output pixel value of the threshold value Ot by conversion using the updated gradation conversion characteristic curve. Is converted to Similarly, in the case of pixel values with cumulative frequencies of 50% and 80%, the pixel values are converted into output pixel values of the threshold value Ot. When the value of In is not selected, the parallel movement amount s is not updated.

  For example, in the case of chest imaging, the acquired image information is distributed with low pixel values in the mediastinum and diaphragm and high pixel values in the lung field region. Therefore, in this case, the cumulative frequency is 20%, 50%, 80 By obtaining three movement candidate points based on the input pixel value of%, it is possible to move quickly to the low signal side, the intermediate signal value, and the high signal side. Thus, an arbitrary number of movement candidate points can be obtained.

  Next, an example in which the gradient g of the gradation conversion characteristic curve is determined from the histogram that is the statistical information of the image information will be described. First, the adjustment amount determination unit 52 statistically analyzes the histogram of the region of interest, and determines a representative signal range that generally includes main pixel values. A histogram in the case of determining a representative signal range is illustrated in the LUT of FIG. Here, the representative signal range is a range in which the cumulative frequency when the histogram of the region of interest is viewed from the low signal value is 5% or more and 95% or less. The pixel value at which the cumulative frequency is 5% is I05, the pixel value at 95% is I95, and the width WI of this range is calculated by WI = I95−I05. In the range where the cumulative frequency is 5% or less and 95% or more, pixel values of structures that are usually unnecessary for noise and interpretation are included, so here the pixels whose cumulative frequency is 5% or more and 95% or less. Although the representative signal range is obtained based on the value, it is not limited to the value of the cumulative frequency, and various statistical quantities other than the cumulative frequency can be used.

  Further, reference values on the low pixel value side and high pixel value side of the output pixel value after the gradation conversion processing of the gradation conversion characteristic curve a, b or c in FIG. 7 are set to Ol and Oh, respectively, and the width of the output pixel value Let WO be WO = Oh-Ol. It is assumed that the conversion characteristic of the gradation conversion characteristic curve is a straight line, and a point where the width of the output pixel value obtained by gradation conversion of the input pixel value within the width WI is WO or ± 20% of WO is a movement candidate. Let it be a point. Thereby, in the histogram of the region of interest, the range width of the output pixel value obtained by converting the input pixel value included in the range of 5% or more and 95% or less of the cumulative frequency is WO * 0.8, WO * 1.0, It is possible to quickly adjust the inclination g to be WO * 1.2.

Here, the inclinations g1, g2, and g3 are
g1 = 0.8 * WO / WI
g2 = 1.0 * WO / WI
g3 = 1.2 * WO / WI
These correspond to the gradation conversion characteristic curves c, b and a in FIG. When the output pixel value exceeds the dynamic range width, the upper limit of the dynamic range is set.

  Here, when the left-pointing arrow of the button 206 shown in FIG. 4 is selected, a value that is smaller than the gradient g of the gradation conversion characteristic curve used and is closest to g from g1, g2, and g3. Is set as a new g, and when the right arrow of the button 206 is selected, the gradient conversion characteristic curve used is larger than the gradient g of the gradation conversion characteristic curve used and is closest to g. The value is set as the new g. In this case, the point where the brightness or density of the image is not extreme and the inclination value that changes moderately perceptually changes by ± 20% from the reference inclination is set as the movement candidate point, but this is limited to this ratio. Instead, an arbitrary ratio can be used as the reference for the movement candidate point.

  Subsequently, when the imaging part includes a plurality of human body structures that are likely to be noticed at the time of interpretation, a plurality of gradation conversions having parallel movement amounts s and inclinations g suitable for each structure. An example using a characteristic curve is shown. Note that a standard gradation conversion characteristic curve is generated from the analysis of the input pixel value, and the parallel movement amount s and the inclination g are adjusted with respect to the gradation conversion characteristic curve, for example, a specific structure in the imaging region. It is known to derive and use a plurality of gradation conversion characteristic curves such as a gradation conversion characteristic curve optimized for each object (for example, see JP-A-5-75925). Here, when the parameter setting values that generate these gradation conversion characteristic curves are used as movement candidate points, it is desirable to pay attention to the gradation conversion characteristic curve that is optimal for the diagnosis at that time, for example, a specific structure in the imaging region This makes it possible to find the optimum tone conversion characteristic curve for a simple button operation.

