Please select the most similar patent number from A, B, C and D. Which number is?
Disclosed are a human eye protection method for a projector, and a projector. The human eye protection method comprises: acquiring first image information that is output by a projector and second image information that is projected and displayed on a projection screen corresponding to the projector at the same moment; comparing the first image information with the second image information so as to determine a dark field region; carrying out, according to the dark field region, dark field processing on an image received by the projector, so that the brightness of a portion, corresponding to the dark field region, in an image output by the projector is lower than a brightness threshold value. By means of the human eye protection method for a projector provided in the present application, the eyesight of a user can be protected without affecting a projection effect.
A: A projection and focusing method, and a projector. The projection and focusing method comprises: acquiring initial image information about a projection plane of a projector via dual cameras; according to the acquired initial image information, determining whether the flatness of the projection plane satisfies a pre-set flatness criterion; when it is determined that the flatness of the projection plane satisfies the pre-set flatness criterion, according to the initial image information, acquiring a projection distance between the projector and the projection plane and a focal length adjustment parameter corresponding to the projection distance; and performing focusing according to the focal length adjustment parameter.
B: An interactive projection method and system. The method comprises: projecting, by an infrared projection device, and to a projection area, infrared light, and acquiring, by an infrared acquisition device, an initial infrared image in the projection area (S201); projecting, by a content projector, to the projection area, a projection image (S203); when projecting using the content projector, and an interactive operation device performs an interactive operation in a space between the infrared projecting device and the projection area, acquiring, by the infrared acquisition device, a deformed infrared image in the projection area (S204); identifying a different area different between the deformed infrared image and the initial infrared image (S205); and adjusting, according to the different area, projection content, and inputting, to the content projector, the adjusted projection content, to project, by the content projector, according to the input projection content, and in the projection area, a projection image (S206). According to the embodiment, the method and system can implement interactive projection without blocking a projected image and affecting a projection result of the projected image.
C: The present application relates to the field of protection display, and disclosed are a projection device and a field of view adjustment method therefor. A control circuit in the projection device is used for determining a target distance between a target object and the projection device according to a light output time value of a light signal transmitting assembly and a light receiving time value of a light signal receiving assembly, adjusting a receiving field of view of the light signal receiving assembly according to the target distance, and performing brightness adjustment on a laser light source according to the target distance. Because the size of the adjusted receiving field of view is negatively correlated with the target distance, a large receiving field of view can expand a detection range of the light signal receiving assembly when the target object is close to the projection device, so that the detection range for the target object is more comprehensive, thereby improving the reliability of detecting the target object. Moreover, human eyes are effectively protected because the brightness of the laser light source can be adjusted according to the target distance.
D: A vehicle rearview projector. One camera each is provided at where existing left and right rearview mirrors of a vehicle are located, one projector each is provided at left and right sides of a vehicle dashboard, and each projector projects images captured by the camera of the corresponding side onto a front-door glass of the corresponding side. One light sensor is provided at where the front windshield of the vehicle is located. The brightness of the projection is adjusted on the basis of changes in the intensity of external ambient light: if the external ambient light is bright, then the brightness of the images of the projectors is high, and if the external ambient light is dim, then the brightness of the images of the projectors is low. An image processor is used for reverse morphing processing of the projected images to effect lossless projection on the glasses. The vehicle rearview projector replaces existing left and right reflective rearview mirrors of the vehicle, is capable of reducing wind noise, reduces fuel consumption, is environmentally friendly, adapts to existing driving habits, and facilitates promotions and applications.
Answer: C