IMAGE PROCESSING METHOD AND DEVICE

Abstract

The invention provides an image processing method and device to determine whether the timing signal is abnormal by detecting timing signal related to the image signal output to the display. When the timing signal is abnormal, the display receives no the timing signal related to the image signal. The horizontal synchronous signal and vertical synchronous signal prevent the elements in the display, such as electron gun, from operating with abnormal signals, enhancing display lifetime.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:

FIG. 1 shows a conventional CRT display.

FIG. 2 shows a conventional CRT display receiving an output image signals from image processing terminals.

FIG. 3 is flowchart illustrating a method for image processing of an embodiment of the invention.

FIG. 4 shows an image processing device of an embodiment of the invention.

FIG. 5 shows detailed circuitry of a clock state detecting device of FIG. 4 of an embodiment of the invention.

FIG. 6 is a normal time order diagram of each node of the circuit in FIG. 5.

FIG. 7 shows detailed circuitry of an output state control device of an embodiment of the invention.

Claims

1. An image processing method, comprising: detecting a timing signal associated with an image signal for input to a display;determining if the timing signal is abnormal; andstopping the display to receive a synchronous signal associated with the image signal when the timing signal is abnormal.

2. The image processing method as claimed in claim 1, wherein the timing signal is a clock signal.

3. The image processing method as claimed in claim 2, wherein the timing signal is provided by an image source terminal.

4. The image processing method as claimed in claim 2, further comprising: detecting a first condition in which the clock signal holds at high level for long time; anddetecting a second condition in which the clock signal holds at low level for long time.

5. The image processing method as claimed in claim 2, wherein determining the clock signal as abnormal when the clock signal holds at high level for long time or the clock signal holds at low level for long time is detected.

6. The image processing method as claimed in claim 1, wherein the timing signal is the synchronous signal or a clock signal generated after the synchronous signal is processed.

7. The image processing method as claimed in claim 1, wherein the synchronous signal includes a horizontal synchronous signal and a vertical synchronous signal and the display is stopped to receive the horizontal synchronous signal and the vertical synchronous signal when the timing signal is abnormal.

8. The image processing method as claimed in claim 1, further comprising stopping the display to receive not only the synchronous signal but also the image signal when the timing signal is abnormal.

9. The image processing method as claimed in claim 1, further comprising allowing the display to receive the synchronous signal when the timing signal is normal.

10. An image processing device, comprising: a clock state detecting device, detecting a first clock signal to output a first detecting result signal based on the state of the first clock signal; andan output state control device, receiving a first synchronous signal and a second synchronous signal to determine whether to output a horizontal synchronous signal and a vertical synchronous signal to the display based on the first detecting result signal.

11. The image processing device as claimed in claim 10, further comprising a digital signal processor, receiving and processing the digital image signal and outputting to the display.

12. The image processing device as claimed in claim 10, further comprising: a digital signal processor, receiving and processing the digital image signal; and outputting the processed digital image signal to the display;a D/A converter, receiving the digital image signal from the digital signal processor, and converting the digital image signal into an analog image signal for output to the display.

13. The image processing device as claimed in claim 10, further comprising: a digital signal processor, receiving and processing the digital image signal and outputting the processed digital image signal to the display;a D/A converter, receiving the digital image signal from the digital signal processor, and converting the digital image signal into an analog image signal for output to the display; anda clock generator, receiving a second clock signal to generate the first clock signal, a third clock signal, the first synchronous signal and the second synchronous signal.

14. The image processing device as claimed in claim 10, wherein the clock state detecting device further includes: a long time and high level clock detecting device, detecting if the first clock signal holds at high level for long time, outputting a second detecting result signal;a long time and low level clock detecting device, detecting the clock signal, if the clock signal holds at low level for long time, outputting a third detecting result signal; anda clock determining device, outputting the first detecting result signal according to the second detecting result signal and the third detecting result signal.

