JP6127966B2 - Image output apparatus and program - Google Patents

Description

  The present invention relates to an image output apparatus and a program. More specifically, the present invention relates to an image output apparatus and program for generating image data and plain color determination based on a certain image and outputting image data corresponding to the solid color determination result.

  Conventionally, an image is acquired, image data in an output format is generated based on the acquired image, a plain color determination is performed as to whether or not the acquired image is a solid color image, and a solid color is determined based on the result of the solid color determination. A technique for outputting image data excluding images is known. In the present specification, the term “solid” is used, including not only a white sheet of white paper but also a plain color page that is a single color page that does not include image information in the page.

  For example, Patent Document 1 discloses an image processing apparatus having an image reading unit and an image forming unit, which reads a document image, detects a blank image from the read image, and deletes the detected blank image. It is disclosed.

JP 2012-160873 A

  However, the conventional technique described above has the following problems. That is, when image data to be output is determined according to the result of the plain color determination, the start of image data output is delayed as the solid color determination takes longer. For example, plain color determination based on luminance information of each pixel tends to take time. Therefore, there is a case where the output of the image data is awaited even though the generation of the image data is completed. Also, not only on white paper, but when the acquired image is a plain image not including image information, it is preferable not to output the image data of the image.

  The present invention has been made to solve the above-described problems of the prior art. That is, an object of the present invention is to provide an image output apparatus and a program that can be expected to end plainness determination early and start output early when outputting image data.

  An image output apparatus made for the purpose of solving this problem includes an acquisition unit for acquiring an image and a control unit, and the control unit performs an acquisition process for acquiring an image by the acquisition unit and the acquisition process. A color generation process for generating color image data compressed by a predetermined compression method based on an acquired image that is an image acquired in the above-described manner, and a compression method that is compressed by the same compression method as the color image data based on the acquired image When the difference between the size of the color image data and the size of the gray image data is greater than a threshold value, the acquired image is determined to be a plain image. A determination process for determining whether or not to output image data based on the acquired image according to a determination result of the plain determination process and a determination result of the plain determination process It is characterized by executing and.

  The image output apparatus disclosed in the present specification generates compressed color image data and gray image data based on the acquired image acquired by the acquisition unit. The gray image data is grayscale image data compressed by the same compression method as the color image data. Then, when the difference between the size of the generated color image data and the size of the gray image data is larger than the threshold value, the acquired image is determined as a plain image. Further, it is determined whether to output image data according to the determination result. Examples of the acquired image include an image read in color by a scanner and an image received by a printer driver as a print target. Further, as a compression method, for example, JPEG, GIF, and PNG are applicable. The plain image may be an image that does not include image information, and is not limited to a white image but includes a single color image.

  That is, in the image output device disclosed in this specification, it is determined whether or not the image is a plain image based on a comparison between the size of the color image data and the size of the gray image data, so that the determination algorithm is simple. is there. That is, if the generation of color image data and gray image data is completed, a determination result can be obtained quickly. As a result, for example, although the generation of image data has been completed, it is possible to expect a reduction in the situation where the end of the plain color determination is awaited.

  The control unit may use a ratio between the size of the color image data and the size of the gray image data as a difference between the size of the color image data and the size of the gray image data. The determination based on the size ratio can be applied to a wide range of image data because the influence of the size itself on the determination result is small.

  The control unit may use a difference between the size of the color image data and the size of the gray image data as a difference between the size of the color image data and the size of the gray image data. The size difference is easy to calculate and can be determined early.

  Further, the control unit executes a component solid color determination process for determining whether the acquired image is a solid image or a non-solid image based on at least a luminance component of the acquired image. In the determination process, the control unit performs the solid color determination process. If the acquired image is not determined to be a plain color image, it may be determined whether to output image data based on the acquired image according to the determination result of the component solid color determination process. In the plain color determination process, when the difference between the size of the color image data and the size of the gray image data is not larger than the threshold value, it may not be possible to determine whether the color image data is a plain image or a non-solid image. Therefore, by executing the component solid color determination process as a determination process different from the solid color determination process, it is possible to reliably determine whether the image is a solid image or a non-solid image. According to the component plain color determination process, detailed determination is possible based on the luminance component of the acquired image. The component plain color determination process may be started after the plain color determination process is determined, or may be started before the determination of the plain color determination process is completed.

  Further, in the determination process, when the determination result of the component solid color determination process is obtained prior to the determination result of the solid color determination process, according to the determination result of the component solid color determination process, It may be determined whether to output image data based on the acquired image. Of the plain color determination process and the component solid color determination process, the image data to be output can be determined earlier by adopting the determination result obtained earlier. It is not necessary to start the plain color determination process and the component solid color determination process at the same time.

  Further, the control unit generates a binary image data that is achromatic image data that is binarized based on the acquired image, and the acquired image is a color image. The plain color determination process is executed in an unknown state, and after the acquired image is not determined to be a solid color image in the solid color determination process, the acquired image is determined to be a solid color image in the component solid color determination process. The acquired image is determined to be an achromatic solid image, and based on at least the luminance component of the acquired image, the color type of the acquired image is determined to be a gray image or an achromatic binary image. An achromatic color determination process and an achromatic color data determination process for determining image data to be output based on the determination result of the achromatic color determination process may be executed. A plain color determination process is performed before the acquired image is determined to be a color image, and after the acquired image is not determined to be a solid color image, and the acquired image is determined to be a solid color image in the component solid color determination process Can be determined as an achromatic solid image. However, when achromatic binary image data is generated in addition to gray image data as achromatic image data, it is not determined which of these is to be output image data. Therefore, by determining whether the image is a gray image or an achromatic binary image, more appropriate image data output can be expected.

  The control unit determines a color determination process for determining a color type of the acquired image based on at least a color difference component of the acquired image, and image data to be output based on a determination result of the color determination process. Data determination processing may be executed. Since at least two types of image data of color image data and gray image data are generated, it is preferable to determine the color type of the acquired image and to output more appropriate image data.