  Here, the image information indicates a case where the chest is used as an imaging region. The histogram generated from the image information of the chest shown in FIG. 8A exists in a peak that exists in a high input pixel value region that belongs to the lung field and a low input pixel value region that generally belongs to the mediastinum. It consists of a peak.

  FIG. 8B shows a gradation conversion characteristic curve optimized by the adjustment amount determining means 52 for such a histogram. Here, the gradation conversion characteristic curve a for interpretation of the entire chest, the gradation conversion characteristic curve b for interpretation of the mediastinum part, and the gradation conversion characteristic curve c for interpretation of the lung field part. Is prepared.

  Here, the gradation conversion characteristic curve a in the case of interpreting the entire chest is an output pixel value over a wide range of input pixel values so that it can be interpreted appropriately for both the lung field and the mediastinum. Is intended to be obtained. This gradation conversion characteristic curve a is used in standard interpretation.

  Further, the gradation conversion characteristic curve b in the case of interpretation with the mediastinal portion as the center moves to the left by increasing the parallel movement amount s in order to increase the output pixel value as a whole, and the mediastinum. The gradient g is increased to increase the contrast of the portion, and the mediastinal region of the input pixel value is projected onto the entire output pixel value.

  Further, the gradation conversion characteristic curve c in the case of interpretation with the lung field portion as the center moves to the right by reducing the parallel movement amount s to reduce the output pixel value as a whole, and the lung field. In order to increase the contrast of the area, the gradient g is increased, and the lung field area of the input pixel value is projected onto the entire output pixel value.

  The setting from the display means 54 shown in FIG. 4 uses, for example, buttons 202 and 206 as the movement candidate points with the parallel movement amounts s1, s2, and s3 and the gradients g1, g2, and g3 of the gradation conversion characteristic curves a to c. And set.

  Subsequently, based on the statistical characteristics of the histogram, which is statistical information generated from the image information, an adjustable range when setting the parallel movement amount s and the inclination g using the button or slider of the display unit 54, An example of setting by the adjustment range restriction means 53 is shown.

  First, an adjustment range setting for the input parallel movement amount s when the adjustment is performed on the parallel movement amount s from the basic LUT by the buttons 201 and 202 or the slider 203 will be described.

  FIG. 9 is a diagram illustrating setting of an adjustment range for the parallel movement amount s on the LUT. The horizontal axis represents the input pixel value, and the vertical axis represents the output pixel value. A histogram of input image information is shown on the horizontal axis, and a histogram of output image information is shown on the vertical axis.

  Here, the higher threshold value and the lower threshold value of the output pixel value of the basic LUT set in advance are set to Oh and Ol. Further, in the histogram of the input image information shown in FIG. 9, the pixel values whose cumulative frequencies from the low pixel value side are 20% and 80% are I20 and I80. The gradation conversion characteristic curve moves to the left and right on the basic LUT based on the set parallel movement amount s.

  The adjustment range limiting unit 53 obtains the input pixel value Ih that becomes the output pixel value Oh and the input pixel value Il that becomes the output pixel value Ol by using the gradation conversion characteristic curve on the basic LUT. For example, when the pointer of the button 201, 202 or the slider 203 is set in the left direction, the adjustment range limiting unit 53 moves the gradation conversion characteristic curve to the right, and the gradation conversion characteristic curve Il is When I80 is exceeded (illustrated by the gradation conversion characteristic b in FIG. 9), it is outside the curve adjustable range. The adjustment range limiting means 53 moves the gradation conversion characteristic curve to the left when the button 201, 202 or the pointer of the slider 203 is set to the right direction. When exceeding I20 (illustrated by gradation conversion characteristic a in FIG. 9), it is out of the adjustable range.

