JP2012053359A - Image processing apparatus and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a gloss reproduction image for gloss reproduction by using a lenticular lens.SOLUTION: An image input section 302 inputs an object image of gloss reproduction. A region input section 304 sets a region where gloss is to be reproduced in the object image. An image processing section 301 generates a plurality of images obtained by performing gloss reproduction processing on the region where gloss is to be reproduced in the object image. An image composition section 309 generates stripe images into which the plurality of images are divided on the basis of characteristics of the lenticular lens and arranges the stripe images into which the plurality of images are divided in a prescribed order to generate a gloss reproduction image for gloss reproduction by using the lenticular lens.

Description

  The present invention relates to image processing for reproducing gloss.

  With the evolution of devices that handle images such as digital cameras, displays, and printers, there is an increasing demand for reproduction of the texture of subjects and stereoscopic viewing. As a texture reproduction, for example, a technique for correcting an image of an input video signal based on a reflected light model and generating a metallic luster as a texture is proposed (for example, Patent Document 1). This method obtains a metallic luster texture based on the luminance signal of the image.

  Further, it is known that when an image with low correlation is presented to the right and left eyes of the observer, no fusion occurs, and only one image is dominantly observed alternately. This phenomenon is called “binocular rivalry” because it fluctuates in an unstable manner over time and the eyelids appear to compete for the right and left eyes. When images with different luminance are presented to the right eye and the left eye, a glossiness called “binocular luster” occurs.

  Also, there is a known method for obtaining a stereoscopic view by combining an image obtained by combining a plurality of parallax images into strips according to lens characteristics (hereinafter referred to as a stripe image) and a lenticular lens (for example, patents). Reference 2). The main use of the lenticular lens is to present different parallax images to the viewer's right eye and left eye.

  In general, the gloss of an object greatly depends on a bidirectional reflectance distribution function (BRDF). BRDF represents the reflectance with respect to the incident angle and the outgoing angle of light on the object surface. A lower gloss object has a substantially constant BRDF regardless of the incident angle and the outgoing angle. Conversely, the higher the glossy object, the greater the value of the specular reflection component. That is, the luminance difference is large between a high gloss area and a low gloss area in the image. Here, there are reproducible luminance ranges for devices and media that handle images. Therefore, if an image containing a glossy subject is output to a medium with a narrow luminance reproduction range, such as matte paper, the luminance difference between the high and low gloss areas is not sufficiently reproduced, and the glossiness is impaired. There's a problem.

Japanese Patent Laid-Open No. 10-285459 JP-A-10-319214

  An object of the present invention is to generate a gloss reproduction image for reproducing gloss using a lenticular lens.

  The present invention has the following configuration as one means for achieving the above object.

  In the image processing according to the present invention, when a gloss reproduction image for reproducing gloss using a lenticular lens is generated, a target image for reproducing the gloss is input, and the gloss is reproduced in the target image. To generate a plurality of images that have been subjected to gloss reproduction processing in the region that reproduces the gloss of the target image, to generate a stripe image obtained by dividing the plurality of images based on the characteristics of the lenticular lens, The gloss reproduction image is generated by arranging the stripe images divided from the plurality of images in a predetermined order.

  According to the present invention, it is possible to generate a gloss reproduction image for reproducing gloss using a lenticular lens.

The schematic diagram explaining the image observed through a lenticular lens. 1 is a block diagram illustrating a configuration example of an image processing device. The block diagram explaining the example of a function structure which image processing AP implement | achieves. The flowchart explaining the image processing by image processing AP. The flowchart explaining the process of an area | region input part. The flowchart explaining the process of the lightness conversion part for right eyes. The flowchart explaining the process of an image synthetic | combination part. The figure explaining formation of a stripe image and the synthesis | combination of a gloss reproduction image. The figure explaining the creation method of the regular reflection LUT and the diffuse reflection LUT. FIG. 6 is a block diagram illustrating an example of a functional configuration realized by an image processing AP according to the second embodiment. 9 is a flowchart for explaining image processing by an image processing AP according to the second embodiment. The figure explaining formation of a gloss reproduction image.

  Hereinafter, image processing according to an embodiment of the present invention will be described in detail with reference to the drawings. In the following, a process for generating an image for a lenticular lens capable of reproducing a glossy feeling regardless of the luminance reproduction range of a device or media will be described.

[Lenticular lens]
An image observed through a lenticular lens will be described with reference to the schematic diagram of FIG.