  The control unit may determine that the color type of the acquired image is a color image when the acquired image is determined to be a non-solid image in the plain color determination process. For example, if the acquired image is YCbCr data and the compression method for generating color image data and gray image data is JPEG, if the acquired image is a chromatic color, the gray image does not use the color difference component and is compressed to the size. Differences are likely to occur. On the other hand, when the acquired image is an achromatic color, there is little change in the color difference component of the acquired image, and therefore it is difficult to cause a difference in size even after compression. In this way, when the acquired image is determined to be a solid image in the plain color determination process, that is, when the difference between the size of the color image data and the size of the gray image data is large, the color type is determined to be a color image. Therefore, it is preferable to determine the color type.

  The control unit determines that the acquired image is a solid image when the acquired image is determined to be a color image in the color determination process and is not determined to be a plain image in the plain determination process. If the acquired image is determined not to be a color image in the color determination process before the determination result of the solid color determination process is obtained, the acquired image is determined according to the determination result of the component solid color determination process. It may be determined whether to output the image data based on it. If it is not determined that the image is a plain image, there is a possibility of an achromatic image and a color plain image. Therefore, when it is known in advance that the image is a color image, it can be determined that the image is a color solid image based on the result of the solid color determination process. On the other hand, if it is determined that the image is not a color image, it may be determined whether the image is a solid image or a non-solid image after waiting for the determination result of the component solid color determination process. In other words, if some of the possibilities are excluded in advance, the subsequent determination process becomes simple.

  Further, the control unit is configured to generate a binary color image data that is achromatic image data binarized and compressed based on the acquired image, and the achromatic color binary image data. When the size of the image is smaller than a reference value, a binary solid color determination process is performed to determine that the acquired image is a solid color image. In the determination process, the second image is determined prior to the determination result of the solid color determination process. When the determination result of the value solid color determination process is obtained, it is preferable to determine whether to output image data based on the acquired image according to the determination result of the binary solid color determination process. Of the plain color determination process and the binary solid color determination process, the image data to be output can be determined earlier by adopting the determination result obtained earlier. It should be noted that the size of the achromatic color binary image data becomes extremely small when it is compressed in the case of a plain image. Therefore, it is possible to determine whether the image is a plain image. The solid color determination process can be executed when the generation of the color image data and the gray image data is completed, and the binary solid color determination process can be executed when the generation of the achromatic color binary image data is completed. It is not necessary to start the solid color determination process and the binary solid color determination process simultaneously. Either may be executed first.

  The acquisition unit may read an image of a document, and the control unit may acquire an image that has been color-read by the acquisition unit in the acquisition process. Whether or not to output image data can be determined based on image data acquired by color reading.

  The control unit may set the threshold based on at least one of a document size and a reading resolution. The size of the generated image data varies depending on the size of the read document and the reading resolution. Therefore, by changing the determination threshold based on these pieces of information, there is a high possibility that the determination will be more accurate compared to a case where the threshold is a fixed value.

  In the present specification, an image output device is provided with an acquisition process for acquiring an image, and a color for generating color image data compressed by a predetermined compression method based on an acquired image that is an image acquired by the acquisition process. Generation processing, gray generation processing for generating gray image data that is grayscale image data compressed by the same compression method as the color image data based on the acquired image, the size of the color image data, and the gray image data When the difference from the size of the image data is larger than a threshold value, a plain color determination process for determining the acquired image as a solid color image and outputting image data based on the acquired image according to the determination result of the solid color determination process There is also disclosed a program characterized in that a determination process for determining whether or not to execute is executed.

  According to the present invention, an image output apparatus and a program that can be expected to start outputting at an early stage when the plain color determination is finished early and image data is output are realized.

It is a block diagram which shows the electric constitution of the scanner which concerns on this form. It is a block diagram which shows schematic structure which concerns on the reading output operation | movement of a scanner. It is a flowchart which shows the procedure of a reading output process. It is a flowchart which shows the procedure of a color determination process. It is a flowchart which shows the procedure of a component solid color determination process. It is a flowchart which shows the procedure of the determination process after color determination. It is a flowchart which shows the procedure of a size plainness determination process. It is a flowchart which shows the procedure of an achromatic color determination process.

  Embodiments of the image output apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. In this embodiment, the present invention is applied to a scanner having an image reading function.

  First, the electrical configuration of the scanner 100 will be described. As shown in FIG. 1, the scanner 100 includes a controller 30 including a CPU 31, a ROM 32, a RAM 33, an NVRAM (nonvolatile RAM) 34, and an ASIC 35. The scanner 100 includes an image reading unit 20, a network interface 37, a USB interface 38, and an operation panel 40, which are electrically connected to the controller 30.

  The ROM 32 stores various control programs for controlling the scanner 100, various settings, initial values, and the like. The RAM 33 is used as a work area from which various control programs are read, or as a storage area for temporarily storing data. The CPU 31 controls each component of the scanner 100 while storing the processing result in the RAM 33 or the NVRAM 34 according to the control program read from the ROM 32.

  The CPU 31 is an example of a control unit. The controller 30 may be a control unit, and the ASIC 35 may be a control unit. Note that the controller 30 in FIG. 1 is a collective term for hardware used for controlling the scanner 100 such as the CPU 31, and does not necessarily represent a single piece of hardware that actually exists in the scanner 100.

  The image reading unit 20 has a configuration for reading an image of a document. The scanner 100 of this embodiment is capable of color reading. The reading method may be a CCD method or a CIS method. The image reading unit 20 is an example of an acquisition unit.

  The network interface 37 is hardware for communicating with a network via a LAN cable or the like. The USB interface 38 is hardware for performing communication via a USB cable or the like. The operation panel 40 includes a liquid crystal display and a group of buttons including a start key, a stop key, a numeric keypad, and the like, and is responsible for various displays and reception of instruction inputs by the user.

