Color image reader

• US 6,621,598 B1
• Filed: 10/20/1999
• Issued: 09/16/2003
• Est. Priority Date: 10/22/1998
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Oda, Akihiko
• Primary Examiner(s): Coles, Edward
• Assistant Examiner(s): Safaipour, Houshang
• Application Number:
  US09/421,500
• Time in Patent Office: 1,427 Days
• Field of Search: 358/473, 358/482, 358/445, 358/448, 382/313, 382/318
• US Class Current: 358/473
• CPC Class Codes: H04N 1/047 Detection, control or error compensation of scanning velocity or position H04N1/0402 and H04N1/17 take precedence
• CPC Class Codes: H04N 1/107 with manual scanning
• CPC Class Codes: H04N 1/486 with separate detectors, each detector being used for one specific colour component
• CPC Class Codes: H04N 2201/0471 using dedicated detectors
• CPC Class Codes: H04N 2201/04724 on a separate encoder wheel
• CPC Class Codes: H04N 2201/04734 Detecting at frequent intervals, e.g. once per line for sub-scan control
• CPC Class Codes: H04N 2201/04787 by changing or controlling the addresses or values of pixels, e.g. in an array, in a memory, by interpolation

Abstract

The present invention provides a color image reader installed on an image reader such as a hand scanner whose reading speed may change during reading. A hand scanner has an encoder sensor which outputs movement amount data to a relative speed monitoring unit. In response to relative hand scanner speed data (normalized value) output from the relative speed monitoring unit, a positional compensation processing unit aligns the R, G, and B signals and outputs the aligned R, G, and B signals

Claims

1. A color image reader including photoelectric conversion means on which a plurality of image sensors are arranged, each of said plurality of image sensors including a plurality of light receiving cells arranged in a primary scan direction, said color image reader comprising:

speed monitoring means for monitoring a read speed of a read object; and

positional compensation means for compensating positions of image data of primary colors based on a monitoring result of said speed monitoring means, the image data being output from said photoelectric conversion means,

wherein said positional compensation means sequentially stores therein the image data of the primary colors,

said image data being output from said photoelectric conversion means and, when outputting the image data of one of the primary colors with said one of the primary colors as reference data, selects and outputs the image data of other primary colors from the stored image data according to the monitoring result of said speed monitoring means,

said image data of the other primary colors corresponding to a position in the read object where the image data of said one of the primary colors was read.

2. The color image reader according to claim 1, wherein said positional compensation means has a plurality of line memories for the image data of the primary colors and, when outputting the image data of one of the primary colors to be used as the reference data from said plurality of line memories, selects the line memories where the image data of other corresponding primary colors is stored according to the monitoring result of said speed monitoring means, and outputs the image data from the selected line memories.

3. The color image reader according to claim 2, wherein said speed monitoring means outputs relative values for a reference speed.

4. The color image reader according to claim 3, wherein the relative values are natural numbers.

5. The color image reader according to claim 3, wherein said positional compensation means performs operation on the relative values output from said speed monitoring means to select the line memories where the image data of other primary colors is stored.

6. The color image reader according to claim 5, wherein said positional compensation means comprises:

selectors outputting the image data of the primary colors from the line memories;

a relative speed data storage unit storing therein the relative values output from said speed monitoring means; and

selector controllers selecting, when outputting the image data of the reference primary color from the line memories, the line memories where the image data of other primary colors is stored based on the relative speed data stored in said relative speed data storage unit, said relative speed data corresponding to the reference color image data, and sends selection signals to said selectors.

7. The color image reader according to claim 3, further comprising a secondary-scan direction resolution compensation unit that compensates a secondary-scan direction resolution of the image data of the primary colors output by the positional compensation means.

8. The color image reader according to claim 4, further comprising a secondary-scan direction resolution compensation unit that compensates a secondary-scan direction resolution of the image data of the primary colors output by the positional compensation means, wherein said secondary-scan direction resolution compensation unit comprises:

data line memories storing therein the primary color image data output from said positional compensation means;

an output controller outputting the image data from said data line memories a number of times corresponding to the relative value for the reference speed received via said positional compensation means; and

a line density data storage unit storing therein line density data.

9. The color image reader according to claim 1 wherein the color image reader comprises a hand scanner.

10. The color image reader according to claim 8 wherein the color image reader comprises a hand scanner.