  As shown in FIG. 1, images obtained by dividing a right-eye image (hereinafter, right image) 11 and a left-eye image (hereinafter, left image) 12 into strips (hereinafter, strip images) are alternately arranged. When the alternately arranged strip images are observed through the lenticular lens 10, the right image and the left image are presented separately. Therefore, if the right image and the left image are images having a binocular parallax (hereinafter referred to as a parallax image), stereoscopic vision can be obtained from alternately arranged strip images.

  If the right image 11 and the left image 12 are not parallax images but images having different brightness, an image having a glossiness due to binocular gloss is observed.

[Device configuration]
A configuration example of the image processing apparatus will be described with reference to the block diagram of FIG.

  The microprocessor (CPU) 201 uses the RAM of the main memory 202 as a work memory, executes a program stored in the ROM of the main memory 202 or the hard disk drive (HDD) 203, and controls the configuration described later via the system bus 206. To do. An interface (I / F) 204 is a serial bus interface such as USB (Universal Serial Bus) or IEEE1394, and is connected to an input device 207 such as a keyboard and a mouse and an image output device 208 such as a printer. A monitor 209 is connected to the video card 205 which is a video interface.

  Hereinafter, an operation of the image processing application (AP) of the embodiment that operates on a general-purpose operating system (OS) that operates in the image processing apparatus illustrated in FIG. 2 will be described. Note that details of the operation of the image processing AP on the OS are omitted.

  When the CPU 201 activates the image processing AP stored in the HDD 203 in accordance with a user instruction input from the input device 207, the image processing AP displays a user interface (UI) on the monitor 205. The image processing AP (CPU 201) loads data stored in the HDD 203 or data input from the interface 204 into the RAM of the main memory 202 based on a user instruction input via the UI, and executes various calculations. . The image processing AP displays the calculation result on the monitor 205, stores it in the HDD 203, and outputs it to the image output device 208.

[Functional configuration of image processing]
Next, a process in which the image processing AP inputs image data, brightness information, and lenticular lens characteristics (hereinafter referred to as lens characteristics) according to a user instruction, and generates image data of an image combined with the lenticular lens from these data will be described. .

  A functional configuration example realized by the image processing AP will be described with reference to the block diagram of FIG.

  The image processing unit 301 inputs image data and lens characteristics, determines an area to be given glossiness in an image represented by the image data (hereinafter referred to as a target image), and performs image processing (hereinafter referred to as glossiness) to the target image. A gloss reproduction image that has been subjected to gloss reproduction processing is output.

  The image input unit 302 acquires image data of the target image from the HDD 203, for example. The lens characteristic input unit 303 acquires lens characteristics from the HDD 203, for example. The area input unit 304 acquires, for example, a calculation or an input device 207 in the target image represented by the image data acquired by the image input unit 302, which gives a glossy area (area where gloss reproduction processing is performed).

  The right-eye lightness conversion unit 305 refers to, for example, the diffuse reflection lookup table (LUT) 307 stored in the HDD 203, performs lightness conversion on the pixels included in the region acquired by the region input unit 304, and performs the target image To generate a right image (first image). The left-eye lightness conversion unit 306 refers to, for example, the regular reflection LUT 308 stored in the HDD 203, performs lightness conversion on the pixels included in the region acquired by the region input unit 304, and converts the left image (second image) from the target image. Image). Note that the right-eye lightness conversion unit 305 may refer to the regular reflection LUT 308, and the left-eye lightness conversion unit 306 may refer to the diffuse reflection LUT 307 to generate the first image and the second image. The LUT creation units 312 and 311 for creating the diffuse reflection LUT 307 and the regular reflection LUT 308 in which the brightness conversion characteristics are recorded will be described later.

  The image composition unit 309 composes the right image and the left image based on the lens characteristics acquired by the lens property input unit 303 to generate a gloss reproduction image. The output unit 310 outputs the gloss reproduction image to the image output device 208 or the like in order to form the gloss reproduction image.

  Image processing by the image processing AP will be described with reference to the flowchart of FIG.

  The image processing unit 301 acquires the image data of the target image using the image input unit 302 (S401), and acquires the lens characteristics using the lens characteristic input unit 303 (S402). The lens characteristics include information such as the orientation and width of the lenticular lens. Note that data such as image data and lens characteristics may be acquired or input by an arbitrary method. For example, data stored in the HDD 203 may be read, or may be input as an instruction of a user who operates the keyboard or mouse of the input device 207. Alternatively, image data may be input from an external storage device (not shown) connected to the interface 204 or a digital camera.

