JP2003291417A - Printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer which can output output images matching (conforming) to an observation environment when the observation environment is known. <P>SOLUTION: The printer has a control means for making a gradation of hard copy images to be outputted, a gradation conformed to human sense characteristics. The control means controls to record with the gradation conformed to human sense characteristics within a maximum value and a minimum value of a recording density, which can be outputted by a printing system comprised of the printer and a recording material to be recorded by the printer. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer, and more particularly to a printer capable of outputting an output image matching (adapting) with an observation environment when the observation environment is known.

[0002]

2. Description of the Related Art For recording ultrasonic diagnostic images and the like, heat-sensitive image recording using a heat-sensitive recording material having a heat-sensitive recording layer formed on a support such as paper or film is used. Further, this thermal image recording has advantages that it does not require wet development processing and is easy to handle. Therefore, in recent years, not only small image recording such as ultrasonic diagnosis but also M
In applications such as RI diagnosis and X-ray diagnosis that require large-sized and high-quality images, they are being used for image recording for medical diagnosis.

As is well known, in thermal image recording,
For example, using a thermal head having a glaze in which heating elements corresponding to the number of pixels in one line are arranged in one direction,
With the glaze slightly pressed against the heat-sensitive recording layer of the heat-sensitive recording material, while moving the both relatively in a direction substantially orthogonal to the above-mentioned direction of arrangement of the heat-generating elements, each heat-generating element of the glaze is recorded with image data of an image. By heating according to
An image is recorded by heating the heat-sensitive recording layer of the heat-sensitive recording material. In recent years, as a method that does not require a wet development process, photothermography using a photothermographic material, that is, the photosensitive recording layer of the photothermographic material is exposed by scanning with a laser modulated by an image signal, and then by thermal development. A method of forming an image is also being used.

By the way, in a conventional thermal recording type printer, the gradation of an output recording image is usually constant according to a preset purpose of use, that is, according to characteristics of an image to be recorded. (This is common to ordinary general printers, not limited to thermal recording systems).

In the observation of images for medical diagnosis as described above (usually referred to as image interpretation), when the images are observed transparently, a dedicated observation device (a type of light box called a Schaukasten) is used. It is usual to observe the transmission image from the Schaukasten under room light.

A problem in this case is that the output image is generally so-called log-linear, that is, it is output linearly with a density value which is a logarithmic value of the luminance of the original subject. It has become. Of course, the visual sense of a human being, who is an observer, is almost linear, but according to recent research, it has been found that the human's contrast discrimination ability becomes worse as the luminance becomes lower.
This is because, for example, when observing a certain image through transmission, when observing with a high-intensity Schaukasten (a kind of light box) that is an observation device, the contrast that can be identified is the same image observed with a low-intensity Schaukasten If you do, it may not be possible to identify.

In a medical institution, a large number of observing schaukastens are arranged at various places, and the luminosity of these schaukastens is not necessarily the same. Therefore, although the problems described above are always possible problems, no solution has been found to date for such problems. In particular, the place where the image is created (a place near the imaging device) and the place where the created image is observed (a doctor,
Even if the radiologist does a radiological reading, etc.), the target for gradation setting when creating an image could not be clearly grasped.

That is, in the past, the main idea was to set the printer with an average gradation as a temporary target, and to cope with any inconvenience individually. In this case, the individual coping method is mainly to change the observation conditions on the observing side (for example, to change the brightness of a certain specific Schaukasten or to make an agreement that this Schaukasten is not used for this purpose). It was However, this does not solve any of the underlying problems.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to solve the problems in the conventional technique and to make an observation when the observation environment is known. It is to provide a printer capable of outputting an output image that matches (matches) the environment.

[0010]

In order to achieve the above object, a printer according to the present invention has a control means for adjusting the gradation of a hard copy image to be output so as to match the characteristics of human perception. Is characterized by.

Here, the control means is within the maximum and minimum values of the print density that can be output by a printing system including a printer and a printing material on which printing is performed by the printer. It is preferable to control so as to perform recording having a gradation that matches the characteristics of perception.

Further, it is preferable that the gradation matching the characteristics of human perception is a gradation specified by GSDF of DICOM.

