Patent Publication Number: US-2017359485-A1

Title: Image processing apparatus and image processing method

Description:
TECHNICAL FIELD 
     The present invention relates to image processing for reproducing the material appearance of images. 
     BACKGROUND ART 
     The need for image processing that reproduces the material appearance of images by controlling the gloss in addition to colors has been increasing. PTL 1 describes a technology for reproducing specular reflection light from an object to be reproduced within the dynamic range of the display device to excellently reproduce the gloss of the object using computer graphic techniques. 
     CITATION LIST 
     Patent Literature 
     PTL 1: Japanese Patent Laid-Open No. 2010-246049 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, according to PTL 1, there still remains a mismatch between the range of the material appearance further including a material appearance element other than the specular reflection light from the object to be reproduced and the range of the material appearance reproducible by a material appearance reproducing apparatus, such as a printer. Accordingly, if the material appearance of the object to be reproduced cannot be reproduced by the material appearance reproducing apparatus, a reproduced object corresponding to the full reproduction range of the material appearance reproducing apparatus cannot be obtained or the material appearance of the object to be reproduced is damaged. As a result, a user of the material appearance reproducing apparatus cannot obtain reproduction of a desired material appearance. 
     The present invention provides image processing for obtaining a reproduced object having a desired material appearance fully using the reproduction range of the material appearance reproducing apparatus. 
     According to an aspect of the present invention, an image processing apparatus includes an input unit configured to receive first material appearance data representing a material appearance of an image, a material appearance mapping unit configured to convert the first material appearance data into second material appearance data corresponding to a material appearance reproducible by a material appearance reproducing apparatus, and a conversion unit configured to convert the second material appearance data into control data for reproducing the material appearance of the image using the material appearance reproducing apparatus. The first material appearance data includes a gloss signal corresponding to a specular gloss and a gloss signal corresponding to an image clarity. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a flowchart of a material appearance reproducing procedure according to a first exemplary embodiment. 
         FIG. 2  is a flowchart of a material appearance mapping procedure according to the first exemplary embodiment. 
         FIG. 3  is a flowchart of a gloss mapping procedure according to the first exemplary embodiment. 
         FIG. 4  is a flowchart of the first half of block building procedure according to the first exemplary embodiment. 
         FIG. 5  is a flowchart of the second half of the block building procedure according to the first exemplary embodiment. 
         FIG. 6A  is a schematic illustration of the structure of a head cartridge according to the first exemplary embodiment. 
         FIG. 6B  is a schematic illustration of the structure of the head cartridge according to the first exemplary embodiment. 
         FIG. 7  is a block diagram of the hardware configuration of a material appearance reproducing system according to the first exemplary embodiment. 
         FIG. 8  is a flowchart of a gloss mapping procedure according to a first modification of the first exemplary embodiment. 
         FIG. 9  is a block diagram illustrating the functional configuration of the material appearance reproducing system according to the first exemplary embodiment. 
         FIG. 10  is a schematic illustration of the order in which processing areas are scanned in the block building process. 
         FIG. 11  is a schematic illustration example of a device properties table. 
         FIG. 12A  is a schematic illustration of an example of a pass mask. 
         FIG. 12B  is a schematic illustration of an example of a pass mask. 
         FIG. 12C  is a schematic illustration of an example of a pass mask. 
         FIG. 12D  is a schematic illustration of an example of a pass mask. 
         FIG. 12E  is a schematic illustration of an example of a pass mask. 
         FIG. 12F  is a schematic illustration of an example of a pass mask. 
         FIG. 12G  is a schematic illustration of an example of a pass mask. 
         FIG. 13  is a schematic illustration of typical characteristics of multi angle distribution of reflection. 
         FIG. 14  is a block diagram of the functional configuration of a material appearance reproducing system according to a second exemplary embodiment. 
         FIG. 15  is a schematic illustration of an example of a material appearance reproduction table. 
         FIG. 16  is a flowchart of a material appearance reproducing procedure according to the second exemplary embodiment. 
         FIG. 17  is a schematic illustration of material appearance data used for describing an example of a verification technique. 
         FIG. 18  illustrates an example of CG images displayed in a gloss adjustment UI according to a first modification of a third exemplary embodiment. 
         FIG. 19  is a schematic illustration of gloss mapping. 
         FIG. 20A  is a schematic illustration illustrating the specular gloss and the image clarity. 
         FIG. 20B  is a schematic illustration illustrating the specular loss and the image clarity. 
         FIG. 20C  is a schematic illustration illustrating the specular gloss and the image clarity. 
         FIG. 21  is a flowchart of a material appearance reproducing procedure according to the third exemplary embodiment. 
         FIG. 22  is a schematic illustration of an example of a gloss adjustment UI according to the third exemplary embodiment. 
         FIG. 23  is a block diagram of the functional configuration of a material appearance reproducing system according to the third exemplary embodiment. 
         FIG. 24  is a schematic illustration of a gloss adjustment UI according to a first modification of the third exemplary embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Exemplary embodiments of the present invention are described in detail below with reference to the accompanying drawings. 
     First Exemplary Embodiment 
     Material Appearance Reproducing Technique  1   
     A material appearance reproducing technique according to the present exemplary embodiment is described first. As used herein the term “reproduction of material appearance” refers to outputting a reproduced object having an appearance that is the same as that of the object to be reproduced. In addition, the term “material appearance” refers to a set of properties to be matched between the reproduced object and the object to be reproduced to have the same appearance when the two are comparatively observed. The material appearance has a plurality of elements such as color, gloss, internal scattering, and shape. If the material appearance can be quantitatively expressed using a value, a reproduced object having an appearance that is the same as that of the object to be reproduced can be obtained by outputting the reproduced object so that the value is the same for the reproduced object and the object to be reproduced. Hereinafter, the value is referred to as a “material appearance signal”. If the object to be reproduced is, for example, a printout that is flat and that has a sufficiently small surface roughness, a reproduced object having a shape that is substantially the same as that of the object to be reproduced can be obtained by printing an image on a flat medium of the same type as the printout. In such a case, the important elements of the material appearance are the color and the gloss. That is, the material appearance is formed from the two elements. Even in the other cases, the color and gloss are important elements of the material appearance. 
     As a color signal that is the numerical representation of color, the value defined in existing CIELAB can be used, for example. CIELAB mainly represents the characteristics regarding the brightness and chromaticity of diffuse reflection light. As used herein, the term “diffuse reflection light” refers to reflection light in a diffuse reflection direction which is defined as directions other than the specular direction and its vicinity. By printing the reproduced object so that the CIELAB value of the reproduced object is the same as that of the object to be reproduced, the appearance in terms of color in the diffuse reflection direction can be made to be substantially the same as that of the object to be reproduced. 
     As a gloss signal, which is a numerical representation of the gloss, the value of widely used specular gloss, the value of widely used degree of sharpness of reflected, or the value of widely used reflection haze can be employed, for example. The specular gloss represents the properties regarding the brightness of specular reflection light. The values obtained by dividing the degree of sharpness of reflected and the specular gloss by the reflection haze represent the properties regarding the sharpness of an illumination image produced by reflection at a surface of the object. Hereinafter, the properties regarding the sharpness of the illumination image is referred to as “image clarity”. As the image clarity becomes higher, the degree of sharpness of reflected becomes higher and, thus, the value obtained by dividing the specular gloss by the reflection haze becomes higher.  FIGS. 20A to 20C  are schematic illustrations of the specular gloss and the image clarity. Each of images  2231  to  2234  illustrated in  FIG. 20A  is the image of an illumination light source produced by reflection at a surface of a sample. More specifically, as illustrated in  FIG. 20B , each of the images  2231  to  2234  is the image of the illumination light source  2210  produced by reflection at a surface of a sample  2220  when viewed in the specular direction of the illumination light source  2210 .  FIG. 20C  illustrates the configuration of the illumination light source  2210  of this example. The illumination light source  2210  includes three linear fluorescent light tubes  2211  to  2213  and five louvers  2214  to  2218 . 
     The image  2231  illustrated in  FIG. 20A  is obtained when both the specular gloss and image clarity of the sample  2220  are high. The image of the illumination light source  2210  produced by reflection at a surface of the sample  2220  is bright and sharp. The image  2232  is obtained when both the specular gloss and image clarity of the sample  2220  are low. The image of the illumination light source  2210  produced by reflection at the surface of the sample  2220  is dark and blurred. The image  2233  is obtained when the specular gloss of the sample  2220  is high but the image clarity is low. The image of the illumination light source  2210  produced by reflection at the surface of the sample  2220  is bright but blurry. The image  2234  is obtained when the specular gloss of the sample  2220  is low but the image clarity is high. The image of the illumination light source  2210  produced by reflection at the surface of the sample  2220  is dark but sharp. If the reproduced object is printed so that the gloss signal corresponding to the specular gloss and the gloss signal corresponding to the image clarity are the same as those of the object to be reproduced, the brightness and the sharpness of the illumination image produced by reflection can be made to be substantially the same as those of the object to be reproduced. Conversely, even when only one of the specular gloss and the image clarity is the same, the appearances are not the same. That is, to obtain excellent reproduced material appearance, it is desirable that both the specular gloss and the image clarity be controlled. 