  Next, as will be described in detail later, the image processing unit 301 uses the region input unit 304 to acquire a region (hereinafter referred to as a gloss reproduction region) for performing gloss reproduction processing on the target image represented by the image data (S403). As will be described in detail later, a right image is generated by the right eye lightness conversion unit 305 (S404), and a left image is generated by the left eye lightness conversion unit 306 (S405).

  Next, as will be described in detail later, the image processing unit 301 generates a gloss reproduction image by combining the right image and the left image by the image synthesis unit 309 (S406), and outputs the gloss reproduction image by the output unit 310 (S407). ). Note that the output destination of the gloss reproduction image is not limited to the image output device 208, and any device may be used. For example, it may be stored in the HDD 203 or in an external storage device (not shown) connected to the interface 204.

Area Input Unit The process (S403) of the area input unit 304 will be described with reference to the flowchart of FIG.

  The area input unit 304 recognizes the object of the target image represented by the image data input by the image input unit 302 (S501). For object recognition, a generally used method such as a support vector machine or boosting may be used.

  Next, the region input unit 304 extracts a region having a large luminance change among the recognized objects (S502). The change in luminance may be expressed using a differential component of the image. Further, the target image may be displayed on the monitor 209, and the area may be designated by the user operating the input device 207, for example.

  Next, the area input unit 304 uses the extracted (or designated) area as a gloss reproduction area, and outputs information indicating the gloss reproduction area to the image processing unit 301 (S503). For example, a bitmap having the same height and width as the target image is prepared, and the gloss reproduction area may be indicated by setting the pixel in the gloss reproduction area to ‘1’ and the pixel outside the gloss reproduction area to ‘0’.

Right Eye / Left Eye Lightness Conversion Unit The processing (S404) of the right eye lightness conversion unit 305 will be described with reference to the flowchart of FIG. Note that the processing of the left eye brightness conversion unit 306 may be performed by replacing the diffuse reflection LUT 307 with the regular reflection LUT 308 in the following description.

  The right eye brightness conversion unit 305 initializes the position of the pixel of interest (S601). For example, if the image is stored as a one-dimensional array, 0 indicating the head position of the one-dimensional array may be set. When the image is stored as a two-dimensional array, coordinates (x, y) = (0, 0) indicating the top position of the two-dimensional array (for example, the upper left corner of the image) may be set.

  Next, the right eye brightness conversion unit 305 determines whether or not the target pixel is included in the gloss reproduction region (S602), and if included, refers to the diffuse reflection LUT 307 and performs brightness conversion on the target pixel ( S603), if not included, no brightness conversion is performed. Then, it is determined whether or not the determination in step S602 has been performed for all the pixels of the target image (S604), and if there is an undetermined pixel, the target pixel is moved (S605), and the process returns to step S602 to determine whether or not If there is no pixel, the gloss reproduction process ends.

Image Synthesizer The process (S406) of the image synthesizer 309 will be described with reference to the flowchart of FIG.

The image composition unit 309 inputs the right image and the left image, which are brightness conversion images (S701), and determines the division width when dividing the right image and the left image into strips according to the lens width indicated by the lens characteristics. Determine (S702). For example, when the lenticular lens is 60 LPI, the width per lens is 1/60 inch. When combining two images for a 60 LPI lenticular lens, the split width is 1/120 inch. That is, the division width ΔW in the case of synthesizing M images for the W LPI lenticular lens is expressed by the following equation.
ΔW = 1 / (W × M) (1)

  Next, the image composition unit 309 determines an image division direction according to the direction of the lens indicated by the lens characteristics (S703). In order to observe different images between the right eye and the left eye, it is necessary that the elongated convex lenses are aligned in a direction perpendicular to the line connecting both eyes (the direction of the lens is vertical). Therefore, the upright image is divided in the vertical direction. However, when the direction of the lens is horizontal, for example, if an erect image is divided in the horizontal direction and the lenticular lens and the image are rotated 90 degrees and observed, a glossy image is reproduced. In the following description, the direction of the lens is assumed to be vertical.

  Next, the image composition unit 309 forms a stripe image having a division width ΔW obtained by dividing the right image and the left image in the vertical direction (S704). Then, a gloss reproduction image in which a stripe image divided from the right image (hereinafter, right stripe image) and a stripe image divided from the left image (hereinafter, left stripe image) are arranged in a predetermined order, that is, alternately is synthesized (S705). .

