Projection method and projection device

A projection device, comprising:

• a projection module, configured to project a projection screen picture to a projection region;
• an image acquisition module, configured to acquire an image of the projection region;
• an aperture, configured to control a light flux projected to the projection region;
• and
• a controller, connected to the projection module and the image acquisition module;
• wherein the projection module comprises an illumination light source and a projection lens, the projection lens being arranged on a light exit side of the illumination light source, the aperture being arranged between the illumination light source and the projection lens;
• wherein the controller comprises:
• at least one processor;
• and
• a memory communicably connected to the at least one processor;
• wherein the memory stores instructions executable by the at least one processor, wherein the instructions, when executed by the at least one processor, cause the at least one processor to perform:
• acquiring a projection image and an environmental image when a screen picture is projected to a projection region, wherein the environmental image comprises an image when a predetermined projection screen picture is projected to the projection region or an image when no screen picture is projected to the projection region;
• regulating an aperture based on the projection image and the environmental image, wherein the aperture is configured to control a light flux projected to the projection region;
• wherein regulating the aperture based on the projection image and the environmental image comprises:
• determining a stray light region image of stray light in the projection image and an environmental light region image of environmental light in the environmental image;
• calculating a stray light luminance in the stray light region image and an environmental light luminance in the environmental light region image;
• regulating the aperture based on the stray light luminance and the environmental light luminance.