Paving block

Abstract

In order to generate a risk index of stress symptoms triggered by flashing lights on a scan type video display screen, a video signal processor is provided which operates such as to implement temporal filtering and spatial filtering on a video signal applied thereto every field and detect low temporal frequency components while excluding effects due to high spatial frequencies. A risk index generator receives the low frequency components from the video signal processor and determines the risk index based thereon.

Description

technical field [0001] The invention relates to a pavement block used in public open spaces such as sidewalks in general roads, promenades in parks, and station squares, and a construction method thereof. Background technique [0002] Conventionally, concrete blocks such as interlocking blocks, slabs, bricks, and paving stones were laid on a base layer (sand cushion) such as sand or mortar in places where people come and go, such as sidewalks and public spaces. [0003] As a structure for connecting the above-mentioned concrete blocks, for example, Japanese Utility Model Publication No. 52-57404 discloses that strip-shaped depressions and convex lines are provided on the contact surfaces of adjacent blocks so that they engage and maintain the joint. The planarity prevents the formation of steps. [0004] As another joint structure, for example, Japanese Utility Model Laid-Open No. 4-12506 discloses that joint spacer insertion holes are respectively provided on the left and ...

AI Technical Summary

Problems solved by technology

[0005] However, the step-like height difference and unevenness that have become existing problems are helpless when the construction accuracy is poor.

Moreover, even after it is provided for use, the above-mentioned problems will occur due to the subsidence of the roadbed and sand cushion

When the above-mentioned step-like height difference and unevenness occur, there is a problem that walking, wheelchairs, and strollers are dangerous

Images