     Material Appearance Reproducing Procedure 
       FIG. 1  is a flowchart illustrating the steps (the processes) of a material appearance reproducing procedure according to the first exemplary embodiment. In step S 101 , the material appearance data of the object to be reproduced is input. For example, the material appearance data is image data formed from a material appearance signal corresponding to CIELAB, the specular gloss, and the image clarity. That is, the material appearance data includes a CIELAB-based color signal and a gloss signal corresponding to the specular gloss and image clarity for each of small areas. Note that the image data may be measurement data itself (described in more detail below). In addition, hereinafter, each of the small areas that constitute the material appearance data is referred to as an “area”, an “image area”, or a “pixel”. In step S 102 , a material appearance signal is acquired from the material appearance data input in step S 101 . For example, a color signal or a gloss signal is acquired from the image data. Subsequently, in step S 103 , the material appearance signal acquired in step S 102  is converted into a material appearance signal corresponding to the material appearance reproducible by the material appearance reproducing apparatus. The process in this step is referred to as “material appearance mapping”. The material appearance mapping is described in more detail below. Subsequently, in step S 104 , the material appearance signal converted in step S 103  is converted into a control signal to the material appearance reproducing apparatus. The material appearance reproducing apparatus is, for example, an image printing apparatus, such as a printer. The control signal is, for example, a signal regarding the amount of a color material provided in the image printing apparatus. The control signal is described in more detail below. Finally, in step S 105 , a reproduced object is output by the material appearance reproducing apparatus on the basis of the control signal obtained in step S 104 . Note that the process in each step may be performed for each of the pixels or all the pixels. In the latter case, step S 103  is a step of converting the material appearance signals that constitute the input material appearance data into the material appearance data constituted by the material appearance signals corresponding to the material appearance reproducible by the material appearance reproducing apparatus. Similarly, step S 104  is a step of converting the material appearance data converted in step S 103  into control data constituted by the control signals of the material appearance reproducing apparatus. 
       FIG. 2  is a flowchart illustrating the steps (the processes) of the material appearance mapping procedure.  FIG. 2  illustrates the details of step S 103  illustrated in  FIG. 1 . In step S 201 , it is determined whether the material appearance signal obtained in step S 102  is a material appearance signal corresponding to the material appearance reproducible by the material appearance reproducing apparatus. For example, a combination of the values of the CIELAB, the specular gloss, and the image clarity that are reproducible by the material appearance reproducing apparatus and that are measured in advance is prestored as output material appearance reproducible range information. If the material appearance signal obtained in step S 102 , that is, a combination of CIELAB, the specular gloss, and the image clarity is within the output material appearance reproducible range information, it is determined that the material appearance signal obtained in step S 102  is a material appearance signal reproducible by the material appearance reproducing apparatus. Thereafter, the processing proceeds to step S 202 . Otherwise, it is determined that the material appearance signal is a material appearance signal un reproducible by the material appearance reproducing apparatus. Thereafter, the processing proceeds to step S 203 . In step S 202 , the material appearance signal obtained in step S 102  is not converted and is directly output as a converted material appearance signal. Thereafter, the processing proceeds to step S 104 . 
     In step S 203 , the color signal is converted into a color signal corresponding to a color reproducible by the material appearance reproducing apparatus. The process in step S 203  is referred to as “color mapping”. The color mapping is performed using an existing technique. For example, the color signal is converted into a color signal having a CIELAB color value reproducible by the material appearance reproducing apparatus and having a hue angle that is the same as that of the CIELAB obtained in step S 102  and the smallest color difference ΔE. As the hue angle and the color difference ΔE, the value of a widely used ab hue angle and the value of widely used CIEDE2000 can be employed, respectively. Note that if the color signal obtained in step S 102  is a color signal reproducible by the material appearance reproducing apparatus, the color signal is not converted and is directly output as a converted color signal. Thereafter, the processing proceeds to step S 204 . 
     In step S 204 , the gloss signal is converted into a gloss signal corresponding to the gloss reproducible by the material appearance reproducing apparatus. Thereafter, the processing proceeds to step S 104 . The process in step S 204  is referred to as “gloss mapping”. In the gloss mapping according to the present exemplary embodiment, a gloss element of interest is changed in accordance with the spatial distribution of the material appearance signals obtained in step S 102 . For example, since for a granular area of the reproduced object that glitters, the degree of the specular gloss has a significant impact on the appearance, the reproducibility of the specular gloss is given more weight over the image clarity. Hereinafter, such an area is referred to as an “area having a large gloss change”. In contrast, for an area in which substantially uniform gloss is widely distributed or an area in which the gloss that gently changes is widely distributed, the degree of the image clarity has a significant impact on the appearance. Thus, the reproducibility of the image clarity is given more weight over the specular gloss. Hereinafter, such an area is referred to as an “area having a small gloss change”. In the gloss mapping according to the present exemplary embodiment, a determination signal used for determining whether an area to be processed is an area having a large gloss change or an area having a small gloss change is set on the basis of the spatial distribution of the material appearance signals. Note that the determination signal is described in more detail below. Thereafter, determination is made on the basis of the determination signal. For an area determined to be an area having a large gloss change, the reproducibility of the specular gloss is given more weight, and the gloss signal is converted. In contrast, for an area determined to be an area having a small gloss change, the reproducibility of the image clarity is given more weight, and the gloss signal is converted. The determination signal is set for each of the areas. The determination signal for an area of interest is set on the basis of the material appearance signal of the area of interest and the material appearance signals of areas of non-interest in the vicinity. Note that hereinafter, the area of interest is also referred to as a “pixel of interest”. 
       FIG. 19  is a schematic illustration of the gloss mapping. In  FIG. 19 , the abscissa represents a signal corresponding to the image clarity, and the ordinate represents a signal value corresponding to the specular gloss. A region  201  indicates the range of the specular gloss and the image clarity reproducible by the material appearance reproducing apparatus. For example, if the input data has the specular gloss and the image clarity indicated by a point  202 , the conversion is made as follows. That is, for example, in an area for which determination is made so that the specular gloss is given more weight, the gloss signal is converted into the specular gloss and the image clarity indicated by a point  203 . As a result, a reproduced object having a small difference between the input data and the specular gloss can be provided. In contrast, for example, in an area for which determination is made so that the reproducibility of the image clarity is given more weight, the gloss signal is converted into the specular gloss and the image clarity indicated by a point  204 . As a result, a reproduced object having a small difference between the input data and the image clarity can be provided. 
       FIG. 3  is a flowchart illustrating the steps (the processes) of a detailed gloss mapping procedure. That is,  FIG. 3  illustrates the process in step S 204  illustrated in  FIG. 2  in detail. In step S 301 , in the image, neighboring areas having a small gloss difference are grouped into the same block on the basis of the spatial distribution of the material appearance signals obtained in step S 102 , and a determination signal representing the size of the block is set for each of the areas. The process in step S 301  is referred to as “block building”. More specifically, a block is generated using the spatial distribution of the gloss signal in the input data. An amount regarding the size of a space occupied by a block to which the area of interest belongs in the vicinity of the area of interest is used as the determination signal. A block is a set of areas including one or a plurality of successive areas in which the difference in gloss signal between neighboring areas is smaller than a predetermined threshold value. The determination signal that is small indicates that the area of interest is an area having a large gloss change. However, the determination signal that is large indicates that the area of interest is an area having a small gloss change. In this manner, an area having a large gloss change can be separated from an area having a small gloss change. 
     Subsequently, in step S 302 , one of conversion in which the reproducibility of the specular gloss is given more weight and conversion in which the reproducibility of the image clarity is given more weight is selected for each area on the basis of the input data. In this manner, the processing suitable for each area is performed and, thus, a reproduced object having an appearance that negligibly differs from that of the object to be reproduced indicated by the input data can be obtained. More specifically, it is determined whether the determination signal regarding the size of the block including the area of interest is lower than a predetermined threshold value. For example, the threshold value is set to 0.5. If the size of the block associated with the area of interest is smaller than the threshold value, it is determined that the area is an area of a large gloss change. Thereafter, the processing proceeds to step S 303 . Otherwise, it is determined that the area is an area of a small gloss change. Thereafter, the processing proceeds to step S 305 . 
     In step S 303 , the signal corresponding to the specular gloss is converted to obtain a converted signal. That is, the following signal is obtained: a signal corresponding to a specular gloss reproducible by the material appearance reproducing apparatus and having the smallest difference from the signal corresponding to the specular gloss obtained in step S 102  while maintaining the color signal converted in step S 203 . Subsequently, in step S 304 , the signal corresponding to the image clarity is converted to obtain a converted signal. That is, the following signal is obtained: a signal corresponding to an image clarity reproducible by the material appearance reproducing apparatus and having the smallest difference from the signal corresponding to the image clarity obtained in step S 102  while maintaining the color signal converted in step S 203  and the signal corresponding to the specular gloss obtained in step S 303 . 
     In addition, in step S 305 , the signal corresponding to the image clarity is converted prior to converting the signal corresponding to the specular gloss to obtain a converted signal. That is, the following signal is obtained: a signal corresponding to an image clarity reproducible by the material appearance reproducing apparatus and having the smallest difference from the signal corresponding to the image clarity obtained in step S 102  while maintaining the color signal converted in step S 203 . Subsequently, in step S 306 , the signal corresponding to the specular gloss is converted to obtain a converted signal. That is, the following signal is obtained: a signal corresponding to the specular gloss reproducible by the material appearance reproducing apparatus and having the smallest difference from the signal corresponding to the specular gloss obtained in step S 102  while maintaining the color signal converted in step S 203  and the signal corresponding to the image clarity obtained in step S 305 . 
     Block Building 
       FIG. 10  is a schematic illustration of the order in which the processing areas are scanned in a block building process. Each of cells having a square shape is an area holding the material appearance signal. The processing starts from an area  1201  to another area in a direction indicated by an arrow. After the rightmost area is processed, the processing proceeds to the leftmost area in the next row. Thereafter, scanning is performed in the same manner to repeatedly process the subsequent areas until an area  1202  is reached. 
