Image processing apparatus and method for determining a method of cropping a document in accordance with a result of comparison of coordinates of vertices of two rectangular regions detected in a first and second detection

#1. Field of the Invention

#The present invention relates to an image processing apparatus and method for reading a document placed on an image reader, processing the read image, and outputting the processed image, and a processing program.

#2. Description of the Related Art

#FIG. 1 is a block diagram of an image reader R1 according to an embodiment of the present invention.

#FIG. 2 is a diagram illustrating the appearance of the image reader R1.

#FIG. 3 is a flowchart of an operation for obtaining a document region from an image read by the image reader R1.

#First Embodiment

#FIG. 1 is a block diagram of an image reader R1 according to a first embodiment of the present invention. The image reader R1 includes an imaging lens 2, a charge-coupled device linear image sensor (CCD) 3, an amplifier 4, an analog-to-digital (A/D) converter 5, an image processing circuit 6, a buffer memory 7, an interface circuit 8, and a CPU controller 9. The image reader R1 further includes a light source driving circuit 10, a light source lamp 11, a motor driving circuit 12, a driving motor 13, a working memory 14, a gamma lookup table (LUT) 15, and an operation panel 16. The CCD 3 is a solid state image pickup device. The amplifier 4 amplifies an analog image signal output from the CCD 3. The A/D converter 5 converts the analog image signal output from the amplifier 4 into a digital image signal. The image processing circuit 6 performs image processing, such as offset correction, shading correction, digital gain adjustment, color balance adjustment, color masking conversion, and resolution conversion in the main and sub scanning directions.

#The buffer memory 7 includes a RAM and temporarily stores image data. The interface circuit 8, through which a command is transferred or image communication is performed, is connected to an external information apparatus CT1. As for the interface circuit 8, for example, an SCSI, a parallel interface, a USB interface, an IEEE 1394 interface, a LAN interface, or a wireless LAN interface is used. The CPU controller 9 controls the image reader R1 in accordance with an instruction from the external information apparatus CT1. Specifically, the CPU controller 9 controls the image processing circuit 6, the light source driving circuit 10, and the motor driving circuit 12. The light source driving circuit 10 turns on or off the light source lamp 11. The light source lamp 11 illuminates a document D1. Reflected light having an intensity according to a density on the surface of the document D1 passes through the imaging lens 2, so that an image based on the light is formed on the linear image sensor serving as the CCD 3. The motor driving circuit 12 drives the driving motor 13, such as a stepper motor, and outputs an excitation signal for the driving motor 13 in accordance with a control signal supplied from the CPU controller 9 serving as a system control unit of the image reader R1. The working memory 14 is used as a temporal working memory for image processing by the image processing circuit 6. The working memory 14 is used to correct the RGB interline offset between image signals from R, G, and B linear sensors arranged in parallel to one another with a predetermined offset on the CCD 3. The working memory 14 also temporarily stores various pieces of data for shading correction.