15. The image processing device as claimed in claim 14, wherein the long time and low level clock detecting device further comprises: a first current source having a first terminal and a second terminal, the first terminal of the first current source coupled to a first voltage source;a first electronic switch having a gate, a source and a drain, the source of the first electronic switch coupled to the second terminal of the first current source;a second electronic switch having a gate, a source and a drain, the gate of the second electronic switch, the gate of the first electronic switch and the clock signal coupled to a first node, the drain of the second electronic switch and the drain of the first electronic switch coupled to a second node;a second current source having a first terminal and a second terminal, the first terminal of the second current source coupled to the source of the second electronic switch, the second terminal of the second current source and a second voltage source coupled to a third node, wherein the current value of the second current source exceed the current value of the first current source;a first resistor having a first terminal and a second terminal, the first terminal of the first resistor coupled to the second node;a first capacitor having a first terminal and a second terminal, the first terminal of the first capacitor and the second terminal of the first resistor coupled to a fourth node, the second terminal of the first capacitor coupled to the third node; anda first comparator having a first receiving terminal, a second receiving terminal, and an output terminal, the first receiving terminal of the first comparator coupled to a first reference voltage, the second receiving terminal of the first comparator coupled to the fourth node, the output terminal of the first comparator outputting the second detecting result signal.

16. The image processing device as claimed in claim 14, wherein the long time and high level clock detecting device further comprises: a third current source having a first terminal and a second terminal, the first terminal of the third current source coupled to a first voltage source;a third electronic switch, having a gate, a source and a drain, the source of the third electronic switch coupled to the second terminal of the third current source;a fourth electronic switch having a gate, a source and a drain, the gate of the fourth electronic switch, the gate of the third electronic switch and the clock signal coupled to a fifth node, the drain of the fourth electronic switch and the drain of the third electronic switch coupled to a sixth node;a fourth current source having a first terminal and a second terminal, the first terminal of the fourth current source coupled to the source of the fourth electronic switch, the second terminal of the fourth current source and a second voltage source coupled to a seventh node, a current of the fourth current source being less a current of the third current source;a second resistor having a first terminal and a second terminal, the first terminal of the second resistor coupled to the sixth node;a second capacitor having a first terminal and a second terminal, the first terminal of the second capacitor and the second terminal of the second resistor coupled to an eighth node, the second terminal of the second capacitor coupled to the eighth node; anda second comparator having a first receiving terminal, a second receiving terminal, and a output terminal, the first receiving terminal of the second comparator coupled to a second reference voltage, the second receiving terminal of the second comparator coupled to the eighth node, the output terminal of the second comparator outputting the third detecting result signal.

17. The image processing device as claimed in claim 14, wherein the clock state determining device further comprises a fifth electronic switch having a first receiving terminal, a second receiving terminal, and an output terminal, the first receiving terminal and the second receiving terminal of the fifth electronic switch respectively receiving the second detecting result signal and the third detecting result signal to determine whether to output the first detecting result signal.

18. The image processing device as claimed in claim 15, wherein the first electronic switch is a PMOS transistor, the second electronic switch is a NMOS transistor and the second voltage source is ground.

19. The image processing device as claimed in claim 16, wherein the third electronic switch is a PMOS transistor, the fourth electronic switch is a NMOS transistor and the second voltage source is ground.

20. The image processing device as claimed in claim 17, wherein the fifth electronic switch is an NOR gate.

21. The image processing device as claimed in claim 10, wherein the clock state detecting device further comprises: a delay having a first terminal and a second terminal, the first terminal of the delay coupled to a ninth node to receive the clock signal;a sixth electronic switch having a first receiving terminal, a second receiving terminal and an output terminal, the first receiving terminal of the sixth electronic switch coupled to the ninth node, the second receiving terminal of the sixth electronic switch and the second terminal of the delay coupled to a tenth node;a seventh electronic switch having a first receiving terminal, a second receiving terminal, and an output terminal, the first receiving terminal of the seventh electronic switch coupled to the tenth node, the second receiving terminal of the seventh electronic switch coupled to the ninth node;a long time and low level clock detecting device detecting an first output signal from the output terminal of the sixth electronic switch, if the first output signal holds at low level for long time, outputting a second detecting result signal,a long time and high level clock detecting device, detecting an second output signal from the output terminal of the seventh electronic switch, if the second output signal holds at high level for long time, outputting a third detecting result signal; anda clock state determining device, determining to output the first detecting result signal according to the second detecting result signal and the third detecting result signal.