       FIG. 4  is a flowchart of the steps of the first half of a block building procedure. In the first half processing, the same block number is assigned to areas each having a difference from the gloss signal of a neighboring area that is smaller than a predetermined threshold value. In step S 401 , an initialization process is performed. More specifically, an initial value of the largest block number is set to 1. In addition, the block number of block corresponding to a first area  1201  is set to 1. Subsequently, in step S 402 , the next processing area is selected on the basis of the scan order illustrated in  FIG. 10 . In step S 403 , it is determined whether an area is present to the left of the processing area. If an area is present to the left of the processing area, the processing proceeds to step S 404 . Otherwise, the processing proceeds to step S 406 . In step S 404 , it is determined whether the processing area is in the same block as the left neighboring area. That is, a difference in gloss between the processing area and the left area is obtained. Thereafter, it is determined whether the difference in gloss is less than the predetermined threshold value. For example, as the value of the difference in gloss, the sum of the square of the difference between gloss signals corresponding to the specular gloss and the square of the difference in gloss signals corresponding to the image clarity can he used. When the 20-degree specular gloss measured using a technique defined by JIS Z8741 is used for the gloss signal corresponding to the specular gloss and the degree of sharpness of reflected measured using a technique defined by JIS K7174 is used for the gloss signal corresponding to the image clarity, the threshold value is set to, for example, 50. If the difference in gloss is less than the threshold value, it is determined that the processing block is in the same block as the left neighboring block. Thereafter, the processing proceeds to step S 405 . Otherwise, the processing proceeds to step S 406 . In step S 405 , the block number of the block corresponding to the processing area is set to the block number of the block corresponding to the left neighboring area. Thereafter, the processing proceeds to step S 417 . 
     In step S 406 , it is determined whether an area is present to the upper left of the processing area. If an area is present, the processing proceeds to step S 407 . Otherwise, the processing proceeds to step S 409 . In step S 407 , it is determined whether the processing area is in the same block as the upper left neighboring area of the processing area. That is, the difference in gloss between the processing area and the upper left neighboring area is obtained, and it is determined whether the difference in gloss is less than the predetermined threshold value. The determination is made in the same manner as in step S 404 . If the difference in gloss is less than the threshold value, it is determined that the processing area is in the same block as the upper left neighboring area of the processing area. Thereafter, the processing proceeds to step S 408 . Otherwise, the processing proceeds to step S 409 . In step S 408 , the block number of the block corresponding to the processing area is set to the block number of the upper left neighboring block. Thereafter, the processing proceeds to step S 417 . 
     In step S 409 , it is determined whether an area is present on top of the processing area if an area is present on top of the processing area, the processing proceeds to step S 410 . Otherwise, the processing proceeds to step S 412 . In step S 410 , it is determined whether the processing area is in the same block as the area on top of the processing area. That is, the difference in gloss between the processing area and the area on top of the processing area is obtained, and it is determined whether the difference in gloss is less than the predetermined threshold value. The determination is made in the same manner as in step S 404 . If the difference in gloss is less than the threshold value, it is determined that the processing area is in the same block as the area on top of the processing area. Thereafter, the processing proceeds to step S 411 . Otherwise, the processing proceeds to step S 412 . In step S 411 , the block number of the block corresponding to the processing area is set to the block number of the block corresponding to the area on top of the processing area. Thereafter, the processing proceeds to step S 417 . 
     In step S 412 , it is determined whether area is present the upper right of processing area. If an area is present, the processing proceeds to step S 413 . Otherwise, the processing proceeds to step S 415 . In step S 413 , it is determined whether the processing area is in the same block as the upper right neighboring area of the processing area. That is, the difference in gloss between the processing area and the upper right neighboring area is obtained, and it is determined whether the difference in gloss is less than the predetermined threshold value. The determination is made in the same manner as in step S 404 . If the difference in gloss is less than the threshold value, it is determined that the processing area is in the same block as the upper right neighboring area of the processing area. Thereafter, the processing proceeds to step S 414 . Otherwise, the processing proceeds to step S 415 . In step S 414 , the block number of the block corresponding to the processing area is set to the block number of the upper right neighboring area. Thereafter, the processing proceeds to step S 417 . 
     In step S 415 , the largest block number is updated by incrementing the largest block number by one. Thereafter, the updated largest block number is set for the block corresponding to the processing area. In step S 417 , it is determined whether the processing area is the last area  1202 . If the processing area is the last area  1202 , the first half processing is completed, and the processing proceeds to the second half processing. Otherwise, the processing returns to step S 402 . Note that the first half of the block building process is not limited to the above-described procedure. For example, another labeling process may be employed. 
       FIG. 5  is a flowchart of the steps (the processes) of the second half of the block building processing. In the second half of the block building processing, a determination signal is set for each of areas on the basis of the block number assigned to the area in the first half of the block building processing. In step S 501 , the first area  1201  is defined as the processing area first. Subsequently, in step S 502 , in a region of n (vertically)×m (horizontally) areas at the center of which there is the processing area, the number of areas each having a block number that is the same as the block number assigned to the processing area is counted. Thereafter, a value obtained by dividing the number by the product of n and m is set in the determination signal. For example, the values of n and in are determined so that the shape of a reproduced object corresponding to n (vertically)×m (horizontally) areas is a 10 mm square. In such a case, the determination signal having a value of “1” indicates that all the areas of the 10 mm square belong to the same block. The determination signal having a value of “0.5” indicates that half the areas belong to the same block. Subsequently, in step S 503 , it is determined whether the processing area is the last area  1202 . If the processing area is the last area  1202 , the processing is completed. Otherwise, the processing proceeds to step S 504 , where the next processing area is set on the basis of the scan order illustrated in  FIG. 10 . Thereafter, the processing proceeds to step S 502 . 
     Hardware Configuration of Material Appearance Reproducing System 
       FIG. 7  a block diagram of the hardware configuration of an image printing system serving as a material appearance reproducing system. As illustrated in  FIG. 7 , a host  700  serving as an image processing apparatus (e.g., a computer) includes a micro-processor (a CPU)  701  and a memory  702 , such as a random access memory. The host  700  further include an input unit  703 , such as a keyboard, and an external storage unit  704 , such as a hard disk drive. In addition, the host  700  includes a communication interface  705  (hereinafter referred to as a “printer I/F”) between the host  700  and an image printing apparatus  800  serving as the material appearance reproducing apparatus and a communication interface (hereinafter referred to as a “video I/F”)  706  between. the host  700  and a monitor  900 . The CPU  701  performs a variety of processes in accordance with programs stored in the memory  702 . For example, the CPU  701  performs a material appearance mapping process and a device signal conversion process related to the material appearance reproducing system. The programs are stored in the external storage unit  704  or are provided from an external apparatus (not illustrated). In addition, the host  700  outputs a variety of information items to the monitor  900  via the video I/F  706  and receives a variety of information items from the input unit  703 . Furthermore, the host  700  is connected to the image printing apparatus  800  via the printer I/F  705 . The host  700  sends a device signal converted through the device signal conversion process to the image printing apparatus  800  to perform printing and receives a variety of information items from the image printing apparatus  800 . According to the present exemplary embodiment, the image printing apparatus  800  is an inkjet printer that prints an image using ink. Inkjet printers print an image by moving a print head to perform n main scans on the same line over a recording medium. In general, the material appearance reproducing range can be increased with increasing number of passes n. If the number of printing passes is large, the amount of ink used per printing pass decreases and, thus, the ink is accumulated on a recording medium in granular form. That is, fine irregularities are recorded on the surface of the recording medium. As a result, the gloss having a low image clarity can be reproduced. In contrast, if the number of passes used is limited and, thus, printing is performed through a small number of passes, the amount of ink used per pass increases. Accordingly, the ink forms a layer and, thus, the surface is flat and smooth. As a result, the gloss having a high image clarity can be reproduced. 
     Print Head 
     The configuration of the print head is described below.  FIGS. 6A and 6B  are schematic illustrations of a head cartridge  801 . As illustrated in  FIG. 6A , the head cartridge  801  includes an ink tank  601  that stores ink serving as a recording agent and a print head  602  that ejects ink supplied from the ink tank  601  in accordance with an ejection signal. The head cartridge  801  includes, for example, yellow (Y), magenta (M), cyan (C), black (K), gloss control agent  1  (A), and gloss control agent  2  (B) ink tanks  601 , which are independent from one another. As illustrated in  FIG. 6B , each of the ink tanks  601  is removable from the print head  602 . The gloss control agent  1  and the gloss control agent  2  are clear and colorless ink having different indices of refraction. The index of refraction of the gloss control agent  1  is low, and the index of refraction of the gloss control agent  2  is high. An area having the gloss control agent  1 , which has a high index of refraction, recorded as the topmost surface has a high reflectivity. Thus, the gloss having a high specular gloss can be reproduced. In contrast, an area having the gloss control agent  2 , which has a low index of refraction, recorded as the topmost surface has a low reflectivity. Thus, the gloss having a low specular gloss can be reproduced. In addition, by controlling the ratio of an area recorded using the gloss control agent  1  to an area recorded using the gloss control agent  2 , the specular gloss between those of the gloss control agent  1  and the gloss control agent  2  can be reproduced. 