Further, the control means determines a recording material which can be output by the printing system, which is determined on the basis of the maximum density required for the output hard copy image and information regarding the observation environment of the image. The density information of the usage density range between the maximum and minimum recording densities may be converted into luminance information, and based on this, recording may be performed with gradations that match the characteristics of human perception. preferable.

Furthermore, the control means outputs the brightness information obtained from the utilization density range of the recording material output by the printing system when performing recording having gradation matching the characteristics of human perception. Corresponding to this, it is preferable that the recording is performed by dividing into a number of steps equal to or more than the number of sensible differences regarding the human contrast discrimination, and having a gradation matching the characteristics of the human perception.

Further, in addition to the above configuration, the printer according to the present invention preferably has means for recording information on a recommended viewing environment on the recording material to be output.

Here, the information regarding the recommended viewing environment is the brightness of the Schaukasten to be used and the illuminance of the illumination light in the room to be observed in the case of observation by transmission, and the information on the indoor environment to be observed in the case of observation by reflection. The illuminance of the illumination light is preferable.

According to the present invention, as described above, the gradation matching the characteristics of human perception is DICOM (Digit
GS of alImaging and Communications in Medicine)
It is preferable that the gradation is a gradation defined by DF (Grayscale Standard Display Function), but this gradation will be described below a little.

The above definition quantifies the contrast discrimination ability of human beings by the concept of JND (just recognizable difference), and the perceptual linear gradation in which the relationship between the luminance at various luminances and the JND is graphed. Although it is originally defined as a standard for displaying an image related to medical treatment, here, it is applied to the field of image observation.

In FIG. 1, the graph defined in the DICOM GSDF is reproduced. FIG. 1 is a graph in which the horizontal axis represents the above-mentioned JND and the vertical axis represents the luminance (cd / m ² ). The line extending from the upper right to the lower left of this graph is a straight line at the beginning, and a large downward bend represents a reduction in the human contrast discrimination ability in the low luminance portion.

The point of the printer according to the present invention is that this graph (hereinafter referred to as PL curve) is used to approximate the output image to a PL curve according to its luminance range (converted from the density range of the image). It is a thing. Furthermore, when converting the density value of the image to the brightness value described above, the maximum density required for the image and the maximum density that can be reproduced by the printing system are considered, and the observation environment is also considered. This is an important point.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 2 is a side sectional view showing a schematic structure of the thermal printer according to the embodiment of the present invention. The thermal printer 10 of the illustrated example records a thermal image on a thermal recording material such as a thermal recording film (hereinafter, simply referred to as a film) F having a predetermined size such as B4 size, and the above-mentioned film F is accommodated therein. A loading section 14 in which a magazine 24 is loaded, and a feeding and transporting section 16 existing inside,
The thermal head 66 includes a recording unit 20 for recording a thermal image on the film F, a discharge unit 22, a control unit 12 for controlling the whole, and the like.

The film F has a heat sensitive recording layer formed on one surface of a transparent polyethylene terephthalate (PET) support, for example, and is a laminate of about 100 predetermined units. Then, the sheets are accommodated in the above-mentioned magazine 24, taken out from the magazine 24 one by one, and are subjected to thermal recording.

The loading section 14 has an insertion opening 30 formed in a housing 28 of the thermal printer 10, a guide / support plate 32, guide rolls 34, 34, a stopper 36, and the like. The magazine 24 is inserted into the thermal printer 10 through the insertion opening 30 of the loading section 14 with the lid 26 side facing forward, and the guide / support plate 32 and the guide rolls 34, 34 are provided.
The thermal printer 10 is pushed into a position where it abuts on the stopper 36 while being guided to, and is loaded in a predetermined position of the thermal printer 10.

The supply / conveyance unit 16 takes out the film F from the magazine 24 loaded in the loading unit 14, and the recording unit 2
A sheet-fed mechanism that uses a suction cup 40 that sucks the film F by suction, and a transport unit 42,
The transport guide 44 and the cleaning roller pair 56 located at the exit of the transport guide 44 are included.

