swapnas.blogg.se - Sirius 2.0 camera is blurry

This result is the range to indicate the hardest (shallow and narrow) condition. "Depth of field" calculated in such way means depth which the sensor cannot recognize as blur. The larger of the "pixel pitch" or "airy disk diameter" is "permissible circle of confusion diameter" 4. "Permissible circle of confusion diameter" is determined by "pixel pitch" of the sensor or optical imaging limit of the lens which is called "airy disk diameter". In the machine vision however, since image processing is performed with the data of each pixel, visual observations cannot be used as a reference as in photographs. In the photographic industry, even today, when digital cameras are the mainstream, the permissible circle of confusion values similar to silver halide films, assumed to be "printed on photographic paper of a certain size and viewed visually at a certain distance, are commonly used 3. The smallest size that cannot be recognized as blur is especially called the "permissible circle of confusion diameter". "Circle of confusion" herein means a circular image of a point formed by a lens. "Permissible circle of confusion" is used as variable to calculate "depth of field". Depth of field and permissible circle of confusion This is the phenomena so called small aperture blur, and used as an indication to extract ability of high definition image sensor.Ģ.2. This spread is caused by wave dynamics of light so called diffraction and indicating size limit of point image squeezed by F number of the lens. And representing strength, vertical axis has maximum value of 1.0 for evaluation at optimal position.Īccording to this, it is observed that even through ideal lens, point light source with no area or length images in about 2.7 μm diameter with F2, 3.8 μm with F2.8, 5.4 μm with F4.0 and spread to 7.5 μm with F5.6. In this chart, horizontal axis represents image height, and ☖.0 μm around the optical axis (optical height=0) is shown (1.2 μm/DIV).

Point image by ideal lens with each F number is shown as "point spread function" here. Now let us see the image of point light source by ideal lens. Japan Optomechatronics Association.Ībove characteristics are hardly observed with actual lens due to its optical error. Optics of Optical Equipment I (in Japanese).

Objects on a plane that is not perpendicular to the optical axis and their images are not necessarily similar.ġ Hayamizu Y.

Figures in a plane perpendicular to the optical axis and their images are similar to each other.

Image on the plane perpendicular to the optical axis is perpendicular to the optical axis.

When subject is plane, its image is also plane.

When subject is straight line, its image is also straight line.

"Ideal lens" should have characteristics as below. On the other hand, the sun is hardly regarded as point light source because it is comparatively close to the earth and looks to have area. Stellar such as Sirius are often compared as point light sources. If a light source regarded as a point is imaged with "ideal lens", the point in the output image from the sensor will actually have only one pixel, which is an extremely narrow range in actual. As you know, a point is "only a position, not a length or area". The basic performance of imaging with a lens is that "points are imaged as points".