  Then, when the button 201, 202 or the pointer of the slider 203 is outside the adjustable range, the adjustment range limiting unit 53 does not update the parameter of the parallel movement amount s and invalidates the subsequent input operation. Further, when there are a plurality of input operations for the same parameter, such as the button 201 and the slider 203, it is possible to limit only some of the input operations, for example, the slider.

  For example, in the case of image information of chest radiography, the mediastinum and diaphragm are distributed with low pixel values and the lung field region is distributed with high pixel values. As the reference value on the high pixel value side, a pixel value having a cumulative frequency of 20% and 80% in the histogram is used, and the reference value on the low pixel value side does not exceed the higher threshold value of the output pixel value. Although the reference value on the pixel value side is set not to exceed the lower threshold value of the output pixel value, the reference value based on this cumulative frequency can be set to an arbitrary value.

  Further, since the pixel value of the human body structure that is noticed at the time of diagnosis usually performs gradation conversion within the linear region of the gradation conversion characteristic curve, the thresholds Oh and Ol are set in the straight line portion of the gradation conversion characteristic curve. It is preferable to narrow the adjustable range as the output pixel value included.

  Next, setting of the adjustment range for the input gradient g by the adjustment range restriction unit 53 when the adjustment is performed on the gradient g from the basic LUT by the buttons 205 and 206 or the slider 207 will be described. Here, the case where the same histogram as shown in FIG. 7 is used is illustrated. In this histogram, I05 and I95 are input pixel values at which the cumulative frequency from low pixel values becomes 5% and 95%. Then, the input pixel value included between 5% and 95% of the cumulative frequency is used as the region of interest, and the width WI of the region of interest is calculated as WI = I95−I05.

  Further, the adjustment range limiting means 53 calculates the output pixel value width WO = Oh−Ol from the preset upper limit Oh and lower limit Ol of the output pixel value, and defines this as the output pixel value width. Here, the width WO of the output pixel value is defined as Ol = 0 and Oh = 4095, assuming that it is equal to the output dynamic range.

  Further, assuming that the conversion characteristic of the gradation conversion characteristic curve is a straight line, the input pixel value included in the range WI is gradation-converted, and the resulting output pixel value range falls within 5 times the width WO. Limit the upper limit of the slope g. Here, it is assumed that the input pixel value within the range of 1/5 or less of the width of the region of interest is not expanded to the entire dynamic range of the output pixel value by gradation conversion at the time of image interpretation. The upper limit of the slope g is limited so that the width of the output pixel value obtained by performing tone conversion is 5 times or less of the output dynamic range, but this magnification should be based on an arbitrary value. Can do. As the lower limit of the gradient g, since it is rare that the gradient g of the gradation conversion characteristic curve is 1 or less, for example, 0.5 is set as the lower limit where the gradient g is fixed.

Here, the upper limit Gh of the gradient g of the gradation conversion characteristic curve is specifically
Gh = 5 * WO / WI
It appears in. The lower limit Gh of the inclination g is set to a fixed value of 0.5.

  The setting from the display means 54 shown in FIG. 4 is performed by setting the inclination g after setting to Gl when the left arrow button of the button 205 or 206 is pressed or the pointer on the slider 207 is moved leftward. If g <Gl, it is assumed that the adjustable range has been exceeded, and when the button 205 or 206 with the right arrow is pressed or the pointer on the slider 207 is moved to the right, The slope g after setting is compared with Gh, and if g> Gh, it is assumed that the adjustable range is exceeded.

  As described above, in the second embodiment, the input pixel value and the range of the input pixel value are specified from the histogram of the image information based on the statistical cumulative frequency of the histogram, and the specified value and Using the threshold value set in advance for the output pixel value, the movement candidate points having the parallel movement amount s and the inclination g are calculated, and these movement candidate points are selected by operating the buttons 202 or 206. The amount s and the slope g are set with an appropriate interval, and a curve that approximates the tone conversion characteristic curve intended by the operator can be quickly set.

