Image sensing device and image sensing method

Abstract

An image sensing device and an image sensing method are provided. The image sensing device is adapted to sense a target object in a situation without ambient light. The image sensing device includes a modulated light source, an image sensor, and a processing circuit. The modulated light source includes light sources. The image sensor includes sensing pixels. The image sensor is a color filter-free sensor. In one frame period, the light sources emit sensing light beams at different timings, and the sensing pixels at different timings sense reflected light beams generated by the sensing light beams reflected by the target object. The processing circuit synthesizes first images corresponding to a part of the reflected light beams to generate a complete sensing image. The processing circuit obtains depth information of the target object according to another part of the reflected light beams.

What is claimed is: 
     
         1 . An image sensing device adapted to sense a target object in a situation without ambient light, the image sensing device comprising:
 a modulated light source, comprising a plurality of light sources;   an image sensor, comprising a plurality of sensing pixels, wherein the image sensor is a color filter-free sensor; and   a processing circuit, coupled to the modulated light source and the image sensor and configured to run the modulated light source and the image sensor,   wherein in one frame period, the light sources emit a plurality of sensing light beams at different timings, and the sensing pixels at different timings sense a plurality of reflected light beams generated by the sensing light beams reflected by the target object,   wherein the processing circuit synthesizes a plurality of first images corresponding to a part of the reflected light beams to generate a complete sensing image, and the processing circuit obtains depth information of the target object according to another part of the reflected light beams.   
     
     
         2 . The image sensing device according to  claim 1 , wherein the light sources comprise a plurality of visible light sources and an invisible light source, and a plurality of sub-sensing periods of the depth information and the first images are synchronized with the visible light sources and the invisible light source. 
     
     
         3 . The image sensing device according to  claim 2 , wherein the sensing light beams comprise a plurality of visible light beams and an invisible light beam, and the sensing pixels sense a plurality of first reflected light beams and a second reflected light beam respectively generated by the visible light beams and the invisible light beam reflected by the target object in different time periods,
 wherein the processing circuit synthesizes the first images corresponding to the first reflected light beams to generate the complete sensing image, and the processing circuit obtains the depth information of the target object according to the second reflected light beam.   
     
     
         4 . The image sensing device according to  claim 2 , wherein the visible light sources comprise a red light source, a green light source, and a blue light source, and the invisible light source is an infrared light source. 
     
     
         5 . The image sensing device according to  claim 2 , wherein the sensing pixels sense a plurality of first reflected light beams in a visible light beam sensing period in the frame period, and the sensing sense the second reflected light beam in an invisible light beam sensing period in the frame period, wherein the visible light beam sensing period and the invisible light beam sensing period are not overlapped. 
     
     
         6 . The image sensing device according to  claim 5 , wherein the sensing pixels respectively sense the first reflected light beams in the sub-sensing periods in the visible light beam sensing period, wherein the sub-sensing periods are not overlapped. 
     
     
         7 . The image sensing device according to  claim 5 , wherein a length of the visible light beam sensing period is less than 1/25 second. 
     
     
         8 . The image sensing device according to  claim 2 , wherein each of the visible light sources is individually turned on in a corresponding sub-sensing period of the sub-sensing periods. 
     
     
         9 . The image sensing device according to  claim 2 , wherein at least two of the visible light sources are simultaneously turned on in one of the sub-sensing periods. 
     
     
         10 . The image sensing device according to  claim 1 , wherein the sensing light beams respectively correspond to different wavelengths. 
     
     
         11 . The image sensing device according to  claim 1 , wherein at least one part of the sensing light beams has different polarizations. 
     
     
         12 . The image sensing device according to  claim 1 , wherein the processing circuit performs a direct time of flight calculation according to the another part of the reflected light beams to obtain the depth information. 
     
     
         13 . The image sensing device according to  claim 1 , wherein the processing circuit performs an indirect time of flight calculation according to the another part of the reflected light beams to obtain the depth information. 
     
     
         14 . The image sensing device according to  claim 1 , wherein the another part of the reflected light beams is a structured light beam. 
     
     
         15 . An image sensing method adapted to an image sensing device running in a situation without ambient light to sense a target object, the image sensing device comprising a modulated light source and an image sensor, the image sensing method comprising:
 in one frame period, emitting a plurality of sensing light beams by a plurality of light sources of the modulated light source at different timings;   in the frame period, sensing a plurality of reflected light beams by a plurality of sensing pixels of the image sensor at different timings, wherein the reflected light beams are generated by the sensing light beams reflected by the target object; and   synthesizing a plurality of first images corresponding to a part of the reflected light beams to generate a complete sensing image, and obtaining depth information of the target object according to another part of the reflected light beams.   
     
     
         16 . The image sensing method according to  claim 15 , wherein the light sources comprise a plurality of visible light sources and an invisible light source, and a plurality of sensing periods of the depth information and the first images are synchronized with the visible light sources and the invisible light source. 
     
     
         17 . The image sensing method according to  claim 16 , wherein the sensing light beams comprise a plurality of visible light beams and an invisible light beam, and the sensing pixels sense a plurality of first reflected light beams and a second reflected light beam respectively generated by the visible light beams and the invisible light beam reflected by the target object in different time periods,
 wherein the steps of generating the complete sensing image and obtaining the depth information comprise:   synthesizing the first images corresponding to the first reflected light beams to generate the complete sensing image; and   obtaining the depth information of the target object according to the second reflected light beam.   
     
     
         18 . The image sensing method according to  claim 16 , wherein the sensing pixels sense the first reflected light beams in a visible light beam sensing period in the frame period, and the sensing pixels sense the second reflected light beam in an invisible light beam sensing period in the frame period, wherein the visible light beam sensing period and the invisible light beam sensing period are not overlapped. 
     
     
         19 . The image sensing method according to  claim 16 , wherein each of the visible light sources is individually turned on in a corresponding sub-sensing period of the sub-sensing periods. 
     
     
         20 . The image sensing method according to  claim 16 , wherein at least two of the visible light sources are simultaneously turned on in one of the sub-sensing periods.