  The scanner 100 according to the present embodiment can execute a read output operation of reading a document, generating image data based on the read image, and outputting the image data to another apparatus. When the scanner 100 receives an instruction for a read output operation, the scanner 100 performs color reading of the document. Then, it is determined whether or not the read document is a plain image, and when it is determined that the read document is not a plain image, image data based on the read document image is output. On the other hand, if it is determined that the read original is a plain image, no image data is output. A plain image is a single-color page that does not include image information in the page, and is a blank page or a plain color. Note that the scanner 100 also determines the color type, and when determining that the image is not a plain image, determines the image data to be output according to the determination result of the color type.

  Next, a schematic configuration for the read output operation in the scanner 100 will be described with reference to FIG. The scanner 100 includes an image reading unit 20, an image processing circuit 22, a color type determination circuit 23, a plain color determination circuit 24, a RAM 33, and an image file generation circuit 25. In this embodiment, the image processing circuit 22, the color type determination circuit 23, the plain color determination circuit 24, and the image file generation circuit 25 are included in the ASIC 35 (see FIG. 1).

  Further, the image file generation circuit 25 includes a JPEG encoder 251, a JPEG encoder 252, a binarization circuit 253, a compression circuit 254, a memory 255, a memory 256, and a memory 257. The JPEG encoder 251 and the JPEG encoder 252 may be a common circuit. In addition, the memories 255, 256, and 257 may be a part of the area of the RAM 33 or may be provided as separate hardware.

  The image reading unit 20 performs color reading of a document when executing a reading output operation, and acquires RGB format image data including color information. The image processing circuit 22 converts the image data acquired by the image reading unit 20 to generate YCbCr format image data, and stores the image data in the RAM 33. Of the image data in the YCbCr format, the Y component is a luminance component representing luminance, and the Cb component and the Cr component are color difference components representing color differences of different colors.

  The color type determination circuit 23 executes color determination processing for determining the color type of the read image. That is, based on each component of the image data in the YCbCr format, it is determined whether the document of the read page is a color document, a gray document, or a monochrome document. Specifically, if the image includes a chromatic component, it is determined as a color page. Further, a gray page is determined for an achromatic and multi-tone image, and a monochrome page is determined for a two-tone image of only white and black. In the determination of the color type in the color type determination circuit 23, it is not determined whether it is a plain image or a non-solid image. The contents of the color determination process by the color type determination circuit 23 will be described later.

  The plain color determination circuit 24 executes a component solid color determination process for determining whether the document of the read page is a plain image or a solid color image based on each component of the image data in the YCbCr format. Specifically, it is determined whether or not the page includes a color that differs from the ground color in at least one of color difference and luminance. The content of the component plain color determination process by the solid color determination circuit 24 will be described later.

  The image file generation circuit 25 generates color image data, gray image data, and monochrome image data based on the YCbCr format image data generated by the image processing circuit 22. Specifically, the image file generation circuit 25 generates color image data with the JPEG encoder 251 based on the image data in the YCbCr format, and stores it in the memory 255. Further, gray image data is generated by the JPEG encoder 252 based on the YCbCr format image data and stored in the memory 256. Also, monochrome image data is generated by the binarization circuit 253 and the compression circuit 254 based on the image data in the YCbCr format and stored in the memory 257.

  The color image data is compressed data compressed by the JPEG method using both the luminance component and the color difference component of the image data in the YCbCr format. That is, the color image data is image data including color information. JPEG is an international standard data compression method.

  The gray image data is compressed data compressed by the JPEG method based on data in which the Cb value and the Cr value are replaced with fixed values among the image data in the YCbCr format. That is, the gray image data is grayscale image data generated from image data in the YCbCr format. Alternatively, gray image data may be generated by performing compression using only Y information that is a luminance component of image data. The JPEG encoder 251 and the JPEG encoder 252 have the same configuration, and the color image data and the gray image data are both compressed data compressed by the same compression method with the same compression rate.

  The monochrome image data is achromatic image data binarized based on YCbCr format image data. For this purpose, the binarization circuit 253 acquires only the Y information from the image data in the YCbCr format, binarizes it, and generates binary data. The compression circuit 254 compresses the binary data generated by the binarization circuit 253 and generates compressed data. As a compression method of the compression circuit 254, for example, there is a pack bits method. The compression method for monochrome image data may be a different method from the compression method for color image data or gray image data, or the same method.

  That is, data obtained by compressing an acquired image acquired by color reading by the image reading unit 20 is color image data, and the process of generating color image data by the JPEG encoder 251 is an example of a color generation process. The gray image data is grayscale compressed image data for the same acquired image, and the process of generating gray image data by the JPEG encoder 252 is an example of a gray generation process. The monochrome image data is achromatic image data obtained by binarizing the same acquired image, and the process of generating monochrome image data by the binarization circuit 253 and the compression circuit 254 is an example of a binary generation process. is there.

  Next, a read output operation executed by the scanner 100 of this embodiment will be described. When receiving an instruction to execute the read output operation, the scanner 100 reads the document and generates the various image data described above. Further, the color type of the document is determined and whether it is a plain image or a non-solid image is determined.

  Specifically, the original reading operation by the image reading unit 20, the generation processing of image data in the YCbCr format based on the original image by the image processing circuit 22, the color determination processing by the color type determination circuit 23, and the solid color determination circuit The component solid color determination processing by 24 and the generation processing of various image data by the image file generation circuit 25 are executed in parallel. In the image file generation circuit 25, three types of image data of color image data, gray image data, and monochrome image data are generated in parallel and stored in the corresponding memories.

  Then, when the scanner 100 determines that the read document is not a plain image and determines the color type of the color image, the gray image, or the monochrome image, an image that matches the color type of the document among the generated image data. Output data. On the other hand, if it is determined that the read document is a plain image, no image data is output.

