Image processing apparatus and method of the same, and storage medium

• US 6,917,449 B2
• Filed: 09/20/2002
• Issued: 07/12/2005
• Est. Priority Date: 07/09/1998
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Nakajima, Yasuki, Tahara, Hisatsugu
• Primary Examiner(s): Grant, II, Jerome
• Application Number:
  US10/247,312
• Publication Number:
  US 20030020936A1
• Time in Patent Office: 1,026 Days
• Field of Search: 358/444, 358/409, 358/404, 358/1.16, 358/1.17, 358/448, 358/465, 375/204, 365/189.01, 365/192, 323/212, 323/283, 323/284
• US Class Current: 358/409
• CPC Class Codes: H04N 1/32443 with asynchronous operation of the image input and output devices connected to the memory
• CPC Class Codes: H04N 1/32561 using a programmed control device, e.g. a microprocessor

Abstract

A clock signal is frequency-modulated and an image processing operation is executed synchronously with the frequency-modulated clock signal to generate image data which is stored in a memory. Image data written in the memory is read synchronously with a clock signal having a fixed frequency. The image data written in the memory synchronously with the frequency-modulated clock signal is therefore converted into the image data synchronizing with the clock signal having a fixed frequency. Data subjected to image processing synchronously with the frequency-modulated clock signal can be output on the recording apparatus side without any practical problem.

Claims

1. An image processing apparatus comprising:

a clock signal generation circuit adapted to generate a clock signal;

a frequency modulation circuit adapted to modulate a frequency of a generated clock signal; and

a detection circuit adapted to detect an operation state of said frequency modulation circuit in accordance with a comparison result between an output of said clock signal generating circuit and an output of said frequency modulation circuit,

wherein said detection circuit detects a stopping of a modulation function of said frequency modulation circuit when the comparison result between an output of said clock signal generation circuit and an output of said frequency modulation circuit indicates a value equal to or lower than a reference value.

2. An image processing apparatus according to claim 1, further comprising a control circuit adapted to turn off a power of the image processing apparatus when said detection circuit detects a stopping of the modulation function of said frequency modulation circuit.

3. An image processing apparatus according to claim 1, further comprising an alarm adapted to issue an alarm when said detection circuit detects a stopping of the modulation function of said frequency modulation circuit.

4. An image processing apparatus comprising:

a clock signal generation circuit adapted to generate a clock signal;

a frequency modulation circuit adapted to modulate a frequency of the generated clock signal; and

a detection circuit adapted to detect whether a modulation width of the frequency-modulated clock signal is outside of a reference range.

5. An image processing apparatus according to claim 4, wherein said detection circuit detects whether the modulation width is outside of the reference range in accordance with a comparison result between an output of said clock signal generation circuit and an output of said frequency modulation circuit.

6. An image processing apparatus according to claim 5, wherein said detection circuit determines that the modulation width is outside of the reference range when the comparison result between an output of said clock signal generation circuit and an output of said frequency modulation circuit is smaller than a minimum reference value or larger than a maximum reference value.

7. An image processing apparatus according to claim 6, further comprising a control circuit adapted to turn off a power of the image processing apparatus when said detection circuit detects that the modulation width of said frequency modulation circuit is outside of the reference range.

8. An image processing apparatus according to claim 6, further comprising an alarm adapted to issue an alarm when said detection circuit detects that the modulation width of said frequency modulation circuit is outside of the reference range.

9. An image processing method comprising:

generating a clock signal;

modulating a frequency of a generated clock signal; and

detecting an operation state of frequency modulation in accordance with a comparison result between an output of said generating clock signal and an output of said frequency modulating,

wherein said detecting the operation state includes detecting a stopping of a modulation function of said frequency modulation when the comparison result between an output of said generating the clock signal and an output of said frequency modulating indicates a value equal to or lower than a reference value.

10. An image processing method according to claim 9, further comprising the step of turning off a power of an image processing apparatus when a stopping of the frequency modulation function is detected in said detecting step.

11. An image processing method according to claim 9, further comprising the step of issuing an alarm when a stopping of the frequency modulation function is detected in said detecting step.

12. An image processing method comprising:

generating a clock signal;

modulating a frequency of the generated clock signal; and

detecting whether a modulation width of the frequency-modulated clock signal is outside of a reference range.

13. An image processing method according to claim 12, wherein said detecting the modulation width includes detecting whether a modulation width is outside of the reference range in accordance with a comparison result between a clock signal generated in said generating step and a clock signal modulated in said frequency modulating step.

14. An image processing method according to claim 13, wherein said detecting step includes detecting that the modulation width is outside of the reference range when the comparison result between the clock signal generated in said generating step and the clock signal modulated in said frequency modulating step is smaller than a minimum reference value or larger than a maximum reference value.

15. An image processing method according to claim 14, wherein said detecting step includes turning off power of an image processing apparatus when it is detected in said detecting step that the modulation width in said frequency modulation step is outside of the reference range.

16. An image processing method according to claim 14, wherein said detecting step includes issuing an alarm when it is detected in said detecting step that the modulation width in said frequency modulation step is outside of the reference range.

17. A storage medium storing a program for realizing an image processing method, the method comprising the steps of:

generating a clock signal;

modulating a frequency of a generated clock signal; and

detecting an operation state of frequency modulation in accordance with a comparison result between an output of the generating clock signal and an output of said frequency modulating step,

wherein said detecting step includes detecting a stopping of a modulation function of said frequency modulating when the comparison result between an output of said generating step and an output of said frequency modulating indicates a value equal to or lower than a reference value.

18. A storage medium according to claim 17, wherein said method further comprises the step of turning off power of an image processing apparatus when a stopping of the frequency modulation function is detected in said detecting step.

19. A storage medium according to claim 17, wherein said method further comprises the step of issuing an alarm when a stopping of the frequency modulation function is detected in said detecting step.

20. A storage medium storing a program for realizing an image processing method, the method comprising the steps of:

generating a clock signal;

modulating a frequency of the generated clock signal; and

detecting whether a modulation width of the frequency-modulated clock signal is outside of a reference range.

21. A storage medium according to claim 20, wherein said detecting step includes detecting whether the modulation width is outside of the reference range in accordance with a comparison result between a clock signal generated in said generating step and a clock signal modulated in said frequency modulating step.

22. A storage medium according to claim 21, wherein said detecting step includes detecting that the modulation width is outside of the reference range when the comparison result between the clock signal generated in said generating step and the clock signal modulated in said frequency modulating step is smaller than a minimum reference value or larger than a maximum reference value.

23. A storage medium according to claim 22, wherein said detecting step includes turning off power of an image processing apparatus when said it is detected in said detecting step that the modulation width in said frequency modulation step is outside of the reference range.

24. A storage medium according to claim 22 wherein said method further includes the step of issuing an alarm when it is detected in said detecting step that the modulation width in said frequency modulation step is outside of the reference range.