The formation of the stripe image and the synthesis of the gloss reproduction image will be described with reference to FIG. Left image 801 is divided width ΔW of the stripe image A1, A2, ..., is divided into A _2n, the right image 802 is divided width ΔW of the stripe image B1, B2, ..., is divided into B _2n. Gloss reproduction with stripe images arranged alternately so that A1 and B1 correspond to lens L1 of lenticular lens 804, A2 and B2 correspond to L2, A _2n and B _2n correspond to L _n An image 803 is formed. However, when all the stripe images are arranged, the width of the gloss reproduction image is twice the width of the target image. Therefore, in order to match the width of the gloss reproduction image with the width of the target image, a part of the stripe image is thinned out. For example, A _2i-1 and B _2i are made to correspond to the lens Li (1 ≦ i ≦ n). The width of the gloss reproduction image only needs to match the width of the target image. For example, A _2i and B _2i-1 may correspond to the lens Li, or the width of the target image is reduced to 1/2 before division. It doesn't matter.

LUT Creation Unit A method for creating the regular reflection LUT 308 and the diffuse reflection LUT 307 will be described with reference to FIG.

  First, using a printer and media used to form a gloss reproduction image, a print 901 printed with color patches is formed, and a sample in which a lenticular lens 902 used to reproduce the gloss is superimposed on the print surface of the print 901 is prepared. prepare. This is because the reflected light of the print 901 that has passed through the lenticular lens 902 and the reflected light of the print 901 may have different colors. In order to change the reflected light passing through the lenticular lens 902 to a desired color, a plurality of color patches having different colors are measured through the lenticular lens 902. Then, the color patch corresponding to the desired color is searched with reference to the measurement result of the color patch, and an LUT indicating the relationship between the desired color and the color of the searched color patch is generated. At this time, it is necessary to perform not only color conversion but also lightness conversion by the LUT so that the reflected light passing through the lenticular lens 902 reproduces both the color and gloss of the print.

  Therefore, for example, a color luminance meter or the like is used for the measuring device 903 for acquiring specular reflection light data and the measuring device 904 for acquiring diffuse reflection light data. Then, the measuring device 903 is arranged so that the reflected light of 45 degrees is incident from the sample, and the measuring device 904 is arranged so that the reflected light of 90 degrees is incident from the sample. One measuring device may be used. For example, after measuring 45 degrees of reflected light, 90 degrees of reflected light may be measured. The illumination 905 is arranged so that light is incident on the sample at an angle of −45 degrees. The specularly reflected light reflected from the printing surface of the print 901 is incident on the measuring device 903 via the lenticular lens 902. Further, diffuse reflection light other than regular reflection light is incident on the measuring device 904.

  The reflected light data obtained by the measurement includes information for performing lightness conversion for displaying a desired lightness and color conversion for displaying a desired color in a state where the lenticular lens 902 and the print 901 are combined. Information will be included. That is, even for the reflected light data for the same color, the brightness indicated by the diffuse reflected light data obtained from the measuring device 904 is higher than the brightness indicated by the regular reflected light data obtained from the measuring device 903. By using this difference in brightness, it is possible to create LUTs that perform different brightness conversions. Therefore, the LUT creation unit 311 creates a regular reflection LUT 308 that performs brightness conversion and color conversion corresponding to regular reflected light based on the regular reflected light data of a plurality of color patches with different colors measured by the measuring device 903. . In addition, the LUT creation unit 312 creates a diffuse reflection LUT 307 that performs brightness conversion and color conversion corresponding to diffuse reflected light based on the diffuse reflected light data of a plurality of color patches with different colors measured by the measuring device 904. .

  As described above, the example of creating the regular reflection LUT 308 and the diffuse reflection LUT 307 by measuring the color patch has been described. However, the regular reflection LUT 308 and the diffuse reflection LUT 307 may be created by other methods. The above-mentioned method is more excellent in reproducing the gloss of the print 901. For example, a predetermined brightness conversion is performed on the specular reflection light data created earlier, and the diffuse reflection LUT 307 is created using the specular reflection light data that has undergone the brightness conversion. May be.

  In the above description, the example has been described in which the right-eye lightness conversion unit 305 and the left-eye lightness conversion unit 306 are used to perform lightness conversion on each of the target images. However, the target image may be used as it is without performing lightness conversion for the right eye. In this case, the generation of the diffuse reflection LUT 307 becomes unnecessary.

  In this way, by combining the gloss reproduction image formed by simple image processing using the LUT and the lenticular lens, it is possible to reproduce the gloss feeling regardless of the luminance reproduction range of the device or the media.