  The scanner 100 determines whether or not the document is a plain image as component blanking determination processing executed by the blanking determination circuit 24 in parallel with reading, and each generated after completion of reading one page. A size plainness determination process that is determined based on the size of the image data can be executed. The component plain color determination process is a process of dividing image data obtained by reading a document into blocks and performing determination based on luminance information of pixels in the block for each block. The component plain color determination processing can make a detailed determination and the determination result is highly reliable, but it may take time until the determination result is obtained. On the other hand, the size plainness determination process is a determination based on the comparison of image data sizes, and is a simple process that can be performed in a short time.

  Further, as a process for determining the color type of the document, a color determination process executed by the color type determination circuit 23 in parallel with the reading and an achromatic color executed after it is determined that the image is an achromatic solid image. The determination process can be executed. The color determination process is a process in which image data is divided into blocks and the color type for each block is determined as one of color, gray, and monochrome. In the achromatic color determination process, it is determined whether it is gray or monochrome. The contents of each process will be described later.

  Next, the procedure of the read output process for executing the read output operation in the scanner 100 of this embodiment will be described with reference to the flowchart of FIG. This reading output process is executed by the CPU 31 when a document is set in the image reading unit 20 and an instruction to start a reading output operation is received.

  When the scanner 100 receives an instruction to start a reading output operation, the scanner 100 first starts a document reading operation (S101). S101 is an example of an acquisition process. Then, based on the acquired image, the image file generation circuit 25 starts generating various color, gray, and monochrome image data (S102). In addition, the color type determination circuit 23 starts executing color determination processing (S103). Further, the solid color determination circuit 24 starts to execute the component solid color determination process (S104). As will be described later, the operations started in S101 to S104 are executed in parallel.

  Then, it is determined whether or not reading of one page of the document has been completed (S105). If not finished (S105: NO), reading of the document is continued. Other processes that are being executed in parallel are also continuously executed. If it is determined that the reading has been completed (S105: YES), it is determined whether or not the component solid color determination process by the solid color determination circuit 24 of this page has been completed (S106). If there is a document for the next page, reading of the next page and generation of data are started when the reading of one page is completed even if the processing from S106 onward is not completed.

  If it is determined that the component plain color determination process has been completed (S106: YES), it is determined from the determination result whether or not the page is determined to be a solid image (S107). If it is determined that the image is a plain image (S107: YES), the read output process is terminated. That is, the image data of this page is not output. In addition, you may alert | report that the read image was a plain image.

  On the other hand, if it is determined that the image is not a plain image (S107: NO), it is determined to output image data. Then, it is determined whether or not the color determination process by the color type determination circuit 23 is completed (S108). If it is determined that the color determination process has not ended (S108: NO), the color determination process is continued.

  If it is determined that the color determination process has been completed (S108: YES), image data to be output is determined from the generated image data based on the determination result of the color determination process (S109). Further, output of the determined image data is started (S110), and the reading output process is ended. Here, since the determination that the image is not a plain image and the determination of the color type of the document by the color determination processing are obtained, image data that conforms to the determined color type is designated by the instruction of the read output operation. Output to the output destination. The process of determining image data to be output in S109 is an example of a data determination process.

  On the other hand, when it is determined that the component solid color determination process is not completed even after the reading is completed (S106: NO), it is determined whether the color determination process by the color type determination circuit 23 is completed (S112). . If it is determined that the color determination process has not ended (S112: NO), it is determined whether the generation of each image data by the image file generation circuit 25 has ended (S114). If it is determined that the generation of the image data has not ended (S114: NO), the component solid color determination process, the color determination process, and the generation of the image data are continued until at least one of them ends. And execute.

  If it is determined that the color determination process has ended before the component plain color determination process ends (S112: YES), a post-color determination determination process that determines whether the color type is determined or not is executed. (S116). In the color determination processing by the color type determination circuit 23, it is not determined whether or not the image is a plain image. For example, a blank original is determined as a monochrome page, and a color plain image is determined as a color page. For this reason, the scanner 100 executes post-color determination processing in order to determine whether the image is a plain image. The determination process after color determination will be described later.

  Then, it is determined whether or not it is determined that the document is a plain image by the determination process after color determination (S117). If it is determined that the image is a plain image (S117: YES), it is determined not to output image data, and the reading output process is terminated. On the other hand, when it is determined that the image is a plain image (S117: NO), image data to be output is determined based on the determination result of the color determination process (S109), and the determined image data is output (S110). The read output process is terminated.

  On the other hand, when it is determined that the generation of the image data has been completed in a state in which neither the determination by the component plain color determination process nor the determination by the color determination process has been completed (S114: YES), each of the generated image data A size plainness determination process for determining whether the image is a plain image using the size is executed (S119). This size plainness determination process is a process for determining whether or not the document is a plain image based on the size of each generated image data, and also determining the color type if it is determined that the document is not a plain image. The size plainness determination process will be described later.

  Then, it is determined from the determination result of the size plain color determination process whether or not the document is determined to be a plain image (S117). If it is determined that the image is a plain image (S117: YES), it is determined not to output image data, and the reading output process is terminated. On the other hand, when it is determined that the image is a non-solid image (S117: NO), image data to be output is determined based on the determination result of the size solid-color determination processing (S109), and the determined image data is output (S110). , The read output process is terminated. That is, the determination procedure of S117 is an example of a determination process for determining whether the image is a plain image or a non-solid image based on the size of the image data, and determining whether to output the image data based on the determination.

  That is, in the reading output processing of the scanner 100 of this embodiment, the generation of each image data by the image file generation circuit 25, the color determination processing by the color type determination circuit 23, and the component solid color determination processing by the solid color determination circuit 24 are performed in parallel. And execute. Therefore, even if the generation of each image data is finished, there is a possibility that the determination result of the component plain color determination process and the color determination process is not obtained. The scanner 100 executes the size solid color determination process of S119 when the generation of each image data is completed in a state where neither the component solid color determination process nor the color determination process is completed. In addition, if the color determination process is completed in a state where the component solid color determination process has not been completed, the post-color determination determination process in S116 is executed.