  In the second embodiment, when the histogram of the image information exists approximately separately for each of the plurality of structures included in the imaging region, the input pixel value is set for each structure or for the whole of the plurality of structures. Since multiple gradation conversion characteristic curves that cross over are prepared and selected, the interpretation of each structure and the entire structure should be performed using the most suitable gradation conversion characteristic curve. Can do.

In the second embodiment, the input pixel value and the range of the input pixel value are specified from the histogram of the image information based on the statistical cumulative frequency of the histogram, and the specified value and the output pixel value are set. Since the upper and lower limits for setting the parallel movement amount s and the inclination g are calculated using a preset threshold value, the output pixel value is saturated even when a large change width is set. Inappropriate settings such as the above can be prevented and the time required for gradation processing can be shortened.
(Embodiment 3)
In the first and second embodiments, when the buttons 201 and 205 are pressed and the pointers of the sliders 203 and 207 are moved, the change amount of the parameter value is the adjustment input unit 51 or the adjustment amount determination unit 52. Although the value determined by is used, the amount of change per operation can be made variable. Therefore, the third embodiment shows a case where the amount of change per operation when the parameter is changed using the button or slider on the display unit 54 is variable.

  Here, the hardware configuration according to the second embodiment is exactly the same as that shown in FIGS. 2 to 3, and the display means 54 shown in FIG. The detailed explanation is omitted.

  The buttons 204 and 208 of the display means 54 shown in FIG. 4 change the amount of change in one operation of the button 201 and the slider 203 and the button 205 and the slider 207, respectively. The adjustment amount determination unit 52 doubles or ½ times this change amount each time the button 204 or 208 is pressed. Here, both the buttons 201 and 205 and the sliders 203 and 207 can change the amount of change, but the amount of change of only one of the buttons 201 and 205 and the sliders 203 and 207 can be changed. You can also

  First, a case where the amount of change per operation of the buttons 201 and 205 is changed will be described. When the button 204 displaying Δ × 2 is pressed, the adjustment amount determination unit 52 doubles the change amount Δs that is set in advance or is determined by the adjustment amount determination unit 52, and Δ / When the button 204 displaying 2 is pressed, the reference change amount Δs is halved.

  Further, the adjustment amount determination means 52 doubles the change amount Δg that is set in advance or is determined by the adjustment amount determination means 52 when the button 208 displaying Δ × 2 is pressed, When the button 208 displaying Δ / 2 is pressed, the reference change amount Δg is halved.

  Next, a case where the amount of change when the pointer on the sliders 203 and 207 is moved is changed will be described. Here, the operating range by the pointer on the slider 203 or 207 is not changed, but the change amount when the pointer is moved by a predetermined amount is changed. When the button 204 or 208 displaying Δ × 2 or Δ / 2 is pressed, the adjustment amount determining means 52 doubles or changes the change amount of the set value that can be set within the operating range of the slider 203 or 207. / 2.

  Further, in the slider 203 for adjusting the parallel movement amount s, as in the first embodiment, the gradient g of the gradation conversion characteristic curve used as a reference when determining the lower limit and the upper limit of the parallel movement amount s that can be set by the slider 203. The value of the lower limit value Kl and the upper limit value Kh in the case of 1 is doubled when the button 204 displaying Δ × 2 is pressed, and 1 when the button 204 displaying Δ / 2 is pressed. The above-described operation is performed by multiplying by 2 times.

  Further, the slider 207 for adjusting the inclination g has a lower limit value and an upper limit value of the inclination g that can be set at the time of adjustment, and is set to Ll and Lh. Can be set to continuous values. Here, when the button 208 is pressed, the lower limit value Ll and the upper limit value Lh are updated so that the pointer position on the slider 207 corresponding to the set value at the time of adjustment is positioned at the center of the slider 207.

