Which is better for tilting the camera's dual lens and five lenses?

As a mature mapping technology, tilt photography has been accepted and used by more and more surveyors and industry users. Tilt photography combined with drone systems makes this technology lightweight and economical. Breakthroughs have been made in the areas of rationalization, practicalization, and efficiency.

However, once we go to understand the hardware products of tilt photography, we will find that the tilt camera has thousands of strange lenses. Single lens, double lens, three lens, four lens, five lens, even nine lens can find related products. The data acquisition methods of the lens camera are also different, rotating, swinging, and one-exposure. The effect and quality of the model made by the multi-lens camera are also uneven.

In this slanting photographic hardware market, I would like to analyze and analyze the advantages, disadvantages and operational effects of different types of tilted photographic hardware products from various angles.

Lens performance indicators

Now consider the hardware indicators of tilt camera: nothing more than the following:

Single camera pixel - tilt camera is composed of multiple single cameras facing different angles. By collecting image data of different angles, the original texture data of tilt photography is obtained. The single camera pixel determines the angle of the tilt camera. The data collection ability is different depending on the single camera used by the tilt camera. From this point of view, the multi-lens camera cannot be used for horizontal comparison. The current main pixels in the industry are 2010 million, 24.3 million, 36.4 million. 42.4 million.

Total camera pixels - Total pixels have always been a very competitive indicator for multi-lens camera manufacturers. The five-lens camera calculates the total number of pixels that are toward the camera. The two-lens camera determines the total pixels according to the exposure mode, such as two-lens rotary exposure. If a group takes four shots, the total pixels are calculated according to (single camera pixel *4). , Double-lens swing exposure, a group of 6 to 8 shots, the total pixel is calculated according to (single camera pixel *6) or (single camera pixel *8).

Frame Size - Different frames in the digital age refer to sensors of various sizes. At the same height, the same focal length lens is used for aerial photography. The larger the frame, the larger the floor area that can be acquired. Tilting cameras with different lens counts can be selected on the frame parameters without the need for lateral contrast.

Lens focal length - The focal length of the camera used for aerial surveying of drones is generally adjusted to infinity, and the long focal length of the lens ensures that high-resolution ground images can still be acquired under the altitude of several hundred meters under the drone. The focal length of tilt camera is mostly 10.4mm, 16mm, 25mm, 35mm, 50mm, etc. It is generally recommended to focus on 25mm, 35mm, 50mm lens, suitable for multi-environment large scene tilt aerial survey.

Overall weight - Obviously, the smaller the number of single cameras of the tilt camera, the lighter the overall weight. Therefore, the dual lens contrasts with the five lenses, which has certain advantages in product weight, but it is complete with the development of tilt photography. The integration of single cameras is different. Now some tilt photography manufacturers on the market have made great efforts in single-camera weight reduction and dismantling, and have invested a lot of research and development. The five-lens camera is represented by the Jinan Saier drone. The weight of the five-lens camera is about 1.5KG, which is a suitable weight ratio for the five-lens camera to dismantle the weight loss.

The dual-lens camera, the products sold in the industry, basically does not disassemble and reduce weight for a single camera, so in addition to the weight of a single camera, it is also necessary to calculate the weight of the dual-lens camera electronic pan/tilt, including the structural weight and the rotor motor. the weight of.

Aerial survey of the lens

Well type operation method. In the early stage of the development of tilt photography, single-lens cameras often adopt the “well” type of aerial flight operation method, that is, the lens is oriented at an angle, and then adopts a dense route and cross-flight method to collect data. This collection method is inefficient and complicated.

Double lens operation method. Dual-lens tilt camera Whether it's rocking or selective shooting, there are two exposure methods.

First, continuous flight exposure, that is, in the route, the drone keeps flying at a constant speed, the camera exposes once at the exposure point, and then the exposure is followed a second time to obtain a set of data. This continuous flight operation method, a set of photos, two exposure intervals, and the actual exposure location due to the existence of the flight rate, there is a positioning error.

After the small three calculations of the double-lens products in the market, most of them have stratification and interlacing problems, which need to be repeatedly corrected by empty three calculations. This is tantamount to increasing the workload and reducing the work efficiency.

Second, stop the flight exposure, that is, in the route, the drone hovering in the air at the exposure point, the camera performs a group of exposures, then flies to the next exposure point, this practice is obvious, the operation efficiency is low, do not recommend .

Third, during the double-lens flight operation, it is easy to cause the volatility of the photo exposure, resulting in distortion, which is not conducive to the later data processing and correction.

Five lens operation method. The five-lens camera has uniform exposure at one point, one exposure, and obtains photos of five angles of view from front to back, left and right, so that the exposure data can be stably obtained on the drone platform that is stably running at a constant speed.

Data processing

From the modeling effect, whether it is a swinging double lens or a rotating double lens, the orientation angle lacks a down-view lens, and the lack of a lower-view lens leads to a place like a joint scene such as a joint between buildings. The lack of raw data leads to insufficient details in the later modeling process and voids.

The above list is a problem with the dual lens in these aspects, and the five-lens camera can well avoid these problems.