     Functional Configuration of Material Appearance Reproducing System  1   
       FIG. 9  is a block diagram illustrating the functional configuration of the material appearance reproducing system according to the first exemplary embodiment. The material appearance reproducing system converts input data into a material appearance signal reproducible by the material appearance reproducing apparatus using a material appearance data input unit  1101 , a material appearance signal acquiring unit  1102 , and a material appearance mapping unit  1103 . In addition, the material appearance reproducing system prints an image serving as a reproduced object corresponding to the input data using a device signal conversion A unit  1104 , a device signal conversion B unit  1105 , a device signal conversion C unit  1106 , and an output unit  1107 . Note that in  FIG. 9 , the material appearance data input unit  1101 , the material appearance signal acquiring unit  1102 , the material appearance mapping unit  1103 , the device signal conversion A unit  1104 , the device signal conversion C unit  1105 , and the device signal conversion C unit  1106  are achieved by the host  700 . The output unit  1107  is achieved by the image printing apparatus  800  serving as the material appearance reproducing apparatus. 
     The material appearance data input unit  1101  receives image data in the form of a material appearance signal. The material appearance signal is formed from a color signal and a gloss signal. Each of the pixels of the image data has elements of gloss signals (Gg, Sg) in addition to widely used color signals (R, G, B). The gloss signal Gg is a signal corresponding to the specular gloss. The gloss signal Sg is a signal corresponding to the image clarity. Each of the material appearance signals (R, G, B, Gg, Sg) that constitute the image data is an 8-bit digital signal. However, the format of the input image data is not limited thereto. For example, two types of image data, that is, image data formed from a color signal and image data formed from a gloss signal, may be input to the material appearance data input unit  1101 . 
     The material appearance signal acquiring unit  1102  converts the material appearance signals that constitute the image received by the material appearance data input unit  1101  into color signals (L, a, b) based on CIELAB, a gloss signal (g) corresponding to the specular gloss, and a gloss signal (s) corresponding to the image clarity. It is desirable that the material appearance signals (L, a, b, g, s) output from the material appearance signal acquiring unit  1102  be signals that are based on the measurement values and that do not depend on the apparatus. The conversion from the color signals (R, G, B) into the color signals (L, a, b) is performed using a standard conversion technique, such as sRGB. Alternatively, the conversion may be performed by referring to a color table stored in an input material appearance table storage unit  1108  and using a widely used three-dimensional lookup table technique. The color table contains the relationship between the color signals (R, G, B) and the color signals (L, a, b). The conversion from the gloss signal (Gg) corresponding to the specular gloss into the gloss signal (g) and the conversion from the gloss signal (Sg) corresponding to the image clarity into the gloss signal (s) are performed by referring to a gloss table stored in the input material appearance table storage unit  1108  and using a widely used lookup table technique. The gloss table contains the correspondence between a gloss signal (Gg) and a gloss signal (g) and the correspondence between a gloss signal (Sg) and a gloss signal (s). Preferably, the color table and the gloss table are provided for each of the type of image data and each of the material appearance acquiring apparatuses that generate input image data in advance and are selected in accordance with the image data received by the material appearance data input unit  1101 . Alternatively, the color table and the gloss table may be selected in accordance with a user instruction. 
     The material appearance mapping unit  1103  converts the material appearance signals (L, a, b, g, s) obtained by the material appearance signal acquiring unit  1102  into material appearance signals (L′, a′, b′, g′, s′) each corresponding to the material appearance reproducible by the image printing apparatus  800  through the above-described color mapping and gloss mapping. 
     Color Separation Process 
     The device signal conversion A unit  1104  converts the material appearance signals (L′, a′, b′, g′, s′) into a control signal including color material amount signals (C, M, Y, K), gloss control agent amount signals (A, B), and a pass control signal (P) of the image printing apparatus  800 . The conversion is performed by referring to a device properties table stored in a device properties table storage unit  1109  and using a widely used n-dimensional lookup table technique.  FIG. 11  is a schematic illustration of an example of the device properties table. As illustrated in  FIG. 11 , the device properties table contains the values of material appearance signals (L′, a′, b′, g′, s′) corresponding to discrete control signals (C, M, Y, K, A, B, P). The color material amount signals (C, M, Y, K) are signals related to the amounts of yellow, magenta, cyan, and black color materials, respectively. For example, each of the color material amount signals is an 8-bit digital signal. The gloss control agent amount signals (A, B) indicate the amounts of the gloss control agent  1  and the gloss control agent  2 , respectively. For example, each of the gloss control agent amount signals is an 8-bit digital signal. The pass control signal (P) indicates the number of printing passes, which is in the range from, for example, 1 to 16. If the signal value is 1, one-pass printing is selected. If the signal value is 16, 16-pass printing is selected. 
     Halftone Process 
     The device signal conversion B unit  1105  performs a halftone process on the control signals (C, M, Y, K, A, B) converted by the device signal conversion A unit  1104  and converts the control signals (C, M, Y, K, A, B) into binary signals (C′, M′, Y′, K′, A′, B′), respectively, each indicating whether a dot is printed or not. Each of the binary signals (C′, M′, Y′, K′, A′, B′) indicates the dot print position. For example, a dot is printed at a position having a signal value of “1” and is not printed at a position having a signal value of “0”. To perform the halftone process, a widely used error diffusion technique or systematic dither technique. 
     The device signal conversion C unit  1106  performs a pass separation process on the basis of the control signal (P) related to the number of passes and the control signals (C′, M′, Y′, K′, A′, B′) related to the dot patterns of the color materials and the gloss control material. In the pass separation process, the logical OR of a pass mask and the control signals (C, M′, Y′, K′, A′, B′) is calculated, and control signals (C″, M″, Y″, K″, A″, B″) related to the dot pattern printed in each pass are generated. According to the first exemplary embodiment, the material appearance reproducing system has 16 sets of pass mask (for 1-pass printing to 16-pass printing). One of the sets of pass mask is selected in accordance with the value P and is used. For example, if the value of P is 2 indicating 2-pass printing, the cyan dot pattern for the first pass is generated by the logical OR of the pass mask for a first pass of the 2-pass printing pass mask set and the control signal C′ indicating the cyan dot print positions.  FIGS. 12A to 12G  are schematic illustrations of examples of the pass mask.  FIG. 12A  illustrates a pass mask for a first pass of 1-pass printing. In 1-pass printing, all the dots are printed in the first pass.  FIGS. 12B and 12C  illustrate the pass masks for a first pass and a second pass of 2-pass printing, respectively. In 2-pass printing, the dots are separated into the dots for the first pass and the dots for the second pass and are printed.  FIGS. 12D to 12G  illustrate the pass masks for first to fourth passes of 4-pass printing, respectively. In 4-pass printing, the dots are separated into the dots for four passes, that is, the first to fourth passes and are printed. Similarly, in n-pass printing, the dots are separated into the dots for n passes, that is, the first to n-th passes and are printed. According to the device signal conversion C unit  1106  of the material appearance reproducing system of the first exemplary embodiment, by controlling the number of printing passes for each of the pixels, the shape of the surface can be controlled in accordance with the number of passes and, thus, the image clarity of each of the pixels can be controlled. Note that different pass masks may be provided in accordance with the types of ink. 
     The output unit  1107  ejects each of the color materials and each of the gloss control agents on the basis of the dot pattern data generated by the device signal conversion C unit  1106 . In this manner, an image representing a material appearance reproduced object is formed on a recording medium. 
     In the above-described material appearance reproducing procedure, the processes in steps S 101  to S 103  are performed by the material appearance data input unit  1101 , the material appearance signal acquiring unit  1102 , and the material appearance mapping unit  1103 , respectively. In addition, the process in step S 104  is performed by the device signal conversion A unit  1104 , the device signal conversion B unit  1105 , and the device signal conversion C unit  1106 . Furthermore the process in step S 105  is performed by the output unit  1107 . 
     As described above, according to the first exemplary embodiment, the material appearance reproducing system performs the material appearance mapping to convert the input data into the material appearance data corresponding to the material appearance reproducible by the material appearance reproducing apparatus. In the material appearance mapping, the color signal and the gloss signal are converted so that the colors, the specular gloss, and the image clarity indicated by the input data are mapped to a combination of the colors, the specular gloss, and the image clarity reproducible by the material appearance reproducing apparatus. In this manner, even when the combination of the colors, the specular gloss, and the image clarity indicated by the input data is not reproducible by the material appearance reproducing apparatus, the reproduced object can be output by the material appearance reproducing apparatus. 
     In addition, in the material appearance mapping performed by the material appearance reproducing system according to the first exemplary embodiment, unlike an area having a small change in gloss, the reproducibility of the specular gloss is given more weight in an area having a large change in gloss. That is, when a specular gloss error is defined as a difference between the specular gloss indicated by the input data and the specular gloss of a reproduced object, the gloss signal is converted as follows. That is, the gloss signal is converted so that the specular gloss error in an area having a relatively large change in gloss is lower than the specular gloss error in an area having a relatively small change in gloss. In this manner, for example, a granular area that glitters can be excellently reproduced. 
     In addition, in the material appearance mapping performed by the material appearance reproducing system according to the first exemplary embodiment, unlike an area having a large change in gloss, the reproducibility of the image clarity is given more weight in an area having a small change in gloss. That is, when an image clarity error is defined as a difference between the image clarity indicated by the input data and the image clarity of a reproduced object, the gloss signal is converted as follows. That is, the gloss signal is converted so that the image clarity error in an area having a relatively small change in gloss is lower than the image clarity error in an area having a relatively large change in gloss. In this manner, for example, an area in which the substantially uniform gloss is widely distributed and an area in which gently changing gloss is widely distributed can be excellently reproduced. 
     In addition, according to the first exemplary embodiment, the material appearance reproducing system converts the input material appearance data into a signal value that is reproducible by the material appearance reproducing apparatus in a space having at least axes of the specular gloss and the image clarity. In this manner, for example, two types of gloss having the same specular gloss and different image clarifies can be recognized as different types of gloss and, thus, the appearance of the object to be reproduced indicated by the input data can be made to be the same as the appearance of the reproduced object. 