The conveying means 42 comprises a conveying roller and a nip roller pressed by the conveying roller.
The cleaning roller pair 56 is a roller pair including an adhesive rubber roller and a normal roller, and is for removing dust and the like adhering to the film F.

When the recording start is instructed in the thermal printer 10, the lid 26 of the magazine 24 is opened by an opening / closing mechanism (not shown), and one film F from the magazine 24 is opened by the sheet-fed mechanism using the suction cup 40. The film F is taken out and the leading edge of the film F is supplied between the conveying roller of the conveying means 42 and the nip roller. When the film F is nipped between the transport roller and the nip roller,
The suction by the suction cup 40 is released, and the supplied film F
Are transported along the transport guide 44.

Incidentally, when the film F to be recorded is completely discharged from the magazine 24, the lid 26 is closed by the opening / closing mechanism. The distance defined by the transport guide 44 from the transport unit 42 to the cleaning roller pair 56 is set to be slightly shorter than the length of the film F in the transport direction, and the leading end of the film F is transported by the transport unit 42 to the cleaning roller. Reach pair 56.

Here, the cleaning roller pair 56 may be initially stopped, and the leading edge of the film F may be temporarily stopped here. That is, when the tip of the film F reaches the cleaning roller pair 56, the temperature of the thermal head 66 is confirmed, and if the temperature of the thermal head 66 is a predetermined temperature, the film F by the cleaning roller pair 56 is at that time. Is restarted and the film F is transported to the recording unit 20.

On the other hand, in the system in which the cleaning roller pair 56 is not stopped, the temperature of the thermal head 66 has reached a predetermined temperature in advance (for example, when an instruction to start recording on the film F is given). After confirming it, the transport of the film F is continued, and the film F
Is controlled to be sent to the recording unit 20.

The recording section 20 comprises a thermal head 66, a platen roller 60, a cooling fan (not shown) for cooling the thermal head 66, a guide 58, a guide 62, a film discharge roller pair 63 and the like.

The thermal head 66 is, for example, 300 dp.
a thermal head main body for performing thermal image recording at a recording (pixel) density of i, which performs thermal recording for one line on the film F, and in which a glaze in which heating elements are arranged in one direction is formed; And a heat sink fixed to the thermal head body. In addition, this thermal head 6
6 is supported by a support member 68 which is rotatable about a fulcrum 68a in the direction of arrow a and in the opposite direction.

The platen roller 60 rotates at a predetermined image recording speed while holding the film F at a predetermined position, and is substantially orthogonal to the glaze extending direction (main scanning direction) (sub scanning direction). The film F is conveyed to.

Before the film F is conveyed to the thermal head 66, the supporting member 68 is rotated upward (in the direction opposite to the arrow a direction) so that the glaze of the thermal head 66 and the platen roller 60 come into contact with each other. Not not. When the transport of the film F by the cleaning roller pair 56 is started, the film F is transported while being guided by the cleaning roller pair 56 and the guide 58.

When the leading edge of the film F is conveyed to the recording start position (the position corresponding to the glaze), the above-mentioned supporting member 6 is formed.
8 is rotated in the direction of arrow a, the film F is sandwiched between the glaze of the thermal head 66 and the platen roller 60,
The glaze is pressed against the recording layer. Next, the film F is conveyed in the direction of the arrow b while being held at a predetermined position by the platen roller 60.

The thermal image recording is performed on the film F by heating each heating element of the glaze in synchronization with this conveyance in accordance with the recorded image. The film F on which the thermal image recording has been completed is guided by the guide 62, is conveyed by the platen roller 60 and the film discharge roller pair 63, and is discharged to the tray 18 of the discharge unit 22 provided at the upper portion of the thermal printer 10. .

The thermal printer 10 according to this embodiment is
It is basically configured as described above and operates as described above. The series of operations described above is controlled by the control function of the control unit 12. Next, a gradation conversion operation, which is a characteristic operation of the thermal printer 10 according to the present invention, will be described. Note that this operation is also controlled by the control function of the control unit 12 described above. Although not shown here, the control unit 12 is connected to an input unit having data input keys and an output unit having a display screen for displaying input data and instructions to an operator. Has been done.

