Image reading apparatus which detects document attributes

An image reading apparatus for conducting a document read operation by moving a two-dimensional document sheet having a main-scan direction and a sub-scan direction in the sub-scan direction while sequentially reading lines of the document sheet in the main-scan direction, comprising:

• a document feeding unit for conveying the document sheet onto a document glass plate;
• a light source for emitting a light beam onto the document sheet;
• an optical system for receiving light reflected by the document sheet and producing a focused document image;
• a color image sensor for separating the focused document image into images respectively of a plurality of colors and producing data of the respective color images;
• an image read control section having a plurality of read modes;
• and
• a carriage for setting an image read position,
• wherein the image read control section includes document attribute sense means for detecting document attributes according to the data of the respective color images, the document attributes including color multi-value, color binary, monochrome multi-value, or monochrome binary attributes,
• wherein the document attribute sense means conducts a change-over operation between the plural read modes according to the detected document attributes, and
• wherein the document attribute sense means generates a histogram according to data attained by sampling pixels with respect to pixel data of at least one of the color images and then detects level differences for the sampled pixels, thereby deciding whether the document has the multi-value or binary attribute.

An image reading apparatus for conducting a document read operation by moving a two-dimensional document sheet having a main-scan direction and a sub-scan direction in the sub-scan direction while sequentially reading lines of the document sheet in the main-scan direction, comprising:

• a document feeding unit for conveying the document sheet onto a document glass plate;
• a light source for emitting a light beam onto the document sheet;
• an optical system for receiving light reflected by the document sheet and producing a focused document image;
• a color image sensor for separating the focused document image into images respectively of a plurality of colors and producing data of the respective color images;
• an image read control section having a plurality of read modes;
• and
• a carriage for setting an image read position,
• wherein the image read control section includes document attribute sense means for detecting document attributes according to the data of the respective color images, the document attributes including color multi-value, color binary, monochrome multi-value, or monochrome binary attributes,
• wherein the document attribute sense means conducts a change-over operation between the plural read modes according to the detected document attributes, and
• wherein the document attribute sense means detects a state in which the level difference between respective data of a pair of the color images is equal to or more than a predetermined value and detects according to a signal indicating the state whether or not a continuous period of the signal is equal to or more than a predetermined continuous period and whether or not a range of the signal is beyond a preset range.

An image reading apparatus for conducting a document read operation by moving a two-dimensional document sheet having a main-scan direction and a sub-scan direction in the sub-scan direction while sequentially reading lines of the document sheet in the main-scan direction, comprising:

• a document feeding unit for conveying the document sheet onto a document glass plate;
• a light source for emitting a light beam onto the document sheet;
• an optical system for receiving light reflected by the document sheet and producing a focused document image;
• a color image sensor for separating the focused document image into images respectively of a plurality of colors and producing data of the respective color images;
• an image read control section having a plurality of read modes;
• and
• a carriage for setting an image read position,
• wherein the image read control section includes document attribute sense means for detecting a document attribute according to the data of the respective color images,
• wherein the document attribute sense means conducts a change-over operation between the plural read modes according to the detected document attribute, and
• wherein the image read control section changes, according to the read mode, a format of video data to be transmitted to an external device and a charge accumulation time of the color image sensor, and enables an initial value of the read mode to be set, and
• wherein the control section changes, upon detection that the document sheet has an attribute other than the document attribute in the read mode, the read mode to match the detected document attribute and reversely transports by the document feeding unit the document sheet and conducts a re-read operation of the document sheet.

An image reading apparatus for conducting a document read operation by moving a two-dimensional document sheet having a main-scan direction and a sub-scan direction in the sub-scan direction while sequentially reading lines of the document sheet in the main-scan direction, comprising:

• a document feeding unit for conveying the document sheet onto a document glass plate;
• a light source for emitting a light beam onto the document sheet;
• an optical system for receiving light reflected by the document sheet and producing a focused document image;
• a color image sensor for separating the focused document image into images respectively of a plurality of colors and producing data of the respective color images;
• an image read control section having a plurality of read modes;
• a carriage for setting an image read position,
• a buffer memory;
• and
• a buffer memory control section,
• wherein the image read control section includes document attribute sense means for detecting a document attribute according to the data of the respective color images,
• wherein the document attribute sense means conducts a change-over operation between the plural read modes according to the detected document attribute,
• wherein the buffer memory temporarily stores therein data obtained through the document read operation,
• wherein the image read control section discards, when a read mode set at initiation of the document read operation is different from the read mode corresponding to the document attribute detected by the document attribute sense means, the stored data and executes a re-read operation of the document sheet, and
• wherein the buffer memory control section allows, when the attributes match each other or when the document sheet is read again, the buffer memory to sent the stored video data to an external device.

An image reading apparatus, comprising:

• a document feeding unit for conveying a document sheet bearing an image along a path;
• a light source disposed along the path to illuminate the document sheet;
• an optical system which receives light reflected along a line of the document sheet and which produces a focused image of the line at a predetermined location with respect to the line, the line being transverse to the document path;
• a color image sensor at the predetermined location with respect to the line, the color image sensor producing red, green, and blue video data, and
• reading means, responsive to the video data, for conducting a read operation in one of a plurality of modes as the document sheet is conveyed along the path, the reading means including means for detecting from the video data whether the image on the document sheet is a monochrome binary images a monochrome multi-value image, a colored binary image, or a colored multi-value image.