  Then, based on the determination result obtained earliest, it is determined whether to output image data. That is, if it is determined that the image is a plain image in the size plain color determination process in S119 or the post-color determination process in S116, it is determined that no image data is output. On the other hand, if it is determined that the image is a plain image, image data based on the color type of the image is determined and output in S109. Specifically, when it is determined that the image is a color solid image, the color image data stored in the memory 255 is output. If it is determined that the image is a gray solid image, the gray image data stored in the memory 256 is output. If it is determined that the image is a monochrome plain image, monochrome image data stored in the memory 257 is output. If there is a document for the next page, reading and data generation are executed sequentially, and determination and output are repeated for each page until processing of all pages is completed.

  Next, the color determination process started in S103 of FIG. 3 will be described with reference to the flowchart of FIG. The color determination process is a process for determining the color type of the read image based on at least the color difference component. The scanner 100 executes color determination processing by the color type determination circuit 23.

  In the color determination process, the image data is subdivided into blocks, the color type of each block is determined, and the color type of the page is determined using the result. For this purpose, first, image data for one page is divided into blocks of, for example, 100 pixels × 100 pixels (S201). Then, block determination for determining the color type in block units is executed (S202).

  In block determination, each block is determined as one of a color block, a gray block, and a monochrome block. Specifically, for all the pixels in the block, the average value of the Cb value and the average value of the Cr value are calculated, and it is determined whether or not both average values are within a range where it can be determined as an achromatic color. To do. A block determined not to be an achromatic color is determined as a color block.

  For a block determined to be achromatic, it is further determined whether it is a gray block or a monochrome block based on the Y value of each pixel in the block. For example, in a case where pixels of a predetermined amount or more indicating most of the block are occupied by dark pixels whose Y value is not more than a first specified value and bright pixels whose Y value is not less than a second specified value. Is determined to be a monochrome block. On the other hand, if pixels with an intermediate Y value are included at a certain ratio or more, it is determined as a gray block. Then, the number of color blocks, the number of gray blocks, and the number of monochrome blocks in one page are calculated.

  Next, the mode value of the Cb value and the mode value of the Cr value are obtained for all the pixels in the page. Then, it is determined whether or not these values are close to achromatic colors (S203). For example, whether the Cb value and the Cr value are in the range of 16 to 240, and the mode value of the Cb value and the mode value of the Cr value are both in the range of 112 to 143. to decide.

  If it is determined that both mode values are within the predetermined range (S203: YES), the ratio of the number of color blocks obtained by block determination to the total number of blocks on the page is equal to the predetermined ratio. It is determined whether or not it exceeds (S204). For example, it is determined whether the ratio of the number of color blocks is 0.2% or more.

  Further, when it is determined that the ratio of the number of color blocks is small (S204: NO), the ratio of the gray block number obtained by the block determination to the total number of blocks of the page exceeds a predetermined ratio. Is determined (S205). For example, it is determined whether or not the ratio of the number of gray blocks is 0.3% or more.

  If it is determined that the ratio of the number of gray blocks exceeds the predetermined range (S205: YES), it is determined that the page is a gray page (S207), and the color determination process is terminated. On the other hand, if it is determined that the ratio of the number of gray blocks does not exceed the predetermined range (S205: NO), it is determined that the page is a monochrome page (S208), and the color determination process ends.

  When it is determined in S204 that the ratio of the number of color blocks exceeds the predetermined range (S204: YES), or at least one of the mode values of the Cb value and the Cr value is not within the predetermined range. (S203: NO), it is determined that the page is a color page (S209), and the component determination process is terminated. Thereby, the color type of the read image is determined.

  Next, the component plain color determination process started in S104 of FIG. 3 will be described with reference to the flowchart of FIG. The component plain color determination process is a process for determining whether the read image is a plain image or a non-solid image based on at least the luminance component of the image. In the scanner 100, the solid color determination circuit 24 performs component solid color determination processing.

  Also in the component plain color determination process, the image of one page is divided into blocks as in the color determination process. Then, it is determined for each block whether it is a plain block or a non-solid block, and the number of each block is calculated. Specifically, one page is divided into blocks of, for example, 100 pixels × 100 pixels (S301). Further, the following processing is executed on the basis of the image data of the pixels included in the block unit in order from the block where reading has been completed for all the pixels in the block.

  The mode value of the Y value is calculated for all the pixels in the block (S304). Further, it is determined whether or not the ratio of the mode value of the Y value calculated in S304 is large (S305). For example, it is determined whether or not the proportion of pixels with uniform luminance component values occupies 80% or more of the block. If it is determined that the ratio of the mode value of the Y value is large (S305: YES), it is determined that the block is a plain block (S308). On the other hand, if it is determined that the ratio of the mode value of the Y value is not large (S305: NO), it is determined that the block is a plain block (S309). Then, the number of determined blocks is accumulated.

  Next, it is determined whether or not the determination has been completed for all blocks of one page (S310). If one page has not been completed (S310: NO), the process returns to S304 to determine whether the next block is plain or non-solid. On the other hand, if one page has been completed (S310: YES), it is determined whether the ratio of the number of plain blocks in the total number of blocks on the page exceeds a predetermined ratio (S312). For example, it is determined whether the ratio of the number of plain blocks is 99% or more.

  If it is determined that the ratio of the number of plain blocks is larger than the predetermined ratio (S312: YES), it is determined that the page is a plain image (S313), and the component plain color determination process ends. On the other hand, if it is determined that the ratio of the number of plain blocks is not larger than the predetermined ratio (S313: NO), it is determined that the page is a non-solid image (S314), and the component plain determination process ends.