FIG. 3 shows the flow of a general gradation conversion operation in the printer according to this embodiment. The example shown in FIG. 3 is an operation for obtaining the gradation of the image to be recorded on the film in the form based on the PL curve described above, and the data for actually printing the image on the film based on the operation. It shows the operation to obtain.

Preliminary preparations are as follows: (1) Using a standard sample for density check, the gradation characteristics (printer drive data and density characteristic curve of printer drive data and density) peculiar to the system composed of the recording material and printer used here. ) And its minimum density (Dmin: equivalent to so-called Fog). (2) From the graph shown in FIG. 1, the luminance and JND (0 to 10
Lookup table (L up to 23)
UT). Do the two above.

Next, the specific operation will be described. Step 8
1 is the operator's brightness (Ls) of the used Schaukasten, the brightness (Le) reflected from the film by the illumination light of the observation environment, the minimum density (Dmin :), and the required density range (range: ΔD = Dmax-Dmin). This is a step of calculating the maximum luminance (Lmax) and the minimum luminance (Lmin) here by the following formulas based on the information when receiving the input.

[Equation 1]

In step 82, the brightness value included in the section between the maximum brightness (Lmax) and the minimum brightness (Lmin) calculated in step 81 is calculated by using the LUT described above, and the JND (also included in this section). This is the above-mentioned GSDF
The range of (calculated from JND values corresponding to Lmax and Lmin obtained by the attached conversion table) is assigned to the full scale of the image data, and the relationship between the brightness to be realized and the image data (gradation characteristic data for printing) is assigned. create.

In step 83, the value of the original image data is changed based on the gradation data obtained above and the characteristic curve peculiar to the printing system obtained in advance, and printing is executed. By operating in this manner, the printer according to the present embodiment has a characteristic that the density range has a desired density range, and that each density point between them has a shape along the above-mentioned PL curve, that is, human perception. It is possible to obtain the effect that it is possible to print an image that has gradation matching the characteristics and that is suitable for the viewing environment.

A more concrete example will be described below. Example 1 In this example, a film image for transmission observation is displayed.
This is the case when printing. In addition, here, in advance preparation
From this, it is assumed that it is known that Dmin = 0.15. Well
In addition to this, the brightness of the observation Schaukasten is 300
0 cd / m², The illumination light illuminance is 100 lx,
The brightness of the illumination light reflected by the mushroom film is 10 cd / m ²
And the concentration range (ΔD) needs to be 2.85.

From Dmax = ΔD + Dmin, here Dma
When Lmax and Lmin are calculated by using the above equation with x = 3.0 (= 2.85 + 0.15), in this case,

[Equation 2] Becomes

FIG. 4 shows the above situation. Note that FIG.
The dotted line in the middle is the characteristic curve peculiar to the printing system obtained by the preliminary preparation, and Dinf (= 3.70) indicates the maximum density that can be output by this system. The meaning of FIG. 4 is that, first, the maximum density is changed from Dinf (= 3.70) to Dmax (= 3.0) required here, between the Dmax and Dmin of the gradation curve S1. PL
The gradation along the PL curve is obtained by raising the lower portion on the left side (see arrow) and lowering the higher portion on the right side (see arrow) so as to match the curve.

According to the above result, ΔJND (J
Since the ND range) ≈686, the image data can be represented by, for example, 10 bits (= 1024 steps), and printing can be performed with gradation along the PL curve.
Further, in the above description, the case where the printing means is a thermal printer using a thermal head has been taken as an example, but the printing means may use a laser, as described above.

In the output image (hard copy) printed as described above, the preconditions for printing this image, that is, the brightness of the observation Schaukasten, the illuminance of the indoor illumination light (here, 300 for each
It is preferable to print an indication showing 0 cd / m ² and 100 lx) as a proper observation condition, or print it on a label and attach it.

Such a print sample is shown in FIG. 5 as a schematic diagram. In FIG. 5, 90 is a print carrying an image having a characteristic along the PL curve, which is printed by the printer according to the present embodiment, and 91 is the above-mentioned index for observation, that is, the appropriateness for observation. This is the part that records the conditions.