     First Modification  1   
     According to the material appearance reproducing system of the first exemplary embodiment, the size of a block to which areas belong is used as a determination signal, and one of the process in which the reproducibility of the image clarity is given more weight and the process in which the reproducibility of the specular gloss is given more weight is selected. In first modification, another index is used as the determination signal. The first modification is described below. 
     Gloss Mapping Process 
       FIG. 8  is a flowchart of the steps (the processes) of a gloss mapping procedure according to a first modification.  FIG. 8  illustrates the details of the process in step S 204  illustrated in  FIG. 2 . In step S 1101 , a lowpass filter is applied to the spatial distribution of the material appearance signals first. For example, on the basis of the sampling theorem, the lowpass filter that makes the response to 1 cycle/mm be a half the response to 0.05 cycle/mm is applied to the two-dimensional distribution of the gloss signal corresponding to the specular gloss and the two-dimensional distribution of the gloss signal corresponding to the image clarity. Subsequently, in step S 1102 , a determination signal that corresponds to a difference between the gloss signals before and after application of the lowpass filter is calculated. For example, the sum of the square of the difference between the gloss signals corresponding to the specular gloss and the square of the difference between the gloss signals corresponding to the image clarity is used as the determination signal. Subsequently, in step S 1103 , it is determined whether the determination signal obtained in step S 1102  is higher than a predetermined threshold value. For example, the threshold value is set to 50 if the 20-degree specular gloss measured using an existing technique is used as the gloss signal corresponding to the specular gloss and the image clarity measured using an existing technique is used as the gloss signal corresponding to the image clarity. If the determination value of the area of interest is greater than the threshold value, it is determined that the area of interest has a large gloss change and, thus, the processing proceeds to step S 303 . Otherwise, it is determined that the area of interest has a small gloss change and, thus, the processing proceeds to step S 305 . 
     As described above, according to the material appearance reproducing system of the first modification, a gloss distribution is generated by applying a lowpass filter to the spatial distribution of the material appearance signals, and the difference between the gloss signals for the area of interest before and after application of the lowpass filter is used as the determination signal. A large determination signal indicates that the area of interest has a large gloss change, and a small determination signal indicates that the area of interest has a small gloss change. In this manner, the material appearance reproducing apparatus can distinguish between an area having a large gloss change and an area having a small gloss change. Since fast Fourier transform (FFT) that can provide high-speed calculation can be employed in the lowpass process, the process can be performed at high speed. 
     In general, to distinguish between an area having a large gloss change and an area having a small gloss change, the value regarding the amplitude or the cycle of a gloss change can be used. As used herein, the term “amplitude” refers to a value related to a difference between gloss signals. A large amplitude of a gloss change indicates that a difference between the gloss signal of the area of interest and the gloss signal of an area in the vicinity of the area of interest is large. As used herein, the term “cycle” refers to a value related to spatial breadth or the size of an area. A long cycle of a gloss change indicates that a region having a level of the gloss signal that is substantially the same as the level of the gloss signal of the area of interest is widely distributed so as to be adjacent to the area of interest. If the determination signal indicates a value related to the amplitude of a gloss change, a larger determination signal indicates a larger gloss change. In contrast, if the determination signal indicates a value related to the cycle of a gloss change, a larger determination signal indicates a smaller gloss change. According to the first exemplary embodiment, the determination signal is a value related to the cycle of a gloss change. In contrast, according to the first modification, the determination signal is a value related to the amplitude of the gloss change. Note that the amplitude and the cycle of the gloss change can be acquired from the spatial distribution of the material appearance signals. 
     Other Modifications  1   
     The determination signal may be a combination of a value related to the amplitude of a gloss change and the cycle of the gloss change. If the results of determination of the two types are not the same, the result for the determination signal having a high priority may be selected, for example. The priority may be assigned in advance, or may be assigned in accordance with the type of object to be reproduced, the type of recording medium, or a user instruction. 
     The gloss signal corresponding to the specular gloss need not be limited to a value measured under the standard conditions, but may be a value measured under other conditions or a function of the value. For example, the direction of illumination in the measurement may be at 30 degrees. In addition, the angles of aperture of illumination and received light are not limited to those under the standard conditions. Furthermore, the signal corresponding to the specular gloss may contain color information in addition to the brightness information. For example, as a signal containing color information, a CIELAB value calculated using JIS Z8722 after measuring the amount of specular reflection light can he used. Thereafter, as the gloss signal corresponding to the specular gloss, three signals gL, ga, and gb are used instead of the signal g. In such a case, a signal corresponding to the specular gloss in the gloss mapping is converted in a three-dimensional color space. To convert the signal, an existing color matching technique can be used, as in the conversion of the color signal. 
     In addition, the gloss signal corresponding to the image clarity is not limited to a value measured under the standard conditions. A value measured under other conditions or a function of the value may be used. For example, an angle φ formed by a direction in which the amount of reflection light is half the amount of the specular reflection light in the vicinity of the specular direction and the specular direction is measured, and the inverse function of the angle φ may be used.  FIG. 13  is a schematic illustration of typical characteristics of multi angle distribution of reflection. In  FIG. 13 , a line  1501  represents the amount of reflection light reflected from a point A of a sample  1502 . The direction of an angle θ in which the amount of reflection light is large is the specular direction of the illumination direction. The length of a line segment AB indicates the amount of reflection light in the specular direction. A point C is a midpoint at which the length of a line segment AC is half the length of the line segment AB. The angle formed by the line segment AB and the line segment AC is the angle φ. For samples having a large image clarity, the light diffusion toward the vicinity of the specular direction is small and, thus, the angle φ is small. In contrast, for samples having a small image clarity, the angle φ is large. 
     In addition, as the gloss signal corresponding to the image clarity, the measurement value of the surface regularities or a function of the measurement value may be used. An object to be reproduced having a smooth surface, that is, small surface regularities has a large image clarity. An object to be reproduced having large surface regularities has a small image clarity. 
     In addition, the gloss signal may contain an element related to the normal direction of each of the areas. For some objects to be reproduced, the normal direction may vary from area to area. In such a case, to obtain a reproduced object having an appearance that is the same as the appearance of the object to be reproduced, information regarding the normal direction is needed in addition to the specular gloss and the image clarity as the information held by each area. The normal direction can be reproduced by controlling the surface regularities. The surface regularities can be printed by using, for example, a UV inkjet printer or a 3D printer. In addition, if the gloss signal has the element related to the normal direction, an element related to the difference in the normal direction is set in the gloss signal in addition to the difference in the specular gloss and the difference in the image clarity in order to calculate the gloss difference from an area in the vicinity. That is, the gloss difference used in steps S 404 , S 407 , S 410 , and S 413  illustrated in  FIG. 4  (in the block building procedure according to the first exemplary embodiment) is changed to, for example, the sum of squares of the difference between gloss signals corresponding to the specular gloss, the difference between gloss signals corresponding to the image clarity, and the difference between gloss signals corresponding to the normal direction. Similarly, the determination signal obtained in step S 1002  illustrated in  FIG. 8  (in the gloss mapping procedure according to the present exemplary embodiment) is changed to, for example, the sum of squares of the difference between gloss signals corresponding to the specular gloss, the difference between gloss signals corresponding to the image clarity, and the difference between gloss signals corresponding to the normal direction. In this manner, for the areas having a large change in the normal direction, the specular gloss is given more weight over the image clarity and, thus, the appearance of the object to be reproduced can be made to be more similar to the appearance of the reproduced object. 
     The technique for evaluating the gloss difference is also only an example. Another evaluation technique can be employed. For example, the difference in the specular gloss and the difference in the image clarity may be independently obtained. A threshold value may be set for each of the differences. If one of the differences is greater than the threshold value, it can be determined that the gloss difference is large. 
     The above-described threshold value is only an example. The threshold value is not limited to the value described in the above-described exemplary embodiment. The threshold value may be determined on the basis of the type of recording medium, the type of object that constitutes the material appearance data, or a user instruction. 
     Second Exemplary Embodiment 
     According to the present exemplary embodiment, a configuration in which input data is directly converted into the control signal for controlling the material appearance reproducing apparatus is described. Note that the same numbering will be used in describing the configuration of the present exemplary embodiment as was utilized above in describing the first exemplary embodiment, and description of the same configuration is not repeated. 
     Functional Configuration of Material Appearance Reproducing System  2   
       FIG. 14  is a block diagram of the functional configuration of a material appearance reproducing system according to the second exemplary embodiment. The material appearance reproducing system prints an image serving as a reproduced object on a recording medium using a material appearance data input unit  1101 , a device signal conversion D unit  1601 , a device signal conversion B unit  1105 , a device signal conversion C unit  1106 , and an output unit  1107 . Note that in  FIG. 14 , the material appearance data input unit  1101 , the device signal conversion D unit  1601 , the device signal conversion B unit  1105 , and the device signal conversion C unit  1106  are achieved by a host  700 . The output unit  1107  is achieved by an image printing apparatus  800  serving as the material appearance reproducing apparatus. 
