Edmund Optics® utilise ses propres cookies et ceux de tiers pour optimiser les services techniques de son site internet. En savoir plus.

# Object Space Resolution

This is Section 2.2 of the Imaging Resource Guide

In order to determine the absolute minimum resolvable spot that can be seen on the object, the ratio of the field of view to the sensor size needs to be calculated. This is also known as the Primary Magnification (PMAG) of the system.

(1)$$\text{PMAG} = \frac{\text{Sensor Size} \left[ \text{mm} \right]}{\text{Field of View} \left[ \text{mm} \right]}$$

The ratio associated with system PMAG allows for the scaling of the imaging space resolution which tells us the resolution of the object.

(2)$$\text{Object Space Resolution} \left[ \tfrac{\text{lp}}{\text{mm}} \right] = \text{Image Space Resolution} \left[ \tfrac{\text{lp}}{\text{mm}} \right] \times \, \text{PMAG}$$

Generally when developing an application, a system’s resolution requirement is not given in lp/mm, but rather in microns (μm) or fractions of an inch. There are two ways to make this conversion:

(3)$$\text{Object Space Resolution} \left[ \text{μm} \right] = \frac{1000 \tfrac{\text{μm}}{\text{mm}}}{2 \,\times \, \text{Object Space Resolution} \left[ \tfrac{\text{lp}}{\text{mm}} \right]}$$
(4)$$\text{Object Space Resolution} \left[ \text{μm} \right] = \frac{\text{Pixel Size} \left[ \text{μm} \right]}{\text{PMAG}_{\text{System}}}$$

While one can quickly jump to the limiting resolution on the object by using the last formula, it is very helpful to determine the imaging space resolution and PMAG to simplify lens selection. It is also important to keep in mind that there are many additional factors involved, and this limitation is often much lower than what can be easily calculated using the equations.

## Resolution and Magnification Calculation Examples using a Sony ICX625 sensor

Known Parameters:
Pixel Size = 3.45μm x 3.45μm
Number of Pixels (H x V) = 2448 x 2050
Desired FOV (Horizontal) = 100mm

Limiting Sensor Resolution:

\begin{align} \text{Image Space Resolution} \left[ \tfrac{\text{lp}}{\text{mm}} \right] & = \frac{1000 \tfrac{\text{μm}}{\text{mm}}}{2 \, \times \, \text{Pixel Size} \left[ \text{μm} \right]} \\ \text{Image Space Resolution} \left[ \tfrac{\text{lp}}{\text{mm}} \right] & = \frac{1000 \tfrac{\text{lp}}{\text{mm}}}{2 \, \times \, 3.45 \left[ \text{μm} \right]} \approx \boldsymbol{145} \textbf{μm} \end{align}

Sensor Dimensions:

\begin{align} \text{Horizontal Sensor Dimension} \left[ \text{mm} \right] & = \frac{\left( 3.45 \text{μm} \right) \left( 2448 \right)}{1000 \tfrac{\text{μm}}{\text{mm}}} & = \boldsymbol{8.45} \textbf{μm} \\ \text{Vertical Sensor Dimension} \left[ \text{mm} \right] & = \frac{\left( 3.45 \text{μm} \right) \left( 2050 \right)}{1000 \tfrac{\text{μm}}{\text{mm}}} & = \boldsymbol{7.07} \textbf{μm} \end{align}

PMAG:

$$\text{PMAG} = \frac{8.45 \text{mm}}{100 \text{mm}} = \boldsymbol{0.0845} \textbf{X}$$

Resolution:

$$\text{Object Space Resolution} = 145 \tfrac{\text{lp}}{\text{mm}} \times 0.0845 = 12.25 \tfrac{\text{lp}}{\text{mm}} \approx \boldsymbol{41} \textbf{μm}$$
Ce contenu vous a-t-il été utile ?

Présente plus de 800 objectifs d'imagerie. De plus, nous avons inclus plus de 40 pages de contenu technique pour aider à optimiser la performance de votre système d'imagerie.

Telecentric, fixed focal length, micro-video, fixed magnification, variable magnification, or zoom lenses available. High resolution or large format designs to cover your sensor.

Vidéos de formations gratuites avec des conseils et des astuces donnés en imagerie et en éclairage.

Edmund Optics can not only help you learn how to specify the right imaging optics, but can also provide you with multiple resources and products to surpass your imaging needs.

Avez-vous besoin d´aide pour trouver le meilleur produit? Avez-vous des questions concernant votre application? Contactez-nous pour discuter de vos questions techniques avec nos ingénieurs.

×