[Embodiment 2] In this embodiment, a film image for transmission observation is used as a special case of printing.
This is the case when printing a mammography image. The mammography image has a density range (ΔD) of, for example, 3.
As wide as 45, this is a bright Schaukasten (for example,
This is a special one in which a brightness value of 10000 cd / m ² ) is used and observation is performed in a dark room (for example, a brightness value of reflection by illumination light is 1 cd / m ² ).

When Lmax and Lmin in this case are calculated,

[Equation 3] As described above, since ΔJND≈974, it is possible to print with 10-bit image data here as well.

In the above embodiment, Lmax = 7080
It becomes cd / m ² and exceeds the luminance range shown in FIG. 1, but in such a case, it is possible to extrapolate the right side portion of the PL curve as a straight line. is there.
In this case, the average value of the slopes is calculated based on the conversion table attached to the GSDF, and the JN corresponding to the luminance value in the range is calculated.
It is sufficient to obtain the D value.

[Embodiment 3] In this embodiment, a film image for reflection observation is printed. As the reflection density in this case, the reflection density value of the film offset with the luminance of the Schaukasten set to 0 is used. With such a premise, Lmax and Lmin are calculated, and the subsequent processing may be performed in the same manner as in the case of a transparent image.

By performing the processing as described above, even when a film image for reflection observation is printed, it is possible to print with a gradation along the PL curve.

The above-mentioned embodiments are examples of the present invention, and the present invention should not be limited to these. Appropriate changes or improvements may be made without departing from the scope of the present invention. It goes without saying that you can go.

For example, in the printer shown in the embodiment,
A concentration measuring unit for obtaining the minimum concentration (Dmin) may be provided using the standard sample for the concentration check as described above, and thereby the process of obtaining the minimum concentration (Dmin) can be made efficient. Is obtained. Further, by connecting the brightness measuring means, the illuminance measuring means, etc. to the printer, it is possible to obtain the effect that it is not necessary to input these measurement data. In addition, the various measuring means described above,
It does not matter if it is not directly connected to the printer or online (wired or wireless).

[0056]

As described above in detail, according to the present invention, when the observation environment is known, a printer capable of outputting an output image matching (adapting) the observation environment is realized. It has a remarkable effect that it can be done.

More specifically, the images for transmission observation and the images for reflection observation are matched with the respective observation environments, and are printed out as images having gradations according to the characteristics of human perception, which are important for observation. It is possible to obtain the effect that it is possible to realize a printer capable of performing the above.

[Brief description of drawings]

FIG. 1 is a graph (PL curve) showing characteristics of human perception defined by GSDF of DICOM.

FIG. 2 is a side sectional view showing a schematic configuration of a thermal printer according to an embodiment of the present invention.

FIG. 3 is a diagram showing a flow of a general gradation conversion operation in the printer according to the present embodiment.

FIG. 4 is a diagram illustrating a situation of gradation conversion according to an embodiment.

FIG. 5 is a schematic diagram showing a print sample according to an example.

[Explanation of symbols]

10 thermal printer 12 Control unit 81-83 processing steps 90 print samples 91 Observation condition recording section

Claims (5)

[Claims] 1. A printer comprising control means for adjusting the gradation of a hard copy image to be output so as to match the characteristics of human perception. 2. The human perception as defined by the control means within a maximum and a minimum recording density that can be output by a printing system including a printer and a recording material on which the printer performs recording. 2. The printer according to claim 1, wherein the printer is controlled so as to perform recording having a gradation that matches the characteristics of [1]. 3. The gradation matching the characteristics of human perception is
3. The printer according to claim 1, wherein the gradation is defined by GSDF of DICOM. 4. The recording means, which is determined based on the maximum density required for the output hardcopy image and the information regarding the observation environment of the image, for the recording material that can be output by the printing system. The density information of the usage density range between the maximum value and the minimum value of the recording density is converted into luminance information, and based on this, recording having a gradation matched to the characteristics of human perception is performed. The printer according to claim 1, wherein the printer is a printer. 5. The printer according to claim 1, further comprising, in addition to the configuration, means for recording information regarding a recommended viewing environment on the output recording material.