FIELD OF INVENTION

The invention relates to an image sensing device and an operating method thereof. More particularly, the invention relates to an image sensing device and an operating method thereof with sensing circuits of different sensitivities.

BACKGROUND

Since the LED (light emitting diode) for traffic light is mostly controlled to be flashing at a specific frequency. Generally, the international standard (such as EN12966) is 90 Hz or more, so the exposure time of detecting the LED signal needs to exceed 1/90 (11.1 m sec) to ensure that there is a way to detect the LED signal for each exposure. However, under strong light environment, the exposure time is shortened so as to obtain better scene detection, and the LED detection capability may be sacrificed.

SUMMARY

An embodiment of this disclosure is to provide an operating method of an image sensing device capable of detecting several light emitting diodes each having a flickering cycle time, the image sensing device includes several pixel circuits, each of the several pixel circuits includes a first sensing circuit and a second sensing circuit, the operating method including the following operations: operating the image sensing device in a first operating mode, including: sensing light by the first sensing circuit with a first exposure time longer than the flickering cycle time, thereby obtaining a first sensing result; sensing light, simultaneously by the first sensing circuit and the second sensing circuit with a second exposure time shorter than the flickering cycle time, thereby obtaining a second sensing result and a third sensing result; determining whether there is LED (light emitting diode) flickering or not according to the first sensing result, the second sensing result and the third sensing result.

Another embodiment of this disclosure is to provide An operating method of an image sensing device capable of detecting several light emitting diodes each having a flickering cycle time, the image sensing device includes several pixel circuits, each of the several pixel circuits includes several sensing circuits, the operating method including: determining a first exposure time to detect whether there is LED flickering; and performing an additional light sensing with a second exposure time longer than the flickering cycle time prior to performing light sensing with the first exposure time shorter than the flickering cycle time so as to increase detection accuracy of LED flickering when it is determined to detect whether there is LED flickering or not by sensing light with the first exposure time shorter than the flickering cycle time.

Another embodiment of this disclosure is to provide an image sensing device capable of detecting several light emitting diodes each having a flickering cycle time, the image sensing device including several pixel circuits, wherein each of the several pixel circuits includes: a first sensing circuit, configured to sense light with a first exposure time longer than a flickering cycle time, thereby obtaining a first sensing result; a second sensing circuit, wherein the first sensing circuit and the second sensing circuit are configured to sensing light simultaneously with a second exposure time shorter than the flickering cycle time, thereby obtaining a second sensing result and a third sensing result; and an output circuit, configured to determine whether there is LED flickering or not according to the first sensing result, the second sensing result and the third sensing result.

Therefore, according to the technical concept of the present invention, embodiments of this disclosure are to provide an image sensing device and an operating method thereof, and in particular, the invention relates to an image sensing device and an operating method thereof with sensing circuits of different sensitivities. By performing an additional light sensing with an exposure time longer than the flickering cycle time of the LED under strong light environment, the LED detection capability under strong light is maintained without sacrificing dynamic range.