  Note that the scanner 100 of the present embodiment has one page of the original for each block of the color determination processing by the color type determination circuit 23 and the component solid color determination processing by the solid color determination circuit 24 for each block. Execution can be started even if reading is not completed. Therefore, in the reading output process shown in FIG. 3, the scanner 100 executes a color determination process by the color type determination circuit 23 and a component blank determination process by the blank determination circuit 24 in parallel with the reading of the document. However, the final determination result for one page is obtained only after the reading of one page of the original is completed.

  Next, the post-color determination determination process executed in S116 of the read output process shown in FIG. 3 will be described with reference to the flowchart of FIG. The post-color determination process is a process for further determining whether or not the image is a plain image on the condition that the color type is determined by the color determination process in the color type determination circuit 23.

  In the determination process after color determination, first, it is determined whether or not it is determined as a color page by the color determination process (S401). If it is determined that the page is a color page (S401: YES), it is determined whether the generation of each image data is completed (S402). Even for color pages, the possibility of a solid color image remains. Therefore, when the generation of each image data is completed, a process for determining whether or not the image is a plain image is executed based on the difference between the size of the color image data and the size of the gray image data.

  If the generation of each image data has not ended (S402: NO), the generation of the image data is continued until the end. If it is determined that the generation of the image data has been completed (S402: YES), a threshold value is determined based on the reading condition in the instruction of the reading output operation (S403). The threshold will be described later. Then, the scanner 100 determines whether or not the difference between the size of the color image data and the size of the gray image data is larger than the threshold value determined in S403 (S405).

  As described above, the color image data is compressed data using all the YCbCr components of the image data, and the gray image data is generated with the Cb component and the Cr component as fixed values and only the Y component enabled. It is compressed data. If the original image is an achromatic color, the Cb component and the Cr component are both substantially fixed values, and the color image data and the gray image data generated by the same compression method are image data having substantially the same size. It becomes. Even if the original image is a colored plain image, the variation in the value of each component of YCbCr in the page is small. Also in this case, the color image data and the gray image data are image data having substantially the same size.

  That is, in the case of an achromatic image or a color plain image, the size of the color image data and the size of the gray image data are substantially equal. On the other hand, when the document is a plain image and is a color page, the variation of at least one of the Cb component and the Cr component is large, and the size of the color image data and the size of the gray image data are considerably large. It will be different.

  Therefore, when it is determined that the difference between the size of the color image data and the size of the gray image data is large (S405: YES), it can be determined that the image is not an achromatic image but a color plain image. Since it is determined in S401 that the page is a color page, it is determined that the page is a color non-solid image (S406).

  On the other hand, when the difference between the size of the color image data of the page and the size of the gray image data is not large (S405: NO), the document is an achromatic image or a color plain image. Since it is determined that the page is a color page in S401, the page is determined to be a color plain image (S407). After the determination in S406 or S407, the post-color determination determination process is terminated. Note that the determination procedure in S405 of the determination process after color determination is an example of a plain color determination process.

  Here, the threshold value determined in S403 will be described. The determination in S405 may be performed using the size ratio or may be performed using the size difference. For example, if the ratio of the gray image data size to the color image data size is in the range of 0.8 to 1.2, it is determined that the image is not a color image. When using a ratio, a predetermined fixed value may be used as a threshold value.

  On the other hand, when the size difference is used, it is preferable to set a threshold value based on the document size and the reading resolution in S403. When a document having a large document size or reading at a high reading resolution is performed, the number of pixels on one page is larger than when the document is small. Therefore, the size of the generated image data is likely to vary depending on the document size and the reading resolution.

  Therefore, the scanner 100 uses a value based on the document size and the reading resolution as the threshold value when comparing the sizes of the image data with differences. Specifically, when the document size is large, the threshold value is set to a larger value than when the document size is small. Also, when the reading resolution is high, the threshold value is set to a larger value than when the reading resolution is low.

  The threshold value may be determined and stored in advance for each document size and reading resolution, read out and used, or stored as a calculation formula and calculated based on the document size and reading resolution. . By setting the threshold in this way, it can be expected that the determination is more appropriate than when a fixed threshold is used.

  Returning to the post-color determination processing in FIG. 6, the case where NO is determined in S401 will be described. That is, the determination result by the color determination process is a gray page or a monochrome page. As described above, in any of these cases, it may be a gray plain image or a monochrome plain image. Therefore, if it is determined that the color is not a color in the color determination process (S401: NO), it is determined whether or not the component solid color determination process by the solid color determination circuit 24 is completed (S410).

  If it is determined that the component solid color determination process has not ended (S410: NO), the component solid color determination process is further executed. If it is determined that the component plain color determination process has ended (S410: YES), it is determined whether or not it is determined that the component solid color determination process is a plain image (S411). If it is determined that the image is a plain image (S411: YES), this page is determined to be an achromatic solid image (S413), and the post-color determination determination process is terminated.

  On the other hand, if it is determined that the image is not a plain image in the component plain color determination process (S411: NO), it is determined based on the result of the color determination process whether the page is a gray page or a monochrome page. That is, it is determined whether or not the page is determined to be a gray page in the color determination process (S415). If it is determined that the page is a gray page (S415: YES), it is determined that the image is a gray solid image (S416), and the post-color determination determination process is terminated. On the other hand, if it is determined that the page is not a gray page (S415: NO), it is determined that the image is a monochrome non-solid image (S417), and the post-color determination determination process is terminated.

  Next, the size plainness determination process executed in S119 of the reading output process shown in FIG. 3 will be described with reference to the flowchart of FIG. In the size solid color determination process, each image data is generated in a state where neither the determination by the component solid color determination process of the solid color determination circuit 24 nor the determination of the color type by the color determination process of the color type determination circuit 23 is completed. This process is executed when the process is completed, and determines whether or not the image is a plain image based on the size of each image data.