  Here, the update operation of the lower limit value Ll and the upper limit value Lh will be described in detail. A setting value corresponding to the pointer position at the time of adjustment of the slider 207 is set to Vn. Further, the lower limit value Ll and the upper limit value Lh may be limited as a settable value range so that the range of the adjustment amount of the inclination g that can be set by the slider 207 does not become excessive when the button 208 is pressed. preferable. Therefore, the lower limit value and the upper limit value of the limit range are represented by Ml and Mh, and the range of values that the lower limit value Ll and the upper limit value Lh can take is limited to Ml to Mh. Here, it is defined that Ml = 0.5 and Mh = 20.0.

  When the button 208 displaying Δ × 2 is pressed, Ll = Vn− (Lh−Ll) and Lh = Vn + (Lh = Vn− (Lh = Ln) as the lower limit value Ll and the upper limit value Lh of the inclination adjustment amount Δg that can be set by the slider 207. Lh-Ll) is set. Here, when the lower limit value Ll is smaller than the lower limit value Ml of the limit range, Ml and Ml + (Lh−Ll) * 2 are set as the lower limit value Ll and the upper limit value Lh of the set value, respectively. When the upper limit value Lh is larger than the upper limit value Mh of the limit range, Ll = Mh− (Lh−Ll) * 2 and Lh = Mh are set as the lower limit value and upper limit value of the adjustment amount Δg. As a result, the amount of change in the inclination adjustment amount Δg when the pointer on the slider 207 is moved by a predetermined distance is doubled.

  When the button 208 displaying Δ / 2 is pressed, the lower limit value Ll and the upper limit value Lh of the inclination adjustment amount Δg that can be set by the slider 207 are expressed as Ll = Vn− (Lh−Ll) / 4 and Lh = Vn + (Lh−Ll) / 4 is set. Here, when the lower limit value Ll is smaller than the lower limit value Ml of the limit range, Ml and Ml + (Lh−Ll) / 2 are set as the lower limit value Ll and the upper limit value Lh of the set value, respectively. Further, when the upper limit value Lh is larger than the upper limit value Mh of the limit range, Ll = Mh− (Lh−Ll) / 2 and Lh = Mh are set as the lower limit value and upper limit value of the adjustment amount Δg. As a result, the amount of change in the tilt adjustment amount Δg when the pointer on the slider 207 is moved by a predetermined distance is halved.

  The adjustment amount determining means 52 assumes that the amount of change in one operation when the buttons 204 and 208 are pressed is 1/2 or 2 times. However, this value is an arbitrary magnification. Can be set to Further, Δs or Δg, which is a reference for the amount of change when the button 201 or 205 is pressed, or the lower limit value Ll and the upper limit value Lh of the set values that can be set by the sliders 203 and 207 are used as adjustment amount determination means It is also possible to change the amount of change per operation when the adjustment operation is performed by allowing direct input from 52.

  As described above, in the third embodiment, the amount of change in the adjustment value per operation of the buttons 201 and 205 or the sliders 203 and 207 is doubled, so that the vicinity of the target adjustment value is obtained. Can be moved quickly, and can be fine-tuned with fine resolution by setting it to 1/2, and the amount of change in the adjustment operation can be changed and adjusted in accordance with the adjustment situation or operator preference. The operability at the time of performing can be improved.

6 is a diagram illustrating adjustment of the parallel movement amount of the gradation characteristic curve according to Embodiment 1. FIG. It is a figure which shows the whole structure containing an image processing apparatus. 1 is a functional block diagram illustrating an overall configuration of an image processing apparatus according to a first embodiment. It is a figure which shows the display means of Embodiment 1-3. It is a figure which shows the gradation characteristic curve in LUT of Embodiment 1-3. FIG. 10 is a diagram for adjusting the parallel movement amount of the gradation characteristic curve from the histogram information according to the second embodiment. FIG. 10 is a diagram for adjusting the gradient of the gradation characteristic curve from the histogram information according to the second embodiment. 10 is a diagram for adjusting a gradation characteristic curve from histogram information including a plurality of structures according to Embodiment 2. FIG. FIG. 10 is a diagram for setting an adjustment range of a gradation characteristic curve from histogram information according to the second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image processing apparatus 2 Radiation image acquisition apparatus 3 Image output apparatus 10 Input means 20 Image data storage means 30 Image processing means 40 Processing condition storage means 50 Processing condition adjustment means 51 Adjustment input means 52 Adjustment amount determination means 53 Adjustment range restriction means 54 Display means 60 Output data storage means 70 Output means 201 Slider group 201, 202, 204, 205, 206, 208 Button 203, 207 Slider