  The image processing according to the second embodiment of the present invention will be described below. Note that the same reference numerals in the second embodiment denote the same parts as in the first embodiment, and a detailed description thereof will be omitted.

  In the first embodiment, an example in which there are two LUTs for specular reflection light and diffuse reflection light has been described. In the second embodiment, an example in which a gloss reproduction image is generated using three or more LUTs will be described.

A functional configuration example realized by the image processing AP according to the second embodiment will be described with reference to the block diagram of FIG. The Example 2, brightness conversion unit _{313 1 ~313 n (n ≧ 3} ) performing brightness conversion into a pixel of the gloss reproduction area exists. Thus, LUT315 ₁ ~315 _n corresponding to the brightness conversion unit, the LUT creation unit 317 ₁ ~317 _n exists to create each LUT. Each LUT creation unit creates a LUT for brightness conversion using incident light having different angles of reflected light.

  Image processing by the image processing AP in the second embodiment will be described with reference to the flowchart of FIG. The processing in steps S401 to S403 and S407 is the same as that in the first embodiment.

The image processing unit 301 sets a counter i = 1 (S500), and generates an image (hereinafter referred to as a “lightness conversion image”) that has undergone lightness conversion processing by the lightness conversion unit 313 _i that refers to the LUT 315 _i (S501). Then, it is determined whether or not the counter i is less than the number n of lightness conversion units 313 (i <n) (S502). If i <n, the counter i is incremented and the process returns to step S501. When i = n, a gloss reproduction image is generated by synthesizing n lightness conversion images (S504).

  The formation of the gloss reproduction image will be described with reference to FIG. For example, when n = 3 where there are three brightness conversion images, one gloss reproduction image is generated from the three brightness conversion images. In this case, as shown in FIG. 12, there are three arrangement orders of the stripe image divided from each brightness conversion image, and the arrangement order can be changed according to the glossiness to be reproduced. As a result, it is possible to form a gloss reproduction image for changing the gloss level in more detail than in the case where a gloss reproduction image is formed from two lightness conversion images.

  The arrangement order of the stripe images divided from each brightness conversion image may be determined in the processing of the image composition unit 309 or may be designated by the user. If the stripe image is arranged to increase the brightness difference between the images observed by the right eye and the left eye, the glossiness will increase. The glossiness decreases.

[Other Examples]
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, etc.) of the system or apparatus reads the program. It is a process to be executed.

Claims (6)

An image processing apparatus that generates a gloss reproduction image for reproducing gloss using a lenticular lens,
Input means for inputting a target image to reproduce the gloss;
Setting means for setting an area for reproducing the gloss in the target image;
Processing means for generating a plurality of images obtained by performing gloss reproduction processing on the gloss reproduction region of the target image;
Generating means for generating a stripe image obtained by dividing the plurality of images based on characteristics of the lenticular lens, and generating the gloss reproduction image by arranging the stripe images divided from the plurality of images in a predetermined order; An image processing apparatus.   2. The processing unit generates the plurality of images obtained by converting the brightness of a region that reproduces the gloss of the target image using a plurality of lookup tables having different brightness conversion characteristics. The described image processing apparatus.   3. The generation unit according to claim 1, wherein the generation unit generates the gloss reproduction image by arranging the stripe images divided from the plurality of images in an order according to the glossiness to be reproduced. Image processing device. The processing means includes a first image obtained by performing the gloss reproduction process on a region for reproducing the gloss of the target image using a brightness conversion look-up table created from specular reflection light, and diffuse reflection light. A second image obtained by performing the gloss reproduction process on a region for reproducing the gloss of the target image using a lookup table for brightness conversion created from:
2. The image processing apparatus according to claim 1, wherein the generation unit generates the gloss reproduction image by alternately arranging stripe images divided from the first and second images. An image processing method of an image processing apparatus that includes an input unit, a setting unit, a processing unit, and a generation unit, and generates a gloss reproduction image for reproducing gloss using a lenticular lens,
The input means inputs a target image to reproduce the gloss,
The setting means sets an area for reproducing the gloss in the target image;
The processing means generates a plurality of images that have been subjected to gloss reproduction processing on the gloss reproduction region of the target image,
The generation unit generates a stripe image obtained by dividing the plurality of images based on characteristics of the lenticular lens, and generates the gloss reproduction image by arranging the stripe images divided from the plurality of images in a predetermined order. An image processing method.   5. A program that controls a computer device to function as each unit of the image processing device according to claim 1.

Images