  In the size plainness determination process, first, it is determined whether or not the size of the generated monochrome image data is smaller than a predetermined threshold (S501). Monochrome image data is binarized and compressed image data. By binarization, for example, noise caused by paper shadows is almost ignored. Therefore, if the document is a plain image, there is a high possibility that the image data will be of a very small size by compression.

  Therefore, if it is determined that the size of the monochrome image data is small (S501: YES), it is determined that the image is a plain image (S502), and the size plain color determination process is terminated. Note that the threshold used in S501 is set to a value that can be determined as a plain image based on the compression method used when generating monochrome image data. The determination procedure in S501 of the size solid color determination process is an example of a binary solid color determination process.

  On the other hand, when it is determined that the size of the monochrome image data is not small (S501: NO), processing similar to S403, S405, and S406 of the post-color determination processing is executed. That is, first, a threshold value is determined based on the reading conditions (S403). Further, it is determined whether or not the difference between the size of the color image data and the size of the gray image data is larger than the threshold value determined in S403 (S405). Further, if it is determined that the difference is large (S405: YES), it is determined that the image is a color solid image (S406).

  As described in the post-color determination processing, the difference between the size of the color image data and the size of the gray image data is large when the image is neither an achromatic image nor a solid color image. That is, this is the case of a color solid image. Therefore, in the size plain color determination process, when it is determined in S405 that the size difference is large, it can be determined that the image is a color solid color image.

  On the other hand, if it is determined that the difference between the size of the color image data and the size of the gray image data is not larger than the threshold value determined in S403 (S405: NO), it is an achromatic image or This is a color plain image. Therefore, in order to continue the determination process, it is determined whether or not the component solid color determination process of the solid color determination circuit 24 is completed (S505). If it has not ended (S505: NO), it continues until it ends.

  If it is determined that the component plain color determination process has been completed (S505: YES), it is determined whether or not it is determined that the image is a solid image (S506). When it is determined that the image is a solid image in the component solid color determination process (S506: YES), the size solid color determination process is terminated as a solid image (S507). On the other hand, if it is not determined to be a plain image (S506: NO), an achromatic color determination process for determining whether the image is a gray non-solid image or a monochrome non-solid image is executed (S509).

  Next, the procedure of the achromatic color determination process in step S509 will be described with reference to the flowchart of FIG. 8 in which it is determined whether the image is an achromatic non-solid image and then a gray non-solid image or a monochrome non-solid image. To do. The achromatic color determination process is the same as the above-described color determination process (see FIG. 4) except for the color page determination.

  In the achromatic color determination process, one page is divided into blocks (S201), and the number of gray blocks and the number of monochrome blocks are calculated (S601). In S601, the number of gray blocks and the number of monochrome blocks already calculated in the block determination of the color determination process (S202 in FIG. 4) are inherited up to this point, and the remaining blocks are determined based on the Y value.

  Further, when the calculation of the number of blocks is completed for all blocks in the page, it is determined whether or not the ratio of the obtained gray block number to the total number of blocks on the page exceeds a predetermined ratio (S205). ). For example, it is determined whether or not the ratio of the number of gray blocks is 0.3% or more.

  If it is determined that the ratio of the number of gray blocks exceeds the predetermined range (S205: YES), it is determined that the page is a gray page (S207). That is, it is determined that the image is a gray solid image, and the achromatic color determination process is terminated. On the other hand, if it is determined in S205 that the ratio of the number of gray blocks does not exceed the predetermined range (S205: NO), it is determined that the page is a monochrome page (S208). That is, it is determined that the image is a monochrome non-solid image, and the achromatic color determination process ends. Then, returning to FIG. 7, since the page determination is completed, the size plainness determination process is ended.

  As described above in detail, the scanner 100 according to the present embodiment generates color image data and gray image data based on the image acquired by the image reading unit 20. Then, the size of the generated color image data is compared with the size of the gray image data, and when the difference is larger than the threshold value, it is determined that the image is a plain image. Further, if it is determined that the image is a plain image, it is determined to output image data based on the image of the document, and if it is determined that the image is a plain image, it is determined not to output the image data. Therefore, when the plain color determination is finished early and image data is output, it can be expected that the output is started early.

  Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, the present invention is not limited to a scanner, and can be applied to any apparatus having an image processing function and an image data output function, such as a copying machine, a multifunction machine, and a FAX machine.

  Further, for example, the image to be determined as the color type is not limited to the image data read by the image reading unit 20. For example, image data received by a printer driver as a print target may be used. Further, the image data may be acquired by receiving from another device, or the image data already acquired and stored in the memory may be read. If the image data is not acquired by the reading operation, the image reading unit 20 may be omitted. That is, the present invention can be applied to a program such as a printer driver that acquires image data and outputs the processed image data.

  For example, the compression method of color image data and gray image data is not limited to JPEG. GIF, PNG, or another method may be used. In addition, the compression method of monochrome image data is not limited to the pack bits method.

  Also, for example, numerical values such as the size of divided blocks and various threshold values are examples, and can be changed as appropriate. Also, the threshold value may be a variable value when the size ratio is used as the size difference.

  For example, in the above embodiment, the image processing circuit 22, the color type determination circuit 23, the plain color determination circuit 24, and the image file generation circuit 25 are included in the ASIC 35. However, any processing is performed by the ASIC. Not limited to this, it may be executed by software. For example, each process may be executed by the CPU 31 by software incorporated in the ROM 32.

  In the above embodiment, the color determination processing executed by the color type determination circuit 23 determines the color type of the page after the block determination for one page is completed. Absent. For example, in the middle of the page, it may be determined whether the number of blocks that have been determined as color blocks so far exceeds a predetermined ratio of the total number of blocks in the page. If it is determined that the page is exceeded, the page can be determined as a color page.

