11. A non-transitory computer readable storage medium in conjunction with a digital video conversion device storing one or more program modules, wherein the digital video conversion device is communicatively coupled to a TV set and a TV signal source, respectively, so as to pass TV signals from the TV signal source to the TV set, wherein the one or more program modules further include instructions, which, when executed by one or more processors of the digital video conversion device, cause the processors to perform operations including: receiving a TV channel identification request from a mobile terminal via a wireless communication channel; in response to the TV channel identification request: acquiring an image from the TV signals currently broadcasted on the TV set; extracting a plurality of station logo characteristic sets from the image, wherein each station logo characteristic set corresponds to one of a plurality of station logo templates, wherein each station logo template includes a respective station logo type and logo position information for a respective station logo image region, and wherein extracting the plurality of station logo characteristic set for a corresponding station logo template in the plurality of station logo templates includes: in accordance with a determination that the respective station logo type in the corresponding station logo template is a static opaque station logo type, generating a normalized block-level color histogram for a station logo image region in the image; and in accordance with a determination that the respective station logo type in the corresponding station logo template is a static semi-transparent station logo type, generating a perpetual hash value of the station logo image region in the image; calculating a similarity score between each station logo characteristic set and a corresponding station logo template of said each station logo characteristic set; identifying one of the plurality of station logo templates as matching the image based on their similarity scores; and returning TV channel information associated with the identified station logo template to the mobile terminal.
11. A non-transitory computer readable storage medium in conjunction with a digital video conversion device storing one or more program modules, wherein the digital video conversion device is communicatively coupled to a TV set and a TV signal source, respectively, so as to pass TV signals from the TV signal source to the TV set, wherein the one or more program modules further include instructions, which, when executed by one or more processors of the digital video conversion device, cause the processors to perform operations including: receiving a TV channel identification request from a mobile terminal via a wireless communication channel; in response to the TV channel identification request: acquiring an image from the TV signals currently broadcasted on the TV set; extracting a plurality of station logo characteristic sets from the image, wherein each station logo characteristic set corresponds to one of a plurality of station logo templates, wherein each station logo template includes a respective station logo type and logo position information for a respective station logo image region, and wherein extracting the plurality of station logo characteristic set for a corresponding station logo template in the plurality of station logo templates includes: in accordance with a determination that the respective station logo type in the corresponding station logo template is a static opaque station logo type, generating a normalized block-level color histogram for a station logo image region in the image; and in accordance with a determination that the respective station logo type in the corresponding station logo template is a static semi-transparent station logo type, generating a perpetual hash value of the station logo image region in the image; calculating a similarity score between each station logo characteristic set and a corresponding station logo template of said each station logo characteristic set; identifying one of the plurality of station logo templates as matching the image based on their similarity scores; and returning TV channel information associated with the identified station logo template to the mobile terminal. 12. The non-transitory computer readable storage medium of claim 11 , wherein each station logo template includes respective station logo mask information, and one or more station logo image attributes corresponding to said each logo template.