     The device signal conversion D unit  1601  converts material appearance signals (R, G, B, Gg, Sg) that constitute the image data received by the material appearance data input unit  1101  into a control signal including color material amount signals (C, M, Y, K), gloss control agent amount signals (A, B), and a pass control signal (P) of the image printing apparatus  800 . The conversion is performed by referring to a material appearance reproduction table stored in a material appearance reproduction table storage unit  1602  and using a widely used n-dimensional lookup table technique.  FIG. 15  is a schematic illustration of an example of the material appearance reproduction table. As illustrated in  FIG. 15 , the material appearance reproduction table contains the values of the control signals (C, M, Y, K, A, B, P) corresponding to discrete material appearance signals (R, G, B, Gg, Sg). Two types of table, that is, a table in which the reproducibility of the specular gloss is given more weight and a table in which the reproducibility of the image clarity is given more weight are provided. It is determined which one of the reproducibility of the specular gloss and the reproducibility of the image clarity is given more weight for each of the areas, and the table corresponding to the result of determination is referred to. The tables can be generated by the material appearance signal acquiring unit  1102 , the material appearance mapping unit  1103 , and the device signal conversion A unit  1104  according to the above-described first exemplary embodiment. That is, the material appearance signal acquiring unit  1102  converts the discrete material appearance signals (R, G, B, Gg, Sg) into material appearance signals (L, a, b, g, s) that do not depend on apparatuses first. Subsequently, the material appearance mapping unit  1103  converts the material appearance signal (L, a, b, g, s) into the material appearance signals (L′, b′, g′, s′) corresponding to the material appearance reproducible by the image printing apparatus  800  for each of the case in which the reproducibility of the specular gloss is given more weight and the case in which the reproducibility of the image clarity is given more weight. Thereafter, the device signal conversion A unit  1104  converts the material appearance signals into the control signals (C, M, Y, K, A, B, P) for controlling the image printing apparatus  800 . The result of conversion is stored in the material appearance reproduction table. 
     Material Appearance Reproducing Technique  2   
       FIG. 16  is a flowchart of the steps (the processes) of the material appearance reproducing procedure according to the second exemplary embodiment. In step S 101 , the material appearance data to be reproduced is input first. Subsequently, in step S 1802 , the material appearance data input in step S 101  is converted into the control signals for controlling the material appearance reproducing apparatus. Subsequently, in step S 105 , a reproduced object is output on the basis of the control signals converted in step S 1802 . The process in step S 1802  is performed by the device signal conversion D unit  1601 . 
     First Verification Technique 
     A technique for verifying whether the control signals (C. M, Y, K, A, B, P) that are set in the material appearance reproduction table so as to correspond to material appearance signals (R, G, B, G, S) are suitable is described below. 
       FIG. 17  is a schematic illustration of material appearance data used for describing an example of the verification technique. Material appearance data  1901  is formed from a single material appearance signal for all the areas. The material appearance data is material appearance data corresponding to the specular gloss and the image clarity unreproducible by the material appearance reproducing apparatus. Let Dorg denote the specular gloss of the material appearance data. Material appearance data  1902  is formed from an area  1903  located at the center and two areas on the outer side of the area  1903 . The area  1903  located at the center of the material appearance data  1902  is formed from the material appearance signal that is the same as the material appearance signal of the material appearance data  1901 . The areas on the outer side of the area  1903  are formed form a single material appearance signal different from that of the area  1903 . The material appearance signal of the area  1903  and the material appearance signal of the areas located on the outer side of the area  1903  are set so that the gloss signals sufficiently differ from each other. In addition, setting is made so that the sizes of the material appearance data  1901  and the material appearance data  1902  are the same, the size of the material appearance data  1901  is sufficiently large, and the size of the area  1903  is sufficiently small. By appropriately setting these parameters, material appearance data can be configured such that the center portion of the material appearance data  1901  is determined to be an area having a small gloss change and the area  1903  is determined to be an area having a large gloss change. For example, each of the sizes of the material appearance data  1901  and the material appearance data  1902  is greater than or equal to 20 mm square, and the size of the area  1903  is less than or equal to 10 mm square. 
     The material appearance data  1901  is input to the material appearance reproducing system according to the present exemplary embodiment. The material appearance reproducing apparatus outputs the reproduced object. In this manner, the reproduced object can be obtained. Let Dout 1  denote the value obtained by measuring the specular gloss of the reproduced object using a technique defined in JIS Z8741. In the same manner, the material appearance data  1902  is input to the material appearance reproducing system according to the present exemplary embodiment, and the material appearance reproducing apparatus outputs the reproduced object. In this manner, the reproduced object is obtained. Let Dout 2  denote the measurement value of the specular gloss of the area corresponding to the area  1903  of the reproduced object. To remove the adverse effect of a variation of the material appearance reproducing apparatus, the average of the specular gloss values of a plurality of reproduced objects may be used for the values of Dout 1  and Dout 2 . 
     If the material appearance reproduction table is appropriately set, the reproducibility of the specular gloss is given more weight in an area having a large gloss change than in an area having a small gloss change. Accordingly, the difference between the specular gloss indicated by the material appearance data and the specular gloss of the reproduced object is small. That is, if the absolute value of (Dorg-Dout 2 ) is less than the absolute value of (Dorg-Dout 1 ), it is determined that the material appearance reproduction table is appropriate. However, if the absolute value of (Dorg-Dout 2 ) cannot be less than the absolute value of (Dorg-Dout 1 ) in any setting of the parameters of the material appearance data  1901  and the material appearance data  1907 , it is determined that the material appearance reproduction table is inappropriate. 
     According to the above-described technique, a process in which the reproducibility of the image clarity is given more weight and a process in which the reproducibility of the specular gloss is given more weight are reliably switched in accordance with the spatial distribution of the material appearance signals so that the difference between the appearances becomes smaller. 
     As described above, the material appearance reproducing system according to the second exemplary embodiment refers to the material appearance reproduction table describing a correspondence between a discrete material appearance signal and the control signal for controlling the material appearance reproducing apparatus and performs the processes that are performed by the units of the first exemplary embodiment through only a single conversion process. That is, the processes performed by the material appearance signal acquiring unit  1102 , the material appearance mapping unit  1103 , and the device signal conversion A unit  1104  of the first exemplary embodiment are performed as a single conversion process. 
     Third Exemplary Embodiment 
     When a user of the material appearance reproducing apparatus wants to adjust the material appearance of a reproduced object into desired material appearance, it is difficult to freely adjust the distribution of the material appearance signal. According to the present exemplary embodiment, the user adjusts an input image instead of the material appearance reproducing apparatus. In such a case, the user does not know which adjustment operation to perform on the input image to obtain desired material appearance. Accordingly, the user tends to repeatedly attempt the adjustment operation. According to the third exemplary embodiment, a configuration including a material appearance adjustment unit is provided. Note that the same numbering will be used in describing the configuration of the present exemplary embodiment as was utilized above in describing the first exemplary embodiment, and description of the same configuration is not repeated. 
     Material Appearance Reproducing Technique  3   
       FIG. 21  a flowchart of the steps of the material appearance reproducing procedure according to the third exemplary embodiment. According to a material appearance reproducing apparatus of the third exemplary embodiment, in step S 101 , the material appearance data to be reproduced is input. In step S 102 , the material appearance signal is obtained. Thereafter, in step S 2301 , a material appearance adjustment value is obtained. The material appearance adjustment value serves as control information used to control the output of the material appearance reproducing apparatus to exhibit desired material appearance. According to the present exemplary embodiment, the material appearance reproducing system obtains the gloss adjustment values related to the specular gloss and the image clarity in addition to the color adjustment values. 
     The color adjustment value is formed from a brightness adjustment value ΔL and color adjustment values Δa and Δb. The value ΔL corresponds to L* defined in CIELAB. To perform control so that the reproduced object is brighter, the value ΔL is set to a larger positive value. In contrast, to perform control so that the reproduced object is darker, the value ΔL is set to a smaller negative value. The value Δa corresponds to a* defined in CIELAB. To perform control so that the red components of the reproduced object increase, the value Δa is set to a larger positive value. In contrast, to perform control so that the green components of the reproduced object increase, the value Δa is set to a smaller negative value. Similarly, the value Δb corresponds to b* defined in CIELAB. To perform control so that the yellow components of the reproduced object increase, the value Δb is set to a larger positive value. In contrast, to perform control so that the blue components of the reproduced object increase, the value Δb is set to a smaller negative value. A user interface (hereinafter simply referred to as a “UI”) may include a slide bar to acquire the adjustment values. In addition, for example, a slide bar for controlling the brightness has the displayed text “DARK” on one end and the display text “BRIGHT” on the other end. Thus, the user can intuitively set the adjustment value. 
     The adjustment value of the gloss is formed from an adjustment value Δg of the specular gloss and an adjustment value Δs of the image clarity. To perform control so that the specular gloss increases, a larger positive value Δg is set. In contrast, to perform control so that the specular gloss decreases, a smaller negative value Δg is set. Similarly, to perform control so that the image clarity increases, a larger positive value Δs is set. In contrast, to perform control so that the image clarity decreases, a smaller negative value Δs is set. A UI for acquiring the adjustment values of the gloss displays the images of the illumination light source (hereinafter also referred to as “illumination images”, which represent the appearance of the images produced by reflection at a surface of an object. Thus, the user can intuitively set the adjustment values. 