22. The image processing device as claimed in claim 21, wherein the sixth electronic switch is an OR gate and the seventh electronic switch is an AND gate.

23. The image processing device as claimed in claim 10, wherein the clock detecting device further comprises: a delay having a first terminal and a second terminal, the first terminal of the delay coupled to a ninth node;a sixth electronic switch having a first receiving terminal, a second receiving terminal and an output terminal, the first receiving terminal of the sixth electronic switch coupled to the ninth node, the second receiving terminal of the sixth electronic switch and the second terminal of the delay coupled to the tenth node;a seventh electronic switch having a first receiving terminal, a second receiving terminal, and an output terminal, the first receiving terminal of the seventh electronic switch coupled to the tenth node, the second receiving terminal of the seventh electronic switch coupled to the ninth node;an eighth electronic switch having a first receiving terminal, a second receiving terminal, and an output terminal, the first receiving terminal of the eighth electronic switch coupled to the clock signal, the output terminal of the eighth electronic switch coupled to the ninth node;a power starter having an output terminal, the output terminal of the power starter and the second receiving terminal of the eighth electronic switch coupled to a eleventh node;an inverter having an input terminal and an output terminal, the input terminal of the inverter coupled to the eleventh node;a long time and low level clock detecting device having a first, a second, a third, a fourth and a fifth terminal, the first, the second and the third terminals coupled to the output terminal of the sixth electronic switch, a first voltage source and a second voltage source respectively, the fifth terminal of long time and high level clock detecting device outputting a second detecting result signal;a long time and high level clock detecting device detecting the clock signal from the output terminal of the seventh electronic switch, having a first, a second, a third, a fourth and a fifth terminal, the first, the second and the third terminal coupled to the output terminal of the seventh electronic switch, the first voltage source and the second voltage source respectively, the fifth terminal of the long time and low level clock detecting device outputting a third detecting result signal;a clock state determining device determining to output the first detecting result signal according to the second detecting result signal and the third detecting result signal;a ninth electronic switch, having a gate a source and a drain, the gate, the source and the drain of the ninth electronic switch coupled to the output terminal of the inverter, the second voltage source, the fourth terminal of the long time and low level clock detecting device respectively; anda tenth electronic switch, having a gate a source and a drain, the gate, the source and the drain of the tenth electronic switch coupled to the input terminal of the inverter, the first voltage source, the fourth terminal of the long time and high level clock detecting device respectively.

24. The image processing device as claimed in claim 23, wherein the sixth, the seventh, the eighth, the ninth and the tenth electronic switches respectively are an OR gate, a first AND gate, a second AND gate, a NMOS transistor and a PMOS transistor and the second voltage source is ground.

25. The image processing device as claimed in claim 23, wherein the outputting state control device further comprises: an eleventh electronic switch having a first receiving terminal, a second receiving terminal, and an output terminal, the first receiving terminal and the second receiving terminal of the eleventh electronic switch coupled to the horizontal synchronous signal and the first detecting result signal respectively to determine whether to output the horizontal synchronous signal; anda twelfth electronic switch having a first receiving terminal, a second receiving terminal, and an output terminal, the first receiving terminal and the second receiving terminal of the twelfth electronic switch coupled to the vertical synchronous signal and the first detecting result signal respectively to determine whether to output the vertical synchronous signal.

26. An image processing device, comprising: a clock state detecting device, detecting a first clock signal and a second clock signal to output a first detecting result signal based on the state of the first clock signal and the second clock signal; andan output state control device, receiving a first synchronous signal and the second synchronous signal to determine whether to output a horizontal synchronous signal and a vertical synchronous signal to the display based on the first detecting result signal.