Claims (17)

An input means for inputting image information;
Image processing means for converting the input pixel value included in the image information using a gradation conversion characteristic curve having a parallel movement amount and an inclination as variable parameters;
Processing condition adjusting means for adjusting by changing the value of the variable parameter;
Output means for outputting image information comprising the gradation-converted output pixel values;
An image processing apparatus comprising:
When the variable parameter is a parallel movement amount, the processing condition adjustment unit is configured to determine a change width of the parallel movement amount for the same input operation designating the change, and an output change of the output pixel value for each change. An image processing apparatus comprising adjustment amount determination means for setting so as to be constant.   When the variable parameter is an inclination, the adjustment amount determining means sets the change width for each input operation that specifies the change to a value obtained by multiplying the inclination of the gradation conversion characteristic curve by a certain ratio. The image processing apparatus according to claim 1.   The image processing apparatus according to claim 1, wherein the processing condition adjustment unit includes an adjustment input unit that performs the input operation.   4. The image processing according to claim 1, wherein the adjustment amount determination unit obtains a plurality of movement candidate points of the variable parameter value based on statistical information of the input pixel value. 5. apparatus.   The image processing apparatus according to claim 3, wherein the adjustment input unit includes a changing unit that changes the value of the variable parameter to the movement candidate point.   The processing condition adjusting unit calculates an adjustment range of the variable parameter value based on the statistical information of the input pixel value, and the input is performed when the value of the variable parameter outside the adjustment range is input. The image processing apparatus according to claim 1, further comprising an adjustment range restriction unit for invalidating the image processing apparatus.   The image processing apparatus according to claim 3, wherein the adjustment input unit makes a change width of a variable parameter value variable for each of the same input operations.   The image processing apparatus according to claim 1, wherein the processing condition adjustment unit includes a display unit that displays image information including the output pixel value. An input process for inputting image information;
An image processing step of converting the input pixel value included in the image information using a gradation conversion characteristic curve with a variable amount of parallel movement and inclination;
A process condition adjusting step for adjusting by changing the value of the variable parameter; and
An output step of outputting image information composed of the output pixel values subjected to the gradation conversion;
An image processing method comprising:
In the processing condition adjustment step, when the variable parameter is a parallel movement amount, a change width of the parallel movement amount for the same input operation designating the change is set as an output change of the output pixel value for each change. An image processing method characterized by comprising an adjustment amount determining step for setting so as to be constant.   In the adjustment amount determination step, when the variable parameter is an inclination, a change width for each identical input operation designating the change is a value obtained by multiplying the inclination of the gradation conversion characteristic curve by a certain ratio. The image processing method according to claim 9.   The image processing method according to claim 9, wherein the processing condition adjustment step includes an adjustment input step for performing the input operation.   12. The image processing according to claim 9, wherein the adjustment amount determining step obtains a plurality of movement candidate points of the variable parameter value based on statistical information of the input pixel value. Method.   The image processing method according to claim 11, wherein the adjustment input step includes a changing step of changing the value of the variable parameter to the movement candidate point.   The processing condition adjustment step calculates an adjustment range of the variable parameter value based on the statistical information of the input pixel value, and the input is performed when the value of the variable parameter outside the adjustment range is input. The image processing method according to claim 9, further comprising an adjustment range limiting step for invalidation.   The image processing method according to claim 11, wherein in the adjustment input step, a change width of a variable parameter value for each of the same input operations is made variable.   16. The image processing method according to claim 9, wherein the processing condition adjustment step includes a display step of displaying image information including the output pixel value.   A program for causing a computer to execute the method according to claim 9.

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