       FIG. 22  is a schematic illustration of an example of a gloss adjustment UI. Images  2401  to  2408  are images of the illumination light source. In the illumination images  2401  to  2403 , the illumination light source is displayed so as to be brighter than in the illumination images  2404  and  2405 . In contrast, in the illumination images  2406  to  2408 , the illumination light source is displayed so as to be darker than in the illumination images  2404  and  2405 . These images of the illumination light source indicate the degree of the specular gloss and the degree of the image clarity thereof and indicate the pseudo images of the illumination light source produced by reflection at a surface of the reproduced object. The images  2401  to  2403  displayed in the upper section indicate the effects obtained when the specular gloss is largely controlled. The images  2406  to  2408  displayed in the lower section indicate the effects obtained when the specular gloss is slightly controlled. In addition, in the images  2403 ,  2405 , and  2408 , the illumination light source is more sharply displayed than in the images  2402  and  2407 . In the images  2401 ,  2404 , and  2406 , the illumination light source is displayed so as to be more blurred than in the images  2402  and  2407 . The images  2403 ,  2405 , and  2408  displayed in the right section indicate the effects when the image clarity is largely controlled, and the images  2401 ,  2404 , and  2406  displayed on the left section indicate the effects when the image clarity is slightly controlled. Cells  2409  form a five (vertically) by five (horizontally) matrix. The cell at the center is assigned “0”, which indicates that the adjustment value Δg of the specular gloss and the adjustment value Δs of the image clarity are not changed. In addition, for each of the other cells, an adjustment value determined in accordance with the distance between the illumination image displayed at a position in the same direction from the center cell and the center cell is assigned. That is, a cell located at a higher position is assigned a larger positive value Δg, and a cell located at a lower position is assigned a smaller negative value Δg. In addition., a cell located more rightward is assigned a larger positive value Δs, and a cell located more leftward is assigned a smaller negative value Δs. Any one of the cells is selected by the user who operates a mouse pointer  2412  and, thus, the adjustment value assigned to the cell is tentatively selected. At that time, an OK button  2410  is enabled. Subsequently, if the user selects the OK button  2410 , the adjustment value is finally set to the tentatively set value. However, if a cancel button  2411  is selected, each of the adjustment values Δg and Δs is set to “0”, which indicates that no adjustment is performed. 
     Subsequently, in step S 2302 , the material appearance signals obtained in step S 102  is corrected using the adjustment values obtained in step S 2301 . That is, adjusted material appearance signals L_a, a_a, b_a, g_a, and s_a are calculated as follows: 
         L _ a=L+ΔL    (1),
 
         a _ a=a+Δa    (2),
 
         b _ a=b+Δb    (3)
 
         g _ a=g+Δg    (4), and
 
         s _ a=s+Δs    (5),
 
     Subsequently, in step S 2303 , the material appearance signals adjusted in step S 2302  are converted into the material appearance signals corresponding to the material appearance reproducible by the image printing apparatus  800  serving as the material appearance reproducing apparatus using the above-described color mapping and gloss mapping. 
     Subsequently, in step S 104 , the material appearance signals converted in step S 2303  are converted into the control signal for controlling the material appearance reproducing apparatus. Finally, in step S 105 , a reproduced object is output by the material appearance reproducing apparatus on the basis of the control signal obtained in step S 104 . 
     Functional Configuration of Material Appearance Reproducing System  3   
       FIG. 23  is a block diagram of the functional configuration of a material appearance reproducing system according to the third exemplary embodiment. The material appearance reproducing system includes a material appearance adjustment value acquiring unit  2501 , a material appearance adjustment value storage unit  2502 , and a material appearance correcting unit  2503  in addition to the configuration of the material appearance reproducing system according to the first exemplary embodiment. The material appearance adjustment value acquiring unit  2501  performs the above-described process in step S 2301 . The material appearance adjustment value acquiring unit  2501  acquires the material appearance adjustment values (ΔL, Δa, Δb, Δg, Δs) and stores the material appearance adjustment values in the material appearance adjustment value storage unit  2502 . The adjustment values can be acquired using a that allows the user to intuitively set the adjustment values, such as the UI illustrated in  FIG. 22 . The material appearance correcting unit  2503  calculates adjusted material appearance signals L_a, a_a, b_a, g_a, and s_a from the material appearance adjustment values stored in the material appearance adjustment value storage unit  2502  and the material appearance signals (L, a, b, g, s) acquired by the material appearance signal acquiring unit  1102  using equations (1) to (5). The material appearance mapping unit  1103  according to the third exemplary embodiment converts the adjusted material appearance signals corrected by the material appearance correcting unit  2503  into the material appearance signals (L′, a′, b′, g′, s′) corresponding to the material appearance reproducible by the image printing apparatus  800  through the above-described color mapping and gloss mapping. 
     As described above, according to the third exemplary embodiment, the material appearance reproducing system includes an adjustment unit that controls the image clarity in terms of the gloss. That is, the material appearance reproducing system includes an adjustment unit that controls the sharpness of the illumination image produced by reflection at a surface of an object to be reproduced. In this manner, for example, even when the image clarity of the output reproduced object differs from the desired image clarity, the gloss of the reproduced object can be adjusted to the desired gloss. In addition, according to the third exemplary embodiment, the material appearance reproducing system includes an adjustment unit that controls the specular gloss in terms of the gloss. That is, the material appearance reproducing system includes an adjustment unit that controls the brightness of the illumination image generated by reflection at a surface of the object to be reproduced. In this manner, even when the specular gloss of the output reproduced object differs from the desired specular gloss, the gloss of the reproduced object can he adjusted to the desired gloss. Furthermore, the material appearance reproducing system according to the third exemplary embodiment includes two gloss adjustment units in terms of gloss, one of which controls the image clarity while the other controls the specular gloss. Even when the specular gloss is adjusted, the reproducibility of the image clarity is not improved. In addition, even when the image clarity is adjusted, the reproducibility of the specular gloss is not improved. Accordingly, to adjust the gloss of the reproduced object to the desired gloss, it is desirable that the material appearance reproducing system include two gloss adjustment units, one of which controls the image clarity while the other controls the specular gloss. 
     In addition, according to the third exemplary embodiment, the material appearance reproducing system acquires the above-described adjustment information by using a UI that displays images having different sharpness levels. In general, the users are not aware that the gloss includes the image clarity element and that the image clarity is a property regarding the sharpness of an image produced by reflection at a surface of the object. Accordingly, the user gets in a situation where the user cannot figure out which adjustment produces desired gloss and, thus, the user repeatedly performs the adjustment operation. By displaying images having different sharpness levels in the UI used to acquire the adjustment values of the gloss, the user can intuitively recognize that the sharpness of the illumination image produced by reflection at a surface of the object to be produced can be adjusted. As a result, the user does not get in a situation where the user cannot figure out which adjustment causes which effect and, thus, the user can obtain a reproduced object of a desired material appearance without repeating the adjustment operation. In addition, the material appearance reproducing system according to the third exemplary embodiment obtains the above-described adjustment information using a UI that displays images having different brightness levels and images having different sharpness levels. It is not generally known that the gloss has two elements, that is, the specular gloss and the image clarity and that the specular gloss represents the property regarding the brightness of an image produced by reflection at a surface of the object and the image clarity represents the property regarding the sharpness of the image produced by reflection at a surface of the object. Accordingly, the user gets in a situation where the user cannot figure out which adjustment produces desired gloss and, thus, the user repeatedly performs the adjustment operation. By displaying the above-described images in the UI used to acquire the adjustment values of the gloss, the user can be intuitively aware that the two elements, that is, the brightness of the illumination image produced by reflection at s surface of the object to be reproduced and the sharpness of the illumination image produced by reflection at a surface of the object to be reproduced can be adjusted. As a result, the user does not get in a situation where the user cannot figure out which adjustment causes which effect and, thus, the user can obtain the reproduced object of a desired material appearance without repeating the adjustment operation. 
     First Modification  2   
     A UI for acquiring the adjustment values of the gloss according to the present modification that, differs from the UI according to the third exemplary embodiment is described below. 
       FIG. 24  is a schematic illustration of a UI for adjusting the gloss according to the first modification. An image indicating the gloss properties prior to adjustment is displayed in a display area  2601 . More specifically, the illumination image having adjustment values Δg and Δs each set to zero is displayed. The illumination image is an image indicating the level of the specular gloss and the level of the image clarity of an object and is the pseudo image of the illumination light source produced by reflection at a surface of the object. In addition, an image indicating the gloss properties after adjustment is displayed in a display area  2602 . In an initial stage, the same illumination images are displayed in both the display area  2601  and display area  2602 . In addition, a slide bar  2603  is used to set the adjustment value Δg of the specular gloss, and a slide bar  2604  is used to set the adjustment value Δs of the image clarity. Each of the levels of the adjustment value Δg and the adjustment value Δs is indicated by a slider position in the corresponding slide bar. A value “ 0 ”, which indicates no adjustment, is assigned to the midpoint of each of the slide bars. In addition, the value positively increases toward the right from the midpoint, and the value negatively decreases toward the left from the midpoint. If the slider position is moved by using a mouse pointer  2605 , a value assigned to the slider position is tentatively set in the adjustment value, and an OK button  2606  is enabled. At the same time, the image in the display area  2602  is updated so that the illumination image corresponding to the tentatively set adjustment value is displayed. For example, if Δg is tentatively set to a positive value, an illumination image having a brightness that is brighter than that of the image displayed in the display area  2601  is displayed. A brighter illumination image is displayed with increasing tentatively set Δg. If the Δs is tentatively set to a negative value, an illumination image that is more blurred than the image displayed in the display area  2601  is displayed in the display area  2602 . If the OK button  2606  is selected, the adjustment value is finally set to the tentatively set value. However, if a cancel button  2607  is selected, the adjustment value Δg and the adjustment value Δs are set to “0”, which indicates no adjustment. 