  Further, in the above embodiment, in the component solid color determination process executed by the solid color determination circuit 24, the block determination for one page is performed after the block determination for one page is completed. However, the present invention is not limited to this. For example, in the middle of a page, it may be determined whether the number of blocks that have been determined as plain blocks so far exceeds a predetermined percentage of the total number of blocks in the page. If it is determined that the page is exceeded, the page can be determined as a plain image. For example, as described above, when it is determined that the page is a color page in the middle of the page and is further determined to be a plain image, the image data to be output can be determined as color image data.

  Further, for example, the present invention can be applied to an apparatus that generates color image data and gray image data and outputs either one without determining monochrome image data. In that case, the achromatic color determination process for determining whether the page is a gray page or a monochrome page is not necessary.

  The processing disclosed in the embodiments may be executed by a single CPU, a plurality of CPUs, hardware such as an ASIC, or a combination thereof. Further, the processing disclosed in the embodiment can be realized in various modes such as a recording medium or a method recording a program for executing the processing.

20 Image reading unit 31 CPU
100 scanner

Claims (13)

An acquisition unit for acquiring images;
A control unit;
With
The controller is
An acquisition process of acquiring an image in the acquisition unit;
A color generation process for generating color image data compressed by a predetermined compression method based on an acquired image that is an image acquired by the acquisition process;
Gray generation processing for generating gray image data, which is grayscale image data compressed by the same compression method as the color image data, based on the acquired image;
A solid color determination process for determining the acquired image as a solid color image when a difference between the size of the color image data and the size of the gray image data is larger than a threshold;
A component plain color determination process for determining whether the acquired image is a plain image or a solid color image based on at least a luminance component of the acquired image;
A determination process for determining whether to output image data based on the acquired image according to a determination result of the solid color determination process or the component solid color determination process ;
The execution,
Furthermore, the control unit
Even if the generation of the color image data by the color generation process and the generation of the gray image data by the gray generation process are completed, if the component solid color determination process is not completed, the solid color determination process is executed. An image output apparatus characterized by starting . The image output apparatus according to claim 1,
The image output apparatus, wherein the control unit uses a ratio between the size of the color image data and the size of the gray image data as a difference between the size of the color image data and the size of the gray image data. The image output apparatus according to claim 1,
The image output apparatus according to claim 1, wherein the control unit uses a difference between the size of the color image data and the size of the gray image data as a difference between the size of the color image data and the size of the gray image data. In the image output device according to any one of claims 1 to 3,
Wherein,
In the previous SL determination process, the acquired image in the non-coating determination processing when it is not determined that the non-solid color image in accordance with the determination result of the component solid judgment processing, and outputs the image data based on the acquired image An image output apparatus that determines whether or not. The image output device according to claim 4,
The controller is
In the determination process, when the determination result of the component solid color determination process is obtained prior to the determination result of the solid color determination process, image data based on the acquired image according to the determination result of the component solid color determination process Determining whether or not to output the image. In the image output device according to claim 4 or 5,
The controller is
A binary generation process for generating achromatic binary image data which is a binarized achromatic image data based on the acquired image;
The solid color determination process is executed in a state where it is unknown that the acquired image is a color image, and after the acquired image is not determined to be a solid color image in the solid color determination process, the solid color determination process is performed. When the acquired image is determined to be a plain image, it is determined that the acquired image is an achromatic solid image, and the color type of the acquired image is determined based on at least the luminance component of the acquired image. An achromatic color determination process for determining whether the image is an achromatic binary image;
Achromatic color data determination processing for determining image data to be output based on the determination result of the achromatic color determination processing;
The image output apparatus characterized by performing. In the image output device according to any one of claims 1 to 6,
The controller is
A color determination process for determining a color type of the acquired image based on at least a color difference component of the acquired image;
A data determination process for determining image data to be output based on a determination result of the color determination process;
The image output apparatus characterized by performing. The image output apparatus according to claim 7 ,
The controller is
If it is determined that the acquired image is a color image in the color determination process and is not determined to be a plain image in the plain determination process, it is determined to be a plain image;
If it is determined in the color determination process that the acquired image is not a color image before the determination result of the solid color determination process is obtained, based on the acquired image according to the determination result of the component solid color determination process An image output apparatus for determining whether or not to output image data. In the image output device according to any one of claims 1 to 8 ,
The controller is
An image output apparatus, wherein when the acquired image is determined to be a non-solid image in the plain determination process, the color type of the acquired image is determined to be a color image. In the image output device according to any one of claims 1 to 9,
The controller is
A binary generation process for generating achromatic binary image data which is binarized and compressed achromatic image data based on the acquired image;
When the size of the achromatic binary image data is smaller than a reference value, a binary plain determination process for determining that the acquired image is a plain image;
And
In the determination process, when the determination result of the binary solid color determination process is obtained prior to the determination result of the solid color determination process, the determination process is based on the acquired image according to the determination result of the binary solid color determination process. An image output apparatus for determining whether or not to output image data. In the image output device according to any one of claims 1 to 10,
The acquisition unit reads an image of a document,
The controller is
In the acquisition process, an image that has been subjected to color reading by the acquisition unit is acquired. The image output apparatus according to claim 11,
The controller is
An image output apparatus, wherein the threshold is set based on at least one of a document size and a reading resolution. In the image output device,
Acquisition processing to acquire images,
A color generation process for generating color image data compressed by a predetermined compression method based on an acquired image that is an image acquired by the acquisition process;
Gray generation processing for generating gray image data, which is grayscale image data compressed by the same compression method as the color image data, based on the acquired image;
A solid color determination process for determining the acquired image as a solid color image when a difference between the size of the color image data and the size of the gray image data is larger than a threshold;
A component plain color determination process for determining whether the acquired image is a plain image or a solid color image based on at least a luminance component of the acquired image;
A determination process for determining whether to output image data based on the acquired image according to a determination result of the solid color determination process or the component solid color determination process ;
Was executed,
Further, when the generation of the color image data by the color generation process and the generation of the gray image data by the gray generation process are not completed, the solid color determination process is not completed. A program characterized by starting execution .

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