     In addition, if an output preview check box  2608  is checked, the image in the display area  2601  is changed to a CG image of the object to be reproduced corresponding to the input material appearance data input in step S 101 . At the same time, the image in the display area  2602  is changed to a CG image of the object to be reproduced that is corrected using the tentatively set adjustment value. The CG image is an image obtained by simulating the appearance of the object to be reproduced viewed in the specular direction of a predetermined illumination light source when the object is illuminated by the illumination light source under predetermined conditions.  FIG. 18  is a schematic illustration of an example of the CG images displayed in the display area  2601  and the display area  2602 . An illumination image  2701  is an image of the illumination light source produced by reflection at a surface of the oil painting of an apple, which is the object to be reproduced. The object to be reproduced displayed in the display area  2601  indicates the illumination image corresponding to the specular gloss and the image clarity before adjustment. In addition, the object to be reproduced displayed in the display area  2602  indicates the illumination image corresponding to the specular gloss and the image clarity after the adjustment. By comparing the illumination image in the CG image displayed in the display area  2601  with the illumination image in the CG image displayed in the display area  2602 , the user can recognize the difference in the gloss before and after the adjustment for the object to be reproduced indicated by the input data. By moving the slider position in the slide bar  2603  or the slide bar  2604 , the corresponding adjustment value is tentatively set to a value corresponding to the slider position, and the image in the display area  2602  is updated. Preferably, by moving the mouse pointer (not illustrated) over the CG image, the direction of observation in the CG simulation is changed in accordance with the position of the mouse pointer. Thus, the appearance viewed in the direction of observation corresponding to the position of the mouse pointer is exhibited in this manner, the user can recognize the difference in the gloss before and after the adjustment in a variety of directions of observation. By changing the direction of lighting instead of the direction of observation, the appearance may be exhibited. In addition, the conditions of the CG simulation may be changed. For example, the type of illumination light source and the background scene may be selectable. If the output preview check box  2608  is unchecked, each of the images in the display area  2601  and the display area  2602  is changed to the original illumination image. 
     More preferably, the images displayed in the display areas  2601  and  2602  when the output preview check box  2608  is checked are CU images of the object to be reproduced corresponding to the material appearance data after the material appearance mapping performed in step  52303 . By employing such a configuration, the image corresponding to the material appearance of the reproduced object actually output after the material appearance mapping can be examined before being output. 
     Note that the illumination image in the gloss adjustment UI according to the third exemplary embodiment may be an image corresponding to the input material appearance data. Alternatively, the image may be an image corresponding to the material appearance data after the material appearance mapping. 
     As described above, according to the first modification, the material appearance reproducing system acquires the above-described adjustment information using a user interface displaying the images having the sharpness that varies in accordance with an instruction provided externally. When adjustment is made, the sharpness of the illumination image produced by reflection at a surface of the object changes and, thus, the user can intuitively figure out the adjusted sharpness of the illumination image. As a result, the reproduced object having a desired image clarity can be obtained without repeating the adjustment operation. In addition, according to the first modification, the material appearance reproducing system acquires the adjustment information using user interface displaying images each exhibiting the sharpness and brightness of the illumination image that vary in accordance with an instruction provided externally. If the adjustment is made, the sharpness and brightness of the illumination image produced by reflection at a surface of the object vary. Thus, the user can intuitively recognize that the two elements, that is, the sharpness and brightness of the illumination image can be adjusted. As a result, a reproduced object having a desired material appearance can be obtained without repeating the adjustment operation. 
     In addition, according to the first modification, the material appearance reproducing system acquires the above-described adjustment information using a user interface displaying the images that vary in accordance with an instruction provided externally and that correspond to the input material appearance data. Thus, the gloss can be adjusted using the image of the object to be reproduced indicated by the input data. In this manner, the reproduced object having a desired material appearance can be obtained. 
     In addition, according to the first modification, the material appearance reproducing system acquires the above-described adjustment information using a user interface displaying the images having a sharpness that varies in accordance with an instruction provided externally and that correspond to the material appearance data obtained after the material appearance mapping. Thus, the gloss can be adjusted using the image corresponding to the material appearance of the reproduced object actually output after the material appearance mapping. In this manner, the reproduced object having a desired material appearance can be obtained. 
     Other Modifications  2   
     The material appearance may be adjusted for a particular area instead of all the areas of input data, in such a case, the configuration of the above-described embodiments may additionally include a unit for specifying an adjustment area. In addition, the material appearance adjustment value acquiring unit  2501  may acquire the adjustment value for the specified adjustment area, and the material appearance correcting unit  2503  may correct the material appearance signal of only the specified adjustment area. Furthermore, the adjustment operation may be performed a plurality of times as needed. In such a case, a unit for acquiring information as to whether additional adjustment operation is performed is further provided. In addition, after the process performed by the material appearance correcting unit  2503  is completed, the information as to whether an additional adjustment operation is performed is acquired. If an additional adjustment operation is performed, the unit for specifying the adjustment area is re-activated to specify the adjustment area. In the second and subsequent adjustment operations, the material appearance correcting unit  2503  further corrects the result of previous correction. That is, instead of the input material appearance signals (L, a, b, g, s) in equations (1) to (5), the input material appearance signals (L-a, a_a, b_a, g_a, s_a) obtained in the previous correction are used. According to the modification, the material appearance of only a particular area can be adjusted, or different adjustments can be performed on different areas. In this manner, a reproduced object having a desired material appearance can be obtained. 
     In addition, the material appearance adjustment value acquiring unit  2501  may restrict acquirable adjustment information in accordance with the material appearance reproducible by the material appearance reproducing apparatus. For example, even when the slide bar  2603  allow an adjustment value Δg in the range of −10 &lt;Δg &lt;10 to be selected, the slider is inhibited to move to the right end of the slide bar if the specular gloss Δg reproducible by the material appearance reproducing apparatus &lt;5. According to such a modification, the adjusted value is within the reproducible range at all times. Thus, a reproduced object having a desired material appearance can be obtained without repeating the adjustment operation. 
     In addition, as described in the first exemplary embodiment and some modifications, the signal corresponding to the specular gloss may contain the color information in addition to the brightness information. That is, the material appearance reproducing apparatus may control the color of the illumination image produced by reflection at a surface of the object in addition to the brightness of the illumination image. For example, instead of g, three signals gL, ga, and gb may be used as the gloss signal corresponding to the specular gloss. Note that gL, ga, and gb are signals corresponding to L*, a*, and b* of the CIELAB color space regarding the specular reflection light, respectively. In such a case, the material appearance adjustment value acquiring unit  2501  has a configuration to acquire the adjustment value of the chromaticity in addition to the adjustment value of the brightness as the adjustment value of the specular gloss. For example, by using the slide bar  2603  of the adjustment acquiring UI illustrated in  24 , an adjustment value ΔgL regarding the brightness of the gloss is acquired instead of Δg. In addition, a UI for acquiring adjustment values Δga and Δgb regarding the chromaticity of the gloss is further provided. For example, the adjustment values of a red component and a green component of the specular reflection light are acquired by using the slide bar for acquiring the adjustment value Δga. In addition, the adjustment values of a yellow component and a blue component of the specular reflection light are acquired by using the slide bar for acquiring the adjustment value Δgb. Alternatively, in another example, a two-dimensional plane having axes of Δga and Δgb may be displayed in a UI. By acquiring any given position in the plane, a combination of Δga and AΔb may be acquired. In such a case, the material appearance correcting unit  2503  adds ΔgL, Δga, and Δgb to the material appearance signals gL, ga, and gb, respectively, to obtain adjusted material appearance signals. According to the present modification, the color of the specular reflection light can be also adjusted. Thus, the reproduced object having a desired material appearance can be obtained. 
     In addition, the images having different brightness levels or having different sharpness levels displayed in the UI for acquiring the material appearance adjustment values need not be the images of the illumination light source. That is, the images  2401  to  2408  illustrated in  FIG. 22  and the images  2601  and  2602  illustrated in  FIG. 24  need not be the images of the illumination light source. Although the image of the illumination light source having a high luminance is desirable to determine the specular gloss and the image clarity of an object, another image may be employed. 
     Other Embodiments 1 
     The functional configuration of the material appearance reproducing system may be a configuration in which part or whole of the above-described configuration achieved using the host  700  is achieved by the image printing apparatus  800 . In addition, while the above-described exemplary embodiments have been described with reference to six types of recording material (C, M, Y, K, A, and B), another type of recording material may be used. For example, a red recording material, a white recording material, or a gold recording material may be used. In addition, three or more types of gloss control agent may be used. While the above-described exemplary embodiments have been described with reference to a serial inkjet printer serving as the material appearance re-producing apparatus, a full-line inkjet printer, an electrophotographic printer, a sub-limation printer, or a silk printing may be used as the material appearance reproducing apparatus. Alternatively, a UV printer that prints a surface shape or a 3D printer that prints a 3D shape may be used. In addition to printers, the present technology may be applied to image display apparatuses, such as a display or a projector. 
     All the areas of the material appearance data need not be processed using the technique described in the above exemplary embodiments. A technique in which the technique of the above-described embodiment is not applied to some of the areas and a technique in which the technique of the above-described exemplary embodiment is applied to only some of the areas are encompassed within the scope and spirit of the present invention. For example, some of the areas of the material appearance data may be reproduced using a particular color material without performing the material appearance mapping. 
     In addition, the present invention can be achieved by supplying a program that provides at least one function of the above-described exemplary embodiment to a system or an apparatus via a network or a recording medium and reading out and executing the program using at least one processor of the system or the apparatus. Alternatively, the present invention can be achieved by a circuit (e.g., ASIC) that provides at least one function of the above-described exemplary embodiment. 
     According to the present invention, the image processing for obtaining a reproduced object having a desired material appearance using a reproducible range of the material appearance reproducing apparatus can be provided. 
     Other Embodiments 2 
     Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like. 
     While the present invention has been described with reference to exemplary embodiments, it is to he understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2014-254595, filed Dec. 16, 2014, which is hereby incorporated by reference herein in its entirety.